Hypogammaglobulinemia and infection risk in myotonic dystrophy type 1.

INTRODUCTION/AIMS: Hypogammaglobulinemia is a common yet under-recognized feature of myotonic dystrophy type 1 (DM1). The aims of our study were to determine the frequency of immunoglobulin G (IgG) deficiency in our cohort, to examine the association between immunoglobulin levels and cytosine-thymine-guanine (CTG) repeat length in the DMPK gene, and to assess whether IgG levels are associated with an increased risk of infection in DM1 patients. METHODS: We conducted a single-center, retrospective cross-sectional study of 65 adult patients with DM1 who presented to the Neuromuscular Clinic at Concord Repatriation General Hospital, Sydney, Australia, between January 2002 and January 2022. We systematically collected and analyzed clinical, laboratory, and genetic data for all patients with available serum electrophoresis and/or IgG level results. RESULTS: Forty-one percent of DM1 patients had IgG deficiency despite normal lymphocyte counts, IgA, IgM, and albumin levels. There was an association between CTG repeat expansion size and the degree of IgG deficiency (F = 6.3, p = .02). There was no association between IgG deficiency and frequency of infection in this group (p = .428). DISCUSSION: IgG deficiency is a frequent occurrence in DM1 patients and is associated with CTG repeat expansion size. Whether hypogammaglobulinemia is associated with increased infection risk in DM1 is unclear. A prospective multicenter cohort study is needed to evaluate this.

Hypogammaglobulinemia and Infection Events in Patients with Autoimmune Diseases Treated with Rituximab: 10 Years Real-Life Experience.

OBJECTIVES: To investigate predictors of hypogammaglobulinemia (HGG) and severe infection event (SIE) in patients with autoimmune disease (AID) receiving rituximab (RTX) therapy. METHODS: This was a retrospective study conducted in a tertiary medical center in China. Predictors of HGG or SIE were assessed using Cox analysis. Restricted cubic spline (RCS) analysis was applied to examine the correlation between glucocorticoid (GC) maintenance dose and SIE. RESULTS: A total of 219 patients were included in this study, with a cumulative follow-up time of 698.28 person-years. Within the study population, 117 patients were diagnosed with connective tissue disease, 75 patients presented with ANCA-associated vasculitis, and 27 patients exhibited IgG4-related disease. HGG was reported in 63.3% of the patients, where an obvious decline in IgG and IgM was shown three months after RTX initiation. The rate of SIE was 7.2 per 100 person-years. An increase in the GC maintenance dose was an independent risk factor for both hypo-IgG (HR 1.07, 95% CI 1.02-1.12, p = 0.003) and SIE (HR 1.06, 95% CI 1.02-1.1, p = 0.004). Further RCS analysis identified 7.48 mg/d prednisone as a safe threshold dose for patients who underwent RTX treatment to avoid a significantly increased risk for SIE. CONCLUSION: HGG was relatively common in RTX-treated AID patients. Patients with chronic lung disease or who were taking ≥ 7.5 mg/d prednisone during RTX treatment were at increased risk for SIE and warrant attention from physicians.

A Nationwide Study of the Delayed Diagnosis and the Clinical Manifestations of Predominantly Antibody Deficiencies and CTLA4-Mediated Immune Dysregulation Syndrome in Greece.

Background and Objectives: Predominantly antibody deficiencies (PAD) represent the most common type of primary immunodeficiencies in humans, characterized by a wide variation in disease onset, clinical manifestations, and outcome. Considering that the prevalence of PAD in Greece is unknown, and there is limited knowledge on the clinical and laboratory characteristics of affected patients, we conducted a nationwide study. Materials and Methods: 153 patients (male/female: 66/87; median age: 43.0 years; range: 7.0-77.0) diagnosed, and followed-up between August 1979 to September 2023. Furthermore, we classified our cohort into five groups according to their medical history, immunoglobulin levels, and CTLA4-mutational status: 123 had common variable immunodeficiency (CVID), 12 patients with "secondary" hypogammaglobulinemia due to a previous B-cell depletion immunotherapy for autoimmune or malignant disease several years ago (median: 9 years, range 6-14) displaying a typical CVID phenotype, 7 with combined IgA and IgG subclass deficiencies, 5 patients with CVID-like disease due to CTLA4-mediated immune dysregulation syndrome, and 6 patients with unclassified hypogammaglobulinemia. Results: We demonstrated a remarkable delay in PAD diagnosis, several years after the onset of related symptoms (median: 9.0 years, range: 0-43.0). A family history of PAD was only present in 11.8%, with the majority of patients considered sporadic cases. Most patients were diagnosed in the context of a diagnostic work-up for recurrent infections, or recurrent/resistant autoimmune cytopenias. Interestingly, 10 patients (5.6%) had no history of infection, diagnosed due to either recurrent/resistant autoimmunity, or during a work-up of their medical/family history. Remarkable findings included an increased prevalence of lymphoproliferation (60.1%), while 39 patients (25.5%) developed bronchiectasis, and 16 (10.5%) granulomatous disease. Cancer was a common complication in our cohort (25 patients, 16.3%), with B-cell malignancies representing the most common neoplasms (56.7%). Conclusion: Our findings indicate the necessity of awareness about PAD and their complications, aiming for early diagnosis and the appropriate management of affected patients.

