Switched Memory B-cells Research Articles

Impact of Immune Cells on Stroke Limited to Specific Subtypes: Evidence from Mendelian Randomization Study.

Stroke is one of the common diseases that pose a severe threat to human health, with immune cells playing a crucial role in its onset and recovery. However, the specific mechanisms and causal relationships of different immune cell groups in various clinical stroke subtypes are unclear. This study explored the causal relationship between immune cells and stroke and its subtypes using Mendelian randomization (MR) analysis. Data from genome-wide association studies were analyzed using inverse-variance weighted (IVW), MR-Egger, and weighted median methods for MR analysis, along with heterogeneity tests, sensitivity analysis, and pleiotropy analysis. CD45RA+CD28-CD8+ Tcell %Tcell (OR 1.002, 95%CI 1.001-1.003; PFDR = 0.02), CD27 on CD24+CD27+ Bcell (OR 1.127, 95%CI 1.061-1.198; PFDR = 0.04), CD27 on IgD-CD38dim Bcell (OR 1.138, 95%CI 1.076-1.203; PFDR = 0.005), and CD27 on switched memory Bcell (OR 1.144, 95%CI 1.076-1.216; PFDR = 0.01) were found to increase the risk of large artery stroke. Switched memory Bcell %lymphocyte (OR 1.206, 95%CI 1.103-1.318; PFDR = 0.02) increased the risk of small vessel stroke. Reverse MR analysis did not reveal any reverse causal associations. Furthermore, by substituting the outcome data, a secondary MR analysis was conducted to validate the primary findings. Our study reveals several causal links between immune phenotypes and stroke and its different subtypes, highlighting the complex interactions between the immune system and stroke. These findings provide new directions for further uncovering the biological basis of stroke and assist in advancing research on early interventions and treatment strategies.

Deep phenotyping of post-infectious myalgic encephalomyelitis/chronic fatigue syndrome

Post-infectious myalgic encephalomyelitis/chronic fatigue syndrome (PI-ME/CFS) is a disabling disorder, yet the clinical phenotype is poorly defined, the pathophysiology is unknown, and no disease-modifying treatments are available. We used rigorous criteria to recruit PI-ME/CFS participants with matched controls to conduct deep phenotyping. Among the many physical and cognitive complaints, one defining feature of PI-ME/CFS was an alteration of effort preference, rather than physical or central fatigue, due to dysfunction of integrative brain regions potentially associated with central catechol pathway dysregulation, with consequences on autonomic functioning and physical conditioning. Immune profiling suggested chronic antigenic stimulation with increase in naïve and decrease in switched memory B-cells. Alterations in gene expression profiles of peripheral blood mononuclear cells and metabolic pathways were consistent with cellular phenotypic studies and demonstrated differences according to sex. Together these clinical abnormalities and biomarker differences provide unique insight into the underlying pathophysiology of PI-ME/CFS, which may guide future intervention.

The clinical and immunological characteristics of common variable immunodeficiency in adults and older adults.

The aim of this study was to determine the clinical and immunological characteristics of older adults with common variable immunodeficiency (CVID). Patients aged ≥18 years who were followed up with the diagnosis of CVID between 2015 and 2020 were included in the study. The patients were separated into two age groups according to the age at diagnosis: the adult group, aged 18-65 years (n=49) and the older adult group, aged ≥65 years (n=11). Splenomegaly (55.1% vs. 9.1%, p=0.006), bronchiectasis (53.0% vs. 9.1%, p=0.008), and autoimmunity (42.8% vs. 9.1%, p=0.036) were determined to be more common in the adult group than in the older adults. A similar frequency of malignancy was seen in both groups (6.1% vs. 9.1%, p=0.721). There were significantly more patients with no comorbidity in the older adult group than in the adult group (45.5% vs. 16.3%, p=0.034). Serum IgG and IgA levels were determined to be significantly higher in the older adult group than in the adult group (p=0.001 for all). The CD19+ B-cell count at the time of diagnosis was determined to be lower and the CD19+CD27+IgD- switched memory B-cells and CD16+CD56+ natural killer cell counts were higher in the older adults than in the adult group (p=0.016, p=0.032, p=0.044, respectively). Knowledge of clinical and immunological differences in older adult CVID patients may be of benefit in polyclinic follow-up and in respect of changes to be made to the treatment plan.

