Safety, efficacy, and immune reconstitution after rituximab therapy in pediatric patients with chronic or refractory hematologic autoimmune cytopenias

Autoimmune Hemolytic Anemia in Children: Clinical Profile and Outcome

OBJECTIVE

To discover the common triggers for AIHA in children, their clinical profile, treatment response, and outcome.

METHODS

This was an ambispective descriptive study conducted between 2013 and 2020. Children aged 1 mo to 14 y with hemolytic anemia and a positive direct antiglobulin test (DAT) were included. Children with a positive DAT but without any clinicolaboratory evidence of hemolysis were excluded. Data were collected from a structured pro forma with particulars comprising clinicolaboratory profile, treatment administered, and disease outcome.

RESULTS

A total of 46 children (aged between 1 mo and 14 y) were enrolled in the study. The mean age of onset was 8.7 (± 4.34) y, and 24 (52.8%) were males. Secondary causes were observed in 29 (63%) cases, while the primary cause was found in 17 (37%). Systemic lupus erythematosus (SLE) was the common trigger in 13 (45%) cases, followed by malignancy in 4 (14%) cases. Pallor (98%), hepatomegaly (72%), and splenomegaly (48%) were the most commonly observed clinical signs. The mixed immunophenotype was observed in 27 (59%) cases, followed by warm type in 12 (26%) and cold agglutinin type in 7 (15%) cases. All children received glucocorticoid therapy, and mycophenolate mofetil was commonly used as second-line therapy in 15 (33%) cases. 13 cases (71%) of primary AIHA and only 4 (14%) cases of secondary anemia achieved complete remission. Overall, 7 children (15%) died, all belonging to secondary AIHA.

CONCLUSION

Secondary AIHA was more common than primary in the present study, and SLE was the standard trigger. Primary AIHA carries a better prognosis than secondary.

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.

Pediatric refractory immune thrombocytopenia: A systematic review

Pediatric immune thrombocytopenia (ITP) is an acquired disorder associated with autoimmune destruction and impairment of platelet production in children. Some children exhibit poor or transient response to ITP-directed treatments and are referred to as having refractory ITP (rITP). There is currently no consensus on the definition of rITP, nor evidence-based treatment guidelines for patients with rITP. After a survey of pediatric ITP experts demonstrated lack of consensus on pediatric rITP, we pursued a systematic review to examine the reported clinical phenotypes and treatment outcomes in pediatric rITP. The search identified 253 relevant manuscripts; following review, 11 studies proposed a definition for pediatric rITP with no consensus amongst them. Most definitions included suboptimal response to medical management, while some outlined specific platelet thresholds to define this suboptimal response. Common attributes identified in this study should be used to propose a comprehensive definition, which will facilitate outcome comparisons of future rITP studies.

Systemic loxoscelism induced warm autoimmune hemolytic anemia: clinical series and review

OBJECTIVES

Describe the development of warm autoimmune hemolytic anemia warm (AIHA) secondary to a brown recluse spider (Loxosceles reclusa) bite is known as systemic loxoscelism; and review epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism.

METHODS

Cases series of two cases of warm AIHA due to systemic loxoscelism and a review of the current literature: epidemiology, clinical manifestations, diagnostic work-up, pathophysiology, and treatment options associated with warm AIHA secondary to systemic loxoscelism.

RESULTS

Presented here are two cases of warm AIHA due to systemic loxoscelism. Each patient was generally healthy appearing and presented with symptomatic anemia in the setting of brown recluse spider bites. Both patients were eventually found to have warm AIHA. Upon recognition of the diagnosis, the patients were started on corticosteroids and aggressive intravenous fluid hydration. In addition, they received transfusions of packed red blood cells. Their clinical courses improved, and they recovered to eventually be discharged home.

CONCLUSION

Envenomation by a brown recluse spider, Loxosceles reclusa, can result in systemic loxoscelism which can cause warm AIHA. The diagnosis of warm AIHA is confirmed by the direct antiglobulin/Coomb's test. Warm AIHA can be a life-threatening disease process. Hemodynamic support with intravenous fluids and RBC transfusion is the initial step in the management of these patients. Corticosteroids are the mainstay of current management. Second line treatments include rituximab. Rarely patients require splenectomy for refractory disease. Corticosteroids should be tapered over a three-month period.

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.

Management of Chronic Graft-vs.-Host Disease in Children and Adolescents With ALL: Present Status and Model for a Personalised Management Plan

Herein we review current practice regarding the management of chronic graft-vs.-host disease (cGvHD) in paediatric patients after allogeneic haematopoietic stem cell transplantation (HSCT) for acute lymphoblastic leukaemia (ALL). Topics covered include: (i) the epidemiology of cGvHD; (ii) an overview of advances in our understanding cGvHD pathogenesis; (iii) current knowledge regarding risk factors for cGvHD and prevention strategies complemented by biomarkers; (iii) the paediatric aspects of the 2014 National Institutes for Health-defined diagnosis and grading of cGvHD; and (iv) current options for cGvHD treatment. We cover topical therapy and newly approved tyrosine kinase inhibitors, emphasising the use of immunomodulatory approaches in the context of the delicate counterbalance between immunosuppression and immune reconstitution as well as risks of relapse and infectious complications. We examine real-world approaches of response assessment and tapering schedules of treatment. Furthermore, we report on the optimal timepoints for therapeutic interventions and changes in relation to immune reconstitution and risk of relapse/infection. Additionally, we review the different options for anti-infectious prophylaxis. Finally, we put forth a theory of a holistic view of paediatric cGvHD and its associated manifestations and propose a checklist for individualised risk evaluation with aggregated considerations including site-specific cGvHD evaluation with attention to each individual's GvHD history, previous medical history, comorbidities, and personal tolerance and psychosocial circumstances. To complement this checklist, we present a treatment algorithm using representative patients to inform the personalised management plans for patients with cGvHD after HSCT for ALL who are at high risk of relapse.

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.

