Defective Antibody Production Research Articles

Immunogenetic Landscape in Pediatric Common Variable Immunodeficiency.

Common variable immunodeficiency (CVID) is the most common symptomatic antibody deficiency, characterized by heterogeneous genetic, immunological, and clinical phenotypes. It is no longer conceived as a sole disease but as an umbrella diagnosis comprising a spectrum of clinical conditions, with defects in antibody biosynthesis as their common denominator and complex pathways determining B and T cell developmental impairments due to genetic defects of many receptors and ligands, activating and co-stimulatory molecules, and intracellular signaling molecules. Consequently, these genetic variants may affect crucial immunological processes of antigen presentation, antibody class switch recombination, antibody affinity maturation, and somatic hypermutation. While infections are the most common features of pediatric CVID, variants in genes linked to antibody production defects play a role in pathomechanisms of immune dysregulation with autoimmunity, allergy, and lymphoproliferation reflecting the diversity of the immunogenetic underpinnings of CVID. Herein, we have reviewed the aspects of genetics in CVID, including the monogenic, digenic, and polygenic models of inheritance exemplified by a spectrum of genes relevant to CVID pathophysiology. We have also briefly discussed the epigenetic mechanisms associated with micro RNA, DNA methylation, chromatin reorganization, and histone protein modification processes as background for CVID development.

Inborn errors of immunity: features of epidemiology and continuity of medical care in the Republic of Tatarstan

BACKGROUND: Currently, inborn errors of immunity represent one of the most interesting problems in clinical immunology. The data obtained in the field of studying pathogenetic mechanisms and clinical manifestations, expanding diagnostic capabilities, including molecular genetic methods, formed the basis for revising the classification and introducing new modern treatment methods. The study of regional characteristics of inborn errors of immunity is important because it allows us to determine epidemiological indicators, clinical features of diseases and evaluate the therapy being carried out.
 AIM: To assess the effectiveness and level of continuity of medical care in the Republic of Tatarstan based on an epidemiological analysis of a group of patients diagnosed with primary immunodeficiency.
 MATERIALS AND METHODS: analysis of the register of patients living in the Republic of Tatarstan with an established diagnosis of primary immunodeficiency, observed from 1994 to 2023. A total of 240 patients were included in the study.
 RESULTS: An epidemiological analysis of inborn errors of immunity in the Republic of Tatarstan revealed an overall prevalence of 6.0 per 100,000 population, with the status "alive" ― 4.98 per 100,000 population, excluding patients with selective IgA deficiency ― 5.3 and 4.4 per 100,000 population, respectively, with a high proportion of patients over 18 years of age (53%), with the largest group of patients having defects in antibody production (42%).
 CONCLUSION: The increasing relevance of the problem of primary immunodeficiency requires special attention to the organization of medical care for patients with primary immunodeficiency, increasing continuity between specialized pediatric services and the adult network, as well as developing issues of interdisciplinary interaction.

B-cell intrinsic regulation of antibody mediated immunity by histone H2A deubiquitinase BAP1.

BAP1 is a deubiquitinase (DUB) of the Ubiquitin C-terminal Hydrolase (UCH) family that regulates gene expression and other cellular processes, through its direct catalytic activity on the repressive epigenetic mark histone H2AK119ub, as well as on several other substrates. BAP1 is also a highly important tumor suppressor, expressed and functional across many cell types and tissues. In recent work, we demonstrated a cell intrinsic role of BAP1 in the B cell lineage development in murine bone marrow, however the role of BAP1 in the regulation of B cell mediated humoral immune response has not been previously explored. In the current study, we demonstrate that a B-cell intrinsic loss of BAP1 in activated B cells in the Bap1 fl/fl Cγ1-cre murine model results in a severe defect in antibody production, with altered dynamics of germinal centre B cell, memory B cell, and plasma cell numbers. At the cellular and molecular level, BAP1 was dispensable for B cell immunoglobulin class switching but resulted in an impaired proliferation of activated B cells, with genome-wide dysregulation in histone H2AK119ub levels and gene expression. In summary, our study establishes the B-cell intrinsic role of BAP1 in antibody mediated immune response and indicates its central role in the regulation of the genome-wide landscapes of histone H2AK119ub and downstream transcriptional programs of B cell activation and humoral immunity.

