Use and interpretation of diagnostic vaccination in primary immunodeficiency: a working group report of the Basic and Clinical Immunology Interest Section of the American Academy of Allergy, Asthma & Immunology

Clinical updates in inborn errors of immunity: a focus on the noninfectious clinical manifestations

PURPOSE OF REVIEW

In the last 5 years, several new inborn errors of immunity (IEI) have been described, especially in the areas of immune dysregulation and autoinflammation. As a result, the clinical presentation of IEIs has broadened. We review the heterogeneous presentation of IEIs and detail several of the recently described IEIs with a focus on the noninfectious manifestations commonly seen.

RECENT FINDINGS

IEIs may present with early onset and/or multiple autoimmune manifestations, increased risk for malignancy, lymphoproliferation, severe atopy, autoinflammation and/or hyperinflammation. Because of this, patients can present to a wide array of providers ranging from primary care to various pediatric subspecialists. The International Union of Immunological Societies (IUIS) expert committee has created a phenotypic classification of IEIs in order to help clinicians narrow their evaluation based on the laboratory and clinical findings.

SUMMARY

Both primary care pediatricians and pediatric subspecialists need to be aware of the common clinical features associated with IEI and recognize when to refer to allergy-immunology for further evaluation. Early diagnosis can lead to earlier treatment initiation and improve clinical outcomes for our patients.

The autoimmune rheumatological presentation of Common Variable Immunodeficiency Disorders with an overview of genetic testing

Primary immunodeficiency Disorders (PIDS) are rare, mostly monogenetic conditions which can present to a number of specialties. Although infections predominate in most PIDs, some individuals can manifest autoimmune or inflammatory sequelae as their initial clinical presentation. Identifying patients with PIDs can be challenging, as some can present later in life. This is often seen in patients with Common Variable Immunodeficiency Disorders (CVID), where symptoms can begin in the sixth or even seventh decades of life. Some patients with PIDs including CVID can initially present to rheumatologists with autoimmune musculoskeletal manifestations. It is imperative for these patients to be identified promptly as immunosuppression could lead to life-threatening opportunistic infections in these immunocompromised individuals. These risks could be mitigated by prior treatment with subcutaneous or intravenous (SCIG/IVIG) immunoglobulin replacement or prophylactic antibiotics. Importantly, many of these disorders have an underlying genetic defect. Individualized treatments may be available for the specific mutation, which may obviate or mitigate the need for hazardous broad-spectrum immunosuppression. Identification of the genetic defect has profound implications not only for the patient but also for affected family members, who may be at risk of symptomatic disease following an environmental trigger such as a viral infection. Finally, there may be clinical clues to the underlying PID, such as recurrent infections, the early presentation of severe or multiple autoimmune disorders, as well as a relevant family history. Early referral to a clinical immunologist will facilitate appropriate diagnostic evaluation and institution of treatment such as SCIG/IVIG immunoglobulin replacement. This review comprises three sections; an overview of PIDs, focusing on CVID, secondly genetic testing of PIDs and finally the clinical presentation of these disorders to rheumatologists.

Impact of steroids on the immune profiles of children with asthma living in the inner-city

Background: Inner-city asthma is associated with high morbidity and systemic steroid use. Chronic steroid use impacts immune function; however, there is a lack of data with regard to the extent of immunosuppression in patients with asthma and who are receiving frequent systemic steroids. Objective: To identify the impact of frequent systemic steroid bursts on the immune function of children with asthma who live in the inner city. Methods: Children ages 3-18 years with asthma were divided into study (≥2 systemic steroid bursts/year) and control groups (0-1 systemic steroid bursts/year). Lymphocyte subsets; mitogen proliferation assay; total immunoglobulin G (IgG) value, and pneumococcal and diphtheria/tetanus IgG values were evaluated. Results: Ninety-one participants were enrolled (study group [n = 42] and control group [n = 49]). There was no difference in adequate pneumococcal IgG value, diphtheria/tetanus IgG value, mitogen proliferation assays, lymphocyte subsets, and IgG values between the two groups. Children who received ≥2 steroid bursts/year had a significantly lower median pneumococcal IgG serotype 7F value. Most of the immune laboratory results were normal except for the pneumococcal IgG value. Most of the participants (n/N = 72/91 [79%]) had an inadequate pneumococcal IgG level (<7/14 serotypes ≥1.3 µg/mL). The participants with inadequate pneumococcal IgG level and who received a pneumococcal polysaccharide vaccine 23 (PPSV23) boost had a robust response. There was no significant difference in infection, steroid exposure, asthma severity, or morbidities between those with adequate versus inadequate pneumococcal IgG values. Conclusion: Children with asthma who live in the inner city and receive ≥2 steroid bursts/year do not have a significantly different immune profile from those who receive ≤1 steroid bursts/year do not have a significantly different immune profile from those who do not. Although appropriately vaccinated, most participants had an inadequate pneumococcal IgG level, regardless of steroid exposure and asthma severity. These children may benefit from PPSV23.

Mycophenolate mofetil hampers antibody responses to a broad range of vaccinations in kidney transplant recipients: Results from a randomized controlled study

OBJECTIVES

To study the effect of mycophenolate mofetil (MMF) on various vaccination responses in kidney transplant recipients.

METHODS

In a randomized controlled trial (EudraCT nr.: 2014-001372-66), low immunologically risk kidney transplant recipients were randomized to TAC/MMF or TAC-monotherapy (TACmono), six months post-transplantation. One year after transplantation, in a pre-specified sub-study, recipients were vaccinated against pneumococcus, tetanus and influenza. Blood was sampled before and 21 days after vaccination. Adequate vaccination responses were defined by international criteria. A post-hoc analysis was conducted on SARS-CoV-2 vaccination responses within the same cohort.

RESULTS

Seventy-one recipients received pneumococcal and tetanus vaccines (TAC/MMF: n = 37, TACmono: n = 34), with 29 also vaccinated against influenza. When vaccinated, recipients were 60 (54-66) years old, with median eGFR of 54 (44-67) ml/min, tacrolimus trough levels 6.1 (5.4-7.0) ug/L in both groups and TAC/MMF daily MMF dose of 1000 (500-2000) mg. Adequate vaccination responses were: pneumococcal (TAC/MMF 43%, TACmono 74%, p = 0.016), tetanus (TAC/MMF 35%, TACmono 82%, p < 0.0001) and influenza (TAC/MMF 20%, TACmono 71%, p = 0.0092). Only 7% of TAC/MMF responded adequately to all three compared to 36% of TACmono (p = 0.080). Additionally, 40% of TAC/MMF responded inadequately to all three, whereas all TACmono patients responded adequately to at least one vaccination (p = 0.041). Lower SARS-CoV-2 vaccination antibody responses correlated with lower pneumococcal antibody vaccination responses (correlation coefficient: 0.41, p = 0.040).

CONCLUSIONS

MMF on top of tacrolimus severely hampers antibody responses to a broad range of vaccinations.

Immunoglobulin replacement therapies in inborn errors of immunity: a review

Immunoglobulins (Ig) were used as a therapeutic modality for the first time in a patient with X-linked agammaglobulinemia in 1952 by Colonel Ogden Bruton, decades before the molecular mechanisms causing the disease were unraveled. In many autoimmune and inflammatory illnesses, human immunoglobulin has been employed as a significant immunomodulatory and immunosuppressive drug. In patients with inborn errors of immunity (IEI), immunoglobulin remains a cornerstone of management. IEIs are notable causes of recurrent infections and autoimmunity due to inheritable single-gene defects in genes encoding for different components of the immune system. As there is decreased immunoglobulin production in IEIs with antibody defects, immunoglobulin replacement is the mainstay of therapy in these disorders. Although serum immunoglobulin levels may not be low in combined immune defects, immunoglobulin replacement is still necessary in these disorders due to a deficiency of functional antibodies and qualitative defects of immunoglobulins. Commercial immunoglobulin preparations are generated from plasma donated by thousands of donors. Immunoglobulin preparations are usually available in two forms: intravenous and subcutaneous immunoglobulins. In the developed world, both intravenous immunoglobulin (IVIg) and subcutaneous immunoglobulin (SCIg) are available, and SCIg is preferred over IVIg for replacement therapy in patients with IEIs. In developing countries, IVIg remains the mainstay of replacement therapy. The rate of adverse events has significantly reduced over the last few years due to advancements in the production process. In this review article, we discuss different aspects of the use of Ig (indications, dosing, mechanism of action, route, adverse effects) in patients with IEIs.