New-onset Hypogammaglobulinemia and Infectious Complications Associated with Rituximab Use in Childhood-onset Rheumatic Diseases

OBJECTIVE

To investigate the incidence and risk factors for hypogammaglobulinemia and infectious complications associated with rituximab treatment in childhood-onset rheumatic diseases.

METHODS

We performed a single-center retrospective study of patients (n = 85) treated at Boston Children's Hospital (BCH) from 2009 to 2019. Study subjects included patients (ages 6 to 24) who received rituximab for the treatment of a childhood-onset rheumatic disease.

RESULTS

New-onset hypogammaglobulinemia developed in 23 (27.1%) patients within 18 months of rituximab induction treatment. 22 patients (25.9%) developed at least one infectious complication in the 18 months following the first rituximab infusion; of these, 11 (50%) had serious infections requiring inpatient treatment. After adjusting for potential confounders, exposure to pulse corticosteroid therapy in the month prior to rituximab use was a significant predictor of both new-onset hypogammaglobulinemia (OR 3.94; 95% CI 1.07-16.0; p = 0.044) and infectious complications (OR 15.3; 95% CI 3.04-126.8; p = 0.003). Post-rituximab hypogammaglobulinemia was the strongest predictor of serious infectious complications (OR 7.89; 95% CI 1.41-65.6; p = 0.028). Younger age at rituximab use was also a significant predictor of new-onset hypogammaglobulinemia (OR 0.83; 95% CI 0.70-0.97; p = 0.021). Compared with other rheumatic diseases, patients with vasculitis had a higher likelihood of developing infectious complications, including serious infections.

CONCLUSION

Although rituximab was well tolerated in terms of infectious complications in the majority of patients with childhood-onset rheumatic diseases, a substantial proportion developed new-onset hypogammaglobulinemia and infectious complications following treatment. Our study highlights a role for heightened vigilance of rituximab-associated hypogammaglobulinemia and infections in pediatric patients with rheumatic conditions.

Rituximab-induced hypogammaglobulinemia and infection risk in pediatric patients

BACKGROUND

Rituximab is a B-cell depleting agent used in B-cell malignancies and autoimmune diseases. A subset of adult patients may develop prolonged and symptomatic hypogammaglobulinemia following rituximab treatment. However, this phenomenon has not been well delineated in the pediatric population.

OBJECTIVES

This study sought to determine the prevalence, risk factors, and clinical significance of hypogammaglobulinemia following rituximab therapy in children.

METHODS

This was a multicenter, retrospective cohort study that extracted clinical and immunological data from pediatric patients who received rituximab.

RESULTS

The cohort comprised 207 patients (median age, 12.0 years). Compared to baseline values, there was a significant increase in hypogammaglobulinemia post-rituximab therapy, with an increase in prevalence of hypo-IgG (28.7%-42.6%; P = .009), hypo-IgA (11.1%-20.4%; P = .02), and hypo-IgM (20.0%-62.0%; P < .0001). Additionally, low IgG levels at any time post-rituximab therapy were associated with a higher risk of serious infections (34.4% vs 18.9%; odds ratio, 2.3; 95% CI, 1.1-4.8; P = .03). Persistent IgG hypogammaglobulinemia was observed in 27 of 101 evaluable patients (26.7%). Significant risk factors for persistent IgG hypogammaglobulinemia included low IgG and IgA levels pre-rituximab therapy. Nine patients (4.3%) within the study were subsequently diagnosed with a primary immunodeficiency, 7 of which received rituximab for autoimmune cytopenias.

CONCLUSIONS

Hypogammaglobulinemia post-rituximab treatment is frequently diagnosed within the pediatric population. Low IgG levels are associated with a significant increase in serious infections, and underlying primary immunodeficiencies are relatively common in children receiving rituximab, thus highlighting the importance of immunologic monitoring both before and after rituximab therapy.

Benefits of Prophylactic Short-Course Immune Tolerance Induction in Patients With Infantile Pompe Disease: Demonstration of Long-Term Safety and Efficacy in an Expanded Cohort

Immune tolerance induction (ITI) with a short-course of rituximab, methotrexate, and/or IVIG in the enzyme replacement therapy (ERT)-naïve setting has prolonged survival and improved clinical outcomes in patients with infantile Pompe disease (IPD) lacking endogenous acid-alpha glucosidase (GAA), known as cross-reactive immunologic material (CRIM)-negative. In the context of cancer therapy, rituximab administration results in sustained B-cell depletion in 83% of patients for up to 26–39 weeks with B-cell reconstitution beginning at approximately 26 weeks post-treatment. The impact of rituximab on serum immunoglobulin levels is not well studied, available data suggest that rituximab can cause persistently low immunoglobulin levels and adversely impact vaccine responses. Data on a cohort of IPD patients who received a short-course of ITI with rituximab, methotrexate, and IVIG in the ERT-naïve setting and had ≥6 months of follow-up were retrospectively studied. B-cell quantitation, ANC, AST, ALT, immunization history, and vaccine titers after B-cell reconstitution were reviewed. Data were collected for 34 IPD patients (25 CRIM-negative and 9 CRIM-positive) with a median age at ERT initiation of 3.5 months (0.1–11.0 months). B-cell reconstitution, as measured by normalization of CD19%, was seen in all patients (n = 33) at a median time of 17 weeks range (11–55 weeks) post-rituximab. All maintained normal CD19% with the longest follow-up being 248 weeks post-rituximab. 30/34 (88%) maintained negative/low anti-rhGAA antibody titers, even with complete B-cell reconstitution. Infections during immunosuppression were reported in five CRIM-negative IPD patients, all resolved satisfactorily on antibiotics. There were no serious sequelae or deaths. Of the 31 evaluable patients, 27 were up to date on age-appropriate immunizations. Vaccine titers were available for 12 patients after B-cell reconstitution and adequate humoral response was observed in all except an inadequate response to the Pneumococcal vaccine (n = 2). These data show the benefits of short-course prophylactic ITI in IPD both in terms of safety and efficacy. Data presented here are from the youngest cohort of patients treated with rituximab and expands the evidence of its safety in the pediatric population.