Association between serum IgG concentrations and the incidence of infections in patients with chronic lymphocytic leukemia and secondary immunodeficiency under treatment with Privigen.

OBJECTIVE: To investigate the association between serum immunoglobulin G (IgG) concentrations and the incidence of infections in patients with chronic lymphocytic leukemia (CLL) and secondary immunodeficiency receiving treatment with Privigen. MATERIALS AND METHODS: Data was analyzed from a non-interventional study conducted in 31 centers in Germany and 1 in Austria. Adult CLL patients with hypogammaglobulinemia and recurrent infections were allowed to enter the study upon signing informed consent, if a prior decision for treatment with Privigen had been made. All infections requiring an antimicrobial treatment were subject to analysis. Patients were stratified according to their mean post-baseline serum IgG trough levels in a group with lower IgG trough levels (≤ 5.0 g/L), and a group with higher IgG trough levels (> 5.0 g/L). RESULTS: Overall, 89 patients and 840 treatment cycles were analyzed. Up to 11 treatment cycles (average duration 29 days) were documented in each patient. In the group with higher IgG trough levels (> 5.0 g/L, N = 72), significantly fewer infections were observed than in the group with lower IgG trough levels (≤ 5.0 g/L, N = 17), including fewer severe and serious infections. The Privigen dosage was a major determinant of the post-baseline serum IgG levels. Overall tolerability of Privigen was assessed as very good or good in 91% of patients. CONCLUSION: This analysis confirms the association of serum IgG trough levels with the incidence of infections and highlights the importance of careful monitoring of IgG levels during treatment of secondary immunodeficiencies in CLL patients.

Multiple Sclerosis, Rituximab, Hypogammaglobulinemia, and Risk of Infections.

BACKGROUND AND OBJECTIVES: B-cell-depleting therapies increase the risk of infections and hypogammaglobulinemia. These relationships are poorly understood. The objectives of these analyses were to estimate how much of this rituximab-associated infection risk is mediated by hypogammaglobulinemia and to identify other modifiable risk factors in persons with multiple sclerosis (pwMS). METHODS: We conducted a retrospective cohort study of rituximab-treated pwMS from January 1, 2008, to December 31, 2020, in Kaiser Permanente Southern California. Cumulative rituximab dose was defined as ≤2, >2 and ≤4, or >4 g. Serious infections were defined as infections requiring or prolonging hospitalizations, and recurrent outpatient infections as seeking care for ≥3 within 12 months. Exposures, outcomes, and covariates were collected from the electronic health record. Adjusted hazard ratios (aHRs) were estimated using Andersen-Gill hazards models, and generalized estimating equations were used to examine correlates of IgG values. Cross-sectional causal mediation analyses of rituximab and hypogammaglobulinemia were conducted. RESULTS: We identified 2,482 pwMS who were treated with rituximab for a median of 2.4 years (interquartile range = 1.3-3.9). The average age at rituximab initiation was 43.0 years, 71.9% were female, 49.7% were White, non-Hispanic patients, and 29.6% had advanced disability (requiring walker or worse). Seven hundred patients (28.2%) developed recurrent outpatient infections, 155 (6.2%) developed serious infections, and only 248 (10.0%) had immunoglobulin G (IgG) < 700 mg/dL. Higher cumulative rituximab dose (>4 g) was correlated with lower IgG levels (Beta = -58.8, p < 0.0001, ref ≤2 g) and, in models mutually adjusted for hypogammaglobulinemia, both were independently associated with an increased risk of serious (>4 g, aHR = 1.56, 95% CI 1.09-2.24; IgG < 500, aHR = 2.98, 95% CI 1.56-5.72) and outpatient infections (>4 g, aHR = 1.73, 95% CI 1.44-2.06; IgG < 500 aHR = 2.06, 95% CI 1.52-2.80; ref = IgG ≥ 700). Hypogammaglobulinemia explained at most 17.9% (95% CI -47.2-119%) of serious infection risk associated with higher cumulative rituximab exposure but was not significant for outpatient infections. Other independent modifiable risk factors were advanced physical disability for serious (aHR = 5.51, 95% CI 3.71-8.18) and outpatient infections (aHR = 1.24, 95% CI 1.06-1.44) and COPD (aHR = 1.68, 95% CI 1.34-2.11) and obesity (aHR = 1.25, 95% CI 1.09-1.45) for outpatient infections. DISCUSSION: Higher cumulative rituximab doses increase the risk of infections even in this population where 90% of patients maintained normal IgG levels. Clinicians should strive to use minimally effective doses of rituximab and other B-cell-depleting therapies and consider important comorbidities to minimize risks of infections.