Disease activity in chronic inflammatory demyelinating polyneuropathy: association between circulating B-cell subsets, cytokine levels, and clinical outcomes.

Chronic inflammatory demyelinating polyneuropathy (CIDP), a common and treatable autoimmune neuropathy, is frequently misdiagnosed. The aim of this study is to evaluate the relationship between immunological markers and clinical outcome measures in a mixed cohort of patients with typical CIDP and CIDP variants at different disease stages. Twenty-three typical, 16 multifocal and five distal CIDP patients were included. Twenty-five sex and age-matched healthy controls and 12 patients with Charcot-Marie-Tooth type 1A (CMT1A) disease served as controls. Peripheral B-cell populations were analyzed by flow cytometry. IL6, IL10, TNFA mRNA and mir-21, mir-146a, and mir-155-5p expression levels were evaluated by real-time polymerase chain reaction in peripheral blood mononuclear cells (PBMC) and/or skin biopsy specimens. Results were then assessed for a possible association with clinical disability scores and intraepidermal nerve fiber densities (IENFD) in the distal leg. We detected a significant reduction in naive B cells (P ≤ 0.001), plasma cells (P ≤ 0.001) and regulatory B cells (P < 0.05), and an elevation in switched memory B cells (P ≤ 0.001) in CIDP compared to healthy controls. CMT1A and CIDP patients had comparable B-cell subset distribution. CIDP cases had significantly higher TNFA and IL10 gene expression levels in PBMC compared to healthy controls (P < 0.05 and P ≤ 0.01, respectively). IENFDs in the distal leg showed a moderate negative correlation with switched memory B-cell ratios (r = -0.51, P < 0.05) and a moderate positive correlation with plasma cell ratios (r = 0.46, P < 0.05). INCAT sum scores showed a moderate positive correlation with IL6 gene expression levels in PBMC (r = 0.54, P < 0.05). Altered B-cell homeostasis and IL10 and TNFA gene expression levels imply chronic antigen exposure and overactivity in the humoral immune system, and seem to be a common pathological pathway in both typical CIDP and CIDP variants.

B-cell targeting with anti-CD38 daratumumab: implications for differentiation and memory responses.

B cell-targeted therapies, such as CD20-targeting mAbs, deplete B cells but do not target the autoantibody-producing plasma cells (PCs). PC-targeting therapies such as daratumumab (anti-CD38) form an attractive approach to treat PC-mediated diseases. CD38 possesses enzymatic and receptor capabilities, which may impact a range of cellular processes including proliferation and differentiation. However, very little is known whether and how CD38 targeting affects B-cell differentiation, in particular for humans beyond cancer settings. Using in-depth in vitro B-cell differentiation assays and signaling pathway analysis, we show that CD38 targeting with daratumumab demonstrated a significant decrease in proliferation, differentiation, and IgG production upon T cell-dependent B-cell stimulation. We found no effect on T-cell activation or proliferation. Furthermore, we demonstrate that daratumumab attenuated the activation of NF-κB in B cells and the transcription of NF-κB-targeted genes. When culturing sorted B-cell subsets with daratumumab, the switched memory B-cell subset was primarily affected. Overall, these in vitro data elucidate novel non-depleting mechanisms by which daratumumab can disturb humoral immune responses. Affecting memory B cells, daratumumab may be used as a therapeutic approach in B cell-mediated diseases other than the currently targeted malignancies.