Single-cycle rituximab-induced immunologic changes in children: Enhanced in neuroimmunologic disease?

OBJECTIVE

To investigate the immunologic impact of a single cycle of rituximab (RTX) in children and adolescents with immune-mediated disorders, we evaluated B cells and immunoglobulin levels of 20 patients with neuroimmunologic, nephrologic, dermatologic, and rheumatologic disorders treated under recommended guidelines.

METHODS

Retrospective study of immunologic changes in children (aged ≤18 years) diagnosed with immune-mediated disorders in which RTX was prescribed between June 2014 and February 2019. Patients were excluded if they had prior diagnosis of malignant disease or primary immunodeficiency. Patients were clinically and immunologically followed up every 3 months. Only patients having received a single cycle of RTX and with a follow-up greater than 12 months were included in the analysis of persistent dysgammaglobulinemia.

RESULTS

Twenty children were included. Median age at RTX treatment was 12.8 years (interquartile range [IQR] 6.6-15.5 years). Median follow-up was 12.6 months (IQR 10.2-24 months). Of the 14 patients eligible for persistent dysgammaglobulinemia analysis (3 had received RTX retreatment, 2 had <12 months post-RTX follow-up, and in 1 data for this time point was missing), 2/14 (14%) remained with complete B-cell depletion, and 5/14 (36%) had dysgammaglobulinemia. Patients with dysgammaglobulinemia were younger (7.8 vs 15.6 years, p = 0.072), had more underlying neuroimmunologic diseases (5/5 vs 0/9, p < 0.001), and had received more frequently concentrated doses of RTX (3/5 vs 1/9, p = 0.05) than patients without dysgammaglobulinemia. Kinetics of immunoglobulins in the 20 patients revealed a decrease as early as 3 months after RTX in patients with neuroimmunologic disorders.

CONCLUSION

In our cohort, single-cycle RTX-induced dysgammaglobulinemia was enhanced in patients with neuroimmunologic diseases. Further studies are needed to confirm this observation.

Rituximab Unveils Hypogammaglobulinemia and Immunodeficiency in Children with Autoimmune Cytopenia

BACKGROUND

Rituximab (RTX; anti-CD20 mAb) is a treatment option in children with refractory immune thrombocytopenia, autoimmune hemolytic anemia (AHA), and Evans syndrome (ES). Prevalence and clinical course of RTX-induced hypogammaglobulinemia in these patients are poorly known.

OBJECTIVE

To evaluate the prevalence and risk factors for persistent hypogammaglobulinemia (PH) after RTX use.

METHODS

Clinical and immunologic data from children treated with RTX for immune thrombocytopenia, AHA, and ES were collected from 16 Italian centers and 1 UK center at pre-RTX time point (0), +6 months, and yearly, up to 4 years post-RTX. Patients with previously diagnosed malignancy or primary immune deficiency (PID) were excluded.

RESULTS

We analyzed 53 children treated with RTX for immune thrombocytopenia (n = 36), AHA (n = 13), and ES (n = 4). Median follow-up was 30 months (range, 12-48). Thirty-two percent of patients (17 of 53) experienced PH, defined as IgG levels less than 2 SD for age at last follow-up (>12 months after RTX). Significantly delayed B-cell recovery was observed in children experiencing PH (hazard ratio, 0.55; P < .05), and 6 of 17 (35%) patients had unresolved B-cell lymphopenia at last follow-up. PH was associated with IgA and IgM deficiency, younger age at RTX use (51 vs 116 months; P < .01), a diagnosis of AHA/ES, and better response to RTX. Nine patients with PH (9 of 17 [53%]) were eventually diagnosed with a PID.

CONCLUSIONS

Post-RTX PH is a frequent condition in children with autoimmune cytopenia; a sizable proportion of patients with post-RTX PH were eventually diagnosed with a PID. In-depth investigation for PID is therefore recommended in these patients.

Primary and Secondary Immune Cytopenias: Evaluation and Treatment Approach in Children

This review summarizes the evaluation and management of the autoimmune cytopenias, a heterogeneous group of conditions including, but not limited to, autoimmune hemolytic anemia, immune thrombocytopenia, and multilineage disorders in Evans syndrome. These diseases can be challenging to treat and there are limited data comparing second-line therapeutics. The understanding of the molecular cause of these conditions is improving with the goal of advancing therapies and making them more targeted.

Recommendations on RBC Transfusion Support in Children With Hematologic and Oncologic Diagnoses From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative

OBJECTIVES

To present the recommendations and supporting evidence for RBC transfusions in critically ill children with hematologic and oncologic disease from the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

DESIGN

Consensus conference series of international, multidisciplinary experts in RBC transfusion management of critically ill children.

METHODS

The panel of 38 experts developed evidence-based and, when evidence was lacking, expert-based clinical recommendations and research priorities for RBC transfusions in critically ill children. The hematologic/oncologic subgroup included seven experts. Electronic searches were conducted using PubMed, EMBASE, and Cochrane Library databases from 1980 to May 2017. Agreement was obtained using the Research and Development/UCLA Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method.

RESULTS

The hematologic/oncologic subgroup developed 14 recommendations (seven clinical, seven research); all achieved greater than 80% agreement. In patients with sickle cell disease, Transfusion and Anemia Expertise Initiative recommends: 1) RBC transfusion to achieve a target hemoglobin concentration of 10 g/dL rather than hemoglobin of less than 30% prior to surgical procedures requiring general anesthesia and 2) exchange transfusion over simple (nonexchange) transfusion if the child's condition is deteriorating (based on clinical judgment), otherwise a simple, nonexchange RBC transfusion is recommended. There is insufficient evidence to make recommendations on transfusion thresholds for patients with sickle cell disease prior to minor procedures, with acute stroke or with pulmonary hypertension. For patients with oncologic disease or undergoing hematopoietic stem cell transplant, a hemoglobin concentration of 7-8 g/dL is recommended. Due to lack of evidence, research is needed to clarify the appropriate transfusion thresholds in these patients.