Prediction of severe infections in chronic lymphocytic leukemia: a simple risk score to stratify patients at diagnosis.

Chronic Lymphocytic Leukemia (CLL) is well-known for increasing susceptibility to infections. Factors such as immune dysregulation, IGHV status, hypogammaglobulinemia, and patient comorbidity and treatment, contribute to higher infection rates and mortality. However, the impact of hypogammaglobulinemia on infection rates is controversial. We aimed to identify clinical and biological parameters linked to the risk of severe infectious events. Additionally, we set up a straightforward risk infection score to stratify CLL patients at diagnosis, thereby enabling the development of suitable infection prevention strategies. We retrospectively evaluated 210 unselected CLL patients diagnosed between 1988 and 2018. This evaluation encompassed demographics, Binet stage, immunoglobulin (Ig) levels, treatment history, comorbidities, and IGHV mutational status at diagnosis. The frequency and severity of infectious events were recorded. Analysis revealed that age, IGHV mutational status, Binet stage, and hypogammaglobulinemia were statistically associated with the Time to First Infection (TTFI) in univariate and multivariate analyses. Using hazard ratios from the multivariate analysis, we finally devised a risk scoring system that integrated age, IGHV mutational status, immunoglobulin levels, and Binet stage to stratify patients at diagnosis based on their specific infection risk. In our cohort, disease progression and infections were the leading cause of death. These findings pointed out the clinical need for a screening process strategic for defining infectious risk at the time of CLL diagnosis, with a significant enhancement in the clinical management of these patients.

Secondary hypogammaglobulinemia in adults-A large retrospective cohort study.

BACKGROUND AND OBJECTIVE: IgG replacement therapy (IgG-RT) has radically changed the clinical evolution of primary immunodeficiencies, yet the information regarding secondary hypogammaglobulinemia (SHG) is insufficient or conflicting. We aim to describe clinical features, evolution and treatment of SHG patients in our center. METHODS: Dynamic retrospective cohort between January 2001 and July 2021 of adults with gamma globulin fraction <0.6g/dL in a serum protein electrophoresis and a coincident decrease of IgG levels - with a disease-related SHG or treatment that reduces serum immunoglobulins. RESULTS: We included 1012 patients with SHG with a median follow-up of 5 years (IQR 2-8). Hematological diseases were identified in 95% of the patients and 61% received drugs related to SHG. Sixty five percent had more than one etiological factor associated with SHG. Infectious diseases were present in 69% of the patients, 48% had respiratory infections and 17% had severe infections. There was statistical association between respiratory and severe infections with multiple myeloma (MM), lymphoma and rituximab. MGUS had less infections and death compared with other etiologies. IgG-RT was indicated in 18.7% of the patients and 4.6% received it for more than 6 months with variable intervals. Among the latter group, there was a significant reduction of all-type infections and respiratory infections with IgG-RT (p<0.001), and it was consistent with similar findings in lymphoma, MM and all IgG levels subgroups. CONCLUSION: SHG was associated with more than one etiological factor and a high frequency of infections. IgG-RT indication was irregular yet still effective. It is relevant to consider IgG levels screening, monitoring and accurate indication of IgG-RT.