Prevalence of Gastrointestinal (GI), Hepatic, and Infectious Manifestations in Patients with Common Variable Immunodeficiency (CVID)

RationaleCommon variable immunodeficiency (CVID) is the most common, symptomatic, primary immunodeficiency in adults. Gastrointestinal (GI) and hepatic manifestations in CVID remain poorly delineated. We assessed the prevalence of GI, hepatic, and infectious manifestations among patients with CVID and correlated the findings with immunophenotype. MethodsWe conducted a retrospective cohort study of CVID patients at our large, academic center. We evaluated baseline patient characteristics, GI, hepatic, and infectious manifestations of 319 CVID patients. Laboratory studies and immunologic profiles of the patients were evaluated. Results: 291/319 CVID patients (91%) had documented GI or hepatic manifestations. The most common GI symptoms were diarrhea (n = 153), vomiting/dysphagia (n = 146), abdominal pain (n = 117), and weight loss/malabsorption/protein wasting (n = 43). Autoimmune/inflammatory GI disease was reported in 72/319 (23%) of patients. 135/238 (57%) of patients had abnormal liver biochemistries at some point [ALT: 63/135 (47%), AST: 78/135 (58%), Alkaline phosphatase: 76/135 (56%)]. Chronic inflammatory hepatitis was identified in 43/319 (13%); including autoimmune hepatitis (n = 32), transaminitis hepatitis (n = 6), infectious hepatitis (n = 6). Other hepatic conditions were portal hypertension (n = 30), liver cirrhosis (n = 18), and nonalcoholic fatty liver disease (n = 15). 23/319 (7%) had undergone transient elastography, 42/319 (13%) had undergone liver biopsy, of which 22/42 (52%) had a diagnosis of nodular regenerative hyperplasia. The most common GI infections were H. pylori (n = 22), C. difficile (n = 18), Giardia (n = 8). Low absolute CD3+ cells were associated with autoimmune hepatitis [OR 2.91; 95%CI (1.07–7.87); P = 0.03], portal hypertension [OR 5.14; 95%CI (1.86–14.17); P = 0.002], autoimmune/inflammatory GI disease [OR 2.69; 95%CI (1.13–6.41); P = 0.02], and IBD [OR 5.09; 95%CI (1.07–24.20); P = 0.04]. Low absolute CD4+ cells were associated with portal hypertension [OR 5.11; 95%CI (1.87–13.93); P = 0.001], autoimmune/inflammatory GI disease [OR 3.47; 95%CI (1.49–8.12); P = 0.004], and autoimmune gastroenteropathy [OR 3.78; 95%CI (1.44–9.92); P = 0.007]. Low absolute CD19+ cells were associated with autoimmune gastroenteropathy [OR 3.66; 95%CI (1.16–11.6); P = 0.02]. Low switched memory B-cells (IgM-IgD-CD27+CD19+) were associated with autoimmune gastroenteropathy [OR 5.07; 95%CI (1.35–19.04); P = 0.01], and portal hypertension [OR 5.89; 95%CI (1.13–28.16); P = 0.02]. Conclusions: CVID patients had a high prevalence of GI, hepatic, and infectious manifestations, which was associated with more severe immunophenotypes.

Characterization of Adaptive Immune Responses to SARS-CoV-2 Updated Bivalent Booster