A stepwise approach to the adult immunodeficiency evaluation for the rhinologist

PURPOSE OF REVIEW

Patients with an immunodeficiency may present to their Rhinologist with a history of recurrent, severe, and chronic infections. Therefore, it is essential for the Rhinologist to have a basic understanding of clinically relevant immune deficiencies.

RECENT FINDINGS

After describing different types of immunodeficiencies, their presentations, and management strategies, an evaluation algorithm is described.

SUMMARY

Through a collaborative approach, Rhinologists and Clinical Immunologists can provide comprehensive medical care to patients with immunodeficiencies.

Combined deficient response to polysaccharide-based and protein-based vaccines predicts a severe clinical phenotype

OBJECTIVES

Antibody response on polysaccharide- and protein-based vaccines is useful to test B cell functionality. As only few studies have explored the value of studying immune response to both vaccines, we evaluated the clinical value of anti-polysaccharide and anti-protein Luminex-based multiplex assays in context of primary immunodeficiency (PID) diagnosis.

METHODS

A 10-plex Luminex-based assay detecting antibodies to ten pneumococcal polysaccharide (PnPS) serotypes [present in unconjugated Pneumovax, not in 13-valent pneumococcal conjugated vaccine (PCV)] and a 5-plex assay detecting antibodies to five protein antigens (present in DTap/Tdap) were clinically validated in healthy individuals (n=99) and in retrospective (n=399) and prospective (n=108) patient cohorts. Clinical features of individuals with impaired response to PnPS and/or proteins were compared to those with normal response.

RESULTS

Antigen-specific antibody thresholds were determined in healthy individuals. Individuals with impaired anti-PnPS responses and deficient immunoglobulin levels suffered more from autoimmune diseases and had lower B cell levels compared to individuals with impaired anti-PnPS response with normal immunoglobulin levels. Individuals with combined impaired response to PnPS and proteins showed more severe clinical manifestations compared to individuals with isolated impaired response to PnPS or proteins. Eight of the 11 individuals with severely impaired responses to both PnPS and proteins had common variable immunodeficiency. Evaluation of the anti-PnPS response to four serotypes not contained in 20-valent PCV was comparable to evaluation to ten serotypes not contained in 13-valent PCV.

CONCLUSIONS

Multiplexed assessment of anti-PnPS and anti-protein responses combined with immunoglobulin quantification provides useful clinical information to support PID diagnosis.

Spleen function is reduced in individuals with NR5A1 variants with or without a difference of sex development: a cross-sectional study

OBJECTIVE

NR5A1 is a key regulator of sex differentiation and has been implicated in spleen development through transcription activation of TLX1. Concerns exist about hypo- or asplenism in individuals who have a difference of sex development (DSD) due to an NR5A1 disease-causing variant. We aimed to assess spleen anatomy and function in a clinical cohort of such individuals and in their asymptomatic family member carriers.

DESIGN

Cross-sectional assessment in 22 patients with a DSD or primary ovarian insufficiency and 5 asymptomatic carriers from 18 families, harboring 14 different NR5A1 variants.

METHODS

Spleen anatomy was assessed by ultrasound, spleen function by peripheral blood cell count, white blood cell differentiation, percentage of nonswitched memory B cells, specific pneumococcal antibody response, % pitted red blood cells, and Howell-Jolly bodies.

RESULTS

Patients and asymptomatic heterozygous individuals had significantly decreased nonswitched memory B cells compared to healthy controls, but higher than asplenic patients. Thrombocytosis and spleen hypoplasia were present in 50% of heterozygous individuals. Four out of 5 individuals homozygous for the previously described p.(Arg103Gln) variant had asplenia.

CONCLUSIONS

Individuals harboring a heterozygous NR5A1 variant that may cause DSD have a considerable risk for functional hyposplenism, irrespective of their gonadal phenotype. Splenic function should be assessed in these individuals, and if affected or unknown, prophylaxis is recommended to prevent invasive encapsulated bacterial infections. The splenic phenotype associated with NR5A1 variants is more severe in homozygous individuals and is, at least for the p.(Arg103Gln) variant, associated with asplenism.

Vaccine Immunity in Children After Hematologic Cancer Treatment: A Retrospective Single-center Study

BACKGROUND

Children lose their vaccine-induced protection and are particularly vulnerable to vaccine-preventable diseases after chemotherapy. However, revaccination guidelines are heterogeneous, and there is often a lack of revaccination post-treatment.

AIMS

We conducted a retrospective study of children with hematologic cancer to evaluate vaccine immunity before and after the end of treatment and to determine whether the current institutional revaccination program based on vaccine serology results was followed and effective.

MATERIALS AND METHODS

Data of all children treated by chemotherapy between April 2015 and July 2021 were extracted from hospital medical records for analysis. Serum antibody levels and time of vaccination were evaluated for diphtheria, tetanus, Streptococcus pneumoniae , Haemophilus influenzae type b (Hib), measles, varicella, and hepatitis B.

RESULTS

We included 31 patients (median age, 9 years). At cancer diagnosis, 90% of children were protected against tetanus, diphtheria, and measles; 65% to 67% were protected against pneumococcus and varicella; and 25% against hepatitis B. At the end of chemotherapy, 67% to 71% of patients were protected against tetanus, varicella, and measles; 40% remained protected against hepatitis B; and 27% to 33% against pneumococcus and diphtheria. Patients were revaccinated at various times after the end of treatment but not systematically. During the first-year post-treatment, 20% to 25% of children remained unprotected against pneumococcus, measles, and hepatitis B, one third against diphtheria, but all were protected against tetanus and varicella.

CONCLUSIONS

An effective individualized vaccination program post-cancer based on serology results should be accompanied by an appropriate serology tracking method and follow-up to assess if booster doses are necessary. Our study supports vaccinating all children with a dose of the 13-valent pneumococcal conjugate at cancer diagnosis and at 3 months post-treatment with the combined diphtheria-tetanus-acellular pertussis/poliomyelitis vaccine/hepatitis B virus plus or minus Hib and 13-valent pneumococcal conjugate and meningococcal vaccine, including measles/mumps/rubella-varicella zoster virus vaccine if good immune reconstitution is present.

Non-protective immunity after standard pneumococcal vaccination series identified as a potential contributing risk factor for refractory otolaryngologic conditions in children

OBJECTIVE

To examine the relationship between conferred immunity after standard pneumococcal series and refractory otolaryngologic infections in pediatric patients using post-vaccination antibody titers, and to identify contributory underlying conditions revealed when vaccination/re-vaccination fails to confer protective immunity.

STUDY DESIGN

IRB-reviewed and "exempt" retrospective case series with chart review using the Epic® Electronic Medical Record system from 2013 to 2021.

SETTING

Dedicated tertiary referral children's hospital.

METHODS

Pneumococcal antibody titer results were assessed for children ages 0 to 21 years and: (1) at least 1 of 7 otolaryngologic disease diagnoses and (2) having received the 4-dose schedule of pneumococcal conjugate vaccine (PCV 7 or 13).