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

OBJECTIVES: B-cell depletion induced by rituximab (RTX) in ANCA-associated vasculitis (AAV) is a risk factor for hypogammaglobulinemia. Aggregating data on gammaglobulin levels kinetics during RTX and its association with the risk of relapse and severe infection is of interest. METHODS: Gammaglobulin levels were collected before induction therapy and during RTX maintenance therapy. We used different definitions of gammaglobulin decline: 1/gammaglobulin levels <6 g/L after induction; 2/>25 % decline in gammaglobulin levels between induction and maintenance, and 3/both. Our primary objective was the impact of gammaglobulin decline on the risk of relapse and severe infections. RESULTS: We included 98 patients. Patients with gammaglobulin level <6 g/L after induction and gammaglobulin decline >25 % were older (OR 3.9; 95%CI 1.1-16.1), had more frequently baseline gammaglobulin levels <10 g/L (OR 6.0; 95%CI 1.7-25.8) and received more frequent pulses of methylprednisolone at induction (OR 4.6; 95%CI 1.3-18.5). Severe infection-free survival was significantly poorer in patients with both gammaglobulin <6 g/L and gammaglobulin decline >25 % (adjusted HR 2.3; 95%CI 1.0-5.1) and in those who received pulses of methylprednisolone (HR 5.6; 95%CI 2.3-13.4). Gammaglobulin decline was in contrast not associated with the risk of relapse. CONCLUSION: Older age, low gammaglobulin levels and pulses of methylprednisolone at induction increase the likelihood of gammaglobulin decline after induction therapy. Such decline was associated with an increased risk of severe infections but not lower risk of vasculitis relapse. Pulses of methylprednisolone at induction had an independent negative impact on gammaglobulin levels and the risk of severe infections.

Associations between Antiepileptic Use and Hypogammaglobulinaemia: Findings from a Population-Based Case-Control Study Using Data Linkage.

BACKGROUND AND OBJECTIVES: Increased mortality in epilepsy due to infections (other than pneumonia) has been demonstrated. Small case series of people on antiepileptic drugs (AEDs) have described hypogammaglobulinaemia, which may predispose to infections. It is unclear whether hypogammaglobulinaemia is more frequent in people on AEDs, what AEDs it is associated with, or what clinical impact it has. In this population-based study, we aimed to determine whether AEDs were associated with hypogammaglobulinaemia, which AEDs were associated, and whether the associations may be causal. METHODS: We conducted an unmatched case-control study using data linkage of routinely collected biochemistry, prescribing, and morbidity datasets in North-East Scotland from 2009-2021. Cases were participants with immunoglobulin levels less than the reference range. Controls were those with normal/high immunoglobulin levels. Logistic regression was used to investigate associations between AED exposure and any hypogammaglobulinaemia, adjusting for age, sex, and comorbidity. We also analysed low IgA, IgM, and IgG separately. We analysed "any AED" exposure and common individual drugs separately. Cumulative exposure data were used to determine whether an exposure-response relationship was present. RESULTS: 18,666 cases and 127,157 controls were identified. Use of any AED was associated with increased risk of hypogammaglobulinaemia (adjusted odds ratio [aOR] 1.20 [95% CI: 1.15-1.25]). Phenytoin use was strongly associated with low IgA (aOR 5.90 [95% CI: 3.04, 10.43]). Carbamazepine and lamotrigine were also associated with low IgA. Apart from topiramate, which was associated with a non-significant decrease in odds of hypogammaglobulinaemia, there was a consistent increase in odds of hypogammaglobulinaemia across most AEDs studied. Panhypogammaglobulinaemia was associated with any AED use, carbamazepine, lamotrigine, gabapentin, and multiple AED use. There was evidence of an exposure-response relationship between any AED use and any hypogammaglobulinaemia, low IgA, and low IgG. Carbamazepine and probably lamotrigine also had an exposure-response relationship with any hypogammaglobulinaemia. DISCUSSION: AEDs may increase hypogammaglobulinaemia risk. Specific classes of immunoglobulins are differentially affected, and the exposure-response analysis suggests this may be causal. Further work should investigate the clinical impact of these findings. Clinicians should check immunoglobulin levels if unusual or recurrent infections occur in patients treated with AEDs.

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

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

[Prevalence of persistent hypogammaglobulinemia in patients with autoimmune rheumatic disease who received treatment with Rituximab in a national medical center in Mexico]. / Prevalencia de hipogammaglobulinemia persistente en pacientes con enfermedad autoinmune que reciben rituximab en un centro de referencia nacional en México.