CONCLUSIONS

Transfusion and Anemia Expertise Initiative developed specific pediatric recommendations regarding RBC transfusion management in critically ill children with sickle cell disease, oncologic disease, and hematopoietic stem cell transplant and recommendations to help guide future research priorities.

Anti-CD20 Treatment of Autoimmune Hemolytic Anemia Refractory to Corticosteroids and Azathioprine: A Pediatric Case Report and Mini Review

Autoimmune hemolytic anemia (AIHA) is a relatively uncommon hematological entity in children and sometimes is characterized by a severe course requiring more than one line course therapy. Treatment decisions depend on the severity and chronicity of the anemia and the characteristics of the autoantibodies. Immunosuppression with corticosteroids is the first-line treatment, especially in warm-reactive AIHA. Refractory cases are treated with immunosuppressive drugs, cytotoxic agents, androgens, or splenectomy, with various side effects and questionable efficacy. Another second-line option is rituximab, an anti-CD20 monoclonal antibody, which has been used as an off-label agent with encouraging results from small limited studies or case reports. Herein, we add our experience on the safety and clinical efficacy of rituximab by presenting the case of a boy with warm-type AIHA resistant to corticosteroids and azathioprine, successfully treated with rituximab. We also offer a review of the relevant literature.

Natural History, Pathogenesis, and Treatment of Evans Syndrome in Children

Primary Evans syndrome (ES) is defined by the concurrent or sequential occurrence of immune thrombocytopenia and autoimmune hemolytic anemia in the absence of an underlying etiology. The syndrome is characterized by a chronic, relapsing, and potentially fatal course requiring long-term immunosuppressive therapy. Treatment of ES is hardly evidence-based. Corticosteroids are the mainstay of therapy. Rituximab has emerged as the most widely used second-line treatment, as it can safely achieve high response rates and postpone splenectomy. An increasing number of new genetic defects involving critical pathways of immune regulation identify specific disorders, which explain cases of ES previously reported as "idiopathic".

Benefits of rituximab as a second-line treatment for autoimmune haemolytic anaemia in children: a prospective French cohort study

Childhood autoimmune haemolytic anaemia (AIHA) requires second-line immunosuppressive therapy in 30-50% of cases. It appears that rituximab is indicated in such circumstances. This prospective national study reports the practice, efficacy and tolerance of rituximab in children with isolated AIHA and AIHA in the setting of Evans syndrome (ES). Sixty-one children were given rituximab between 2000 and 2014. The median interval from diagnosis to rituximab was 9·9 [interquartile range (IQR) 1·6-28·5] months. Forty-six patients responded (75%) and the 6-year relapse-free survival (RFS) was 48%. Twenty patients relapsed at a median interval of 10·8 (IQR 3·9-18·7) months, rituximab allowed steroid withdrawal in 44/61 (72%) of children. In isolated AIHA, complete response and 6-year RFS were significantly higher than in ES (P < 0·05). Ten out of 61 patients were infants, seven of who responded with a 6-year RFS of 71%. Among patients without immunoglobulin substitution before rituximab, 4 are still receiving substitutions. Five patients died, including one potentially attributable to rituximab. This large observational series of childhood AIHA established the rituximab benefit-risk ratio, allowing steroid withdrawal, with 37% of long-term responders, mainly in isolated AIHA. All subgroups of patients drew benefit. Our long-term results indicate the baseline to be challenged by new treatment approaches.

A novel immunomodulatory treatment involving mycophenolate mofetil and corticosteroids for pediatric autoimmune cytopenias

BACKGROUND

Successful treatment of both pediatric autoimmune hemolytic anemia (AIHA) and immune thrombocytopenic purpura (ITP), specifically those that are refractory to first-line therapies, remains unsatisfactory in terms of long-term remission and medication side effects. Here, we propose a novel combination therapy of mycophenolate mofetil (MMF), an adjunct immunosuppressive, and short-term corticosteroids for the treatment of persistent or chronic autoimmune cytopenias in children. This combination may allow for rapid decrease of steroid usage as well as prolonged count stabilization with minimal toxicity to the patient.

PROCEDURE

Prospective case series of nine patients, six with persistent or chronic ITP and three with persistent or chronic AIHA, between the ages of 5 and 19 years who are being treated with combination therapy consisting of corticosteroids and MMF.

RESULTS

All patients with ITP (Patients 4-9) and AIHA (Patients 1-3) met complete response (CR) criteria, as they all initially achieved platelet counts 100 × 10⁹ l^-1 or more or hemoglobin level greater than or equal to 10 g/dl, respectively, while on combination therapy and then maintained this level or higher while on MMF alone after steroids were discontinued.

CONCLUSIONS

Our results are very promising, as MMF appears to be an effective and well-tolerated adjunct immunosuppressant that allows for rapid weaning of steroid usage, minimal adverse side effects to the patients, and long-term stabilization of counts, a goal that has not been achieved successfully with other secondary treatment modalities. Therefore, this novel combination therapy may be an excellent alternative for the treatment of persistent or chronic autoimmune cytopenias in the pediatric population.

The Centenary of Immune Thrombocytopenia-Part 2: Revising Diagnostic and Therapeutic Approach

Primary immune thrombocytopenia (ITP) is the most common cause of thrombocytopenia in children and adolescents and can be considered as a paradigmatic model of autoimmune disease. This second part of our review describes the clinical presentation of ITP, the diagnostic approach and overviews the current therapeutic strategies. Interestingly, it suggests an algorithm useful for differential diagnosis, a crucial process to exclude secondary forms of immune thrombocytopenia (IT) and non-immune thrombocytopenia (non-IT), which require a different therapeutic management. Advances in understanding the pathogenesis led to new therapeutic targets, as thrombopoietin receptor agonists, whose role in treatment of ITP will be discussed in this work.

Influence of R-CHOP Therapy on Immune System Restoration in Patients with B-Cell Lymphoma

OBJECTIVE

To assess the immunosuppressive effect of R-CHOP in patients with B-cell lymphoma at 2 years.