Defective antibody production in double-strand DNA breakage syndromes: insights and implications

DNA double-strand breakage (DSB) syndrome are rare monogenic inborn errors of immunity with a vast spectrum of manifestations. In addition to a high predisposition to malignancies, these patients are also at risk of recurrent, severe, or opportunistic infections. Therefore, monitoring of immunoglobulin levels and responses to vaccination, as well as interventions such as immunoglobulin replacement therapy should be considered to improve the patients’ outcomes. As DNA double-strand breakage repair pathways have a great impact on lymphocyte development through involvement in the generation of B and T cell receptors, disruption in one of their components may lead to genomic instability, aberrant B-cell receptor (BCR)/T-cell receptor (TCR) development, impaired B cell lymphocyte development and antibody production. The aim of this review is to describe the most common of DBSs, such as ataxia telangiectasia (AT), AT-like disorder (ATLD), Nijmegen breakage syndrome (NBS), Nijmegen breakage syndrome-like disorder (NBSLD), Bloom syndrome (BS), Fanconi anemia (FA) and some others with a focus on the role of DNA repair proteins in the development of humoral immunity. We also describe the immunoglobulin profile, recommendations for diagnosis, screening, and interventions for the ideal management of affected patients.

The Integrin Adaptor Kindlin-3 Is a Gatekeeper for Germinal Center Responses and the Development of Chronic Lymphocytic Leukemia

Background: High affinity antibody production occurs in the germinal centers (GCs), which are segregated into a dark zone (DZ) and a light zone (LZ). GC B cells proliferate in the DZ and encounter follicular dendritic cells in the LZ. Cell trafficking between the two zones is regulated by CXCR4 (DZ) and CXCR5 (LZ) signaling. Integrins may regulate B cell positioning and B cell immune synapse formation. Recently, we have shown that the integrin adaptor kindlin-3 is not only required for integrin activation in B cells, but unexpectedly also acts as a brake on CXCR5 responsiveness. Kindlin-3 thereby prevents B cell hyperactivation and differentiation into GC-like B cells in absence of antigen. 1 Here we investigate the impact of kindlin-3 on GC responses upon antigen challenging and on malignant transformation. Methods: We developed a B cell-specific knockout mouse model (mb1Cre Fermt3fl/fl (K3ΔB)) in which kindlin-3 ( Fermt3) was knocked out in all B cells. K3ΔB and control wild-type (WT) mice were challenged with sheep red blood cells (SRBC). GC formation and immunoglobulin (Ig) production were analyzed by flow cytometry. Ex vivo B cell proliferation and Ig class switching formation assays were performed. We investigated the immune synapse formation of WT and kindlin-3-deficient B cells using a biomimetic model involving a planar artificial lipid bilayer containing GPI-linked integrin ligands and bound fluorescently labeled surrogate antigens. The formation of immune synapse and central antigen aggregation in the immune synapse were analyzed by real-time interference reflection microscopy and laser scanning confocal microscopy. To investigate the contribution of kindlin-3 in a model of mature B cell malignancy, we used TCL1 transgenic (TCL1) mice resembling chronic lymphocytic leukemia (CLL) to generate the mb1Cre Fermt3fl/fl Tcl1 (TCL1-K3ΔB) mouse model. Tumor burden in TCL1-K3ΔB and TCL1 control mice was monitored by flow cytometry over time and at sacrifice using CD19/CD5 antibodies. B cell receptor (BCR) signaling of CLL cells was analyzed using Phosphoflow. Results: K3∆B mice immunized with SRBC exhibited defective GC responses (30% reduction in GC-B cells compared to WT) and antibody production (49% reduction in SRBC-specific IgG2b production in serum compared to WT) on day 7 after immunization. Ex vivo, kindlin-3-deficient B cells were unable to form immune synapses (Figure 1A), to proliferate, and to switch antibody classes. The tumors in TCL1 mice started in the peritoneal cavity and subsequently spread to the spleen, blood and bone marrow. TCL1-K3ΔB mice presented with an almost complete abolished leukemia onset in the peritoneal cavity (92% less tumor burden in TCL1-K3ΔB compared to control TCL1 mice) in 4-month-old mice (Figure 1B i). Moreover, tumor burden in blood (Figure 1B ii), spleen, and bone marrow (Figure 1B iii) was strongly reduced at the late stage of disease (11.5-month-old mice), with an 82% lower tumor burden in spleen and a 90% lower tumor burden in bone marrow of TCL1-K3ΔB mice compared to TCL1 control mice. In addition, kindlin-3-deficient CLL cells exhibited impaired phosphoAkt and phosphoSyk signaling upon BCR engagement. Summary/Conclusion: In summary, kindlin-3 maintains the balance between a state of B cell homeostasis and an effective antigenic response by acting as a gatekeeper of GC formation, and is substantial for leukemic onset in CLL. Reference: 1. Härzschel A, Li L, Krenn PW, et al. Kindlin-3 maintains marginal zone B cells but confines follicular B cell activation and differentiation. J Leukoc Biol. 2022 Apr;111(4):745-758.