Bivalent COVID-19 vaccines that contain two mRNAs encoding Wuhan-1 and Omicron BA.4/5 spike proteins are successful in preventing infection from the original strain and Omicron variants, but the quality of adaptive immune responses is still not well documented. This study aims at characterizing adaptive immune responses to the bivalent booster vaccination in 46 healthy participants. Plasma and PBMC were collected prior and three weeks after bivalent booster.We measured anti-N, anti-S, and RBD IgM, IgA, IgG plasma titers against original, Omicron BA.1, and BA.5 variants (pending) as well as total anti-S IgG titers and surrogate Virus Neutralization capacity against the Alpha, Delta, and BA.1 variant. With spectral flow-cytometry we identified peripheral blood B-cells specific for the RBD of the S-protein of the original and BA.1 variants. T-cell-specific responses were assessed by cytokine release assay after stimulation with SARS-CoV-2 peptides from the original, BA.1, BA.4, and BA.5 variants (pending). Finally, we performed TRB and IGH repertoire studies on sorted CD4+, CD8+, CD19+ lymphocytes, to study breadth of SARS-CoV-2 specific clonotypes (pending).27/46 participants were analyzed; 9 had SARS-CoV-2 infection (COVID+), while 18 are infection naïve (COVID-). In both groups, median time since last dose of SARS-CoV-2 vaccine (3rd or 4th) was 11 months.All subjects were positive for anti-S IgG prior to bivalent booster. The COVID + group displayed anti-S IgG pre-booster levels and neutralization against BA.1 higher than the COVID- group. Significant increase post-boost of total anti-S IgG and BA.1 neutralizing activity was detected in the COVID- but not in the COVID+ group; however, no difference in neutralization activity post-boost was detected between the two groups. Furthermore, the COVIDgroup showed significant increase in the frequency of CD19+ and CD27+ switched memory B-cells specific for BA.1 RBD in post-boost compared to pre-boost samples. However, post-boost frequencies of the same B-cells were higher in the COVID+ compared to the COVID- group. These preliminary findings confirm that among individual immunized with the original COVID-19 mRNAvaccine, prior COVID infection provides increased protection against SARS-CoV-2 variants. They also demonstrate that booster immunization with the bivalent vaccine induces robust adaptive immune responses against Omicron variant. [Display omitted] [Display omitted]

B cells and T cells abnormalities in patients with selective IgA deficiency

BackgroundSelective IgA deficiency (SIgAD) is the most prevalent inborn errors of immunity with almost unknown etiology. This study aimed to investigate the clinical diagnostic and prognostic values of lymphocyte subsets and function in symptomatic SIgAD patients.MethodsA total of 30 available SIgAD patients from the Iranian registry and 30 age-sex-matched healthy controls were included in the present study. We analyzed B and T cell peripheral subsets and T cell proliferation assay by flow cytometry in SIgAD patients with mild and severe clinical phenotypes.ResultsOur results indicated a significant increase in naïve and transitional B cells and a strong decrease in marginal zone-like and switched memory B-cells in SIgAD patients. We found that naïve and central memory CD4+ T cell subsets, as well as Th1, Th2 and regulatory T cells, have significantly decreased. On the other hand, there was a significant reduction in central and effector memory CD8+ T cell subsets, whereas proportions of both (CD4+ and CD8+) terminally differentiated effector memory T cells (TEMRA) were significantly elevated in our patients. Although some T cell subsets in severe SIgAD were similar, a decrease in marginal-zone and switched memory B cells and an increase in CD21low B cell of severe SIgAD patients were slightly prominent. Moreover, the proliferation activity of CD4+ T cells was strongly impaired in SIgAD patients with a severe phenotype.ConclusionSIgAD patients have varied cellular and humoral deficiencies. Therefore, T cell and B cell assessment might help in better understanding the heterogeneous pathogenesis and prognosis estimation of the disease.

A UNIQUE CLINICAL PRESENTATION OF COMMON VARIABLE IMMUNODEFICIENCY: MALAKOPLAKIA OF RECTUM.

<h3>Introduction</h3> Common variable immunodeficiency (CVID) is the most common primary immunodeficiency in adults and present with a broad range of clinical manifestations including granulomatous diseases. Malakoplakia is a rare chronic granulomatous disease (CGD) that can affect multiple organs and shown as a manifestation in immunocompromised individuals. In this case report, we present rectal malakoplakia as a clinical manifestation of a CVID in patient for the first time. <h3>Case Description</h3> This is a 62-year-old man with no significant past medical history except hypertension. He did not report recurrent infections, autoimmune disorders or malignancy. Recently, the patient underwent first screening colonoscopy, had a resection of one tubular polyp of rectum and the biopsy of polyp contained malakoplakia. Underlying etiology for rectal malakoplakia was investigated and all results were unremarkable except serum protein electrophoresis showing hypogammaglobulinemia without monoclonal gammopathy. Serum immunoglobulin levels were low (IgG: 538, IgA: 65 and IgM: 14, mg/dL). Flow cytometry analyses of lymphocytes showed markedly decreased absolute cell counts of CD4⁺ (221/ul) and CD19⁺ (28/ul) cells with low memory and switched-memory B-cells. <h3>Discussion</h3> This is a unique case of a completely asymptomatic patient who was incidentally found to have rectal malakoplakia. Work up for malakoplakia led to the diagnosis of CVID. CVID present with a broad range of clinical manifestations including granulomatous disease, however, rectal malakoplakia - a rare chronic granulomatous disease, was never reported as a manifestation of CVID. Although this patient is currently asymptomatic, it will be crucial to closely monitor his immune profile and clinical manifestations.