OBJECTIVE: To describe the prevalence of persistent hypogammaglobulinemia in patients receiving Rituximab as a treatment for autoimmune rheumatological diseases. METHODS: A transversal, retrospective and unicentric study, carried out in patients with autoimmune rheumatic diseases who were admitted to the Rheumatology service of the Hospital de Especialidades Dr. Antonio Fraga Mouret, Centro Médico Nacional La Raza, Mexico City, to receive treatment with rituximab between January 2013 and January 2018. Descriptive and inferential statistics of serum levels of immunoglobulins, clinical-demographic characteristics, diagnosis, and treatment received were performed. RESULTS: from 262 patients with autoimmune rheumatological disease who received treatment with Rituximab; We identified 8 patients with persistent hypogammaglobulinemia (6 women and 2 men), this is a prevalence of 3.1%. No associated factors with the development of hypogammaglobulinemia were identified. CONCLUSIONS: Until now, no associated prognostic or predictive factors have been identified with persistent hypogammaglobulinemia. Additional prospective studies are required to understand more precisely the implications of persistent hypogammaglobulinemia in patients with autoimmune diseases.

OBJECTIVO: Determinar la prevalencia de hipogammaglobulinemia persistente en pacientes con enfermedades reumatológicas autoinmunes que reciben rituximab. MÉTODOS: Estudio trasversal, retrospectivo y unicéntrico, emprendido en pacientes con enfermedades reumatológicas autoinmunes, que acudieron a la Consulta externa del servicio de Reumatología del Hospital de Especialidades Dr. Antonio Fraga Mouret, Centro Médico Nacional La Raza, Ciudad de México, entre enero de 2013 y enero de 2018, para recibir tratamiento con rituximab. El análisis de los datos se efectuó con estadística descriptiva e inferencial, para la evaluación de las concentraciones séricas de inmunoglobulinas, características clínico demográficas, diagnóstico y tratamiento. RESULTADOS: Estudio trasversal, retrospectivo y unicéntrico, emprendido en pacientes con enfermedades reumatológicas autoinmunes, que acudieron a la Consulta externa del servicio de Reumatología del Hospital de Especialidades Dr. Antonio Fraga Mouret, Centro Médico Nacional La Raza, Ciudad de México, entre enero de 2013 y enero de 2018, para recibir tratamiento con rituximab. El análisis de los datos se efectuó con estadística descriptiva e inferencial, para la evaluación de las concentraciones séricas de inmunoglobulinas, características clínico demográficas, diagnóstico y tratamiento. CONCLUSIONES: Hasta el momento no se han identificado factores asociados, pronósticos o predictivos, con hipogammaglobulinemia persistente. Se requieren estudios prospectivos adicionales para conocer con mayor precisión las implicaciones de la hipogammaglobulinemia persistente en pacientes con enfermedades autoinmunes.

A Registry Study of 240 Patients with X-Linked Agammaglobulinemia Living in the USA.

PURPOSE: To understand the natural history and clinical outcomes for patients with X-linked agammaglobulinemia (XLA) in the United States utilizing the United States Immunodeficiency Network (USIDNET) patient registry. METHODS: The USIDNET registry was queried for data from XLA patients collected from 1981 to 2019. Data fields included demographics, clinical features before and after diagnosis of XLA, family history, genetic mutation in Bruton's tyrosine kinase (BTK), laboratory findings, treatment modalities, and mortality. RESULTS: Data compiled through the USIDNET registry on 240 patients were analyzed. Patient year of birth ranged from 1945 to 2017. Living status was available for 178 patients; 158/178 (88.8%) were alive. Race was reported for 204 patients as follows: White, 148 (72.5%); Black/African American, 23 (11.2%); Hispanic, 20 (9.8%); Asian or Pacific Islander, 6 (2.9%), and other or more than one race, 7 (3.4%). The median age at last entry, age at disease onset, age at diagnosis, and length of time with XLA diagnosis was 15 [range (r) = 1-52 years], 0.8 [r = birth-22.3 years], 2 [r = birth-29 years], and 10 [r = 1-56 years] years respectively. One hundred and forty-one patients (58.7%) were < 18 years of age. Two hundred and twenty-one (92%) patients were receiving IgG replacement (IgGR), 58 (24%) were on prophylactic antibiotics, and 19 (7.9%) were on immunomodulatory drugs. Eighty-six (35.9%) patients had undergone surgical procedures, two had undergone hematopoietic cell transplantation, and two required liver transplantation. The respiratory tract was the most affected organ system (51.2% of patients) followed by gastrointestinal (40%), neurological (35.4%), and musculoskeletal (28.3%). Infections were common both before and after diagnosis, despite IgGR therapy. Bacteremia/sepsis and meningitis were reported more frequently before XLA diagnosis while encephalitis was more commonly reported after diagnosis. Twenty patients had died (11.2%). The median age of death was 21 years (range = 3-56.7 years). Neurologic condition was the most common underlying co-morbidity for those XLA patients who died. CONCLUSIONS: Current therapies for XLA patients reduce early mortality, but patients continue to experience complications that impact organ function. With improved life expectancy, more efforts will be required to improve post-diagnosis organ dysfunction and quality of life. Neurologic manifestations are an important co-morbidity associated with mortality and not yet clearly fully understood.