Common variable immunodeficiency-an independent risk factor for atherosclerotic cardiovascular diseases.

Atherosclerosis, a disease of chronic inflammation of the arterial wall, is the main cause of most cardiovascular diseases (CVDs). Common variable immunodeficiency (CVID), a group of diseases characterized by frequent infections due to defective antibody production and lack of human immunoglobulins, plays a role in immune activation and inflammation. Thus, it can be hypothesized that CVID increases the risk for atherosclerotic CVDs. On the other hand, it is also possible that CVID patients are protected from atherosclerotic CVDs based on their life-long immunoglobulin therapy. Here, we examined whether patients with CVID have an increased risk for atherosclerotic CVDs or whether they are protected from these diseases. Using an electronic patient database registry search of a population of 83 CVID patients and their age- and sex-matched, tenfold larger control population we demonstrate that CVID patients have a statistically significantly higher risk for coronary heart disease (OR 2.4, p = 0.015) and peripheral vascular disease (OR 12.5, p < 0.001). Regarding cerebrovascular disease, there was a trend towards CVID patients having more strokes or ischemic attacks, but the difference was not statistically significant (OR 2.0, p = 0.133). The combined OR for CVID patients for atherosclerotic CVDs was 2.6 (p = 0.001). CVID population had more hypertension, but smoking was more seldom. There were no statistically significant differences in the incidence of diabetes or levels of serum total, HDL or LDL cholesterol, or glycosylated hemoglobin A1c between CVID patients and their controls. CVID patients had infections more frequently and the OR for autoimmune diseases was 3.8 (p < 0.001). Finally, a multivariate logistic analysis showed that CVID is an independent risk factor for atherosclerotic CVDs (p = 0.002). The present study demonstrates for the first time that CVID is an independent risk factor for atherosclerotic CVDs. Further studies are required to fully understand the exact mechanisms behind this.

Reduced numbers of naïve CD4+T cells and an altered CD4/CD8 balance in depressed common variable immune deficiency (CVID) patients. Is thymosin-α1 a possible treatment?