RESULTS

A total of 241 subjects met inclusion criteria with 356 laboratory tests. Recurrent acute otitis media, chronic rhinitis, and chronic otitis media with effusion were the 3 most frequent diagnoses. At presentation, only 27.0% of subjects had titers conferring immunity from their prior vaccinations with PCV. About 85 subjects had been subsequently revaccinated with Pneumococcal Polysaccharide Vaccine (PPSV), and antibody responses conferring immunity reached 91.8%. Seven subjects never developed adequate responses; 5 of these had recurrent acute otitis media as the primary otolaryngologic diagnosis. Secondary "revealed" diagnoses included Juvenile Rheumatoid Arthritis (n = 1), unresolved specific antibody deficiency (n = 2), and Hypogammaglobulinemia (n = 1).

CONCLUSION

In pediatric patients with recurrent infectious otolaryngologic disease refractory to traditional medical and surgical therapy, inadequate responses to pneumococcal vaccination may be revealed. This correlation represents a potential pathway for diagnosis and therapy.

Stability assessment of anti-bacterial antibodies in immunoglobulin G-depleted serum with validated immunoassays

Aim: To investigate the stability of the anti-pneumococcal (PCP) and anti-haemophilus type B (Hib) immunoglobulins (IgGs) in human IgG-depleted serum samples frozen at -20°C. Materials & methods: Modified commercially available immunoassays (ELISAs) were bioanalytically validated. These ELISAs were used to measure levels of the two anti-bacterial IgG in samples kept at -20°C for up to 15 months. Human IgG-depleted serum was spiked with GAMMAGARD Liquid to obtain those samples. Results: Both ELISAs passed the validation test. Anti-PCP IgG and anti-Hib IgG were shown to be stable for at least 15 months at -20°C. Conclusion: These data confirm the stability of anti-bacterial IgG in human IgG-depleted serum and support the common practice of testing frozen samples.

Pneumonia vaccine response in individuals with Down syndrome at three specialty clinics

Individuals with Down syndrome (DS) have been particularly impacted by respiratory conditions, such as pneumonia. However, the description of co-occurring recurrent infections, the response to pneumococcal immunization, and the association of these was previously unknown. We screened individuals with DS using an 11-item screener and prospectively collected pneumococcal titers and laboratory results. We found that the screener did not successfully predict which individuals with DS who would have inadequate pneumococcal titers. Thirty four of the 55 individuals with DS (62%) had abnormal pneumococcal titers demonstrating an inadequate response to routine immunization. In the absence of a valid screener, clinicians should consider screening all individuals with DS through the use of pneumococcal titers to 23 serotypes to assess vaccine response.

Evaluation and treatment of rhinosinusitis with primary antibody deficiency in adults: Evidence-based review with recommendations

BACKGROUND

There is clear evidence that the prevalence of primary antibody deficiency (PAD) is higher in patients with recurrent and chronic rhinosinusitis (CRS) than in the general population. The purpose of this multi-institutional and multidisciplinary evidence-based review with recommendations (EBRR) is to thoroughly review the literature on rhinosinusitis with PAD, summarize the existing evidence, and provide recommendations on the evaluation and management of rhinosinusitis in patients with PAD.

METHODS

The PubMed, EMBASE, and Cochrane databases were systematically reviewed from inception through August 2022. Studies on the evaluation and management of rhinosinusitis in PAD patients were included. An iterative review process was utilized in accordance with EBRR guidelines. Levels of evidence and recommendations on the evaluation and management principles for PAD were generated.

RESULTS

A total of 42 studies were included in this evidence-based review. These studies were evaluated on incidence of PAD in rhinosinusitis patients, incidence of rhinosinusitis in PAD patients, and on the different treatment modalities used and their outcome. The aggregate quality of evidence was varied across reviewed domains.

CONCLUSION

Based on the currently available evidence, PAD can occur in up to 50% of patients with recalcitrant CRS. Despite the presence of multiple studies addressing rhinosinusitis and PAD, the level of evidence supporting different treatment options continues to be lacking. Optimal management requires a multidisciplinary approach through collaboration with clinical immunology. There is need for higher-level studies that compare different treatments in patients with PAD and rhinosinusitis.

Baseline Pneumococcal IgG Levels and Response to 23-Valent Pneumococcal Polysaccharide Vaccine among Adults from Beijing, China

PURPOSE

To investigate the baseline levels of serotype-specific IgG antibodies to Streptococcus pneumoniae (S. pneumoniae) and assess their impact on the assessment of vaccine immunogenicity.

METHODS

We used a subset of serum samples from a randomized controlled trial. The blood of 584 healthy participants was collected on day 0 before and day 28 after the 23-valent pneumococcal polysaccharide vaccine (PPSV23) vaccination. Serotype-specific IgG against PPSV23-covered serotypes were measured by the World Health Organization (WHO) reference enzyme-linked immunosorbent assay (ELISA). Vaccine immunogenicity was compared using conversion rates (proportion of participants with IgG levels following immunization that are 2-fold greater than the baseline) and geometric mean fold rises (GMFRs) between the two groups, which were grouped according to pre-vaccination (baseline) IgG antibody levels.

RESULTS

Our data showed that over half of individuals have baseline IgG levels for 15 out of 23 serotypes above 1.3 µg/mL, and geometric mean concentrations (GMCs) were generally higher in the elderly group and the female group; significant differences were found in 15 serotypes for vaccine immunogenicity based on the seroconversion rate or GMFRs between individuals with baseline IgG ≥ 1.3 µg/mL and individuals with baseline IgG < 1.3 µg/mL. The seroconversion rate decreased with the increase of baseline IgG levels according to a linear regression model.

CONCLUSIONS

The assessment of vaccine immunogenicity could be impacted by the fact that many adults had high baseline antibody levels. This study is registered in the Chinese Clinical Trial Registry, number NCT05298800.

Over-expression of IL-33 enhances rabies virus early antigen presentations and cellular immune responses in mice

Human inactivated rabies virus (RABV) vaccines have been widely used worldwide over 30 years. The mechanisms of humoral immunity elicited by previously reported rabies candidate vaccines have been fully investigated, but little is known about the cellular immunity profiles. Herein, the recombinant RABV rLBNSE-IL-33 overexpressing the mouse interleukin-33 (IL-33) proliferated well in Neuro-2a cells and had no effects with the parent virus on growth kinetic in vitro and viral pathogenicity in mice. The rLBNSE-IL-33 experienced more antigen presentations by MHC-II on DCs and activated more CD4+ T cells which helped recruit more CD19+CD40+ B cells in blood and promote rapid and robust IgG1 antibodies responses at initial infection stage compared with the parent rLBNSE strain. Simultaneously, the rLBNSE-IL-33 were also presented by MHC-I to CD8+ T cells which contributed to produce high levels of IgG2a. The rLBNSE-IL-33 elicited significantly high levels of RABV-specific IFN-γ secreting memory CD4+ T cells, more RABV-specific IL-4 and IFN-γ secreting memory CD8+ T cells in spleens at early infection stage in mice. Altogether, overexpression of IL-33 in rLBNSE-IL-33 enhanced early antigen presentation, markedly promote CD4+, memory CD4+ and CD8+ T cells-mediated responses and provided a 100 % protection from lethal RABV challenge in mice. These findings provided an alternative novel therapy and vaccine strategy in future.

Clinical Validation of a Primary Antibody Deficiency Screening Algorithm for Primary Care

PURPOSE

The diagnostic delay of primary antibody deficiencies (PADs) is associated with increased morbidity, mortality, and healthcare costs. Therefore, a screening algorithm was previously developed for the early detection of patients at risk of PAD in primary care. We aimed to clinically validate and optimize the PAD screening algorithm by applying it to a primary care database in the Netherlands.

