Risk factors predisposing to the development of hypogammaglobulinemia and infections post-Rituximab

Recovery from rituximab-associated persistent hypogammaglobulinaemia in children with nephrotic syndrome

BACKGROUND

There are limited data on the long-term outcomes and risk factors for non-recovery after development of rituximab (RTX)-associated persistent hypogammaglobulinaemia among children with idiopathic nephrotic syndrome (NS).

METHODS

A nationwide Japanese survey was conducted to determine the prognosis of patients with childhood-onset idiopathic NS who developed persistent hypogammaglobulinaemia after RTX administration. Specifically, predictors of IgG level recovery and risk factors for serious infection were examined.

RESULTS

The cohort comprised 118 patients (66.1% boys; median age at initial RTX administration, 7.5 years). Among the 121 patients diagnosed with persistent hypogammaglobulinaemia, only 31 (26.3%) recovered within a median observation period of 2.8 years; approximately 70% of patients continued to exhibit persistent hypogammaglobulinaemia. Among the patients who recovered from hypogammaglobulinaemia, the median time to recovery was 14.1 months. Patients with a history of steroid-resistant NS were less likely to recover from persistent hypogammaglobulinaemia (hazard ratio 0.28; 95% confidence interval 0.09-0.87). In addition, of the 118 eligible patients, 18 (15.3%) developed serious infections requiring hospitalization, and the main risk factor for infection during hypogammaglobulinaemia was agranulocytosis (a well-known adverse effect of RTX in children).

CONCLUSIONS

A significant portion of patients with RTX-associated persistent hypogammaglobulinaemia did not exhibit recovery even after 1 year. Moreover, the data indicate that patients with a history of steroid-resistant NS have a significantly lower probability of recovering from this condition. Agranulocytosis under hypogammaglobulinaemia was significantly associated with an elevated risk of serious infections.

Rituximab for people with multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is the most common neurological cause of disability in young adults. Off-label rituximab for MS is used in most countries surveyed by the International Federation of MS, including high-income countries where on-label disease-modifying treatments (DMTs) are available. This updates the 2021 version of the review.

OBJECTIVES

To assess the benefits and harms of rituximab as 'first choice' and 'switching' treatment for adults with any form of MS.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, and three trials registers on 31 December 2023, together with reference checking and contacting study authors to identify unpublished studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and controlled non-randomised studies of interventions (NRSIs) comparing rituximab with placebo or another DMT for adults with any form of MS.

DATA COLLECTION AND ANALYSIS

We followed standard Cochrane methods. We used RoB 1 to assess risk of bias in RCTs and ROBINS-I in NRSIs. We assessed the certainty of evidence for critical and important prioritised outcomes using GRADE: disability worsening, relapse, serious adverse events (SAEs), health-related quality of life (HRQoL), common infections, cancer, and mortality. We conducted separate analyses for rituximab as 'first choice' or as 'switching' treatment, relapsing or progressive MS, comparison with placebo or another DMT, and RCTs or NRSIs.

MAIN RESULTS

In this update, the number of study participants increased from 16,429 (15 studies) to 37,443 (28 studies; 13 new studies: 1 RCT and 12 NRSIs). The studies were conducted worldwide; most originated from high-income countries (25 studies). Public institutions funded 22 (79%) of the studies. Most studies investigated the effects of rituximab on people with relapsing MS (19 studies; 27,500 (73%) participants). We identified 12 ongoing studies. Rituximab as 'first choice' for active relapsing MS None of the included studies compared rituximab to placebo. One RCT compared rituximab to dimethyl fumarate, with 24 months' follow-up. Rituximab may reduce the recurrence of relapse (odds ratio (OR) 0.16, 95% confidence interval (CI) 0.04 to 0.57; 195 participants; low-certainty evidence). The evidence is very uncertain on disability worsening and SAEs. Rituximab may result in little to no difference in upper respiratory tract infections (rate ratio (RR) 1.03, 95% CI 0.79 to 1.34; low-certainty evidence). The evidence is very uncertain for urinary tract, skin, and viral infections. HRQoL, cancer, and mortality were not reported. One NRSI compared rituximab to other DMTs, with 24 months' follow-up. Disability worsening was not reported. Compared with interferon beta or glatiramer acetate, rituximab likely delays relapse (hazard ratio (HR) 0.14, 95% CI 0.05 to 0.39; 1 study, 335 participants; moderate-certainty evidence). Compared with dimethyl fumarate and natalizumab, rituximab may delay relapse (dimethyl fumarate: HR 0.29, 95% CI 0.08 to 1.00; 1 study, 206 participants; low-certainty evidence; natalizumab: HR 0.24, 95% CI 0.06 to 1.00; 1 study, 170 participants; low-certainty evidence). The evidence for relapse is very uncertain when comparing rituximab to fingolimod. The effect on SAEs is uncertain due to very few events in all the comparison groups. No deaths were reported. HRQoL, common infections, and cancer were not reported. Rituximab as 'first choice' for primary progressive MS One RCT compared rituximab to placebo, with 24 months' follow-up. Rituximab likely results in little or no difference in disability worsening (OR 0.71, 95% CI 0.45 to 1.11; 439 participants; moderate-certainty evidence). The evidence is very uncertain on relapse, SAEs, common infections, cancer, and mortality. HRQoL was not reported. None of the included studies compared rituximab as 'first choice' treatment to other DMTs for primary or secondary progressive MS. Rituximab as 'switching' treatment for relapsing MS One small RCT compared rituximab to placebo, with 12 months' follow-up. Disability worsening was not reported. Rituximab may reduce recurrence of relapses (OR 0.38, 95% CI 0.16 to 0.93; 1 study, 104 participants; low-certainty evidence). The evidence is very uncertain regarding SAEs, common infections, cancer, and mortality. HRQoL was not reported. Twelve NRSIs compared rituximab to other DMTs, with 24 months' follow-up. The evidence on disability worsening is very uncertain in comparison with interferons or glatiramer acetate, natalizumab, alemtuzumab, and ocrelizumab. Rituximab likely delays time to relapse in comparison with interferons or glatiramer acetate (HR 0.18, 95% CI 0.07 to 0.49; 1 study, 1383 participants; moderate-certainty evidence), fingolimod (HR 0.08, 95% CI 0.02 to 0.32; 1 study, 256 participants; moderate-certainty evidence), and may result in little or no difference compared with natalizumab (HR 0.96, 95% CI 0.83 to 1.10; 3 studies, 1922 participants; low-certainty evidence). The evidence is very uncertain on relapse in comparison with alemtuzumab. There is uncertainty regarding SAEs when comparing rituximab to natalizumab and fingolimod. Rituximab likely increases serious common infections when compared with interferon beta or glatiramer acetate (OR 1.71, 95% CI 1.11 to 2.62; 1 study, 5477 participants; moderate-certainty evidence) and natalizumab (OR 1.58, 95% CI 1.08 to 2.32; 2 studies, 5001 participants; moderate-certainty evidence). The evidence for common infections is very uncertain when comparing rituximab to fingolimod and ocrelizumab. Rituximab may slightly reduce the risk of cancer compared with natalizumab (HR 0.79, 95% CI 0.62 to 0.99; 2 studies, 6202 participants; low-certainty evidence), whereas the evidence is very uncertain in comparison with fingolimod. The effect of rituximab on mortality is very uncertain due to very few events in all the comparison groups. HRQoL was not reported.

AUTHORS' CONCLUSIONS

For preventing relapses in relapsing MS, rituximab as 'first choice' and 'switching' treatment compares favourably with a wide range of approved DMTs. The protective effect of rituximab against disability worsening is uncertain. There is limited information to determine the effect of rituximab on primary progressive MS. There is limited evidence for long-term adverse events of rituximab in people with MS. Evidence for serious adverse events, cancer, and mortality was of very low certainty due to few events. There is an increased risk of serious (hospital-treated) infections with rituximab compared with other DMTs, although the absolute risk is low. High-quality (prospectively registered) NRSIs should be conducted to draw more reliable conclusions about the potential benefits and harms of rituximab in people with MS.

A second look at secondary hypogammaglobulinemia

Hypogammaglobulinemia is defined as a reduced immunoglobulin level, which can be either primary due to inborn errors of immunity or acquired in the setting of poor antibody production or increased antibody loss. Secondary hypogammaglobulinemia (SHG) should be considered in patients with a history of immunosuppressive therapy, transplant, protein loss syndromes, certain autoimmune conditions, and malignancies, as it can be associated with increased infectious risk. Appropriate history and lab-based screening in these populations can identify SHG allowing treatment and close monitoring as appropriate. Ideally, treatment focuses on control of the underlying condition or removal of iatrogenic causes of SHG. However, in many cases, treatment of the underlying condition does not reverse SHG or immunosuppressive therapy cannot be discontinued without significant risk to the patient. For these patients, strategies for risk mitigation against infectious complications include vaccination, antibiotic prophylaxis, and immunoglobulin replacement therapy. This report aims to summarize the existing and emerging data in the evaluation and management of SHG and highlight areas that require further investigation.

If and When to Consider Prophylactic Immunoglobulin Replacement Therapy in Secondary Hypogammaglobulinemia

Secondary hypogammaglobulinemia (SHG), or decreased IgG levels due to reduced production or increased loss caused by medications or underlying conditions, can be associated with increased infection risk. Although immunoglobulin replacement therapy (IgRT) is generally accepted as a strategy to help prevent recurrent bacterial infections in SHG, controversy exists as to whether it should be initiated to prevent the first occurrence of infection. This question has been raised particularly in the setting of anti-CD20 therapy, solid organ transplant, and B-cell malignancies and their treatments once IgG levels fall below 300 to 400 mg/dL. This article reviews the evidence for and against initiating IgRT in these settings, as well as associated considerations for evaluation and monitoring. Although it is relatively clear that infection risk increases with decreasing IgG levels, the exact contribution of SHG to overall infection risk and the protective benefit of IgRT in the absence of infections remain unclear. In the absence of clear consensus, shared decision-making is often needed to determine if and when to initiate IgRT.