In the 1990's the macrophage-T-cell-theory of depression was posed stating that low grade inflammation and an abnormal T cell system destabilize the development and function of the emotional brain in such a way, that individuals become ultrasensitive to stress. Recently we gathered evidence that indeed higher frequencies of CD4+ memory T cells, lower frequencies of naive CD4+T cells, higher frequencies of CD8+T cells (the latter two in part elicited by Cytomegalovirus, CMV, infection) are a characteristic of Major Depressive Disorder (MDD). In MDD patients with a history of childhood trauma and severe depression monocytes are inflammatory activated. Low grade inflammation and T cell system defects have also been reported in patients with Common Variable Immune Deficiency (CVID) (next to antibody production defects). CVID patients show a higher prevalence of mild depression. The aim of this study was to determine T cell frequencies and monocyte inflammatory activation in CVID patients with and without depression. This study confirms that CVID patients have CMV independent decreases in the frequency of naïve CD4+T cells and it de novo shows a CMV dependent increase in the expression of inflammatory genes in monocytes. CVID patients with depression are additionally characterized by a CMV independent increase in the frequency of naïve CD8+T cells, while lacking monocyte inflammatory activation. In conclusion, depressed CVID patients have T cell abnormalities comparable to that of patients with regular MDD. These abnormalities are presently targeted by thymosin α1 in an open-label proof of concept trial.

ВЗК-ПОДОБНЫЕ ПОРАЖЕНИЯ У ПАЦИЕНТОВ С Х-СЦЕПЛЕННОЙ АГАММАГЛОБУЛИНЕМИЕЙ: ОБЗОР ЛИТЕРАТУРЫ И КЛИНИЧЕСКОЕ НАБЛЮДЕНИЕ

X-linked agammaglobulinemia (XLA) is a primary immunodeficiency that refers to defects in the humoral link and is characterized by severe recurrent infectious episodes as well as low concentration of serum immunoglobulins up to their complete absence. BTK (Bruton tyrosine kinase), a protein coding gene is responsible for this disease, whose mutations lead to impaired maturation of B-lymphocytes followed by a defect in antibody production. The survival rate of patients with early diagnosis and timely replacement therapy with intravenous (IVIG) and subcutaneous (SCIG) immunoglobulins is quite high. Though patients in this group are predisposed to immune complications such as IBD-like lesions of the gastrointestinal tract (GIT) in addition to recurrent infectious episodes. The differentiation of such complications if often of diagnostic and therapeutic difficulties. This group of patients is being actively studied at the moment aimed to the search for therapeutic options. The Article represents a bibliographical review and clinical case of the development of IBD-like lesions of the GIT in a patient with XLA.

A multimorphic mutation in IRF4 causes human autosomal dominant combined immunodeficiency.

Interferon regulatory factor 4 (IRF4) is a transcription factor (TF) and key regulator of immune cell development and function. We report a recurrent heterozygous mutation in IRF4, p.T95R, causing an autosomal dominant combined immunodeficiency (CID) in seven patients from six unrelated families. The patients exhibited profound susceptibility to opportunistic infections, notably Pneumocystis jirovecii, and presented with agammaglobulinemia. Patients' B cells showed impaired maturation, decreased immunoglobulin isotype switching, and defective plasma cell differentiation, whereas their T cells contained reduced TH17 and TFH populations and exhibited decreased cytokine production. A knock-in mouse model of heterozygous T95R showed a severe defect in antibody production both at the steady state and after immunization with different types of antigens, consistent with the CID observed in these patients. The IRF4T95R variant maps to the TF's DNA binding domain, alters its canonical DNA binding specificities, and results in a simultaneous multimorphic combination of loss, gain, and new functions for IRF4. IRF4T95R behaved as a gain-of-function hypermorph by binding to DNA with higher affinity than IRF4WT. Despite this increased affinity for DNA, the transcriptional activity on IRF4 canonical genes was reduced, showcasing a hypomorphic activity of IRF4T95R. Simultaneously, IRF4T95R functions as a neomorph by binding to noncanonical DNA sites to alter the gene expression profile, including the transcription of genes exclusively induced by IRF4T95R but not by IRF4WT. This previously undescribed multimorphic IRF4 pathophysiology disrupts normal lymphocyte biology, causing human disease.