METHODS

The algorithm was applied to a data set of 61,172 electronic health records (EHRs). Four hundred high-scoring EHRs were screened for exclusion criteria, and remaining patients were invited for serum immunoglobulin analysis and referred if clinically necessary.

RESULTS

Of the 104 patients eligible for inclusion, 16 were referred by their general practitioner for suspected PAD, of whom 10 had a PAD diagnosis. In patients selected by the screening algorithm and included for laboratory analysis, prevalence of PAD was ~ 1:10 versus 1:1700-1:25,000 in the general population. To optimize efficiency of the screening process, we refitted the algorithm with the subset of high-risk patients, which improved the area under the curve-receiver operating characteristics curve value to 0.80 (95% confidence interval 0.63-0.97). We propose a two-step screening process, first applying the original algorithm to distinguish high-risk from low-risk patients, then applying the optimized algorithm to select high-risk patients for serum immunoglobulin analysis.

CONCLUSION

Using the screening algorithm, we were able to identify 10 new PAD patients from a primary care population, thus reducing diagnostic delay. Future studies should address further validation in other populations and full cost-effectiveness analyses.

REGISTRATION

Clinicaltrials.gov record number NCT05310604, first submitted 25 March 2022.

High Rates of Seroprotection and Seroconversion to Vaccine-Preventable Infections in the Early Post-Autologous Stem Cell Transplant Period

In patients early post-autologous stem cell transplant, seroprotection rates were high for Hemophilus influenzae type B and tetanus toxoid (70%-90%) but lower for Streptococcus pneumoniae (30%-50%) including after revaccination. There were high rates of seropositivity (67%-86%) to measles, mumps, and rubella and varicella zoster virus. Durability of protection requires assessment.

SARS-CoV-2 Infection and Response to COVID-19 Vaccination in Patients With Primary Immunodeficiencies

Primary immunodeficiencies (PIDs) are heterogeneous, rare disorders that increase susceptibility to infection and/or immune dysregulation. Individuals with certain PIDs are at high risk of severe or fatal outcomes from SARS-CoV-2 infections (the causative agent of COVID-19), either due to the underlying PID and/or due to the presence of comorbidities such as severe lung and liver disease. Vaccination remains the primary strategy to protect individuals with PID from COVID-19. However, populations with PID exhibit variable vaccine seroresponse rates, antibody titers, and neutralization activity depending on the type of PID and/or COVID-19 vaccine, and consequently, are at an elevated risk of severe disease. In this article, we review the COVID-19 burden in patients with PIDs and focus in-depth on findings from patients with predominantly antibody deficiencies or combined immunodeficiencies. We conclude by providing COVID-19 vaccination recommendations for this population.

Predictors of serological non-response to the 13-valent pneumococcal conjugate vaccine followed by the 23-valent polysaccharide vaccine among adults living with HIV

BACKGROUND

People living with HIV (PLWH) have higher incidence of pneumococcal disease compared to people without HIV. Immunization with pneumococcal vaccines is recommended, but serological non-response to pneumococcal vaccination is common for largely unknown reasons.

METHODS

PLWH on antiretroviral treatment and no prior pneumococcal vaccination received the 13-valent pneumococcal conjugate vaccine (PCV13) followed 60 days later by the 23-valent polysaccharide vaccine (PPV23). Serological response was evaluated 30 days post-PPV23 by antibodies against 12 serotypes covered by both PCV13 and PPV23. Seroprotection was defined as a ≥2-fold rise to a level above 1.3 µg/ml in geometric mean concentration (GMC) across all serotypes. Associations with non-responsiveness were evaluated by logistic regression.

RESULTS

Fifty-two virologically suppressed PLWH (median age of 50 years (IQR 44-55) and median CD4 count of 634 cells/mm3 (IQR 507-792)) were included. Forty-six percent (95 % CI 32-61, n = 24) achieved seroprotection. Serotypes 14, 18C and 19F had the highest, and serotypes 3, 4 and 6B the lowest GMCs. Pre-vaccination GMC levels less than 100 ng/ml were associated with increased odds of non-responsiveness compared to levels above 100 ng/ml (adjusted OR 8.7, 95 % CI 1.2-63.6, p = 0.0438).

CONCLUSION

Less than half of our study population achieved anti-pneumococcal seroprotective levels following PCV13 and PPV23 immunization. Low pre-vaccination GMC levels were associated with non-response. Further research is required to optimize vaccination strategies that achieve higher seroprotection in this high-risk group.

Immunogenicity of the 13-Valent Pneumococcal Conjugated Vaccine Followed by the 23-Valent Polysaccharide Vaccine in Chronic Lymphocytic Leukemia

Patients with Chronic Lymphocytic Leukemia (CLL) have a 29- to 36-fold increased risk of invasive pneumococcal disease (IPD) compared to healthy adults. Therefore, most guidelines recommend vaccination with the 13-valent pneumococcal conjugated vaccine (PCV13) followed 2 months later by the 23-valent polysaccharide vaccine (PPSV23). Because both CLL as well as immunosuppressive treatment have been identified as major determinants of immunogenicity, we aimed to assess the vaccination schedule in untreated and treated CLL patients. We quantified pneumococcal IgG concentrations against five serotypes shared across both vaccines, and against four serotypes unique to PPSV23, before and eight weeks after vaccination. In this retrospective cohort study, we included 143 CLL patients, either treated (n = 38) or naive to treatment (n = 105). While antibody concentrations increased significantly after vaccination, the overall serologic response was low (10.5%), defined as a ≥4-fold antibody increase against ≥70% of the measured serotypes, and significantly influenced by treatment status and prior lymphocyte number. The serologic protection rate, defined as an antibody concentration of ≥1.3 µg/mL for ≥70% of serotypes, was 13% in untreated and 3% in treated CLL patients. Future research should focus on vaccine regimens with a higher immunogenic potential, such as multi-dose schedules with higher-valent T cell dependent conjugated vaccines.

Deficient anterior pituitary with common variable immune deficiency (DAVID syndrome): a new case and literature reports

Deficient anterior pituitary with common variable immune deficiency (DAVID) syndrome is a rare condition characterized by adrenocorticotropic hormone (ACTH) deficiency and primary hypogammaglobulinemia. It is due to heterozygous mutations of the nuclear factor kappa-B subunit 2 (NFKB2) gene. Only a few isolated cases have been reported since its first description by our team. Through the international multicenter GENHYPOPIT network, we identified a new case of DAVID syndrome. We then conducted an extensive review of the DAVID syndrome cases published from 2012 to 2022. A 7-year-old boy was diagnosed with symptomatic hypoglycemia revealing ACTH deficiency. Laboratory tests showed asymptomatic hypogammaglobulinemia. He harbored a heterozygous point mutation in NFKB2 gene (c.2600C > T, p.Ala867Val). His management included hydrocortisone replacement treatment, and he also received subcutaneous immunoglobulins during the Covid-19 pandemic. We analyzed 28 cases of DAVID syndrome with ACTH deficiency. ACTH deficiency was the only hormone deficiency in 79% of patients, but some patients harbored growth hormone (GH) and thyroid stimulating hormone (TSH) deficiencies. The first presenting symptoms were sinus/pulmonary infections (82%, mean age of 3 years) and alopecia (mean age of 4.7 years). ACTH deficiency was the third presenting condition (mean age at diagnosis of 8.6 years). All patients had hypogammaglobulinemia (decreased IgA and IgM levels), and 57% of patients had at least one autoimmune manifestation. Heterozygous mutations at the 3'end of the NFKB2 gene, coding for the C-terminal domain of the protein, were identified in all cases. Better knowledge of DAVID syndrome will help clinicians make an early diagnosis to avoid life-threatening complications.