Impact of rituximab on IgG and IgM levels in patients with autoimmune bullous diseases: a cohort study

Rituximab (RTX) causes hypogammaglobulinemia in a variety of autoimmune diseases. However, the exact incidence and clinical significance in patients with autoimmune bullous diseases (AIBD) remain undetermined. In this cohort study, we enrolled patients with AIBD treated with RTX at a tertiary dermatology center between 2019 and 2021. Serum IgG and IgM levels, cumulative RTX dosage, and other factors were measured at baseline and during a follow-up visit. We used multivariate linear regression to assess the effect of RTX on immunoglobulin levels over time, adjusting for factors such as cumulative RTX dose, time since last infusion, and steroid use. Hypogammaglobulinemia was defined as IgG < 600 mg/dL and IgM < 40 mg/dL. Logistic regression was employed to evaluate adjusted risk factors for developing hypogammaglobulinemia. Age at first infusion was negatively correlated with both IgG (p < 0.0001) and IgM levels (p = 0.002). Total cumulative RTX dosage was negatively associated with IgM levels (p < 0.001). Daily steroid dosage was positively correlated with IgM levels (p = 0.023). Mycophenolate mofetil was associated with lower IgG levels (p = 0.029). Daily steroid dosage was found to be associated with a lower risk of hypo-IgM development (p = 0.0497). No serious infusion-related adverse effects or mortality were observed. There were four cases of infection with no association with cumulative RTX dosage (p = 0.299). Our study shows an association between RTX and lower serum IgM levels in patients with AIBD, highlighting the need to assess serum immunoglobulin levels before RTX therapy to optimize its use and minimize adverse effects.

Rituximab-associated adverse events in nephrotic syndrome: A systematic review and meta-analysis

Objective

Rituximab (RTX) has been recommended to treat nephrotic syndrome (NS), but its safety has not been quantitatively analyzed.

Methods

PubMed, Embase, and the Cochrane Register of Controlled Trials databases were searched from inception to December 31, 2023, for randomized control trials (RCTs) and retrospective studies reporting the adverse events (AEs) related to RTX for treating NS. Data were expressed as odds ratios (OR) and risk difference (RD) with 95 % confidence interval (CI). Heterogeneity was identified using the Cochrane Q test and quantified by the I 2 statistic.

Results

Ten RCTs and five retrospective studies with 1231 patients were enrolled. RTX significantly reduced the risk of total AEs (OR = 0.32, 95 % CI [0.13, 0.78]) compared to the non-RTX group in retrospective studies but was not in RCTs. The pooled rate of infusion reactions was 32 % (95 % CI = [19 %, 45 %]) in RCTs and 8 % (95 % CI = [3 %, 13 %]) in retrospective studies. Subgroup analyses demonstrated a lower risk of hematological events in adult NS patients (OR = 0.21, 95 % CI [0.09, 0.51]) and the 1000 mg RTX intervention (OR = 0.21, 95 % CI [0.09, 0.51]). There is no significant difference in serious AEs, infection, gastrointestinal, renal, cardiovascular, and cancer events between the two groups.

Conclusion

RTX reveals great potential in terms of safety compared to non-RTX treatments due to the relatively few AEs in our results. However, the interaction of other drugs needs to be monitored. The safety of RTX in NS patients needs to be further confirmed in high-quality clinical trials.

[Chinese expert consensus on prevention and treatment of immunotherapeutic and molecular targeted agents-related infections in patients with hematological malignancies (2025)]

As novel therapeutic agents continue to emerge, immunotherapy and molecular-targeted drugs demonstrate expanding application prospects in hematological malignancy treatment. This expert consensus revision incorporates the latest evidence-based medicine from domestic and international sources, updating recommendations for infection diagnosis, prevention, and treatment. The document integrates recommendations for recently launched or imminent antibodies and small molecule targeted compounds, including COVID-19 considerations. This format of recommendations is modified according to the levels of evidence of The Oxford Centre for Evidence-Based Medicine (CEBM).

Sequelae of B-Cell Depleting Therapy: An Immunologist's Perspective

B-cell depleting therapy (BCDT) has revolutionised the treatment of B-cell malignancies and autoimmune diseases by targeting specific B-cell surface antigens, receptors, ligands, and signalling pathways. This narrative review explores the mechanisms, applications, and complications of BCDT, focusing on the therapeutic advancements since the introduction of rituximab in 1997. Various monoclonal antibodies and kinase inhibitors are examined for their roles in depleting B cells through antibody-dependent and independent mechanisms. The off-target effects, such as hypogammaglobulinemia, infections, and cytokine release syndrome, are discussed, emphasising the need for immunologists to identify and help manage these complications. The increasing prevalence of BCDT has necessitated the involvement of clinical immunologists in addressing treatment-associated immunological abnormalities, including persistent hypogammaglobulinemia and neutropenia. We highlight the importance of considering underlying inborn errors of immunity (IEI) in patients presenting with these complications. Furthermore, we discuss the impact of BCDT on other immune cell populations and the challenges in predicting and managing long-term immunological sequelae. The potential for novel BCDT agents targeting the BAFF/APRIL-TACI/BCMA axis and B-cell receptor signalling pathways to treat autoimmune disorders is also explored, underscoring the rapidly evolving landscape of B-cell targeted therapies.

Rituximab in the Treatment of Non-Infectious Uveitis: A Review

Non-infectious uveitis (NIU) is an immune-mediated disorder manifesting as ocular pain, redness, floaters, and photophobia, and is a leading cause of preventable blindness. Managing NIU presents considerable challenges due to the condition's resistance to high-dose corticosteroids and various immunotherapies. This review assesses the efficacy and safety of rituximab (RTX) in the treatment of NIU, based on individual case reports and small-scale studies. A cohort of 78 patients (20 males, 58 females), with a mean onset age of 32.3 years (range 8-72), was analyzed. Juvenile idiopathic arthritis (JIA) was the most frequently associated comorbidity, affecting 28 patients, while anterior uveitis was the predominant subtype, observed in 26 of 47 cases. Prior to RTX therapy, patients had been treated with an average of 1.7 conventional immunosuppressive agents (range 0-5) and 1.1 biologics (range 0-4). RTX was introduced following the failure of high-dose corticosteroids, immunosuppressive drugs, and biologics to control the uveitis. The median time from diagnosis to RTX initiation was 7.7 years (range 0.25-21). Post-RTX, 44.2% of patients experienced improvement in visual acuity, 79.5% achieved resolution of ocular inflammation, and 8.9% showed partial improvement. Additionally, 81.1% were able to reduce their corticosteroid dosage. Overall, 88.6% (69 out of 78) demonstrated a positive response to RTX treatment. These findings indicate that RTX may serve as an effective therapeutic option for NIU unresponsive to steroids and multiple immunotherapies. It may also warrant consideration as a potential first-line treatment in certain cases.

Differences in risk of serious infections between patients with secondary versus primary nephropathy following rituximab treatment: a retrospective cohort study

Background

The incidence of severe infections (SIs) in patients with autoimmune nephropathy after rituximab (RTX) treatment varies significantly. Our study aims to identify high-risk populations, specifically by comparing the differences in the risk of SIs between patients with primary nephropathy and those with nephropathy in the context of systemic autoimmune diseases (referred to as secondary nephropathy).

Methods

This retrospective cohort study investigated the occurrence of SIs in adult patients with immune-related kidney disease who received RTX treatment at our institution from 2017 to 2022. Multivariable COX regression models were used to analyze the association between the type of nephropathy (primary or secondary) and SIs. Propensity score analyses, subgroup analyses, and E-value calculations were performed to ensure the reliability of the results.

Results

Out of 123 patients, 32 (26%) developed 39 cases of SIs during a mean follow-up period of 19.7 ± 14.6 months post-RTX treatment, resulting in an incidence rate of 18.9/100 patient-years. The multivariable COX regression analysis indicated that patients with secondary nephropathy had a significantly higher risk of SIs compared to those with primary nephropathy (HR = 5.86, 95% CI: 1.05-32.63, P = 0.044), even after accounting for confounding variables including gender, age, BMI, history of prior SIs, baseline eGFR, lymphocyte counts, IgG levels, and the utilization of other immunosuppressive therapies. Various sensitivity analyses consistently supported these findings, with an E-value of 5.99. Furthermore, advanced age (HR: 1.03; 95% CI: 1.01-1.06; P = 0.023), low baseline IgG levels (HR: 0.75; 95% CI: 0.64-0.89; P < 0.001), and recent history of SIs (HR: 5.68; 95% CI: 2.2-14.66; P < 0.001) were identified as independent risk factors.

Conclusion

The incidence of SIs following RTX administration in patients with autoimmune nephropathy is significant. It is crucial to note that there are distinct differences between the subgroups of primary and secondary nephropathy. Patients with secondary nephropathy, particularly those who are elderly, have low baseline IgG levels, and have a recent history of SI, are more susceptible to SIs.

B cell subsets reconstitution and immunoglobulin levels in children and adolescents with B non-Hodgkin lymphoma after treatment with single anti CD20 agent dose included in chemotherapeutic protocols: single center experience and review of the literature

BACKGROUND

RTX, an anti-CD20 monoclonal antibody, added to chemotherapy has proven to be effective in children and adolescents with high-grade, high-risk and matured non-Hodgkin lymphoma. RTX leads to prompt CD19+ B lymphocyte depletion. However, despite preserved immunoglobulin production by long-lived plasmablasts after treatment, patients remain at risk of prolonged hypogammaglobulinemia. Further, there are few general guidelines for immunology laboratories and clinical feature monitoring after B cell-targeted therapies. The aim of this paper is to describe B cell reconstitution and immunoglobulin levels after pediatric B-NHL protocols, that included a single RTX dose and to review the literature.