Defining Clinical and Immunological Predictors of Poor Immune Responses to COVID-19 mRNA Vaccines in Patients with Primary Antibody Deficiency.

Immune responses to coronavirus disease 2019 (COVID-19) mRNA vaccines in primary antibody deficiencies (PADs) are largely unknown. We investigated antibody and CD4+ T-cell responses specific for SARS-CoV-2 spike protein (S) before and after vaccination and associations between vaccine response and patients’ clinical and immunological characteristics in PADs. The PAD cohort consisted of common variable immune deficiency (CVID) and other PADs, not meeting the criteria for CVID diagnosis (oPADs). Anti-S IgG, IgA, and IgG subclasses 1 and 3 increased after vaccination and correlated with neutralization activity in HCs and patients with oPADs. However, 42% of CVID patients developed such responses after the 2nd dose. A similar pattern was also observed with S-specific CD4+ T-cells as determined by OX40 and 4-1BB expression. Patients with poor anti-S IgG response had significantly lower levels of baseline IgG, IgA, CD19+ B-cells, switched memory B-cells, naïve CD8+ T-cells, and a higher frequency of EM CD8+ T-cells and autoimmunity compared to patients with adequate anti-S IgG responses. Patients with oPADs can develop humoral and cellular immune responses to vaccines similar to HCs. However, a subset of CVID patients exhibit impairment in developing such responses, which can be predicted by the baseline immune profile and history of autoimmunity.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10875-022-01296-4.

Patterns of Peripheral Blood B-Cell Subtypes Are Associated With Treatment Response in Patients Treated With Immune Checkpoint Inhibitors: A Prospective Longitudinal Pan-Cancer Study.

BackgroundImmune checkpoint inhibitors (ICIs) have revolutionized systemic anti-tumor treatments across different types of cancer. Nevertheless, predictive biomarkers regarding treatment response are not routinely established yet. Apart from T-lymphocytes, the humoral immunity of B-lymphocytes is studied to a substantially lesser extent in the respective setting. Thus, the aim of this study was to evaluate peripheral blood B-cell subtypes as potential predictors of ICI treatment response.MethodsThirty-nine cancer patients receiving ICI therapy were included into this prospective single-center cohort study. All had a first blood draw at the date before treatment initiation and a second at the time of first response evaluation (after 8-12 weeks). Seven different B-cell subtypes were quantified by fluorescence-activated cell sorting (FACS). Disease control- (DCR) and objective response rate (ORR) were co-primary study endpoints.ResultsOverall, DCR was 48.7% and ORR was 25.6%, respectively. At baseline, there was no significant association of any B-cell subtype with neither DCR nor ORR. At the first response evaluation, an increase in the frequency of CD21- B-cells was a statistically significant negative predictor of response, both regarding DCR (OR=0.05, 95%CI=0.00-0.67, p=0.024) and ORR (OR=0.09, 95%CI=0.01-0.96, p=0.046). An increase of the frequency of switched memory B-cells was significantly associated with reduced odds for DCR (OR=0.06, 95%CI=0.01-0.70, p=0.025). Patients with an increased frequency of naïve B-cells were more likely to benefit from ICI therapy as indicated by an improved DCR (OR=12.31, 95%CI=1.13-134.22, p=0.039).ConclusionIn this study, certain B-cell subpopulations were associated with ICI treatment response in various human cancer types.