Estimation of baseline IgG antibody levels to 23 pneumococcal vaccine-type capsular polysaccharides in healthy vaccine naïve Indian adults

Since immunological responses to pneumococcal vaccines are assessed by a fold-increase in antibody levels relative to pre-immunization levels, it is therefore critical to determine baseline antibody levels to establish putative threshold as a measure of normal response. Herein, for the first time, we measured baseline IgG antibody levels in 108 healthy unvaccinated Indian adults using WHO-recommended ELISA. Median baseline IgG concentration ranged between 0.54 µg/mL to 12.35 µg/mL. Highest levels of baseline capsule polysaccharide (cPS)-specific IgG were found against types 14, 19A, and 33F. Whereas, lowest baseline IgG levels were observed against types 3, 4, and 5. Overall, ∼79 % of study population had median baseline IgG levels ≥1.3 µg/mL against 74 % of cPS's. Substantial baseline antibody levels in unvaccinated adults were observed. The study would be critical in bridging gaps in baseline immunogenicity data and may offer a valuable foundation for evaluating immune response of Indian adults to pneumococcal vaccination.

Hesitancy, reactogenicity and immunogenicity of the mRNA and whole-virus inactivated Covid-19 vaccines in pediatric neuromuscular diseases

The mRNA-based BNT162b2 and inactivated whole-virus CoronaVac are two widely used COVID-19 vaccines that confer immune protection to healthy individuals. However, hesitancy toward COVID-19 vaccination appeared to be common for patients with neuromuscular diseases (NMDs) due to the paucity of data on the safety and efficacy in this high-risk patient population. Therefore, we examined the underlying factors associated with vaccine hesitancy across time for NMDs and assessed the reactogenicity and immunogenicity of these two vaccines. Patients aged 8-18 years with no cognitive delay were invited to complete surveys in January and April 2022. Patients aged 2-21 years were enrolled for COVID-19 vaccination between June 2021 and April 2022, and they recorded adverse reactions (ARs) for 7 days after vaccination. Peripheral blood was obtained before and within 49 days after vaccination to measure serological antibody responses compared to healthy children and adolescents. Forty-one patients completed vaccine hesitancy surveys for both timepoints, while 22 joined the reactogenicity and immunogenicity arm of the study. Two or more family members vaccinated against COVID-19 was positively associated with intention of vaccination (odds ratio 11.7, 95% CI 1.81-75.1, p = .010). Pain at the injection site, fatigue, and myalgia were the commonest ARs. Most ARs were mild (75.5%, n = 71/94). All 19 patients seroconverted against the wildtype SARS-CoV-2 after two doses of either vaccine, similar to 280 healthy counterparts. There was lower neutralization against the Omicron BA.1 variant. BNT162b2 and CoronaVac were safe and immunogenic for patients with NMDs, even in those on low-dose corticosteroids.

Reduced quantity and function of pneumococcal antibodies are associated with exacerbations of COPD in SPIROMICS

While hypogammaglobulinemia is associated with COPD exacerbations, it is unknown whether frequent exacerbators have specific defects in antibody production/function. We hypothesized that reduced quantity/function of serum pneumococcal antibodies correlate with exacerbation risk in the SPIROMICS cohort. We measured total pneumococcal IgG in n = 764 previously vaccinated participants with COPD. In a propensity-matched subset of n = 200 with vaccination within five years (n = 50 without exacerbations in the previous year; n = 75 with one, n = 75 with ≥2), we measured pneumococcal IgG for 23 individual serotypes, and pneumococcal antibody function for 4 serotypes. Higher total pneumococcal IgG, serotype-specific IgG (17/23 serotypes), and antibody function (3/4 serotypes) were independently associated with fewer prior exacerbations. Higher pneumococcal IgG (5/23 serotypes) predicted lower exacerbation risk in the following year. Pneumococcal antibodies are inversely associated with exacerbations, supporting the presence of immune defects in frequent exacerbators. With further study, pneumococcal antibodies may be useful biomarkers for immune dysfunction in COPD.

[Principles of the diagnostics of inborn errors of immunity]

Inborn errors of immunity (IEI) are a heterogeneous group of nearly 500 diseases characterized by a congenital dysfunction of the immune system. The vast majority of IEIs are rare diseases but all IEIs share a cumulative prevalence of 1:1200-1:2000. In addition to a pathological susceptibility to infections, IEIs can also present with lymphoproliferative, autoimmune or autoinflammatory manifestations. There is often an overlap with classical rheumatic and inflammatory disease patterns. Therefore, a basic knowledge of the clinical presentation and the diagnostics of IEIs is also relevant for the practicing rheumatologist.

Value of diagnostic vaccination in diagnosis of humoral inborn errors of immunity

Inborn errors of immunity (IEIs) or primary immunodeficiency diseases, are disorders caused by genetic defects affecting immune function. Clinically, IEI presents mainly as recurrent or severe infections, immune dysregulation (autoimmunity or autoinflammatory disorders), and lymphoproliferation with or without dysmorphic features. Humoral IEIs are the largest subgroup of IEI, with a wide spectrum of quantitative and qualitative antibody defects. These disorders are normally diagnosed based on immunological evaluation; diagnostic vaccination is part of this evaluation. This review examines the importance and relevance of diagnostic vaccination in the diagnosis of humoral IEIs and different technologies which can be utilised in diagnosis.

Pneumococcal Conjugate Vaccine Does Not Induce Humoral Response When Administrated Within the Six Months After CD19 CAR T-Cell Therapy

CD19 targeted chimeric antigen receptor-modified T cell therapy (CAR-T) leads to B cell aplasia and low serum immunoglobulin levels. Long-lived CD19-negative plasma cells may persist through the therapy and generate antibodies. There is a paucity of data describing how CAR-T impacts the persistence of antibodies against vaccine-related antigens and the degree to which CAR-T recipients may respond to vaccines. We characterized the effect of CAR-T on pneumococcal immunoglobulin G (IgG) titers and determine whether pneumococcal conjugate vaccine (PCV13) administered after CAR-T develops long-term humoral protection against pneumococcus. A retrospective chart review was performed to identify CAR-T recipients who had serum pneumococcal IgG titers drawn before (baseline) or at days +90, +180, +270, +360, or +540 after CAR-T. We then determined whether they received PCV13 vaccination at these timepoints. IgG concentration ≥1.3 μg/mL was considered protective for that serotype, and patients with ≥6/11 tested vaccine-specific serotypes meeting this threshold were deemed to have humoral protection against pneumococcus. Absolute pneumococcal IgG titers and the proportion of patients with humoral protection, stratified by serotype, and vaccination status were compared by paired nonparametric t-tests. Absolute counts for lymphocyte, CD4 T-cell, and CD19 cell and total IgG level, along with the rate of invasive pneumococcal infections, were measured at these timepoints. A total of 148 CAR-T recipients with pneumococcal IgG titers measured for at least one of the defined time points were identified. At baseline, 25% (19/76) patients with evaluable pneumococcal IgG titers met the definition of humoral protection. Among 44 patients with paired pneumococcal IgG titers at baseline and day+90, absolute IgG titers of all serotypes decreased (geometric mean = 0.41 and 0.32 µg/mL, respectively; P < .001). Thirteen patients were vaccinated following the titer blood draw at day+90 and had paired pneumococcal IgG titers at day+90 and day180. Absolute IgG titers of all vaccine specific serotypes in these vaccinated patients decreased from day+90 to day+180 (geometric mean = 0.36 and 0.29 µg/mL, respectively; P = .03). The proportion of patients meeting the criteria of humoral protection remained the same at day+180 despite vaccination at day+90. The results were similar among 8 patients vaccinated at day+180, as well as 7 patients consecutively vaccinated at day+90 and day+180 with corresponding pneumococcal IgG titers. When all vaccine-specific pneumococcal IgG titers were pooled together by timepoint regardless of vaccination status, the proportion of patients with humoral protection decreased until day+540. Some patients developed humoral protection after vaccination at day+360, maintained seroprotective IgG titers from baseline, or developed protection after receiving intravenous immunoglobulin treatment secondary to recurrent infections. Our study demonstrated that few large B cell lymphoma patients had humoral protection against pneumococcus at baseline, and existing IgG titers decreased after CAR-T. PCV13 vaccination at day+90 or day+180 after CAR-T did not increase humoral protection against pneumococcus. Only at day+540 was there evidence of humoral protection against pneumococcus in a modest proportion of patients. Clinical trials are needed to determine the optimal timing of vaccination, before or after CAR-T, to develop protective immunity against Streptococcus pneumoniae infections.