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

BACKGROUND: There is paucity of information on rituximab-associated hypogammaglobulinemia (HGG) and its potential infectious consequences in children treated for idiopathic nephrotic syndrome (INS). METHODS: A survey was distributed by the European Society Pediatric Nephrology to its members. It addressed the screening and management practices of pediatric nephrology units for recognizing and treating RTX-associated HGG and its morbidity and mortality. Eighty-four centers which had treated an overall 1328 INS children with RTX responded. RESULTS: The majority of centers administered several courses of RTX and continued concomitant immunosuppressive therapy. Sixty-five percent of centers routinely screened children for HGG prior to RTX infusion, 59% during, and 52% following RTX treatment. Forty-seven percent had observed HGG prior to RTX administration, 61% during and 47% >9 months following treatment in 121, 210, and 128 subjects respectively. Thirty-three severe infections were reported among the cohort of 1328 RTX-treated subjects, of whom 3 children died. HGG had been recognized in 30/33 (80%) of them. CONCLUSIONS: HGG in steroid-dependent/frequently relapsing nephrotic syndrome (SDNS/FRNS) children is probably multifactorial and can be observed prior to RTX administration in children with SDNS/FRNS. Persistent HGG lasting >9 months from RTX infusion is not uncommon and may increase the risk of severe infections in this cohort. We advocate for the obligatory screening for HGG in children with SDNS/FRNS prior to, during, and following RTX treatment. Further research is necessary to identify risk factors for developing both HGG and severe infections before recommendations are made for its optimal management. A higher resolution version of the Graphical abstract is available as Supplementary information.

Hypogammaglobulinemia after front-line immunochemotherapy in patients with follicular lymphoma.

INTRODUCTION: Hypogammaglobulinemia after front-line immunochemotherapy for follicular lymphoma is a poorly studied adverse event that could be related to the appearance of severe and/or recurrent non-neutropenic infections which could affect the quality of life of the patients, even motivating a need of long-term replacement therapy with human immunoglobulins. METHODS: Observational, retrospective study aiming to estimate the incidence of hypogammaglobulinemia, as well as its severity and clinical consequences, and to explore possible predictive factors for its development. Specific immunoglobulin deficiencies were also studied. RESULTS: 76.5% of patients had hypogammaglobulinemia during or after front-line treatment, mostly grade 1-2; with 38.8% patients who developed clinically relevant infections and 20% patients requiring human immunoglobulins replacement therapy. A high-risk FLIPI score was identified as a risk factor for hypogammaglobulinemia (ods ratio: 4.51; 95% confidence interval: 1.29-15.68; p < 0.001) and basal gamma globulin level as a protective factor (odds ratio: 0.92; 95% confidence interval: 0.988-0.996; p = 0.018). Any type of immunochemotherapy regimen was associated with different risks of hypogammaglobulinemia in our study. CONCLUSIONS: Hypogammaglobulinemia appears in a high percentage of patients with follicular lymphoma in a real-world population, identifying a high-risk FLIPI score as a risk factor for its development and basal gamma globulins as a protective factor.

Predictors of hypogammaglobulinemia and serious infections among patients receiving ocrelizumab or rituximab for treatment of MS and NMOSD.