METHODS

A retrospective single-center study on the impact of a single RTX dose included in a chemotherapeutic pediatric B Non-Hodgkin Lymphoma (B-NHL) treatment protocols. Immunology laboratory and clinical features were evaluated over an eight hundred days follow-up (FU) period, after completing B-NHL treatment.

RESULTS

Nineteen patients (fifteen Burkitt lymphoma, three Diffuse large B cell lymphoma, and one Marginal zone B cell lymphoma) fulfilled the inclusion criteria. Initiation of B cell subset reconstitution occurred a median of three months after B-NHL treatment. Naïve and transitional B cells declined over the FU in contrast to the marginal zone and the switched memory B cell increase. The percentage of patients with IgG, IgA, and IgM hypogammaglobulinemia declined consistently over the FU. Prolonged IgG hypogammaglobulinemia was detectable in 9%, IgM in 13%, and IgA in 25%. All revaccinated patients responded to protein-based vaccines by specific IgG antibody production increase. Following antibiotic prophylaxes, none of the patients with hypogammaglobulinemia manifested with either a severe or opportunistic infection course.

CONCLUSION

The addition of a single RTX dose to the chemotherapeutic treatment protocols was not shown to increase the risk of developing secondary antibody deficiency in B-NHL pediatric patients. Observed prolonged hypogammaglobulinemia remained clinically silent. However interdisciplinary agreement on regular long-term immunology FU after anti-CD20 agent treatment is required.

Risk of severe infection associated with immunoglobulin deficiency under rituximab therapy in immune-mediated inflammatory disease

OBJECTIVES

We evaluated the risk of severe infection in patients with immune-mediated inflammatory disease (IMID) treated with RTX and with Ig deficiency.

METHODS

This was an observational, retrospective single-centre study of patients undergoing treatment with at least one rituximab (RTX) infusion for an IMID until 31 May 2020. Patients were followed up for at least 12 months after the last infusion or until severe infection or death. Ig deficiency was classified as prevalent (before RTX) or acquired (normal Ig assay results before RTX but Ig deficiency during a follow-up).

RESULTS

Of 311 patients, 10.6% had prevalent and 19.6% acquired Ig deficiency. Prevalent Ig deficiency was related to concomitant treatment with glucocorticoids (GCs), in particular with a high daily dose at baseline; and acquired Ig deficiency to cumulative dose of RTX, mean Disease Activity Score in 28 joints (DAS28), immunosuppressor or GCs therapy at baseline, diabetes mellitus and obesity. Overall, 14.5% of patients had a severe infection during follow-up, which was numerically but not statistically more frequent in patients with prevalent Ig deficiency than normal Ig level. On multivariate analysis, risk of severe infection was associated with chronic pulmonary disease, GCs dose and mean DAS28-C reactive protein. In a time-dependent analysis, risk of severe infection was not associated with Ig deficiency, either acquired or prevalent (adjusted HR 1.04 (95% CI 0.5 to 2.3), p=0.92).

CONCLUSION

Risk of severe infection was not associated with RTX-induced Ig deficiency in patients with an IMID. RTX management should be discussed according to an individual assessment of the infectious risk, especially in patients with GC therapy or chronic lung disease.

Risk factors for hypogammaglobulinemia and association with relapse and severe infections in ANCA-associated vasculitis: A cohort study

OBJECTIVES

B-cell depletion induced by rituximab (RTX) in ANCA-associated vasculitis (AAV) is a risk factor for hypogammaglobulinemia. Aggregating data on gammaglobulin levels kinetics during RTX and its association with the risk of relapse and severe infection is of interest.

METHODS

Gammaglobulin levels were collected before induction therapy and during RTX maintenance therapy. We used different definitions of gammaglobulin decline: 1/gammaglobulin levels <6 g/L after induction; 2/>25 % decline in gammaglobulin levels between induction and maintenance, and 3/both. Our primary objective was the impact of gammaglobulin decline on the risk of relapse and severe infections.

RESULTS

We included 98 patients. Patients with gammaglobulin level <6 g/L after induction and gammaglobulin decline >25 % were older (OR 3.9; 95%CI 1.1-16.1), had more frequently baseline gammaglobulin levels <10 g/L (OR 6.0; 95%CI 1.7-25.8) and received more frequent pulses of methylprednisolone at induction (OR 4.6; 95%CI 1.3-18.5). Severe infection-free survival was significantly poorer in patients with both gammaglobulin <6 g/L and gammaglobulin decline >25 % (adjusted HR 2.3; 95%CI 1.0-5.1) and in those who received pulses of methylprednisolone (HR 5.6; 95%CI 2.3-13.4). Gammaglobulin decline was in contrast not associated with the risk of relapse.

CONCLUSION

Older age, low gammaglobulin levels and pulses of methylprednisolone at induction increase the likelihood of gammaglobulin decline after induction therapy. Such decline was associated with an increased risk of severe infections but not lower risk of vasculitis relapse. Pulses of methylprednisolone at induction had an independent negative impact on gammaglobulin levels and the risk of severe infections.

Access and use of immunoglobulins in supportive cancer care: A thematic analysis of a systematic review data set

Background

Secondary immunodeficiency (SID) disorders are known to occur in patients with haematological malignancies (HM) due to immunosuppressive treatments. Recurring infections causing subsequent morbidity and mortality commonly occur in this patient cohort. Immunoglobulin replacement therapy (IgRT) benefits patients with primary antibody deficiencies. However, evidence supporting their therapeutic role is not as explicit in SID-associated antibody deficiencies, which raises the questions regarding its use in SID and the knock-on effects of this use on its access and availability more generally.

Objectives

This study aimed to learn about the use of immunoglobulins in SID, identify themes concerning its use and access and suggest methods for improving access.

Design

This study included a thematic analysis of a published data set of 43 articles concerning immunoglobulin use and access in SID.

Data Sources and Methods

The data set used to perform the thematic analysis is based on research articles identified from Excerpta Medica Database (EMBASE) and PubMed databases, published as part of a systematic review and part 1 of this two-part publication series.

Results

A thematic synthesis was conducted to identify recurrent themes. The three primary themes included (1) the context for IgRT prescription, which included patient characteristics and cost burden of IgRT administration, and its use in different countries; (2) factors contributing to inappropriate IgRT use, including health care professionals' awareness of IgRT, disparity between guidelines and actual clinical practice, and the effect of shortages on prescription and chemotherapy-induced hypogammaglobulinemia (HGG); and (3) measures identified to improve IgRT use and access, which included multidisciplinary involvement, improved diagnostic tools and safer withdrawal and stewardship protocols.

Conclusions

IgRT use is increasing in HM as a supportive therapy but without comprehensive clinical guidelines and appropriate prescribing recommendations, medication wastage may occur with consequences for immunoglobulin access.

Obinutuzumab in Frequently Relapsing and Steroid-Dependent Nephrotic Syndrome in Children

BACKGROUND

B-cell depletion with rituximab induces sustained remission in children with steroid-dependent or frequently relapsing nephrotic syndrome. However, most patients relapse after B-cell recovery, and some patients do not achieve B-cell depletion. Obinutuzumab is a second-generation anti-CD20 antibody designed to overcome such situations in B-cell malignancies and was recently reported to be safe and effective in other autoimmune diseases affecting the kidneys.

METHODS

We retrospectively report 41 children with steroid-dependent or frequently relapsing nephrotic syndrome treated with a single low-dose infusion of obinutuzumab at Robert-Debre Hospital between April 2018 and December 2020. Participants were treated because of rituximab resistance or relapse after rituximab and received a single infusion of 300 mg/1.73 m 2 obinutuzumab with cessation of oral immunosuppressors within 2 months.

RESULTS

B-cell depletion was achieved in all participants and lasted a median of 8.3 months (interquartile range, 6.4-11.1), a duration exceeding that for last rituximab treatment. At 12 and 24 months, 92% (38/41) and 68% (28/41) of patients, respectively, were in sustained remission. Mild infusion reactions occurred in five participants (12%) and neutropenia in nine (21%). No significant decrease in IgG level was reported during treatment, and whereas IgM levels decreased in 34 patients (83%), they were normal at last follow-up in 32 (78%).

CONCLUSIONS

These results identified low-dose obinituzumab as a promising treatment option in children with steroid-dependent or frequently relapsing nephrotic syndrome, including those resistant to rituximab. The tolerance profile of obinutuzumab was similar to that of rituximab, but hemogram and immunoglobulin levels should be monitored.

Hypogammaglobulinemia after front-line immunochemotherapy in patients with follicular lymphoma

INTRODUCTION

Hypogammaglobulinemia after front-line immunochemotherapy for follicular lymphoma is a poorly studied adverse event that could be related to the appearance of severe and/or recurrent non-neutropenic infections which could affect the quality of life of the patients, even motivating a need of long-term replacement therapy with human immunoglobulins.

METHODS

Observational, retrospective study aiming to estimate the incidence of hypogammaglobulinemia, as well as its severity and clinical consequences, and to explore possible predictive factors for its development. Specific immunoglobulin deficiencies were also studied.

RESULTS

76.5% of patients had hypogammaglobulinemia during or after front-line treatment, mostly grade 1-2; with 38.8% patients who developed clinically relevant infections and 20% patients requiring human immunoglobulins replacement therapy. A high-risk FLIPI score was identified as a risk factor for hypogammaglobulinemia (ods ratio: 4.51; 95% confidence interval: 1.29-15.68; p < 0.001) and basal gamma globulin level as a protective factor (odds ratio: 0.92; 95% confidence interval: 0.988-0.996; p  =  0.018). Any type of immunochemotherapy regimen was associated with different risks of hypogammaglobulinemia in our study.

CONCLUSIONS

Hypogammaglobulinemia appears in a high percentage of patients with follicular lymphoma in a real-world population, identifying a high-risk FLIPI score as a risk factor for its development and basal gamma globulins as a protective factor.