High Frequency of Specific Polysaccharide Antibody Deficiency in Adults With Unexplained, Recurrent and/or Severe Infections With Encapsulated Bacteria

BACKGROUND

Primary immunodeficiencies (PIDs) in adults are mainly revealed by recurrent and/or severe bacterial infections. The objective of this study was to evaluate a systematic research strategy of PIDs in adults with unexplained bacterial infections, with a special focus on specific polysaccharide antibody deficiency (SPAD).

METHODS

In this prospective multicenter study, inclusion criteria were recurrent benign upper and lower respiratory tract infections (RTIs) for at least two years (group 1), at least one upper or lower RTI requiring hospitalization (group 2), and/or at least one invasive infection documented with encapsulated bacteria (group 3). Main exclusion criteria were all local and general conditions that could explain infections. If no PID diagnosis was made, response to polysaccharide antigens was assessed using a pneumococcal polysaccharide vaccine.

RESULTS

From March 2015 to March 2020, 118 patients were included (37 males, median age of 41 years): 73, 17, and 28 in groups 1, 2, and 3, respectively. Forty-seven PIDs were diagnosed, giving an estimated frequency of 39.8% (95% confidence interval [CI] [30.4, 48.8]). SPAD was the most frequent diagnosis by far (n = 37/47, 78.7%), and was made in 23, 5, and 9 patients from groups 1 to 3, respectively. All SPAD patients received conjugate vaccines and, according to their infectious history, were on surveillance or treated with preventive antibiotics (n = 6) and/or with immunoglobulins replacement therapy (n = 10), the latter being dramatically efficient in all cases.

CONCLUSIONS

Considering its high prevalence among adults with unexplained recurrent and/or severe bacterial infections, SPAD should be screened in those patients.

CLINICAL TRIALS REGISTRATION

NCT02972281.

[Evaluation of immunotoxicitiy in biomedical research and development]

Immunotoxicology aims at studying toxic effects of any substance on the immune system and its functions. In its various fields of application, this science is dependent on regulatory texts and guidelines. Studies are based on in vitro, ex vivo and in vivo techniques and are observational or functional allowing the identification of a toxic effect and its underlying mechanisms, respectively. Here, we review the various tests to perform in biomedical research and development, with a particular interest for the T-cell Dependent Antibody Response (TDAR) assay. We also briefly discuss the upcoming evolutions in this domain within a more ethically sound framework such as limiting the use of laboratory animals. These evolutions are represented by the development of relevant cell models.

Genetic Causes, Clinical Features, and Survival of Underlying Inborn Errors of Immunity in Omani Patients: a Single-Center Study

PURPOSE

Early identification of inborn errors of immunity (IEIs) is crucial due to the significant risk of morbidity and mortality. This study aimed to describe the genetic causes, clinical features, and survival rate of IEIs in Omani patients.

METHODS

A prospective study of all Omani patients evaluated for immunodeficiency was conducted over a 17-year period. Clinical features and diagnostic immunological findings were recorded. Targeted gene testing was performed in cases of obvious immunodeficiency. For cases with less conclusive phenotypes, a gene panel was performed, followed by whole-exome sequencing if necessary.

RESULTS

A total of 185 patients were diagnosed with IEIs during the study period; of these, 60.5% were male. Mean ages at symptom onset and diagnosis were 30.0 and 50.5 months, respectively. Consanguinity and a family history of IEIs were present in 86.9% and 50.8%, respectively. Most patients presented with lower respiratory infections (65.9%), followed by growth and development manifestations (43.2%). Phagocytic defects were the most common cause of IEIs (31.9%), followed by combined immunodeficiency (21.1%). Overall, 109 of 132 patients (82.6%) who underwent genetic testing received a genetic diagnosis, while testing was inconclusive for the remaining 23 patients (17.4%). Among patients with established diagnoses, 37 genes and 44 variants were identified. Autosomal recessive inheritance was present in 81.7% of patients with gene defects. Several variants were novel. Intravenous immunoglobulin therapy was administered to 39.4% of patients and 21.6% received hematopoietic stem cell transplantation. The overall survival rate was 75.1%.

CONCLUSION

This study highlights the genetic causes of IEIs in Omani patients. This information may help in the early identification and management of the disease, thereby improving survival and quality of life.

Inborn Errors of Immunity

Inborn errors of immunity occur in 1 in 1000 to 1 in 5000 individuals and are characterized by immune deficiency and immune dysregulation. The primary care provider (PCP) should be familiar with key features of these diagnoses including recurrent and/or severe infections, hyperinflammation, malignancy, and autoimmunity and have a low threshold to refer for evaluation. The PCP can begin a laboratory evaluation before referral by sending a complete blood count (CBC) with differential, antibody levels, vaccine titers, and possibly other tests. Management approaches vary from antibiotic prophylaxis to hematopoietic stem cell transplantation depending on the specific diagnosis.

Combined 13-valent pneumococcal conjugate and 23-valent pneumococcal polysaccharide vaccine regimens for adults with systemic lupus erythematosus: Does the sequence of pneumococcal vaccination affect immunogenicity responses? A single-center cohort study in Brazil

OBJECTIVE

A combination of 13-valent pneumococcal conjugate vaccine (PCV13) and 23-valent pneumococcal polysaccharide vaccine (PPSV23) is currently recommended for adults with systemic lupus erythematosus (SLE). However, data on the immunogenicity elicited by sequential pneumococcal vaccination in this patient population are scarce. In this study, we compared short-term antibody responses to both PCV13/PPSV23 (≥8-week interval) and PPSV23/PCV13 (≥12-month interval) vaccination strategies in pneumococcal vaccine-naive adults with SLE.

METHODS

This longitudinal, open-label, quasi-randomized study was performed in a single-center cohort of adults (18 years or older) with SLE. In both vaccination groups, blood samples were collected immediately before administering the first dose of the pneumococcal vaccine (timepoint T0), 4-6 weeks after the priming dose (T1), and 4-6 weeks after the booster dose (T2). We focused on the 12 shared serotypes between PCV13 and PPSV23, and compared the following immunogenicity outcomes between the groups at T2: anti-pneumococcal antibody geometric mean concentration (ApAb GMC), fold increase in ApAb levels (FI-ApAb), overall seroprotection rate, and overall seroconversion rate. The protective level for each pneumococcal serotype was set at 1.3 μg/mL. We used the multi-analyte immunodetection method to determine serum levels of ApAbs.

RESULTS

Thirty-four patients with SLE were screened between April 2019 and January 2020, and 16 of them (mean age: 39.4 years, 87.5% female, and 100% on immunosuppressants) had evaluable immunogenicity results at T2. The median time elapsed between the pneumococcal vaccinations was 56 days in the PCV13/PPSV23 group (n = 11 patients) and 16 months in the PPSV23/PCV13 group (n = 5 patients). Priming with PCV13 (PCV13/PPSV23 group), as opposed to PPSV23 (PPSV23/PCV13 group), yielded significantly better results regarding FI-ApAb, overall seroconversion rate, and overall seroprotection rate 4-6 weeks after each pneumococcal vaccination. A trend toward augmented ApAb GMC in the patients who received the PCV13/PPSV23 sequence was also observed. No relevant safety issues were identified with sequential pneumococcal vaccination.