METHODS

Parameters of humoral and cell-mediated immunity were assessed in 89 patients with diffuse large B-cell lymphoma or follicular lymphoma before and after 6-8 cycles of R-CHOP-14 or R-CHOP-21 regimen.

RESULTS

Data on pre- and posttreatment serum IgG (sIgG) levels were available for all 89 patients, while the corresponding data on serum CD20+, CD3+, CD4+, and CD8+ lymphocyte counts were available in only 43. Median sIgG levels significantly decreased from 1,221 mg/dl (baseline) to 733 mg/dl (after chemotherapy) (p < 0.001). Although CD20+ and CD4+ cell counts decreased (p < 0.001), no significant effect of chemotherapy on CD3+ and CD8+ cell counts was observed. CD20+ cell counts were restored to baseline levels at the 12-month follow-up. sIgG levels and CD4+ cell counts were not completely restored at 24 months, indicating a sustained immunosuppressive effect of R-CHOP in these patients. The incidence of infections over the 2-year period was 16.3-23.6%.

CONCLUSION

The immunosuppressive effect of R-CHOP in newly diagnosed cases of B-cell lymphoma tends to persist for >2 years, although sIgG levels were restored more quickly than CD4+ cell counts.

Optimal Management of Autoimmune Lymphoproliferative Syndrome in Children

Autoimmune lymphoproliferative syndrome (ALPS) is a disorder of abnormal lymphocyte homeostasis, resulting from mutations in the Fas apoptotic pathway. Clinical manifestations include noninfectious and nonmalignant lymphadenopathy, splenomegaly, and autoimmune pathology-most commonly, autoimmune cytopenias. Rarely, and in association with specific genetic mutations, patients with ALPS may go on to develop secondary lymphoid malignancies. Though ALPS is a rare disorder, it should be suspected and ruled out in children presenting with chronic and refractory multilineage cytopenias associated with nonmalignant lymphoproliferation. Revised diagnostic criteria and insights into disease biology have improved both diagnosis and treatment. Sirolimus and mycophenolate mofetil are the best-studied and most effective corticosteroid-sparing therapies for ALPS, and they should be considered first-line therapy for patients who need chronic treatment. This review highlights practical clinical considerations for diagnosis and management of ALPS.

Rituximab and protection from vaccine preventable diseases: applying the evidence to pediatric patients

INTRODUCTION

This article analyses and highlights the challenge of immunization and preventing vaccine preventable diseases in pediatric patients on rituximab. Rituximab is a chimeric anti-CD 20 monoclonal antibody that is an immunosuppressant affecting both cellular and humoral immunity. Children and adolescents on rituximab are at increased risk of infection and vaccine preventable diseases, and require additional strategies to optimize and maximize their protection against such illnesses. Areas covered: This article provides a comprehensive MEDLINE and Pubmed review of existing literature regarding vaccine immunogenicity and safety in patients on rituximab, and assists in providing an evidence base to develop immunization guidelines. Of particular note, the use of live-attenuated vaccines and optimum timing of vaccines post rituximab is considered and discussed. Expert commentary: The increasing use of rituximab in a variety of novel areas within pediatrics must be accompanied by informed discussion around mitigating the risks. These include immunosuppression, and potential susceptibility to infection. Optimizing vaccine status by establishing adequate antibody titers prior to commencement remains the best preventative strategy.

Rituximab salvage therapy in adults with immune thrombocytopenia: retrospective study on efficacy and safety profiles

Splenectomy remains the preferred treatment for chronic immune thrombocytopenia (ITP) after corticosteroid failure, despite the risks of despite surgical complications and infection. The aim of this study was to assess the efficacy of and tolerance to rituximab through a retrospective analysis of 35 refractory/relapsing ITP patients treated from 2004 to 2013. The median age of subjects was 46 years (14-80). Rituximab was given at a weekly dose of 375 mg/m(2) for 4 weeks. Median time from diagnosis to first infusion was 17 months (1-362) and follow-up was 47 months (2-133). The overall response rates at 1 and 2 years after the first infusion were 47 and 38 %, with complete response rates of 24 and 25 %, respectively. Median duration of response was 38 months (1-123), with 37 % of patients maintaining a durable response (>1 year). Twenty-nine percent of patients had undergone splenectomy. A durable response after rituximab was more frequently observed in patients undergoing second-line therapy than those in third or later (83 versus 35 %, P = 0.01). Forty-four percent of patients experienced mild hypogammaglobulinaemia after rituximab, and no clinical infection occurred. To conclude, rituximab should be considered as an alternative treatment to splenectomy. Its efficacy and safety profile should lead us to choose this medical option therapy before surgery for ITP patients.

Evans Syndrome Secondary to Common Variable Immune Deficiency

Evans syndrome is an underdiagnosed condition consisting of simultaneous or sequential combination of autoimmune hemolytic anemia and immune-mediated thrombocytopenia. We report a case of severe Evans syndrome presenting as altered mental status, a rare presenting sign of the disease. This case highlights the difficulty in diagnosing Evans syndrome and provides a review of the literature and management strategies for treating the disorder.

Rituximab is an effective and safe treatment of relapse in elderly patients with resistant warm AIHA

We evaluated the efficacy and safety of rituximab for the treatment of 23 elderly patients (median age 78 years) with warm autoimmune haemolytic anaemia (AIHA). The median follow-up was 31 months. Patients had received one to five previous treatments. Rituximab was administered by intravenous infusion at a dose of 375 mg/m(2) once weekly for 4 weeks. The OR rate was 86.9 % (CR = 39.1 %, PR = 47.8 %). Median OS was 87 months. The median OS of patients who reached CR could not be calculated, and that of patients with PR was 67 months. At last follow-up, eight of the 20 responding patients, including one patient in CR and seven in PR, had relapsed after a median of 6 months. Failure to achieve CR was a risk factor for relapse (p = 0.028). We did not identify any pretreatment characteristics predictive of response to rituximab. In conclusion, rituximab is an effective treatment for elderly patients with refractory warm AIHA.