Infection Risk, Mortality, and Hypogammaglobulinemia Prevalence and Associated Factors in Adults Treated with Rituximab: A Tertiary Care Center Experience

BACKGROUND

Rituximab is a human monoclonal antibody directed against the B-cell transmembrane protein CD20. Although well-tolerated, given its mechanism of action, rituximab can induce a state of severe immunosuppression, increasing the risk of opportunistic and fulminant infection and mortality.

AIM

To evaluate the risk of infection, mortality, and hypogammaglobulinemia and their associated factors among rituximab receivers.

METHOD

This was a single-center retrospective cohort study of adults treated with rituximab for various indications. Hypogammaglobulinemia was defined by a cut-off value below the normal limit (an IgG level of <7.51 g/L, an IgM level of <0.46 g/L, and/or an IgA level of <0.82 g/L). Patients who met the definition of hypogammaglobinemia solely based on IgA were excluded. Severe infection was defined as any infection that required intensive care unit admission.

RESULTS

A total of 137 adults with a mean age of 47.69 ± 18.86 years and an average BMI of 28.57 ± 6.55 kg/m2 were included. Hematological malignancies and connective tissue diseases were the most common primary diagnoses for which rituximab was used. More than half of the patients received the 375 mg/m2 dose. Rituximab's mean cumulative dose was 3216 ± 2282 mg, and the overall mortality rate was 22.6%. Hypogammaglobulinemia was diagnosed in 43.8% of the patients, and it was significantly more prevalent among males and the 375 mg/m2 and 500 mg doses. Hematological malignancy was the only predictor for infection. Patients with blood type AB or B, hematological malignancies, and corticosteroids had a significantly higher mortality rate. Receiving the 1000 mg dose and having a low CD19 were associated with a significantly lower risk of infection and mortality, respectively.

CONCLUSIONS

Hypogammaglobulinemia was diagnosed in 43.8% of the patients, and it was significantly more common among males and the 375 mg/m2 and 500 mg doses. Hematological malignancies were significantly associated with higher infection and mortality rates, while corticosteroids were significantly associated with a higher mortality. Since the culprit of mortality was infection, these findings highlight the critical need for more frequent immunological monitoring during rituximab treatment period to mitigate the burden of infection and identify candidates for immunoglobulin replacement.

Rituximab-associated hypogammaglobulinemia in children with idiopathic nephrotic syndrome: results of an ESPN survey

BACKGROUND

There is paucity of information on rituximab-associated hypogammaglobulinemia (HGG) and its potential infectious consequences in children treated for idiopathic nephrotic syndrome (INS).

METHODS

A survey was distributed by the European Society Pediatric Nephrology to its members. It addressed the screening and management practices of pediatric nephrology units for recognizing and treating RTX-associated HGG and its morbidity and mortality. Eighty-four centers which had treated an overall 1328 INS children with RTX responded.

RESULTS

The majority of centers administered several courses of RTX and continued concomitant immunosuppressive therapy. Sixty-five percent of centers routinely screened children for HGG prior to RTX infusion, 59% during, and 52% following RTX treatment. Forty-seven percent had observed HGG prior to RTX administration, 61% during and 47% >9 months following treatment in 121, 210, and 128 subjects respectively. Thirty-three severe infections were reported among the cohort of 1328 RTX-treated subjects, of whom 3 children died. HGG had been recognized in 30/33 (80%) of them.

CONCLUSIONS

HGG in steroid-dependent/frequently relapsing nephrotic syndrome (SDNS/FRNS) children is probably multifactorial and can be observed prior to RTX administration in children with SDNS/FRNS. Persistent HGG lasting >9 months from RTX infusion is not uncommon and may increase the risk of severe infections in this cohort. We advocate for the obligatory screening for HGG in children with SDNS/FRNS prior to, during, and following RTX treatment. Further research is necessary to identify risk factors for developing both HGG and severe infections before recommendations are made for its optimal management. A higher resolution version of the Graphical abstract is available as Supplementary information.

Immune response after SARS-CoV-2 vaccination in patients with inflammatory immune-mediated diseases receiving immunosuppressive treatment

BACKGROUND

Real world data on the response to the SARS-CoV-2 vaccine in patients with immunomediated diseases (IMIDs) treated with immunesuppressants is of great interest because vaccine response may be impaired. The main aim was to study the humoral and cellular immune response after SARS-CoV-2 vaccination in patients with IMIDs treated with immunosuppressants. The secondary aim was to describe the frequency of SARS-CoV-2 infections after vaccination in these patients.

MATERIAL AND METHODS

This is an observational study including 86 patients with IMIDs. All patients were treated with biologic or targeted synthetic disease-modifying antirheumatic drugs [b/tsDMARDs: TNF inhibitors (TNFi), rituximab, anti-interleukin 6 receptor (anti-IL6R) or JAK inhibitors (JAKi)]. Demographic and clinical information were collected. After 4-6 weeks of 2nd and 3rd vaccine doses, humoral response was assessed using the Thermo Scientific ELiA SARS-CoV-2-Sp1 IgG Test. Also, in patients with serum SARS-CoV-2 antibody levels under 100UI/ml, cellular response was analyzed using the QuantiFERON SARS-CoV-2 Starter Pack.

RESULTS

A total of 86 patients under b/tsDMARDs and 38 healthy controls were included. Most patients received TNFi (45 with TNFi, 31 with rituximab, 5 with anti-IL6R and 5 with JAKi). SARS-CoV-2 antibodies (Ab) were present in an 86% of patients with IMIDs and in 100% healthy controls (p = 0.017). However, 12 (14%) patients had undetectable SARS-CoV-2 Ab levels, all treated with rituximab. In addition, SARS-CoV-2 Ab (IU/ml) were statistically lower in patients (Mdn (IQR): 59.5 (17-163) in patients vs 625 (405-932) in controls, p < 0.001). Patients treated with rituximab had lower Ab levels than those treated with TNFi and controls (p < 0.001). The cellular response to SARS-CoV-2 vaccine was evaluated in 30 patients. Eleven patients had a positive cellular response, being more frequent in patients treated with rituximab (p = 0.03). SARS-CoV-2 infection was reported in 43% of patients and 34% of controls after vaccination. Only 6 (7%) patients required hospitalization, most of whom treated with rituximab (67%).

CONCLUSION

SARS-CoV-2 antibody levels were lower in patients than in controls, especially in patients treated with rituximab. A cellular response can be detected despite having a poor humoral response. Severe infections in vaccinated patients with IMIDs are rare, and are observed mainly in patients treated with rituximab.

Infectious risk when prescribing rituximab in patients with hypogammaglobulinemia acquired in the setting of autoimmune diseases

We conducted a single-centre retrospective cohort study in a French University Hospital between 2010 and 2018 to describe the risk of severe infectious event (SIE) within 2 years after the date of first rituximab infusion (T0) prescribed after the evidence of acquired hypogammaglobulinemia (gamma globulins [GG] ≤ 6 g/L) in the setting of autoimmune diseases (AID) other than rheumatoid arthritis. SIE occurred in 26 out of 121 included patients. Two years cumulative incidence rates were 12.7 % (95 % CI 5.1-23.9) in the multiple sclerosis/neuromyelitis optica spectrum disorder group (n = 48), 27.6 % (95 % CI 15.7-40.9) in the ANCA-associated vasculitis group (n = 48) and 30.6 % (95 % CI 13.1-50.3) in the 'other AID' group (n = 25). Median GG level at T0 was 5.3 g/l (IQR 4.1-5.6) in the 'SIE' group and 5.6 g/l (IQR 4.7-5.8) in the 'no SIE' group (p = 0.04). In regression analysis, risk of SIE increased with Charlson comorbidity index ≥ 3 (OR 2.77; 95 % CI 1.01-7.57), lung disease (OR 3.20; 95 % CI 1.27-7.99), GG < 4 g/L (OR 3.39; 95 % CI 1.02-11.19), concomitant corticosteroid therapy (OR 4.13; 95 % CI 1.63-10.44), previous cyclophosphamide exposure (OR 2.69; 95 % CI 1.10-6.61), a lymphocyte count < 1000 cells/µL (OR 2.86; 95 % CI 1.12-7.21) and absence of pneumococcal vaccination (OR 3.50; 95 % CI 1.41-8.70). These results may help to inform clinical decision when considering a treatment by rituximab in immunosuppressed AID patients with hypogammaglobulinemia.

Hypogammaglobulinemia, late-onset neutropenia, and infections following rituximab

Rituximab is a chimeric anti-CD20 monoclonal antibody that targets CD20-expressing B lymphocytes, has a well-defined efficacy and safety profile, and is broadly used to treat a wide array of diseases. In this review, we cover the mechanism of action of rituximab and focus on hypogammaglobulinemia and late-onset neutropenia-2 immune effects secondary to rituximab-and subsequent infection. We review risk factors and highlight key considerations for immunologic monitoring and clinical management of rituximab-induced secondary immune deficiencies. In patients treated with rituximab, monitoring for hypogammaglobulinemia and infections may help to identify the subset of patients at high risk for developing poor B cell reconstitution, subsequent infections, and adverse complications. These patients may benefit from early interventions such as vaccination, antibacterial prophylaxis, and immunoglobulin replacement therapy. Systematic evaluation of immunoglobulin levels and peripheral B cell counts by flow cytometry, both at baseline and periodically after therapy, is recommended for monitoring. In addition, in those patients with prolonged hypogammaglobulinemia and increased infections after rituximab use, immunologic evaluation for inborn errors of immunity may be warranted to further risk stratification, increase monitoring, and assist in therapeutic decision-making. As the immunologic effects of rituximab are further elucidated, personalized approaches to minimize the risk of adverse reactions while maximizing benefit will allow for improved care of patients with decreased morbidity and mortality.