CONCLUSION

The PCV13-priming PPSV23-boost strategy in adults with SLE induced greater antibody responses for most immunogenicity outcomes than those elicited by the PPSV23/PCV13 strategy.

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.

Immunogenicity against wild-type and Omicron SARS-CoV-2 after a third dose of inactivated COVID-19 vaccine in healthy adolescents

Introduction

Two doses of inactivated SARS-CoV-2 vaccine CoronaVac cannot elicit high efficacy against symptomatic COVID-19, especially against the Omicron variant, but that can be improved by a third dose in adults. The use of a third dose of CoronaVac in adolescents may be supported by immunobridging studies in the absence of efficacy data.

Methods

With an immunobridging design, our study (NCT04800133) tested the non-inferiority of the binding and neutralizing antibodies and T cell responses induced by a third dose of CoronaVac in healthy adolescents (N=94, median age 14.2 years, 56% male) compared to adults (N=153, median age 48.1 years, 44% male). Responses against wild-type (WT) and BA.1 SARS-CoV-2 were compared in adolescents. Safety and reactogenicity were also monitored.

Results

A homologous third dose of CoronaVac further enhanced antibody response in adolescents compared to just 2 doses. Adolescents mounted non-inferior antibody and T cell responses compared to adults. Although S IgG and neutralizing antibody responses to BA.1 were lower than to WT, they remained detectable in 96% and 86% of adolescents. T cell responses to peptide pools spanning only the mutations of BA.1 S, N and M in adolescents were preserved, increased, and halved compared to WT respectively. No safety concerns were identified.

Discussion

The primary vaccination series of inactivated SARS-CoV-2 vaccines for adolescents should include 3 doses for improved humoral immunogenicity.

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.

Effect of Ibrutinib on Hmphocytic Leukemia: a Single-Center Experience

OBJECTIVE/BACKGROUND

In the era of novel agents, Bruton tyrosine kinase (BTK) inhibitors have changed the dynamics of treating chronic lymphocytic leukemia. However, small studies have shown conflicting results regarding the additive humoral dysfunction with their use.

METHODS

We prospectively compared vaccine responses in patients on ibrutinib (n = 10) with matched controls (n = 16) and analyzed whether a protein-based (tetanus-diphtheria toxoid) or a carbohydrate (Pneumovax) moiety will result in an improved immunological response.

RESULTS

An appropriate serological response in IgG titers for diphtheria was seen in 40% of patients on ibrutinib and 31% of patients in the control group. About 30% of patients on ibrutinib and 44% of patients in the control group had an adequate response to tetanus toxoid. None of the patients on ibrutinib mounted an adequate response to Pneumovax, while 31% of patients in the control arm responded appropriately. These differences in the results were considered insignificant as all p values were greater than the cut-off of 0.05.

CONCLUSION

Our study did not show significant detrimental vaccine responses with ibrutinib and calls for larger multicenter studies to elucidate long-term effects, especially in patients with prior exposure to anti-CD20 monoclonal antibodies.

Antibody and T cell responses against wild-type and Omicron SARS-CoV-2 after third-dose BNT162b2 in adolescents

The high effectiveness of the third dose of BNT162b2 in healthy adolescents against Omicron BA.1 has been reported in some studies, but immune responses conferring this protection are not yet elucidated. In this analysis, our study (NCT04800133) aims to evaluate the humoral and cellular responses against wild-type and Omicron (BA.1, BA.2 and/or BA.5) SARS-CoV-2 before and after a third dose of BNT162b2 in healthy adolescents. At 5 months after 2 doses, S IgG, S IgG Fc receptor-binding, and neutralising antibody responses waned significantly, yet neutralising antibodies remained detectable in all tested adolescents and S IgG avidity increased from 1 month after 2 doses. The antibody responses and S-specific IFN-γ⁺ and IL-2⁺ CD8⁺ T cell responses were significantly boosted in healthy adolescents after a homologous third dose of BNT162b2. Compared to adults, humoral responses for the third dose were non-inferior or superior in adolescents. The S-specific IFN-γ⁺ and IL-2⁺ CD4⁺ and CD8⁺ T cell responses in adolescents and adults were comparable or non-inferior. Interestingly, after 3 doses, adolescents had preserved S IgG, S IgG avidity, S IgG FcγRIIIa-binding, against Omicron BA.2, as well as preserved cellular responses against BA.1 S and moderate neutralisation levels against BA.1, BA.2 and BA.5. Sera from 100 and 96% of adolescents tested at 1 and 5 months after two doses could also neutralise BA.1. Our study found high antibody and T cell responses, including potent cross-variant reactivity, after three doses of BNT162b2 vaccine in adolescents in its current formulation, suggesting that current vaccines can be protective against symptomatic Omicron disease.

Navigating diagnostic options for inborn errors of immunity in children: a case-based illustration

PURPOSE OF REVIEW

In recent years, there has been a dramatic increase in the number of recognized inborn errors of immunity (IEI), many of which present in childhood. This review discusses diagnostic approaches for some of the more common presentations of IEI in childhood.

RECENT FINDINGS

Implementation of newborn screening (NBS) using the T cell receptor excision circle (TREC) assay has led to the timely identification of patients with severe combined immunodeficiency (SCID) as well as both syndromic and nonsyndromic forms of T cell lymphopenia, including DiGeorge syndrome. Improvements in the availability of immunophenotyping assays, genetic testing and advanced diagnostic techniques such as the artificial thymic organoid system can improve diagnostic clarity and impact management plans. Diagnostic improvements in humoral immunodeficiency include development of novel assays to quantify and functionally evaluate polysaccharide vaccine response.

SUMMARY

IEI represent a rapidly growing field, particularly in paediatrics. Use of state-of-the-art diagnostic testing can facilitate rapid identification of IEI, hopefully allowing for initiation of prompt treatment and improved patient outcomes.

Fever of Unknown Origin Reveals a Missed Diagnosis of DiGeorge Syndrome in a 21-Year-Old Female

DiGeorge syndrome, caused by a microdeletion of the 22q11.2 region of chromosome 22, is a relatively rare condition. This syndrome can be difficult to recognize because a constellation of symptoms show different presentations. Most individuals diagnosed with this condition are identified in early childhood. With the emergence of new screening techniques, even fewer individuals with this syndrome are missed. Prior to these screening techniques, it was uncommon for patients to be diagnosed in adulthood. As a result, many internists, who focus only on the adult population, are unlikely to recognize and diagnose DiGeorge syndrome as the patient ages merely because it is not commonly diagnosed later in life. Early recognition and management are essential for the treatment of this condition. Here, we present the case of a 21-year-old woman diagnosed with DiGeorge syndrome as an adult.

Application of vaccine response in the evaluation of patients with suspected B-cell immunodeficiency: Assessment of responses and challenges with interpretation

Diagnostic vaccination is an integral component in the evaluation of patients suspected to have a B cell or humoral deficiency. Evaluation of antibody production in response to both protein- and polysaccharide-based vaccines aids in distinguishing between specific categories of humoral deficiency. Although assessment of pneumococcal polysaccharide responses is widely available and included in diagnostic guidelines, significant variability still exists in the measurement and interpretation of these responses. Interpretation can also be complicated by age, vaccination history and treatment with immunoglobulin replacement therapy. Despite the challenges and limitations of evaluating pneumococcal polysaccharide vaccine responses, it can provide valuable diagnostic and prognostic information to guide therapeutic intervention. Future efforts are needed to further standardize measurement and interpretation of pneumococcal antibody responses to vaccination and to identify and establish other methods and/or vaccines as alternatives to pneumococcal vaccination to address the challenges in certain patient populations.