Late Onset Combined Immune Deficiency (LOCID) Revealed by a Haemolytic Anaemia in a Child: A Case Report

Variable Common Immune Deficiency (VCID) is a very heterogeneous condition both clinically and immunologically. It is a group of molecular abnormalities responsible for a defect in antibody production leading to hypogammaglobulinemia often associated with autoimmune and/or lymphoproliferative manifestations. Late Onset Combined Immune Deficiency (LOCID) is a type of Variable Common Immune Deficiency (VCID) defined by a defect in antibody production (IgG and IgA ± IgM type), profound CD4 T-cell lymphopenia and frequent opportunistic infections. LOCID has been considered as a distinct entity from VCID due to its particular clinical and immunological profile.

From inborn errors of immunity to lymphoma: A hematologist’s point of view

After infections, malignancies, lymphomas especially, are the second most frequent cause of death in patients with inborn errors of immunity. Factors predetermining the appearance and aggressiveness of lymphomas include gene defects, defects of immune surveillance and regulation as well as infections with oncogenic viruses. Aggressive non-Hodgkin lymphomas, mostly diffuse large B-cell and Bukit subtypes are predominant in deoxyribonucleic acid repair defects, while Hodgkin lymphoma becomes equally present in patients with defects of immune regulation. Marginal zone and mucosa-associated lymphoid tissue lymphomas, appear to be frequent in defects of antibody production, especially in patients with common variable immune deficiency. The prevalence of Epstein-Barr virus may vary within entities, but there is no entity without at least a few cases of lymphoma and Epstein-Barr virus co-infection. Standard treatment of lymphomas associated with deoxyribonucleic acid repair defects and severe combined deficiencies, is stem cell transplantation. Lymphomas in inborn errors of immunity with a less severe clinical presentation, should be treated with immunochemotherapy and monoclonal antibodies (Brentuximab, Rituximab) wherever feasible. There is no data about the usefulness of checkpoint inhibitors, bi-specific antibodies and T-cells with chimeric antigen receptor. Allogeneic stem cell transplantation represents a major indication for treatment of relapse/refractory lymphomas in any inborn error of immunity. Potential benefit of therapy with Chimeric antigen receptor Natural-killer cells in lymphomas associated with inborn errors of immunity, remains to be seen in future studies.

M145 MULTIPLE ACYL-COA DEHYDROGENASE DEFICIENCY MASQUERADING AS MYOSITIS IN AN ADULT COMMON VARIABLE IMMUNODEFICIENCY PATIENT

Common variable immunodeficiency (CVID) is a heterogeneous primary immunodeficiency characterized by defective B-lymphocyte differentiation, defective antibody production, and inflammation-induced organ damage. Etiologies for myositis associated with CVID are often elusive. The following is a case of late-onset multiple acyl-CoA dehydrogenase deficiency (MADD) mimicking myositis in a patient concurrently diagnosed with CVID.

The Epidemiology and Genetic Analysis of Children With Idiopathic Type 1 Diabetes in the State of Qatar.

ContextIdiopathic type 1 diabetes is characterized by the absence of autoantibodies and the underlying mechanisms are not clear.ObjectiveWe aimed to study the epidemiology, describe the clinical characteristics, and report results of genetic studies in pediatric patients with idiopathic type 1 diabetes.MethodsThis was a prospective study of type 1 diabetes patients attending Sidra Medicine from 2018 to 2020. Autoantibodies (GAD65, IAA, IA-2A, and ZnT8) were measured and genetic testing was undertaken in patients negative for autoantibodies to rule out monogenic diabetes. Demographic and clinical data of patients with idiopathic type 1 diabetes were compared with patients with autoimmune type 1 diabetes.ResultsOf 1157 patients with type 1 diabetes, 63 were antibody-negative. Upon genome sequencing, 4 had maturity onset diabetes of the young (MODY), 2 had Wolfram syndrome, 1 had H syndrome, and 3 had variants of uncertain significance in MODY genes; 53 patients had idiopathic type 1 diabetes. The most common age of diagnosis was 10 to 14 years. C-peptide level was low but detectable in 30 patients (56.6%) and normal in 23 patients (43.4%) The average body mass index was in the normal range and 33% of the patients had a history of diabetic ketoacidosis (DKA).ConclusionFour percent of the children had idiopathic type 1 diabetes. There were statistically significant differences in the C-peptide level and insulin requirement between the 2 groups. DKA was less common in the idiopathic group. Mutations in MODY genes suggest the importance of autoantibody testing and genetic screening for known causes of monogenic diabetes in idiopathic type 1 diabetes. The mechanism of idiopathic type 1 diabetes is unknown but could be due to defects in antibody production or due to autoantibodies that are not yet detectable or discovered.