Secondary immunodeficiencies and infectious considerations of biologic immunomodulatory therapies

Biologic immunomodulatory medications have rapidly expanded in the previous decades, providing new treatment options for individuals with a spectrum of oncologic, allergic, rheumatologic, and neurologic conditions. Biologic therapies alter immune function and can impair key host defense mechanisms, resulting in secondary immunodeficiency and increased infectious risks. Biologic medications can increase general risk for upper respiratory tract infections but can also be associated with unique infectious risks owing to distinct mechanisms of action. With the widespread use of these medications, providers in every area of medicine will likely care for individuals receiving biologic therapies and understanding their potential infectious complications can help mitigate these risks. This practical review discusses the infectious implications of biologics by class of medication and provides recommendations regarding the examination and screening both before therapy initiation and while the patient is receiving the medication. With this knowledge and background, providers can reduce risk whereas patients receive the treatment benefits of these biologic medications.

[Prevalence of persistent hypogammaglobulinemia in patients with autoimmune rheumatic disease who received treatment with Rituximab in a national medical center in Mexico]

OBJECTIVE

To describe the prevalence of persistent hypogammaglobulinemia in patients receiving Rituximab as a treatment for autoimmune rheumatological diseases.

METHODS

A transversal, retrospective and unicentric study, carried out in patients with autoimmune rheumatic diseases who were admitted to the Rheumatology service of the Hospital de Especialidades Dr. Antonio Fraga Mouret, Centro Médico Nacional La Raza, Mexico City, to receive treatment with rituximab between January 2013 and January 2018. Descriptive and inferential statistics of serum levels of immunoglobulins, clinical-demographic characteristics, diagnosis, and treatment received were performed.

RESULTS

from 262 patients with autoimmune rheumatological disease who received treatment with Rituximab; We identified 8 patients with persistent hypogammaglobulinemia (6 women and 2 men), this is a prevalence of 3.1%. No associated factors with the development of hypogammaglobulinemia were identified.

CONCLUSIONS

Until now, no associated prognostic or predictive factors have been identified with persistent hypogammaglobulinemia. Additional prospective studies are required to understand more precisely the implications of persistent hypogammaglobulinemia in patients with autoimmune diseases.

Immune tolerance breakdown in inborn errors of immunity: Paving the way to novel therapeutic approaches

Up to 25% of the patients with inborn errors of immunity (IEI) also exhibit immunodysregulatory features. The association of immune dysregulation and immunodeficiency may be explained by different mechanisms. The understanding of mechanisms underlying immune dysregulation in IEI has paved the way for the development of targeted treatments. In this review article, we will summarize the mechanisms of immune tolerance breakdown and the targeted therapeutic approaches to immune dysregulation in IEI.

COVID-19 disease frequency, risk factors, and re-infection rates in patients with autoimmune rheumatic disease receiving rituximab

INTRODUCTION

Rituximab, which is used in autoimmune rheumatic diseases (ARD), can cause both an increased risk of development of COVID-19 disease and re-infection due to its potent and long-acting immunosuppression. So, we aimed to evaluate the frequency, risk factors and re-infection rates of COVID-19 in ARD patients receiving rituximab.

METHODS

A single-center retrospective study was performed with patients receiving rituximab for ARD in 12 months before the onset of COVID-19 in Turkey. The data regarding severe acute respiratory syndrome-coronavirus 2 reverse transcription polymerized chain reaction (RT-PCR) test, clinical, laboratory, and mortality data of all patients were collected from medical records. Logistic regression analysis was used for predictors of COVID-19 disease. COVID-19 re-infection was defined as RT-PCR positivity and recurrence of acute COVID-19 symptoms after at least 1 negative RT-PCR in patients with clinical improvement.

RESULTS

Ninety-eight ARD patients with rituximab were evaluated and 23 (23%) of them had COVID-19. The presence of hypogammaglobulinemia increased the risk of COVID-19 disease 8-fold. COVID-19 pneumonia occurred in 13 (57%) and these patients' age was higher than those without pneumonia (59.6 ± 11.8 vs 44.9 ± 14.2 years, P = 0.013). Mortality due to COVID-19 was 13% and COVID-19 re-infection was seen in 20% of survivors.

CONCLUSION

Regardless of the underlying rheumatic disease and organ involvements, hypogammaglobulinemia in ARD could be a risk factor for COVID-19 development, and advanced age could be for COVID-19 severity. Moreover, COVID-19 re-infection rates are high.

The association between hypogammaglobulinemia severity and infection risk in rituximab-treated patients with childhood-onset idiopathic nephrotic syndrome

BACKGROUND

Hypogammaglobulinemia is a major adverse effect from rituximab. However, the association between rituximab-induced hypogammaglobulinemia and infection frequency is unknown.

METHODS

Patients who received rituximab for complicated nephrotic syndrome between February 2006 and October 2020 were enrolled in this retrospective observational study. Infections requiring antibacterial or antiviral agents or hospitalization were identified, and the characteristics of infections were compared according to infection type.

RESULTS

One hundred and forty patients were enrolled. Fifty infection events were detected in 36 patients, 45 infection events in 32 patients required hospitalization, and 1 severe infection event required intensive care unit admission. In eight patients who developed severe hypogammaglobulinemia (serum IgG level < 200 mg/dL) for more than 1 year after rituximab treatment, eight infections occurred in six patients; six of these infections did not occur during the period of severe hypogammaglobulinemia. Febrile neutropenia accounted for 54.2% (13/24) of all infections among the patients with hypogammaglobulinemia. The incidence of infections was 0.028 (95% confidence interval = 0.017-0.448), 0.071 (95% [CI] = 0.041-0.114), and 0.096 (95% [CI] = 0.019-0.282) patient-years in patients with normal serum IgG levels and those with mild and severe hypogammaglobulinemia, respectively. Immunoglobulin replacement therapy was not administered to any patients except for the treatment of infection.

CONCLUSIONS

Our results showed no statistically significant association between hypogammaglobulinemia severity and infection rate. In addition, the frequency of infection was relatively low even in patients with severe hypogammaglobulinemia, suggesting that immunoglobulin replacement therapy may not be necessary for rituximab-treated patients with severe hypogammaglobulinemia. A higher resolution version of the Graphical abstract is available as Supplementary information.

Access and use of immunoglobulins in secondary supportive cancer care: A systematic literature review

Background

Immunoglobulin replacement therapy (IgRT) benefits patients with primary immuno deficiency (PID) originating from the innate or polygenic defects in the immune system. However, evidence supporting their therapeutic role is not as explicit in secondary immuno deficiency (SID) resulting from the treatment of haematological malignancies.

Objectives

This study aimed to (1) create a dataset of relevant research papers, which explore the use of IgRT in SID for analysis, (2) assess the risk of bias within this dataset and (3) study the characteristics of these papers.

Design

This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. In addition to the risk of bias, the study characteristics explored in this article included study design, study geographical location and year of publication.

Data Sources and Methods

To identify studies relevant to the research question, EMBASE and PubMed databases were searched. The Population, Intervention, Comparison and Outcome (PICO) framework was used to assess study quality. Risk of bias and quality of studies were assessed in accordance with the study design. As one model was not appropriate to assess bias in all articles, several tools were used.

Results

A total of 43 studies were identified from the literature search as relevant to the research objective. The most common study design was a retrospective case-control cohort study (n = 16/43), and randomised trials were among the least commonly used approaches (n = 1). Research in this area is occurring around the globe including the United States (n = 7), Italy (n = 7), China, India, Japan and throughout Europe. The annual number of papers in this area has varied from 2012 (n = 1) to 2021 (n = 7). The studies in this article demonstrated a varied risk of bias, with 9 of the 20 cohort studies scoring less than 5 out of 9 stars.

Conclusions

Randomised controlled trials are less frequently used to assess access and use of immunoglobulins. More commonly, a retrospective case-control cohort study was used which correlates with the higher risk of bias seen in the studies in this article. Most of the research concerning immunoglobulin use and access occurs in higher-income countries.

Management of secondary immunodeficiency in hematological malignancies in the era of modern oncology

Secondary immunodeficiency (SID) in patients with B-cell hematological malignancies is a common condition that presents with recurrent infection. SID is due to both the inherent immune defects due to the malignancy, as well as secondary to cancer therapies, many of which have B-cell depleting properties. The early diagnosis of SID and the optimization of intervention strategies are key to delivering the most effective cancer treatments and reducing infection-related morbidity and mortality. This review discusses current practice, recommendations, and challenges for SID diagnosis, based on the evaluation of clinical history and laboratory assessments, and the effectiveness of specific vaccines and immunoglobulin replacement therapy in reducing the frequency and recurrence of infections in patients with SID, and the healthcare system-associated costs.

Immunosuppression in Patients With Primary Immunodeficiency-Walking the Line

Individuals with primary immunodeficiency (PIDD) experience not only infectious complications but also immune dysregulation leading to autoimmunity, inflammation, and lymphoproliferative manifestations. Management of these complications often requires treatment with additional immunosuppressive medications, which pose an additional risk of infectious complications. Immunosuppression in individuals with PIDD therefore requires careful assessment and consideration of risks and benefits. Medications should be closely monitored, and strategies for risk mitigation of adverse events considered, such as exposure reduction, appropriate vaccination, use of antibiotics/antivirals, and optimization of immunoglobulin replacement therapy. In a subset of individuals who are not tolerating immune modulation or experiencing disease progression despite appropriate interventions, hematopoietic stem-cell transplantation is a management option.