Salmonella Typhi Vaccination Response as a Tool for the Stratification of Risk in Patients with Predominantly Antibody Deficiencies

Predominantly antibody deficiencies are the most frequent type of primary immunodeficiency (PID). Diagnosis requires evaluation of the immune function by distinguishing the presence or absence of a response against polysaccharide antigens. Salmonella enterica serovar Typhi-based vaccines have proved to be a suitable tool. We studied a group of patients with suspicion of primary immunodeficiency and classified them by final diagnosis. We analyzed the vaccination response to S. Typhi and other immune biomarkers and clinical data. The aim of this study was to classify patients regarding the intensity of their immune response measured as the difference between specific immunoglobulin G levels before and after vaccination and antibody levels in the post-vaccination sample in order to improve clinical decisions regarding follow up and treatment of immunodeficiency patients. We established four groups of response: Non responders (NR), Low responders (LR), Intermediate responders (IR), and High responders (HR), where we found differences in IgG, IgG1, IgG2, IgG4, IgA, IgA1, IgA2, and IgM, and where the finally achieved diagnosis was also different and corresponding to the level of vaccination response.

The Euroflow PID Orientation Tube in the diagnostic workup of primary immunodeficiency: Daily practice performance in a tertiary university hospital

Introduction

Multiparameter flow cytometry (FCM) immunophenotyping is an important tool in the diagnostic screening and classification of primary immunodeficiencies (PIDs). The EuroFlow Consortium recently developed the PID Orientation Tube (PIDOT) as a universal screening tool to identify lymphoid-PID in suspicious patients. Although PIDOT can identify different lymphoid-PIDs with high sensitivity, clinical validation in a broad spectrum of patients with suspicion of PID is missing. In this study, we investigated the diagnostic performance of PIDOT, as part of the EuroFlow diagnostic screening algorithm for lymphoid-PID, in a daily practice at a tertiary reference center for PID.

Methods

PIDOT was tested in 887 consecutive patients suspicious of PID at the Ghent University Hospital, Belgium. Patients were classified into distinct subgroups of lymphoid-PID vs. non-PID disease controls (non-PID DCs), according to the IUIS and ESID criteria. For the clinical validation of PIDOT, comprehensive characterization of the lymphoid defects was performed, together with the identification of the most discriminative cell subsets to distinguish lymphoid-PID from non-PID DCs. Next, a decision-tree algorithm was designed to guide subsequent FCM analyses.

Results

The mean number of lymphoid defects detected by PIDOT in blood was 2.87 times higher in lymphoid-PID patients vs. non-PID DCs (p < 0.001), resulting in an overall sensitivity and specificity of 87% and 62% to detect severe combined immunodeficiency (SCID), combined immunodeficiency with associated or syndromic features (CID), immune dysregulation disorder (ID), and common variable immunodeficiency (CVID). The most discriminative populations were total memory and switched memory B cells, total T cells, TCD4+cells, and naive TCD4+cells, together with serum immunoglobulin levels. Based on these findings, a decision-tree algorithm was designed to guide further FCM analyses, which resulted in an overall sensitivity and specificity for all lymphoid-PIDs of 86% and 82%, respectively.

Conclusion

Altogether, our findings confirm that PIDOT is a powerful tool for the diagnostic screening of lymphoid-PID, particularly to discriminate (S)CID, ID, and CVID patients from other patients suspicious of PID. The combination of PIDOT and serum immunoglobulin levels provides an efficient guide for further immunophenotypic FCM analyses, complementary to functional and genetic assays, for accurate PID diagnostics.

Effect of FcRn antagonism on protective antibodies and to vaccines in IgG-mediated autoimmune diseases pemphigus and generalised myasthenia gravis

Antagonism of the neonatal Fc receptor (FcRn) by efgartigimod has been studied in several autoimmune diseases mediated by immunoglobulin G (IgG) as a therapeutic approach to remove pathogenic IgGs. Whereas reduction of pathogenic titres has demonstrated efficacy in multiple autoimmune diseases, reducing total IgG could potentially increase infection risk in patients receiving FcRn antagonists. The objective of this study was to analyse the effect of FcRn antagonism with efgartigimod on existing protective antibody titres and the ability to mount an immune response after vaccine challenge. Serum levels of total IgG and protective antibodies against tetanus toxoid (TT), varicella zoster virus (VZV), and pneumococcal capsular polysaccharide (PCP) were measured in all patients enrolled in an open-label trial of efgartigimod for the treatment of pemphigus. Vaccine specific-responses were assessed by measuring changes in IgG titres in patients with generalised myasthenia gravis (gMG) who were treated with efgartigimod and who received influenza, pneumococcal, or coronavirus disease 2019 (COVID-19) vaccines during participation in the double-blind trial ADAPT or open-label extension, ADAPT+ (n = 17). FcRn antagonism reduced levels of protective anti-TT, anti-VZV, and anti-PCP antibodies and total IgG to a similar extent; anti-TT and anti-VZV titres remained above minimally protective thresholds for the majority of patients, (10/12) 83% and (14/15) 93% respectively. Protective antibodies returned to baseline values upon treatment cessation. Antigen-specific IgG responses to influenza, pneumococcal, and COVID-19 immunisation were detected in patients with gMG who received these vaccines while undergoing therapy with efgartigimod. In conclusion, FcRn antagonism with efgartigimod did not hamper generation of IgG responses but did transiently reduce IgG titres of all specificities.

"Common variable immunodeficiency: Challenges for diagnosis"

Common variable immunodeficiency is a heterogeneous condition characterized by B cell dysfunction with reduced serum immunoglobulin levels and a highly variable spectrum of clinical manifestations ranging from recurrent infections to autoimmune disease. The diagnosis of CVID is often challenging due to the diverse clinical presentation of patients and the existence of multiple diagnostic criteria without a universally adopted consensus. Laboratory evaluation to assist with diagnosis currently includes serum immunoglobulin testing, immunophenotyping, assessment of vaccine response, and genetic testing. Additional emerging techniques include investigation of the B cell repertoire and the use of machine learning algorithms. Advances in our understanding of common variable immunodeficiency will ultimately contribute to earlier diagnosis and novel interventions with the goal of improving prognosis for these patients.

Durability of Antibody Response after Primary Pneumococcal Double-Dose Prime-Boost Vaccination in Adult Kidney Transplant Recipients and Candidates: 18-Month Follow-Up in a Non-Blinded, Randomised Clinical Trial

Background: Pneumococcal prime-boost vaccination is recommended for solid organ transplant recipients and candidates. The long-term durability of the antibody (AB) response is unknown. The same applies to a dose-dependent immune response. Methods: We studied the durability of the vaccine response after 18 months in kidney transplant recipients (KTRs) and patients on the kidney transplant waiting list (WLPs). Both groups received either a normal dose (ND) or a double dose (DD) of the 13-valent pneumococcal conjugate vaccine and the 23-valent pneumococcal polysaccharide vaccine. The average pneumococcal AB geometric mean concentration (GMC) was evaluated. A level ≥ 1 mg/L was considered protective against invasive pneumococcal disease (IPD). Results: Sixty WLPs and 70 KTRs were included. The proportion of participants protected declined from 52% to 33% in WLPs and from 29% to 16% in KTRs, with the previously significant dose-effect in WLPs no longer present (40% DD vs. 27% ND; p = 0.273). Average pneumococcal AB GMCs remained significantly above baseline levels (all groups p ≤ 0.001). Drug-induced immunosuppression diminished the vaccine dose-effect. Conclusions: At follow-up, the pneumococcal prime-boost vaccination still provided significantly elevated average pneumococcal AB GMCs in both populations. Though the proportion of participants protected against IPD in WLP-DD and WLP-ND were statistically comparable, a DD may still be recommended for WLPs (EudraCT: 2016-004123-23).