Elevated CD21low B Cell Frequency Is a Marker of Poor Immunity to Pfizer-BioNTech BNT162b2 mRNA Vaccine Against SARS-CoV-2 in Patients with Common Variable Immunodeficiency

PurposeLimited data is available on the effect of COVID-19 vaccination in immunocompromised individuals. Here, we provide the results from vaccinating a single-center cohort of patients with common variable immunodeficiency (CVID).MethodsIn a prospective, open-label clinical trial, 50 patients with CVID and 90 age-matched healthy controls (HC) were analyzed for SARS-CoV-2 spike antibody (Ab) production after one or two doses of the Pfizer-BioNTech BNT162b2 mRNA vaccine. Additionally, in selected patients, SARS-CoV-2 spike-specific T-cells were assessed.ResultsA potent vaccine-induced anti-spike–specific IgG Ab response was observed in all the HC. In contrast, only 68.3% of the CVID patients seroconverted, with median titers of specific Ab being 83-fold lower than in HC. In fact, only 4/46 patients (8.6%) of patients who were seronegative at baseline reached the threshold for an optimal response (250 U/mL). Using the EUROclass definition, patients with either a reduced proportion, but not absolute counts, of switched memory B-cells or having an increased frequency of CD21low B-cells generally generated poor vaccine responses. Overall, CVID-patients had reduced spike-specific IFN-γ positive CD4+ T cell responses 2 weeks after the second dose, compared to HC. The total CD4 and CD4 central memory cell counts correlated with humoral immunity to the vaccine.ConclusionsCVID patients with low frequency of switched memory B-cells or an increased frequency of CD21low B-cells according to the EUROclass definition demonstrated poor responses to Pfizer-BioNTech BNT162b2 mRNA vaccination. Cellular immune responses were significantly affected, affirming that the defect in CVID is not limited to humoral immunity.

Overview of Anti-SARS-CoV-2 Immune Response Six Months after BNT162b2 mRNA Vaccine.

Background: We have designed a prospective study aiming to monitor the immune response in 178 health care workers six months after BNT162b2 mRNA vaccination. Methods: The humoral immune response of all subjects was evaluated by chemiluminescence (CMIA); in 60 serum samples, a live virus-based neutralization assay was also tested. Moreover, 6 months after vaccination, B- and T-cell subsets from 20 subjects were observed by FACS analysis after restimulation with the trimeric SARS-CoV-2 Spike protein as an antigen, thus mimicking reinfection in vitro. Results: A significant decrease of circulating IgG levels and neutralizing antibodies over time were observed. Moreover, six months after vaccination, a variable T-cell immune response after in vitro antigen stimulation of PBMC was observed. On the contrary, the analysis of B-cell response showed a shift from unswitched to switched memory B-cells and an increase of Th17 cells. Conclusions: Although the variability of the CD4+ and CD8+ immune response and an antibody decline was observed among vaccinated subjects, the increase of switched memory B-cells and Th17 cells, correlating with the presence of neutralizing antibodies, opened the debate on the correct timing of vaccination.

Dysregulated B cell differentiation towards antibody-secreting cells in neuromyelitis optica spectrum disorder

BackgroundAnti-aquaporin 4 (AQP4) antibody (AQP4-Ab) is involved in the pathogenesis of neuromyelitis optica spectrum disorder (NMOSD). However, the mechanism involved in AQP4-Ab production remains unclear.MethodsWe analyzed the immunophenotypes of patients with NMOSD and other neuroinflammatory diseases as well as healthy controls (HC) using flow cytometry. Transcriptome analysis of B cell subsets obtained from NMOSD patients and HCs was performed. The differentiation capacity of B cell subsets into antibody-secreting cells was analyzed.ResultsThe frequencies of switched memory B (SMB) cells and plasmablasts were increased and that of naïve B cells was decreased in NMOSD patients compared with relapsing–remitting multiple sclerosis patients and HC. SMB cells from NMOSD patients had an enhanced potential to differentiate into antibody-secreting cells when cocultured with T peripheral helper cells. Transcriptome analysis revealed that the profiles of B cell lineage transcription factors in NMOSD were skewed towards antibody-secreting cells and that IL-2 signaling was upregulated, particularly in naïve B cells. Naïve B cells expressing CD25, a receptor of IL-2, were increased in NMOSD patients and had a higher potential to differentiate into antibody-secreting cells, suggesting CD25+ naïve B cells are committed to differentiate into antibody-secreting cells.ConclusionsTo the best of our knowledge, this is the first study to demonstrate that B cells in NMOSD patients are abnormally skewed towards antibody-secreting cells at the transcriptome level during the early differentiation phase, and that IL-2 might participate in this pathogenic process. Our study indicates that CD25+ naïve B cells are a novel candidate precursor of antibody-secreting cells in autoimmune diseases.