#9: Diagnosis of Campylobacter upsaliensis and Helicobacter canis by plasma-based Next-Generation Sequencing for Microbial Cell-free DNA in twin brothers with XLA

Abstract Background X-linked agammaglobulinemia is a primary immunodeficiency associated with mutations in the B cell tyrosine kinase (BTK) gene leading to failure in B cell maturation and defective antibody production. Campylobacter and closely related Helicobacter species can cause persistent bacteremia, enteritis and cellulitis in patients with XLA and are difficult to diagnose and eradicate. In this context, detection of circulating microbial cell-free DNA (mcfDNA) by next-generation sequencing (NGS) can be used to identify infectious agents in susceptible immunocompromised hosts. Methods We report 4-year-old fraternal twins with XLA presenting with disparate clinical manifestations due to C. upsaliensis and coinfection with C. upsaliensis and H. canis respectively. Results Patient #1 was diagnosed with XLA at 11 months-old and was started on weekly immunoglobulin replacement. At 2.5 yo he developed recurrent fever, abdominal pain and diarrhea. Endoscopy/colonoscopy revealed focal ileocolitis without ulceration or granulomas. Stool infectious workup, including bacterial stool cultures, was negative. At 3 yo he developed gram- rod bacteremia that was not further identified but successfully treated with ceftriaxone. He presented 2 months later with fever and diarrhea; blood cultures were negative, but stool culture grew C. jejuni. His symptoms recrudesced after two months and he was treated for presumed recurrent Campylobacter infection. Intermittent fevers and diarrhea recurred, and repeat stool culture grew C. upsaliensis identified by MALDI-TOF resulting in a 3-month course of azithromycin. Stool PCR remained positive for Campylobacter species after one month of therapy. Fever and diarrhea recurred after completion of therapy and stool culture again grew C. upsaliensis but sensitivities could not be obtained. McfDNA testing confirmed C. upsaliensis and therapy with ertapenem, ciprofloxacin, amoxicillin and doxycycline was initiated. He remained symptom free three months into therapy. Patient #2 was diagnosed with XLA at 1 yo and started weekly immunoglobulin replacement. At 3.5 yo he developed fever, erythema nodosum (EN) and arthritis. Given his twin’s diagnosis of Campylobacter enteritis with likely bacteremia, a presumptive diagnosis of Campylobacter related reactive arthritis and EN was made. Treatment with Naprosyn and 14 days of azithromycin failed to prevent the return of EN post therapy. He had multiple courses of azithromycin each followed by return of EN rash. Following completion of therapy, he presented with high fevers, worsening rash, leukocytosis and elevated ESR. Blood and stool cultures were obtained and returned negative. Despite completion of a 3 month course of azithromycin, stool PCR remained positive for Campylobacter species and his symptoms persisted. The recrudescence of fevers and worsening rash 2 months after completion of therapy prompted repeat blood and stool cultures that returned negative. McfDNA testing was obtained in that context and identified Helicobacter canis and Campylobacter upsaliensis. Treatment with ertapenem, ciprofloxacin, amoxicillin and doxycycline was initiated and he remained symptom free three months into therapy. Conclusions Physicians should be aware of the varied presentations of chronic Campylobacter and Helicobacter infection in XLA patients. Plasma NGS for circulating mcfDNA in immunocompromised patients offers a rapid, non-invasive means of detecting these fastidious organisms that can be difficult to diagnose using more conventional means.