Treatment of autoimmune hemolytic anemias

Autoimmune hemolytic anemia (AIHA) is a relatively uncommon disorder caused by autoantibodies directed against self red blood cells. It can be idiopathic or secondary, and classified as warm, cold (cold hemagglutinin disease (CAD) and paroxysmal cold hemoglobinuria) or mixed, according to the thermal range of the autoantibody. AIHA may develop gradually, or have a fulminant onset with life-threatening anemia. The treatment of AIHA is still not evidence-based. The first-line therapy for warm AIHA are corticosteroids, which are effective in 70-85% of patients and should be slowly tapered over a time period of 6-12 months. For refractory/relapsed cases, the current sequence of second-line therapy is splenectomy (effective approx. in 2 out of 3 cases but with a presumed cure rate of up to 20%), rituximab (effective in approx. 80-90% of cases), and thereafter any of the immunosuppressive drugs (azathioprine, cyclophosphamide, cyclosporin, mycophenolate mofetil). Additional therapies are intravenous immunoglobulins, danazol, plasma-exchange, and alemtuzumab and high-dose cyclophosphamide as last resort option. As the experience with rituximab evolves, it is likely that this drug will be located at an earlier point in therapy of warm AIHA, before more toxic immunosuppressants, and in place of splenectomy in some cases. In CAD, rituximab is now recommended as first-line treatment.

Immunreconstitution and infectious complications after rituximab treatment in children and adolescents: what do we know and what can we learn from adults?

Rituximab, an anti CD20 monoclonal antibody, is widely used in the treatment of B-cell malignancies in adults and increasingly in pediatric patients. By depleting B-cells, rituximab interferes with humoral immunity. This review provides a comprehensive overview of immune reconstitution and infectious complications after rituximab treatment in children and adolescents. Immune reconstitution starts usually after six months with recovery to normal between nine to twelve months. Extended rituximab treatment results in a prolonged recovery of B-cells without an increase of clinically relevant infections. The kinetic of B-cell recovery is influenced by the concomitant chemotherapy and the underlying disease. Intensive B-NHL treatment such as high-dose chemotherapy followed by rituximab bears a risk for prolonged hypogammaglobulinemia. Overall transient alteration of immune reconstitution and infections after rituximab treatment are acceptable for children and adolescent without significant differences compared to adults. However, age related disparities in the kinetic of immune reconstitution and the definitive role of rituximab in the treatment for children and adolescents with B-cell malignancies need to be evaluated in prospective controlled clinical trials.

Diagnostic and therapeutic challenges of primary autoimmune haemolytic anaemia in children

Autoimmune haemolytic anaemias (AIHAs) are extracorpuscular haemolytic anaemias produced by antierythrocyte autoantibodies which cause a shortened red blood cell life span. There are several reasons why the diagnosis and treatment of AIHAs in children represent a bigger challenge than in adult patients, including the presence of particular AIHA types, the uncertainty of serological tests and the limited clinical experience. All these facts have added up to a poor understanding and management of some topics in childhood AIHA. We discuss some of these questions, for example, the occurrence of AIHA with negative direct antiglobulin (Coombs) test, the correct diagnosis and actual incidence of paroxysmal cold haemoglobinuria, the most appropriate second-line therapy of AIHA in childhood or the management of transfusion procedures in these patients. This review takes a practical point of view, providing with some ground rules on how to identify and deal with these paediatric patients.

Long-term follow-up of children with refractory immune thrombocytopenia treated with rituximab

Data on long-term outcomes of children with refractory immune thrombocytopenia (ITP) treated with rituximab are limited. We retrospectively analyzed the long-term effect of rituximab on 22 pediatric ITP patients (11 boys and 11 girls). Compete response (CR) (platelet count ≥100 × 10(9)/L) and partial response (PR) (platelet count 30-99 × 10(9)/L) were achieved in nine (41 %) and two (9 %) patients, respectively. Of the 11 responders, eight subsequently relapsed 2-26 months after initial rituximab treatment. The 5-year relapse-free rate was 14 % (3/22, 95 % confidence interval: 0-27 %) with a median follow-up period of 6.4 years. Five initial responders with subsequent relapse and one non-responder received multiple rituximab treatments of nine courses; all patients responded to the second rituximab therapy without any significant toxicity. All eight patients who relapsed after an initial response and six of 11 non-responders achieved CR or PR with subsequent treatment, including repeated courses of rituximab, splenectomy, steroids, and other immunomodulating agents. Our findings indicated that the sustained effect of rituximab on children with refractory ITP is low, but that the long-term outcome of ITP itself is not poor. Furthermore, repeated rituximab administration may be a promising therapy for those who relapse after an initial response.

B-Cell Targeted Therapies in Autoimmune Cytopenias and Thrombosis

Ever since the advent of Rituximab and subsequently the emergence of other compounds targeting B cells, a cornucopia of medical applications have been found for this family of compounds. After their establishment as standard of care in many conditions such as rituximab in lymphoma and rheumatoid arthritis, they have been progressively found to aid in the treatment of many other conditions. This area constituted a fertile area of research in the past 12 years. Physicians have investigated the B-cell depleting agents use in cases of autoimmune hematologic cytopenias such as immune thrombocytopenia, Evans syndrome, cold and warm autoimmune hemolytic anemia, and other thrombophilic disorders such as the antiphospholipid syndrome and thrombocytopenic purpura. This chapter presents a historical perspective reviewing the various studies that have been published in this field. In addition, it offers a current assessment of the evidence regarding the use of B-cell depleting agents in the aforementioned conditions.

Diagnosis and management of autoimmune cytopenias in childhood

The diagnosis and management of children with autoimmune cytopenias can be challenging. Children can present with immune-mediated destruction of a single-cell lineage or multiple cell lineages, including platelets (immune thrombocytopenia [ITP]), erythrocytes (autoimmune hemolytic anemia), and neutrophils (autoimmune neutropenia). Immune-mediated destruction can be primary or secondary to a comorbid immunodeficiency, malignancy, rheumatologic condition, or lymphoproliferative disorder. Treatment options generally consist of nonspecific immune suppression or modulation. This nonspecific approach is changing as recent insights into disease biology have led to targeted therapies, including the use of thrombopoietin mimetics in ITP and sirolimus for cytopenias associated with autoimmune lymphoproliferative syndrome.