Low IgG trough and lymphocyte subset counts are associated with hospitalization for COVID-19 in patients with primary antibody deficiency

Low IgG trough and lymphocyte subset counts are associated with hospitalization for COVID-19 in patients with primary antibody deficiency

Association of the CXCL9-CXCR3 and CXCL13-CXCR5 axes with B-cell trafficking in giant cell arteritis and polymyalgia rheumatica

ObjectiveB-cells are present in the inflamed arteries of giant cell arteritis (GCA) patients and a disturbed B-cell homeostasis is reported in peripheral blood of both GCA and the overlapping disease polymyalgia rheumatica (PMR). In this study, we aimed to investigate chemokine-chemokine receptor axes governing the migration of B-cells in GCA and PMR. MethodsWe performed Luminex screening assay for serum levels of B-cell related chemokines in treatment-naïve GCA (n = 41), PMR (n = 31) and age- and sex matched healthy controls (HC, n = 34). Expression of chemokine receptors on circulating B-cell subsets were investigated by flow cytometry. Immunohistochemistry was performed on GCA temporal artery (n = 14) and aorta (n = 10) and on atherosclerosis aorta (n = 10) tissue. ResultsThe chemokines CXCL9 and CXCL13 were significantly increased in the circulation of treatment-naïve GCA and PMR patients. CXCL13 increased even further after three months of glucocorticoid treatment. At baseline CXCL13 correlated with disease activity markers. Peripheral CXCR3+ and CXCR5+ switched memory B-cells were significantly reduced in both patient groups and correlated inversely with their complementary chemokines CXCL9 and CXCL13. At the arterial lesions in GCA, CXCR3+ and CXCR5+ B-cells were observed in areas with high CXCL9 and CXCL13 expression. ConclusionChanges in systemic and local chemokine and chemokine receptor pathways related to B-cell migration were observed in GCA and PMR mainly in the CXCL9-CXCR3 and CXCL13-CXCR5 axes. These changes can contribute to homing and organization of B-cells in the vessel wall and provide further evidence for an active involvement of B-cells in GCA and PMR.

B Cell Abnormalities and Cancer Development in Heart Recipients

Purpose Along with infections, rejection and graft vasculopathy, malignancies comprise a major complication after heart transplant, with a rate of occurrence of over 30% in 10 years. Skin cancers and posttransplant lymphoproliferative disorder are more common in adults. The risk factors for development of a malignancy after heart transplant are the same as for the nontransplant population. Identification of biomarkers that assess post-transplant risk is needed to improve long-term outcomes following heart transplantation. Methods We performed a single center, cohort study of 281 heart transplant recipients followed for a mean time of 9.5 years (2-19 years post-transplant). Mean age was 54.5, male 71.5%. The primary endpoint was development of neoplasia (27.2%). 8.2% developed metastasis. We serially measured funcionally distinct lymphocyte subsets in peripheral blood. We correlated assay results with the outcomes of neoplasia and development of metastasis. Lymphocyte subsets were assessed by four-colour flow-cytometry before transplantation at the time of inclusion in waiting list, at day 7 and 30 after heart transplantation. Results Clinical risk factors of cancer were age, smoking, obesity, ischemic etiology and post-transplant infections. We observed the following abnormalities in heart recipients who developed cancer: lower percentages of naive B-cells and lower mean fluorescence intensity (MFI) of toll like receptor (TLR) 4 on B-cells before transplantation (p=0.01 and p=0.049, respectively); lower non switched memory B-cell percentages and lower MFI of TLR4 on B-cells at 7 days after transplantation (p Conclusion Immunological abnormalities of B-cells and of TLR4 expression on B-cells and CD8 T-cells were observed in heart recipients who developed cancer after heart transplantation. These results suggest a role of these abnormalities in the predisposition to cancer that warrants further evaluation.