Common variable immunodeficiency disorder associated with bronchiectasis: a case report

Common variable immunodeficiency disorder (CVID) is the commonest type of primary immunodeficiency disorders (PIDs) characterized by hypogammaglobulinemia, defective specific antibody production and increased susceptibility of recurrent infections. Autoimmunity, neoplasm and lymphoproliferative disorders are usually associated with CVID. In most cases, the cause is unknown, but multiple gene mutations (10%) may be associated with CVID. Here, we report an eight years old girl with CVID presented with recurrent infections, growth failure, generalized lymphadenopathy and hepatosplenomegaly. Chest examination and radiological findings of this girl were consistent with bronchiectasis. Lack of awareness among health care providers is the reason for delayed diagnosis of several years for this girl. Therefore, it is essential to raise awareness regarding PID patients among the physicians to improve the quality of life.

Dissection of the Pre-Germinal Center B-Cell Maturation Pathway in Common Variable Immunodeficiency Based on Standardized Flow Cytometric EuroFlow Tools.

IntroductionCommon Variable Immunodeficiency (CVID) is characterized by defective antibody production and hypogammaglobulinemia. Flow cytometry immunophenotyping of blood lymphocytes has become of great relevance for the diagnosis and classification of CVID, due to an impaired differentiation of mature post-germinal-center (GC) class-switched memory B-cells (MBC) and severely decreased plasmablast/plasma cell (Pb) counts. Here, we investigated in detail the pre-GC B-cell maturation compartment in blood of CVID patients.MethodsIn this collaborative multicentric study the EuroFlow PID 8-color Pre-GC B-cell tube, standardized sample preparation procedures (SOPs) and innovative data analysis tools, were used to characterize the maturation profile of pre-GC B-cells in 100 CVID patients, vs 62 age-matched healthy donors (HD).ResultsThe Pre-GC B-cell tube allowed identification within pre-GC B-cells of three subsets of maturation associated immature B-cells and three subpopulations of mature naïve B-lymphocytes. CVID patients showed overall reduced median absolute counts (vs HD) of the two more advanced stages of maturation of both CD5+ CD38+/++ CD21het CD24++ (2.7 vs 5.6 cells/µl, p=0.0004) and CD5+ CD38het CD21+ CD24+ (6.5 vs 17 cells/µl, p<0.0001) immature B cells (below normal HD levels in 22% and 37% of CVID patients). This was associated with an expansion of CD21-CD24- (6.1 vs 0.74 cells/µl, p<0.0001) and CD21-CD24++ (1.8 vs 0.4 cells/µl, p<0.0001) naïve B-cell counts above normal values in 73% and 94% cases, respectively. Additionally, reduced IgMD+ (21 vs 32 cells/µl, p=0.03) and IgMD- (4 vs 35 cells/µl, p<0.0001) MBC counts were found to be below normal values in 25% and 77% of CVID patients, respectively, always together with severely reduced/undetectable circulating blood pb. Comparison of the maturation pathway profile of pre-GC B cells in blood of CVID patients vs HD using EuroFlow software tools showed systematically altered patterns in CVID. These consisted of: i) a normally-appearing maturation pathway with altered levels of expression of >1 (CD38, CD5, CD19, CD21, CD24, and/or smIgM) phenotypic marker (57/88 patients; 65%) for a total of 3 distinct CVID patient profiles (group 1: 42/88 patients, 48%; group 2: 8/88, 9%; and group 3: 7/88, 8%) and ii) CVID patients with a clearly altered pre-GC B cell maturation pathway in blood (group 4: 31/88 cases, 35%).ConclusionOur results show that maturation of pre-GC B-cells in blood of CVID is systematically altered with up to four distinctly altered maturation profiles. Further studies, are necessary to better understand the impact of such alterations on the post-GC defects and the clinical heterogeneity of CVID.

Overcoming immune dysfunction in the elderly: trained immunity as a novel approach.