Transient effect of anti-CD20 therapy in a child with 22q11.2 deletion syndrome and severe steroid refractory cytopenias: a case report

We report on the development of steroid-refractory recurrent cytopenias in a child with 22q11.2 deletion syndrome. His first hematological complication was autoimmune hemolytic anemia at 3 months of age. Thereafter, he developed severe autoimmune cytopenias of all 3 hematological lineages with poor response to steroids and intravenous immunoglobulin. At the age of 2½ years, a course of anti-CD20 therapy (Rituximab) was given with transient hematological recovery. Because of persistent symptoms, bone marrow transplantation from a matched unrelated donor was performed. Although the data in the use of anti-CD20 therapy in children with 22q11.2 deletion syndrome and autoimmune cytopenias are limited, our experience suggests its potential benefit.

Reduced antibody formation after influenza vaccination in patients with neuromyelitis optica spectrum disorder treated with rituximab

BACKGROUND AND PURPOSE

Vaccination against infection becomes important in patients with neuromyelitis optica spectrum disorder (NMOSD) because they are at an increased risk of infection due to long-term immunosuppressive therapy. However, it is unclear whether NMOSD patients under immunosuppression therapy show proper antibody formation after vaccination. Thus the antibody formation after influenza A (H1N1) vaccination in patients with NMOSD receiving rituximab was evaluated.

METHODS

The study enrolled 26 patients with NMOSD, nine with multiple sclerosis and eight healthy controls. The enrolled patients had been treated with rituximab (n = 16), mycophenolate mofetil (n = 5), azathioprine (n = 6) and interferon-β (IFN-β) (n = 8). Antibodies against the H1N1 influenza virus were measured in the serum drawn just before (T0) and between 3 and 5 weeks after (T1) vaccination. The immunization states for hepatitis B virus surface antigen, measles and tetanus during the treatment period were also tested.

RESULTS

The rituximab group showed significantly lower geometric mean titer, seroprotection rate and mean fold increase than the azathioprine group, IFN-β group and healthy controls, and a lower seroconversion rate than the IFN-β group. This decrease in vaccination efficacy was also shown in patients receiving mycophenolate mofetil. The immunization state for hepatitis B virus surface antigen, measles and tetanus remained the same during the treatment period with each drug, suggesting that these treatments do not affect previously formed immunity.

CONCLUSION

This study shows a severely hampered humoral immune response to H1N1 influenza vaccine in patients with NMOSD treated with rituximab, although the vaccination itself is safe in these patients.

Evaluation of children with chronic immune thrombocytopenic purpura and Evans syndrome treated with rituximab

The primary objective was to evaluate the response rate of rituximab therapy for children with chronic immune thrombocytopenic purpura (ITP) and Evans syndrome (ES) and immune reconstitution of these children after rituximab therapy. Eleven patients with chronic ITP and 2 with ES between 6 and 18 years of age and platelet count less than 20 × 10(9)/L received rituximab. Overall response (OR) was defined as an increase in platelet count above 50 × 10(9)/L. The mean age of 13 children (9 girls, 4 boys) was 11.2 ± 3.8 years (6-18). One of the patients with ES had been splenectomized; others were not. The patients mean follow-up time was 10.3 ± 9.3 months after rituximab therapy. Two patients achieved complete response, 4 patients achieved partial response, and OR rate was 46% (6 of 13) after therapy. Seven patients have no response. In conclusion, rituximab may be considered prior to splenectomy in children with chronic ITP and ES with an acceptable toxicity profile.

Ofatumumab for a rituximab-allergic child with chronic-relapsing paraneoplastic opsoclonus-myoclonus

Ofatumumab is a fully human anti-CD20 monoclonal antibody in phase II-III trials for various autoimmune and lymphoreticular diseases. We used it to treat a rituximab-allergic child with severe, chronic-relapsing, opsoclonus-myoclonus syndrome (OMS), characterized by persistent cerebrospinal fluid (CSF) B-cell expansion and T-cell dysregulation. He had relapsed despite chemotherapy, plasma exchange with immunoadsorption, and resection of ganglioneuroblastoma, detected 3 years after OMS onset. The four ofatumumab infusions (1,195 mg/m(2) total dose) were well tolerated, and CSF B-cell expansion was eliminated. No further relapses have occurred in 3 years, but he remains on low-dose ACTH with neuropsychiatric residuals of OMS.

Rituximab in steroid refractory autoimmune hemolytic anemia

Autoimmune hemolytic anemia is rare in children and infants and steroids are the corner stone of therapy. Management of the patients with steroid refractory/dependent disease is difficult .Rituximab is being used in the treatment of a variety of autoimmune diseases including Autoimmune hemolytic anemia (AIHA),especially in adults but there is scarce data regarding the use of this agent in pediatric AIHA patients.The authors report two cases of steroid refractory AIHA, who responded to rituximab with review the literature of its use in pediatrics.

Rituximab for children with immune thrombocytopenia: a systematic review

Background

Rituximab has been widely used off-label as a second line treatment for children with immune thrombocytopenia (ITP). However, its role in the management of pediatric ITP requires clarification. To understand and interpret the available evidence, we conducted a systematic review to assess the efficacy and safety of rituximab for children with ITP.