Acquired B-cell deficiency secondary to B-cell-depleting therapies

The advantage of the newer biological therapies is that the immunosuppressive effect is targeted, in contrast, to the standard, traditional immunomodulatory agents, which have a more global effect. However, there are unintended targets and consequences, even to these "precise" therapeutics, leading to acquired or secondary immunodeficiencies. Besides depleting specific cellular immune subsets, these biological agents, which include monoclonal antibodies against biologically relevant molecules, often have broader functional immune consequences, which become apparent over time. This review focuses on acquired B-cell immunodeficiency, secondary to the use of B-cell depleting therapeutic agents. Among the many adverse consequences of B-cell depletion is the risk of hypogammaglobulinemia, failure of B-cell recovery, impaired B-cell differentiation, and risk of infections. Factors, which modulate the outcomes of B-cell depleting therapies, include the intrinsic nature of the underlying disease, the concomitant use of other immunomodulatory agents, and the clinical status of the patient and other co-existing morbidities. This article seeks to explore the mechanism of action of B-cell depleting agents, the clinical utility and adverse effects of these therapies, and the relevance of systematic and serial laboratory immune monitoring in identifying patients at risk for developing immunological complications, and who may benefit from early intervention to mitigate the secondary consequences. Though these biological drugs are gaining widespread use, a harmonized approach to immune evaluation pre-and post-treatment has not yet gained traction across multiple clinical specialties, because of which, the true prevalence of these adverse events cannot be determined in the treated population, and a systematic and evidence-based dosing schedule cannot be developed. The aim of this review is to bring these issues into focus, and initiate a multi-specialty, data-driven approach to immune monitoring.

Secondary rituximab-associated versus primary immunodeficiencies: The enigmatic border

Rituximab (RTX), a chimeric monoclonal antibody targeting CD20-positive cells, is a valuable treatment option for malignant and benign immune-related disorders. The rationale of targeting the CD20 antigen relies on depletion of both healthy and autoreactive/malignant CD20-espressing cells, but normal B-cell reconstitution is expected within months after treatment. Nevertheless, a number of recent studies have documented prolonged B-cell deficiency associated with new-onset hypogammaglobulinemia in patients receiving RTX. Awareness of post-RTX hypogammaglobulinemia has become wider among clinicians, with a growing number of reports about the increased incidence, especially in children. Although these patients were previously regarded as affected by secondary/iatrogenic immunodeficiency, atypical clinical and immunological manifestations (e.g., severe or opportunistic infections; prolonged B-cell aplasia) raise concerns of delayed manifestations of genetic immunological disorders that have been unveiled by B-cell perturbation. As more patients with undiagnosed primary immune deficiency receiving RTX have been identified, it remains the challenge in discerning those that might display a higher risk of persistent RTX-associated hypogammaglobulinemia and need a tailored immunology follow-up. In this review, we summarize the principal evidence regarding post-RTX hypogammaglobulinemia and provide a guideline for identifying patients at higher risk of RTX-associated hypogammaglobulinemia that could harbor an inborn error of immunity.

Practical guidance for the diagnosis and management of secondary hypogammaglobulinemia: A Work Group Report of the AAAAI Primary Immunodeficiency and Altered Immune Response Committees

Secondary hypogammaglobulinemia (SHG) is characterized by reduced immunoglobulin levels due to acquired causes of decreased antibody production or increased antibody loss. Clarification regarding whether the hypogammaglobulinemia is secondary or primary is important because this has implications for evaluation and management. Prior receipt of immunosuppressive medications and/or presence of conditions associated with SHG development, including protein loss syndromes, are histories that raise suspicion for SHG. In patients with these histories, a thorough investigation of potential etiologies of SHG reviewed in this report is needed to devise an effective treatment plan focused on removal of iatrogenic causes (eg, discontinuation of an offending drug) or treatment of the underlying condition (eg, management of nephrotic syndrome). When iatrogenic causes cannot be removed or underlying conditions cannot be reversed, therapeutic options are not clearly delineated but include heightened monitoring for clinical infections, supportive antimicrobials, and in some cases, immunoglobulin replacement therapy. This report serves to summarize the existing literature regarding immunosuppressive medications and populations (autoimmune, neurologic, hematologic/oncologic, pulmonary, posttransplant, protein-losing) associated with SHG and highlights key areas for future investigation.

Incidence and risk factors of rituximab-associated hypogammaglobulinemia in patients with complicated nephrotic syndrome

BACKGROUND

Hypogammaglobulinemia is a major adverse event after rituximab treatment; however, the precise incidence and risk factors are unclear in complicated steroid-dependent or frequently relapsing nephrotic syndrome (SDNS/FRNS) patients.

METHODS

This was a single-center, retrospective, observational study. Patients who received a single dose of rituximab for complicated SDNS or FRNS between February 2007 and May 2019 were enrolled. Serum IgG levels were plotted, and their trends were evaluated after rituximab treatment. The incidence of transient and persistent hypogammaglobulinemia was examined, and risk factors were calculated by multivariate analysis using logistic regression.

RESULTS

We enrolled 103 patients who received 238 single doses of rituximab. Hypogammaglobulinemia was observed in 58.4% of the patients at least once after a single dose of rituximab treatment and 22.3% developed persistent hypogammaglobulinemia. Serum IgG levels gradually increased during B-cell depletion, and patients with low serum IgG levels at rituximab treatment had persistent hypogammaglobulinemia. Repeated courses of rituximab treatment increased the incidence of hypogammaglobulinemia. A past history of steroid-resistant nephrotic syndrome (SRNS) (odds ratio [OR] = 10.02; 95% confidence interval [CI] = 2.65-37.81; P < 0.001) and low serum IgG levels at rituximab treatment (OR = 7.63; 95% CI = 2.10-27.71; P = 0.002) was significantly associated with hypogammaglobulinemia in multivariate analysis.

CONCLUSIONS

Hypogammaglobulinemia is a frequent adverse event after rituximab treatment, although IgG levels slightly increase during B-cell depletion. Low serum IgG levels at rituximab treatment and a past history of SRNS are significant risk factors for the development of hypogammaglobulinemia after rituximab treatment.

Prognostic factors of severe pneumonia in patients treated with rituximab in the intensive care unit

Objective

The aim of this study was to describe the clinical characteristics and prognostic factors of patients treated with rituximab (RTX) who developed severe pneumonia in the intensive care unit (ICU).

Methods

We systematically reviewed the medical records of 40 patients who received RTX and developed severe pneumonia in the ICU at our hospital from January 2009 to January 2019 to evaluate the underlying conditions, clinical course, and possible prognostic factors.

Results

Most patients had underlying hematologic malignancies (n = 21, 52.5%), followed by rheumatologic diseases (n = 17, 42.5%). The most frequent causative pathogens were fungi (n = 11, 27.5%), followed by bacteria (n = 9, 22.5%) and Pneumocystis jirovecii pneumonia (n = 8, 20%). Thirty patients (75%) died, and the other 10 patients (25%) survived. Compared with survivors, patients who died were significantly older (60.6 ± 10.6 vs 44.4 ± 18.3 years) and had chronic lung disease (40% vs 0%).

Conclusion

Older age and chronic lung disease were significantly associated with mortality in patients treated with RTX.

Rituximab in the Treatment of Interstitial Lung Diseases Related to Anti-Melanoma Differentiation-Associated Gene 5 Dermatomyositis: A Systematic Review

Objective

The effectiveness of rituximab in anti-melanoma differentiation-associated gene 5 (MDA5) dermatomyositis (DM) with interstitial lung disease (ILD) has been explored only in isolated case reports and small series. This paper aims to review the current evidence regarding rituximab (RTX) use in the treatment of ILD related to anti-MDA5 DM (anti-MDA5 DM-ILD).

Methods

We conducted a review by searching PubMed, Web of Science, Embase, and Cochrane for articles with information on patients with anti-MDA5 DM and RTX treatment, published until August 2021, in English language. The selected studies listed variation in chest high-resolution computed tomography (HRCT) and/or pulmonary function test (PFT) as a primary outcome, in patients with anti-MDA5 DM-related ILD after using RTX.

Results

Of the 145 potentially eligible articles, 17 were selected. The information gathered from a total of 35 patients with anti-MDA5 DM-ILD was reviewed, including 13 men and 22 women. Patient age at onset was 47.60 ± 13.72 years old. A total of 11.43% (4/35) of the patients were found to have chronic ILD (C-ILD) and 88.57% (31/30) exhibited rapidly progressive ILD (RP-ILD). Most patients (29/30) had typical DM rashes. Prior to RTX administration, the majority of patients (27/35) were treated with medium- or high-dose glucocorticoids and at least one additional immunotherapeutic agent. With regard to RTX efficacy for ILD in anti-MDA5 DM, 71.43% (25/35) of the patients responded to treatment. Skin rash also improved in more than half of the patients after RTX treatment. The most common side effects were infections, reported by 37.14% (13/35) of the patients after using RTX.

Conclusion

As a CD20 targeting drug, RTX is a promising therapeutic tool for anti-MDA5 DM-ILD, although the risk of infections should be considered before treatment. Further prospective controlled studies are required to evaluate the optimal RTX treatment regimen.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021289714, identifier CRD42021289714.

Efficacy of rituximab versus tacrolimus in difficult-to-treat steroid-sensitive nephrotic syndrome: an open-label pilot randomized controlled trial

BACKGROUND

Rituximab and tacrolimus are therapies reserved for patients with frequently relapsing or steroid-dependent nephrotic syndrome who have failed conventional steroid-sparing agents. Given their toxicities, demonstrating non-inferiority of rituximab to tacrolimus may enable choice between these medications.

METHODS

This investigator-initiated, single-center, open-label, pilot randomized controlled trial examined the non-inferiority of two doses of intravenous (IV) rituximab given one-week apart to oral therapy with tacrolimus (1:1 allocation), in maintaining sustained remission over 12 months follow-up, in patients with difficult-to-treat steroid-sensitive nephrotic syndrome, defined as frequently relapsing or steroid-dependent disease that had failed ≥ 2 steroid-sparing strategies. Secondary outcomes included frequency of relapses, proportion with frequent relapses, time to relapse and frequent relapses, and adverse events (CTRI/2018/11/016342).