People with advanced age have a higher susceptibility to infections and exhibit increased mortality and morbidity as the ability of the immune system to combat infections decreases with age. While innate immune cells display functional defects such as decreased phagocytosis, chemotaxis and cytokine production, adaptive immune cells exhibit reduced receptor diversity, defective antibody production and a sharp decline in naive cell populations. Successful responses to vaccination in the elderly are critical to prevent common infections such as influenza and pneumonia, but vaccine efficacy decreases in older individuals compared with young adults. Trained immunity is a newly emerging concept that showed that innate immune cells possess non-specific immunological memory established through epigenetic and metabolic reprogramming upon encountering certain pathogenic stimuli. Clinical studies suggest that trained immunity can be utilized to enhance immune responses against infections and improve the efficiency of vaccinations in adults; however, how trained immunity responses are shaped with advanced age is still an open question. In this review, we provide an overview of the age-related changes in the immune system with a focus on innate immunity, discuss current vaccination strategies for the elderly, present the concept of trained immunity and propose it as a novel approach to enhance responses against infections and vaccinations in the elderly population.

Otoimmun Komplikasyonlarla Seyreden Yaygın Değişken İmmün Yetmezlik Hastasında Renal Amiloidoz

Common variable immune deficiency (CVID) is a rare primary immunodeficiency disorder that is characterized by defective antibody production and inadequate B cell differentiation. While frequently recurrent respiratory tract infections are the most prominent clinical feature in CVID patients, CVID is a heterogeneous immune deficiency disorder that involves many systems and organs such as lymphoid hyperplasia, autoimmune cytopenia, chronic lung diseases, granulomatous diseases and susceptibility to malignancy. This may lead to delay in diagnosis and immunoglobulin replacement therapy, not being able to receive antibiotics at the appropriate dose and time, chronic inflammation, and therefore secondary amyloidosis. In this case report it is aimed to present a CVID patient with autoimmune complications and developing renal amyloidosis during follow-up.

A possible role for B cells in COVID-19? Lesson from patients with agammaglobulinemia

Summary COVID-19 had a mild clinical course in patients with Agammaglobulinemia lacking B lymphocytes, whereas it developed aggressively in Common Variable Immune Deficiency. Our data offer mechanisms for possible therapeutic targets.

Lymphocyte Subset Abnormalities in Pediatric-Onset Common Variable Immunodeficiency

Introduction: Common variable immunodeficiency (CVID) is characterized by recurrent infections, autoimmunity, lymphoproliferation, hypogammaglobulinemia, and defective antibody production. In CVID, B-cell abnormalities were described to predict end organ involvement and prognosis. Pediatric-onset CVID is much rarer than adult CVID, and lymphocyte subset abnormalities have not been thoroughly evaluated. Objective: We sought to determine lymphocyte subset abnormalities and their association with end organ involvement in pediatric-onset CVID patients. Methods: The clinical manifestations and laboratory findings including absolute numbers and percentages of B-, T-, and NK cell populations were assessed in pediatric-onset CVID patients and compared to age-matched healthy controls. The patients were divided into 2 groups according to age at assessment (pediatric CVID patients: 10–16 years, n = 9; and adult CVID patients: >16 years, n = 13). The comparisons between lymphocyte subsets and organ involvement were also evaluated. Results: Mean age at symptom onset was 18 (3–204) months. All CVID patients with pediatric onset had decreased levels of total and memory B cells, CD4⁺ T cells, CD4⁺CD45RA⁺ naive T cells, and recent thymic emigrant (RTE) cells. On the other hand, they had increases in CD8⁺CD45RO⁺ memory T cells. Interestingly, adult CVID patients demonstrated high frequencies of activated and double-negative T cells, which were unique only for this group of patients. Specific cellular abnormalities associated with the reduction in B and NK cells and increase in CD8⁺ T cells were found in patients with bronchiectasis. Moreover, in pediatric CVID patients, low serum IgA levels and decreased numbers of naive T and RTE cells were determined as risk factors for chronic diarrhea. Conclusions: Specific abnormalities in B- and T-lymphocyte compartments were identified in pediatric-onset CVID patients and appear to be associated with end organ manifestations.