BACKGROUND AND OBJECTIVES: Ocrelizumab and rituximab are monoclonal antibodies targeting the CD20 marker on B lymphocytes. The enhanced efficacy of B lymphocyte depleting therapies poses a greater risk of decreased immunoglobulin (Ig) levels. The rate and risk factors of hypogammaglobulinemia in MS and NMOSD patients treated with anti-CD20 therapies are unknown. METHODS: A retrospective study was conducted among patients who received anti-CD20 therapy for the treatment of MS, NMOSD, and other related neurological disorders. The goal was to determine the incidence and risk factors of hypogammaglobulinemia and serious infections in patients receiving ocrelizumab versus rituximab. The secondary goals were to determine the rates of lymphopenia, neutropenia, and early B cell repopulation among patients on anti-CD20 therapy. RESULTS: Overall, 184 patients (mean age 48.4 ± 13.7, 66.8% female) met inclusion criteria; 152 patients received ocrelizumab and 32 patients received rituximab. A total of 22 patients (12%) developed hypogammaglobulinemia. Patients who developed hypogammaglobulinemia were more likely to have been ≥50 years of age (p = .0275) with lower baseline IgG (p = .001) and IgA (p = .0038) levels. Serious infections were observed in 21 patients (11%) and seen more commonly in those that developed total lymphopenia (<1.0 × 109/L) and had longer duration of B-cell therapy. Multivariate analysis identified age ≥ 50 years, white race, and rituximab as independent predictors of hypogammaglobulinemia, and absolute lymphopenia as an independent risk factor for serious infections. DISCUSSION: Among patients receiving anti-CD20 therapy, 12% of patients experienced hypogammaglobulinemia which was seen more commonly in white patients, at least 50 years old, with lower baseline IgG and IgA levels and in those treated with rituximab. Serious infections were seen more commonly in patients with total lymphopenia and longer exposure to anti-CD20 therapy.

Predictors of hospitalization due to infection in rituximab-treated MS patients.

BACKGROUND: Rituximab is extensively used off-label to treat multiple sclerosis (MS), and long-term vigilance for adverse events is needed. This study was conducted to determine frequencies and predictors of hematological adverse events, including hypogammaglobulinemia, severe lymphopenia, neutropenia, and infections leading to hospitalization. METHODS: This retrospective cohort study included all patients with MS initiating rituximab treatment at Haukeland University Hospital between January 1st, 2017, and July 1st, 2021. Patients were followed by clinical monitoring and repeated blood sampling every six months. Clinical outcomes and laboratory results were retrieved from the Norwegian MS Registry and Biobank and the patient administrative system at Haukeland University Hospital. RESULTS: Five hundred and fifty-six patients were included, 515 with relapsing-remitting MS (RRMS) and 41 with progressive MS. Overall, 33 patients (5.9%) experienced 56 episodes of infections requiring hospital admission. Sixty patients (10.8%) had confirmed hypogammaglobulinemia, 17 (3.1%) had confirmed severe lymphopenia, and 10 (1.8%) had confirmed severe neutropenia. Predictors of infection requiring hospital admission were progressive MS (adjusted OR (aOR): 4.81; 95%CI: 1.25-18.48), duration of treatment with rituximab (aOR: 1.52; 95%CI: 1.11-2.09) and confirmed severe lymphopenia (aOR: 13.58; 95%CI: 3.41-54.06) and neutropenia (aOR: 13.40; 95%CI: 2.93-61.25). Of the hematological abnormalities, only hypogammaglobulinemia was associated with treatment duration (aOR: 1.35; 95%CI: 1.09-1.69). CONCLUSION: The risk of hospitalization due to infection is associated with time on rituximab treatment, in patients with lympho- or neutropenia, and in patients with primary progressive MS. We observed a time-dependent decline in IgG values, in contrast to neutrophil and lymphocyte count, suggesting a cumulative dose-dependent response. These predictors can assist clinicians in assessing and monitoring MS patients receiving rituximab.

Hypogammaglobulinemia in pediatric kidney transplant recipients.

Infections remain the most common cause of hospitalization after kidney transplantation, contributing to significant post-transplant morbidity and mortality. There is a growing body of literature that suggests that immunoglobulins may have a significant protective role against post-transplant infections, although the literature remains sparse, inconsistent, and not well publicized among pediatric nephrologists. Of great concern are data indicating a high prevalence of immunoglobulin abnormalities following transplantation and a possible link between these abnormalities and poorer outcomes. Our educational review focuses on the epidemiology and risk factors for the development of immunoglobulin abnormalities after kidney transplantation, the outcomes in patients with low immunoglobulin levels, and studies evaluating possible interventions to correct these immunoglobulin abnormalities.