RESULTS

Baseline characteristics were comparable for 41 patients randomized to receive rituximab (n = 21) or tacrolimus (n = 20). While 55% of patients in each limb were in sustained remission at 1 year, non-inferiority of rituximab to tacrolimus was not demonstrated (mean difference 0%; 95% CI - 30.8%, 30.8%; non-inferiority limit - 20%; P = 0.50). Frequent relapses were more common in patients administered rituximab compared to tacrolimus (risk difference 30%, 95% CI 7.0, 53.0, P = 0.023). Both groups showed similar reductions in relapse rates and prednisolone use. Common adverse events were infusion-related with rituximab and gastrointestinal symptoms with tacrolimus.

CONCLUSIONS

Therapy with rituximab was not shown to be non-inferior to 12-months treatment with tacrolimus in maintaining remission in patients with difficult-to-treat steroid-sensitive nephrotic syndrome. Frequent relapses were more common with rituximab. While effective, both agents require close monitoring for adverse events. A higher resolution version of the Graphical abstract is available as Supplementary information.

Case Report: Persistent Hypogammaglobulinemia More Than 10 Years After Rituximab Given Post-HSCT

Rituximab (RTX) is an anti-CD20 monoclonal antibody that targets B cells-from the immature pre-B-cell stage in the bone marrow to mature circulating B cells-while preserving stem cells and plasma cells. It is used to treat autoimmune diseases, hematological malignancies, or complications after hematopoietic stem cell transplantation (HSCT). Its safety profile is acceptable; however, a subset of patients can develop persistent hypogammaglobulinemia and associated severe complications, especially in pediatric populations. We report the unrelated cases of two young men aged 17 and 22, presenting with persistent hypogammaglobulinemia more than 7 and 10 years after treatment with RTX, respectively, and administered after HSCT for hemolytic anemia and Epstein-Barr virus reactivation, respectively. Both patients' immunological workups showed low levels of total immunoglobulin, vaccine antibodies, and class switched-memory B cells but an increase in naive B cells, which can also be observed in primary immunodeficiencies such as those making up common variable immunodeficiency. Whole exome sequencing for one of the patients failed to detect a pathogenic variant causing a Mendelian immunological disorder. Annual assessments involving interruption of immunoglobulin replacement therapy each summer failed to demonstrate the recovery of endogenous immunoglobulin production or normal numbers of class switched-memory B cells 7 and 10 years after the patients' respective treatments with RTX. Although the factors that may lead to prolonged hypogammaglobulinemia after rituximab treatment (if necessary) remain unclear, a comprehensive immunological workup before treatment and long-term follow-up are mandatory to assess long-term complications, especially in children.

Derisking CD20-therapies for long-term use

Anti-CD20 have quickly become the mainstay in the treatment of multiple sclerosis (MS) and other neuroinflammatory conditions. However, when they are used as a maintenance therapy the balance between risks and benefits changes. In this review, we suggested six steps to derisk anti-CD20. Firstly and secondly, adequate infectious screening followed by vaccinations before starting anti-CD20 are paramount. Third, family planning needs to be discussed upfront with every woman of childbearing age. Fourth, infusion reactions should be adequately managed to avoid treatment interruption. After repeated infusions, it becomes important to detect and prevent anti-CD20-related adverse events. Fifth, we recommended measuring immunoglobulin levels and reviewing vaccinations annually as well as counselling adequate fever management. For female patients, we emphasised the importance to engage with the local breast cancer screening programs. Sixth, to fundamentally derisk anti-CD20 therapies, we need evidence-based approaches to reduce dosing intervals and guide retreatment.

Characterizing hospital pathways for the care of acquired hemophilia in France using comprehensive national health data

PURPOSE

Acquired hemophilia (AH) is a rare, serious bleeding disorder most often associated with older age and life-threatening complications. The patient care pathway for AH is complex because of the different types of bleeding, the presence of comorbidities, and the heterogeneity of medical specialists who care for these patients.

METHODS

This observational study used the French national PMSI (Programme de médicalisation des systèmes d'information) database to characterize patients with AH in real-life practice and analyze their hospital pathway. In total, 180 patients with AH were identified over a 5-year study period (January 2010 to December 2014), based on three criteria: bypassing agent use, International Classification of Diseases, 10th revision code allocation, and aged over 65 years. Comparison of the incidence rate of AH versus registry data validated the PMSI as an epidemiological database.

RESULTS

Rituximab was prescribed more often (60/180; 33.3%) than expected following guidelines and was associated in half of cases to early infections (32/60; 53.3%), surgery procedures were frequently performed during the year before AH onset (29/159; 18.2%), which may suggest a triggering effect, extended hospital stays (median: 20 days) and mortality remaining high (66/180; 36.7%) that occurred mainly during the first month after AH diagnosis. Median costs and number of injections were comparable between recombinant activated factor VII and plasma-derived activated prothrombin complex concentrate.

CONCLUSION

These findings could inform future medico-economic approaches in this AH population (duration of stays, bypassing agents, rituximab use, comorbidities, hospitalizations with infections).

Pathogenic implications, incidence, and outcomes of COVID-19 in autoimmune inflammatory joint diseases and autoinflammatory disorders

As the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread rapidly, there are still many unresolved questions of how this virus would impact on autoimmune inflammatory joint diseases and autoinflammatory disorders. The main aim of this paper is to describe the main studies focusing their attention on COVID-19 incidence and outcomes of rheumatoid arthritis (RA), spondylarthritis (SpA), and autoinflammatory disease cohorts. We also revised possible pathogenic mechanisms associated with. Available data suggest that, in patients with RA and SpA, the immunosuppressive therapy, older age, male sex, and the presence of comorbidities (hypertension, lung disease, diabetes, CVD, and chronic renal insufficiency/end-stage renal disease) could be associated with an increased risk of infections and high rate of hospitalization. Other studies have shown that lower odds of hospitalization were associated with bDMARD or tsDMARDs monotherapy, driven largely by anti-TNF therapies. For autoinflammatory diseases, considering the possibility that COVID-19 could be associated with a cytokine storm syndrome, the question of the susceptibility and severity of SARS-CoV-2 infection in patients displaying innate immunity disorders has been raised. In this context, data are very scarce and studies available did not clarify if having an autoinflammatory disorder could be or not a risk factor to develop a more severe COVID-19. Taking together these observations, further studies are likely to be needed to fully characterize these specific patient groups and associated SARS-CoV-2 infection.

Hypogammaglobulinemia after rituximab for rheumatoid arthritis is not rare and is related with good response: 13 years real-life experience

OBJECTIVES

Rituximab (RTX) use in the treatment of RA can be complicated by decrease in IgG, IgM or IgA levels (hypogammaglobulinemia-HGG). The aim of this study was to define the frequency of HGG in RA patients treated with RTX and to identify associations between its occurrence and patients' characteristics, disease outcomes and serious infections rate.

METHODS

RA patients treated with RTX in two rheumatology centers from January 2007 to January 2020 were retrospectively examined. Demographical, clinical and laboratory parameters were recorded at baseline and at last visit.

RESULTS

Eighty-three patients (84.3% females) with a mean age of 63.2 years were enrolled. They had baseline DAS28(CRP) of 5.2  (1.1) and received a median (range) of 8 (2-20) RTX cycles. A total of 43.4%, 24.1% and 31.3% developed 'any HGG', 'low IgG' and 'low IgM', respectively. Lower baseline IgG and IgM levels were predictors of 'low IgG' and 'low IgM' occurrence, respectively. Patients who developed 'low IgM' exhibited lower DAS28(CRP) and increased rates of remission and low disease activity compared with those with normal IgM levels. Patients who maintained normal IgG were receiving methotrexate more frequently. No differences were observed in serious infections rate among subgroups.

CONCLUSION

HGG occurred in 43% of RTX-treated patients. Patients who developed low IgG or low IgM had lower baseline levels than those who did not. Concomitant DMARD and corticosteroid therapy was not associated with HGG. Low IgM, but not low IgG, development was associated with better disease outcomes. HGG was not associated with an increased incidence of serious infections.

Rituximab-associated hypogammaglobulinemia in autoimmune rheumatic diseases: a single-center retrospective cohort study

B-cell targeted therapies, such as rituximab (RTX), are used widely in autoimmune rheumatic diseases (AIRD). RTX can cause hypogammaglobulinemia and predispose patients to infections. Herein, we asked whether the underlying diagnosis influences the risk for hypogammaglobulinemia in patients treated with RTX. All patients who received RTX infusions and carried a diagnosis of rheumatoid arthritis (RA), ANCA-associated vasculitis (AAV), or connective tissue disease (CTD) were included in this single-center retrospective cohort study. We used STATA® for analysis: Chi-square test was used for comparing categorical variables. Based on distribution, continuous variables were compared using the t test/ANOVA or the Wilcoxon/Kruskal-Wallis tests. Of the 163 patients who received RTX for an AIRD, 60 with pre- and post- RTX immunoglobulins were analyzed. A higher incidence of post-treatment hypogammaglobulinemia was seen in AAV (45%) compared to RA (22%) and CTD (9.1%) groups (p = 0.03). Glucocorticoid exposure of 10 mg or more was identified as a significant risk factor for hypogammaglobulinemia. Finally, we observed a higher number of clinically significant infections per person in the AAV group than in the RA and CTD groups. We observed an increased incidence of hypogammaglobulinemia in the RTX-treated AAV group, with almost half of patients developing post-RTX hypogammaglobulinemia. The rate of infections per person was highest in the AAV group. Screening immunoglobulins were not consistently measured pre- and post-RTX. Results highlight a need for increased awareness of the role of immunoglobulin measurement before maintenance doses of RTX, especially in patients with AAV and steroid exposure.

Serious Infectious Events and Immunoglobulin Replacement Therapy in Patients With Autoimmune Disease Receiving Rituximab: A Retrospective Cohort Study

BACKGROUND

Rituximab (RTX) is widely administered to patients with autoimmune disease (AID). This study aimed to estimate the incidence of serious infectious events (SIEs) after RTX initiation in patients with AID. We also described the characteristics and risk factors of SIEs, and immunoglobulin replacement therapy (IgRT) strategies.