Methodology/Principal Findings

We searched MEDLINE, EMBASE, Cochrane Library, CBM, CNKI, abstract databases of American Society of Hematology, American Society of Clinical Oncology and Pediatric Academic Society. Clinical studies published in full text or abstract only in any language that met predefined inclusion criteria were eligible. Efficacy analysis was restricted to studies enrolling 5 or more patients. Safety was evaluated from all studies that reported data of toxicity. 14 studies (323 patients) were included for efficacy assessment in children with primary ITP. The pooled complete response (platelet count ≥100×10⁹/L) and response (platelet count ≥30×10⁹/L) rate after rituximab treatment were 39% (95% CI, 30% to 49%) and 68% (95%CI, 58% to 77%), respectively, with median response duration of 12.8 month. 4 studies (29 patients) were included for efficacy assessment in children with secondary ITP. 11 (64.7%) of 17 patients associated with Evans syndrome achieved response. All 6 patients with systemic lupus erythematosus associated ITP and all 6 patients with autoimmune lymphoproliferative syndrome associated ITP achieved response. 91 patients experienced 108 adverse events associated with rituximab, among that, 91 (84.3%) were mild to moderate, and no death was reported.

Conclusions/Significance

Randomized controlled studies on effect of rituximab for children with ITP are urgently needed, although a series of uncontrolled studies found that rituximab resulted in a good platelet count response both in children with primary and children secondary ITP. Most adverse events associated with rituximab were mild to moderate, and no death was reported.

Outcomes 5 years after response to rituximab therapy in children and adults with immune thrombocytopenia

Treatments for immune thrombocytopenic purpura (ITP) providing durable platelet responses without continued dosing are limited. Whereas complete responses (CRs) to B-cell depletion in ITP usually last for 1 year in adults, partial responses (PRs) are less durable. Comparable data do not exist for children and 5-year outcomes are unavailable. Patients with ITP treated with rituximab who achieved CRs and PRs (platelets > 150 × 10(9)/L or 50-150 × 10(9)/L, respectively) were selected to be assessed for duration of their response; 72 adults whose response lasted at least 1 year and 66 children with response of any duration were included. Patients had baseline platelet counts < 30 × 10(9)/L; 95% had ITP of > 6 months in duration. Adults and children each had initial overall response rates of 57% and similar 5-year estimates of persisting response (21% and 26%, respectively). Children did not relapse after 2 years from initial treatment whereas adults did. Initial CR and prolonged B-cell depletion predicted sustained responses whereas prior splenectomy, age, sex, and duration of ITP did not. No novel or substantial long-term clinical toxicity was observed. In summary, 21% to 26% of adults and children with chronic ITP treated with standard-dose rituximab maintained a treatment-free response for at least 5 years without major toxicity. These results can inform clinical decision-making.

Maintenance rituximab in follicular non-Hodgkin lymphoma: facts and controversies

The advent of rituximab, a chimeric monoclonal antibody against CD20, has arguably improved and changed the natural history of non-Hodgkin lymphoma and has become an essential component of front-line and relapsed disease treatment strategies. Given its tolerability and long half-life, rituximab has been investigated in the maintenance setting in follicular lymphoma. Several landmark studies have demonstrated improvement in progression-free survival in patients receiving maintenance rituximab compared to those observed. These favorable results were witnessed in front-line and in the relapsed setting using a variety of induction programs such as rituximab monotherapy or chemoimmunotherapy. Importantly, toxicities were predictable and manageable. Despite these encouraging results, many vital and practical questions remain unanswered. In this review, we critically analyze the data that led to the widespread use of maintenance rituximab in follicular lymphoma and attempt to answer the most important questions facing practicing oncologists when deciding on using this approach in their patients.

Effect of rituximab on human in vivo antibody immune responses

BACKGROUND

B-lymphocyte depletion with rituximab has been shown to benefit patients with various autoimmune diseases. We have previously demonstrated that this benefit is also apparent in patients with newly diagnosed type 1 diabetes.

OBJECTIVES

The effect of rituximab on in vivo antibody responses, particularly during the period of B-lymphocyte depletion, is incompletely determined. This study was designed to assess this knowledge void.

METHODS

In patients with recent-onset type 1 diabetes treated with rituximab (n = 46) or placebo (n = 29), antibody responses to neoantigen phiX174 during B-lymphocyte depletion and with hepatitis A (as a second neoantigen) and tetanus/diphtheria (as recall antigens) after B-lymphocyte recovery were studied. Anti- tetanus, diphtheria, mumps, measles, and rubella titers were measured before and after treatment by means of ELISA. Antibody titers and percentage IgM versus percentage IgG to phiX174 were measured by means of phage neutralization. B-lymphocyte subsets were determined by means of flow cytometry.

RESULTS

No change occurred in preexisting antibody titers. Tetanus/diphtheria and hepatitis A immunization responses were protective in the rituximab-treated subjects, although significantly blunted compared with those seen in the controls subjects, when immunized at the time of B-lymphocyte recovery. Anti-phiX174 responses were severely reduced during the period of B-lymphocyte depletion, but with B-lymphocyte recovery, anti-phiX174 responses were within the normal range.

CONCLUSIONS

During the time of B-lymphocyte depletion, rituximab recipients had a decreased antibody response to neoantigens and significantly lower titers after recall immunization with diphtheria and tetanus toxoid. With recovery, immune responses return toward normal. Immunization during the time of B-lymphocyte depletion, although ineffective, does not preclude a subsequent response to the antigen.

How I treat autoimmune lymphoproliferative syndrome

Autoimmune lymphoproliferative syndrome (ALPS) represents a failure of apoptotic mechanisms to maintain lymphocyte homeostasis, permitting accumulation of lymphoid mass and persistence of autoreactive cells that often manifest in childhood with chronic nonmalignant lymphadenopathy, hepatosplenomegaly, and recurring multilineage cytopenias. Cytopenias in these patients can be the result of splenic sequestration as well as autoimmune complications manifesting as autoimmune hemolytic anemia, immune-mediated thrombocytopenia, and autoimmune neutropenia. More than 300 families with hereditary ALPS have now been described; nearly 500 patients from these families have been studied and followed worldwide over the last 20 years by our colleagues and ourselves. Some of these patients with FAS mutations affecting the intracellular portion of the FAS protein also have an increased risk of B-cell lymphoma. The best approaches to diagnosis, follow-up, and management of ALPS, its associated cytopenias, and other complications resulting from infiltrative lymphoproliferation and autoimmunity are presented.