Algerian Registry for Inborn Errors of Immunity in Children: Report of 887 Children (1985-2021).

INTRODUCTION: Inborn errors of immunity (IEI) represent a heterogeneous large group of genetic disorders characterized by susceptibility of affected individuals to recurrent infections, autoimmune/inflammatory diseases, allergy, and malignancy. We aimed to report for the first time the Algerian registry for IEI in children. METHODS: We described the characteristics of IEI in Algerian children from the data collected in the Algerian registry for IEI between 1985 and 2021. RESULTS: Over a period of 37 years, we included 887 children (530 male, 59.6%) with a mean age at diagnosis of 3.23 years and a mean diagnosis delay of 2 years. The prevalence rate was estimated at 1.97/100,000 inhabitants or 5.91/100,000 children. The parental consanguinity was found in 52.6%. The most prevalent category was combined immunodeficiencies (CID) (35.5%), followed by predominantly antibody deficiencies (24.5%) and CID with syndromic features (18.3%). The most predominant diseases were severe CID (134 cases), MHC II deficiency (99 cases), agammaglobulinemia (82 cases), common variable immunodeficiency (78 cases), hyper IgE syndromes (61 patients), ataxia-telangiectasia (46 patients), Wiskott-Aldrich syndrome (40 patients) and chronic granulomatous disease (39 cases). The clinical presentation was dominated by lower respiratory tract infections (69%), failure to thrive (38.3%), and chronic diarrhea (35.2%). Genetic analysis was performed in 156 patients (17.6%). The global mortality rate was 28.4% mainly caused by CID. CONCLUSION: This is the first report of the Algerian registry for IEI in children. Data is globally similar to that of the Middle East and North African (MENA) registries with high consanguinity, predominance of CID, and significant mortality. This registry highlights the weak points that should be improved in order to provide better patient care.

Rituximab-Induced Hypogammaglobulinemia and Risk of Infection in Neuromyelitis Optica Spectrum Disorders: A 14-Year Real-Life Experience.

BACKGROUND AND OBJECTIVES: To investigate the frequency and predictors of hypogammaglobulinemia during long-term rituximab (RTX) treatment in patients with neuromyelitis optica spectrum disorder (NMOSD) and its association with infections. METHODS: We retrospectively reviewed the data of patients with NMOSD who received RTX through the maintenance regimen based on memory B-cell detection for at least 1 year from 2006 to 2021 at an institutional referral center for NMOSD. RESULTS: A total of 169 patients received a median of 10 courses (range 1-27) of RTX reinfusion after induction over a median of 8 (range, 1-15) years. Their mean serum immunoglobulin (Ig)G level began to decline significantly after 2 years of treatment, steadily declined at a rate of 2%-8% per year for the following 8 years, and then plateaued after 10 years. The proportion of patients with hypo-IgG (<6 g/L) increased from 1.2% after 1 year of treatment to 41% after 14 years of treatment. While being treated with RTX, 58 (34%) patients had 114 infections, of whom 14 (8%) patients had 15 severe infections. Multivariable logistic regression analyses identified duration of RTX treatment in years (odds ratio [OR] 1.234, 95% confidence interval [CI] 1.015-1.502), mean annual RTX dose (OR 0.063, 95% CI 0.009-0.434), history of mitoxantrone (OR 3.318, 95% CI 1.109-9.93), hypo-IgG at baseline (OR 40.552, 95% CI 3.024-543.786), and body mass index >25 kg/m2 (OR 4.798, 95% CI 1.468-15.678) as independent predictors of hypo-IgG. The risk of infection during RTX treatment was independently associated with high Expanded Disability Status Scale scores (OR 1.427, 95% CI 1.2-1.697) and relapses during RTX treatment (OR 1.665, 95% CI 1.112-2.492), but not with hypogammaglobulinemia. DISCUSSION: Over 14 years of long-term RTX treatment, IgG levels gradually decreased, and the frequency of hypo-IgG increased to 41% of the patients. Patients with prolonged memory B-cell depletion after RTX, previous mitoxantrone history, hypo-IgG at baseline, or obesity were at risk of developing RTX-induced hypogammaglobulinemia. Nevertheless, infection rates remained low during treatment, and reduced immunoglobulin levels were not associated with an increased incidence of infections.