METHODS

Patients treated between 2005 and 2016 were included in this retrospective monocentric cohort study. An RTX course was defined as the complete RTX treatment regimen received by a given patient for AID. SIEs and IgRT were right-censored at 24 months after RTX initiation.

RESULTS

Two hundred twenty-one patients were included (corresponding to 276 RTX courses). Reasons for RTX initiation included connective tissue disease (38%), systemic vasculitis (36%), and autoimmune cytopenia (22%). The 1- and 2-year incidences of SIEs were 17.3 (95% confidence interval [CI], 12.0-22.5) and 11.3 (95% CI, 8.1-14.5) per 100 person-years, respectively. Forty-seven SIEs were observed, mostly comprising pneumonias (45%) and bacteremias (21%). When documented, the microorganisms were bacterial (55%) and fungal (12%). Identified risk factors of SIEs were age, history of diabetes, history of cancer, concomitant steroid treatment, and low CD4 lymphocyte count at RTX initiation. IgRT was started in 22 RTX courses (8%).

CONCLUSIONS

In patients with AID treated with RTX, the 1- and 2-year incidence of SIE was 17.3 and 11.3 per 100 person-years, respectively. Reports of SIE characteristics, risk factors, and IgRT strategies highlight the need for an appropriate and individualized assessment prior to and following RTX to prevent SIEs, particularly in patients with comorbidities.

[Pediatric expert consensus on the application of intravenous immunoglobulin in children with hematological/neoplastic diseases]

Intravenous immunoglobulin (IVIG) has been widely used in chemotherapy for hematological malignancies, targeted therapy, and hematopoietic stem cell transplantation; however, there are still no available guidelines or consensus statements on the application of IVIG in pediatric hematological/neoplastic diseases at present in China and overseas. This consensus is developed based on the research advances in the application of IVIG in pediatric hematological/neoplastic diseases across the world and provides detailed recommendations for the clinical application of IVIG in pediatric hematological/neoplastic diseases and the prevention and treatment of related adverse reactions.

Rituximab in the treatment of immune-mediated necrotizing myopathy: a review of case reports and case series

Immune-mediated necrotizing myopathy (IMNM) is a group of immune-related myopathies characterized by progressive proximal muscle weakness, extremely high serum creatine kinase (CK) levels, and necrotic muscle fibers with a relative lack of inflammation. Treatment of IMNM is challenging, with most cases refractory to high-dose steroids in combination with multiple immunotherapies. The role of rituximab (RTX) for IMNM has been explored in isolated case reports and small series. The aim of this article was to perform a literature review of patients with IMNM treated with RTX and to evaluate RTX efficacy and safety. A total of 34 patients with IMNM were reviewed: 52.9% (18/34) with anti-signal recognition particle (SRP) antibodies and 47.1% (16/34) with anti-3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) antibodies. Patient age at onset varied from 11 years to 81 years (mean 41 years). The majority of patients presented as a severe proximal muscle weakness and the peak level of CK varied from 3900 IU/L to 56,000 IU/L (mean 18,440 IU/L). Prior to RTX administration, all patients were treated with high-dose steroids and most were treated with multiple immunotherapies. The reason for initiating RTX was that 64.7% (22/34) of patients showed no improvement after previous treatments, and 35.3% (12/34) of patients relapsed when attempting to wean steroids or other immunosuppressive agents. With regard to RTX efficacy, 61.8% (21/34) of patients presented a response to RTX. Our data may support the use of RTX as an effective treatment strategy against IMNM resistant to steroids and multiple immunotherapies. Meanwhile, RTX as a first-line therapy could be a choice in IMNM, particularly in African Americans with anti-SRP antibody-positive subsets. ANA, antinuclear antibody; CK, creatine kinase; HMGCR, 3-hydroxy-3-methylglutaryl-CoA reductase; IMNM, immune-mediated necrotizing myopathy; MAC, membrane attack complex; MHC-I, major histocompatibility complex-I; RTX, rituximab; SRP, signal recognition particle.

Treating secondary antibody deficiency in patients with haematological malignancy: European expert consensus

OBJECTIVES

Secondary antibody deficiency (SAD), associated with severe, recurrent or persistent infections, is common in patients with haematological malignancies (HM), but unifying guidance on immunoglobulin replacement therapy (IgRT) in these patients is lacking. We aimed to develop consensus statements for the use of IgRT in patients with HM.

METHODS

A Delphi exercise was employed to test the level of agreement on statements developed by a Task Force based on available data and their clinical experience. In Round 1, an Expert Panel, comprising specialist EU physicians caring for patients with HM, helped to refine the statements. In Round 2, experts rated their agreement with the statements. In Round 3, experts who had scored their agreement as ≤4 were invited to review their agreement based on the overall feedback.

RESULTS

Three definitions and 20 statements were formulated and tested for consensus, covering measurement of IgG levels, initiation and discontinuation of IgRT, dosing, and the use of subcutaneous IgG. Consensus (agreement ≥70% on Likert-type scale) was reached for all three definitions and 18 statements.

CONCLUSIONS

Recommendations have been developed with the aim of providing guidance for the use of IgRT to prevent severe, recurrent or persistent infections in patients with HM and SAD.

Association of Rituximab Use With Adverse Events in Children, Adolescents, and Young Adults

IMPORTANCE

Rituximab is among the most frequently used immunotherapies in pediatrics. Few studies have reported long-term adverse events associated with its use for children.

OBJECTIVE

To describe the use of rituximab and to assess whether its use is associated with short- or long-term adverse events, infections, or time to immune reconstitution in a diverse group of young people.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 468 patients aged younger than 21 years who received rituximab for diverse indications between October 1, 2010, and December 31, 2017, at Texas Children's Hospital, a large pediatric referral hospital. Patterns of adverse events, infections, and immune recovery are described. Data analyses were conducted from December 2019 to June 2020.

EXPOSURE

One or more doses of rituximab.

MAIN OUTCOMES AND MEASURES

Adverse drug events (eg, anaphylaxis), incidence of mild and severe infections, and time to recovery of B lymphocyte subset counts and immunoglobulin levels. Survival models and logistic regression analyses and were used to identify associated risk factors of infectious and noninfectious adverse drug events.

RESULTS

We identified 468 patients receiving at least 1 dose of rituximab. The total follow-up time was 11 713 person-months. Of the 468 patients, 293 (62.6%) were female, the median (interquartile range) age at receipt of dose was 14.3 (9.9-16.8) years, and 209 (44.7%) were self-reported White Hispanic. Adverse events associated with rituximab infusion occurred in 72 patients (15.4%), and anaphylaxis occurred in 17 patients (3.6%). Long-term adverse events, such as prolonged neutropenia and leukoencephalopathy, were absent. Infections occurred in 224 patients (47.9%); 84 patients (17.9%) had severe infections, and 3 patients (0.6%) had lethal infections. Concurrent use of intravenous chemotherapy, treatment of systemic lupus erythematosus, neutropenia, and use of intravenous immunoglobulin were associated with increased risk of infection. Among 135 patients (28.8%) followed up to B cell count recovery, CD19+ or CD20+ cell numbers normalized in a median of 9.0 months (interquartile range, 5.9-14.4 months) following rituximab use; 48 of 95 patients (51%) evaluated beyond a year had low-for-age B cell counts. Recovery of CD27+ memory B cell number occurred in a median of 15.7 months (interquartile range, 6.0-22.7 months). Among patients with normal baseline values, low immunoglobulin G (IgG) levels developed in 67 of 289 patients (23.2%) and low IgM levels in 118 of 255 patients (40.8%); of these patients evaluated beyond 12 months from rituximab, 16 of 117 (13.7%) had persistently low IgG and 37 (33.9%) of 109 had persistently low IgM.

CONCLUSIONS AND RELEVANCE

Rituximab is well tolerated among young people and is associated with few serious adverse events, but infections are common, corresponding to a prolonged period of B cell count recovery often lasting for longer than a year. Further examination of strategies to prevent infections following rituximab should be pursued.

A Retrospective Analysis of Rituximab Treatment for B Cell Depletion in Different Pediatric Indications

Background: Rituximab (RTX) is used in cancer therapy as well as in the treatment of autoimmune diseases and alloimmune responses after transplantation. It depletes the disease-causing B cells by binding to the CD (cluster of differentiation) 20 antigen. We evaluate different pediatric treatment protocols (via fixed treatment schedule, B cell- or symptom-controlled) and their therapeutic effects. Methods: Demographic information, clinical and laboratory characteristics, and special laboratory values such as immunoglobulin G (IgG), CD19 positive B cells and Epstein-Barr viral load were retrospectively analyzed in children treated with RTX between 2008 and 2016. Results: Seventy-six patients aged 1 to 19 (median 13) years were treated with 259 RTX infusions. The spectrum of diseases was very heterogeneous. RTX led to a complete depletion of the B cells. The reconstitution time varied between patients and was dependent on the application schedule (median 11.8 months). Fourteen out of 27 (52%) patients developed hypogammaglobulinaemia. The risk of IgG deficiency was 2.6 times higher in children under 4 years of age than in olderones. In the last group IgG deficiency developed in only 38% of the cases (n = 8). Recurrent and severe infections were observed each in 11/72 (15%) patients. Treatment-related reactions occurred in 24/76 (32%) cases; however, treatment had to be discontinued in only 1 case. In 16/25 (76%), the Epstein-Barr viral load dropped below the detection limit after the first RTX infusion. Conclusion: RTX is an effective and well-tolerated drug for the treatment of oncological diseases as well as autoimmune and alloimmune conditions in children. B cell depletion and reconstitution varies both intra- und interindividually, suggesting that symptom-oriented and B cell-controlled therapy may be favorable. Treatment-related reactions, IgG deficiency and infections must be taken into account.