A clinical case of the X-linked moesin deficiency

With the increasing availability of genetic testing, the population of patients diagnosed with CVID breaks down into groups depending on monogenic defects. There is more and more evidence that adults can have combined immunodeficiencies with a late onset.&#x0D; This article discusses a clinical case of X-linked moesin-associated immunodeficiency (X-MAID). This is a recently described immunodeficiency, which mostly manifests itself at an early age with severe lymphopenia and hypogammaglobulinemia, fluctuating monocytopenia and neutropenia, a weak immune response to vaccine antigens, and increased susceptibility to bacteria and type 3 human herpesvirus.&#x0D; X-MAID, X-linked immunodeficiency with a recessive mode of inheritance, is caused by genetic defects in the MOESIN gene (membrane organizing spike elongation protein, MSN). Until recently, there were records of 10 people with this mutation, 9 of which have the phenotype of severe combined immunodeficiency (SCID). The patient described in this article has been under observation since the age of 12 and diagnosed with SCID due to an IgG decrease accompanied by infectious-purulent processes of the respiratory tract and diarrheal syndrome.&#x0D; However, the patient did not entirely fit into the typical clinical picture of CVID due to a severe therapy-torpid papillomavirus infection, the increased number of switched memory B-cells, IgG isolated decrease, persistent severe leukopenia and lymphopenia of CD4+ cells. In accordance with the clinical picture and the results of the immunological examination, combined immunodeficiency was surmised. After a full exome DNA sequencing chrX: g.64951012C T missense type mutation was found in exon 5 of the MSN gene (change in the ENSP00000353408.5:p.Arg171Trp protein). X-MAID was therefore confirmed.&#x0D; Of the 9 described patients with a similar mutation, 8 had a clinical picture of severe combined immune deficiency. This clinical case confirms the possibility of a milder clinical phenotype development with a late onset under the guise of CVID and shows the need for molecular genetic examination of the adult population of patients with impaired antibody synthesis. The verification of the diagnosis allows not only to determine the prognosis and tactics of the therapy, but also to carry out genetic family counseling and to offer a possibility of giving birth to healthy offspring.

Proportions of B-cell subsets are altered in incomplete systemic lupus erythematosus and correlate with interferon score and IgG levels.

ObjectivesIncomplete SLE (iSLE) patients display symptoms typical for SLE but have insufficient criteria to fulfil the diagnosis. Biomarkers are needed to identify iSLE patients that will progress to SLE. IFN type I activation, B-cell-activating factor (BAFF) and B-cell subset distortions play an important role in the pathogenesis of SLE. The aim of this cross-sectional study was to investigate whether B-cell subsets are altered in iSLE patients, and whether these alterations correlate with IFN scores and BAFF levels.MethodsiSLE patients (n = 34), SLE patients (n = 41) with quiescent disease (SLEDAI ≤4) and healthy controls (n = 22) were included. Proportions of B-cell subsets were measured with flow cytometry, IFN scores with RT-PCR and BAFF levels with ELISA.ResultsProportions of age-associated B-cells were elevated in iSLE patients compared with healthy controls and correlated with IgG levels. In iSLE patients, IFN scores and BAFF levels were significantly increased compared with healthy controls. Also, IFN scores correlated with proportions of switched memory B-cells, plasma cells and IgG levels, and correlated negatively with complement levels in iSLE patients.ConclusionIn this cross-sectional study, distortions in B-cell subsets were observed in iSLE patients and were correlated with IFN scores and IgG levels. Since these factors play an important role in the pathogenesis of SLE, iSLE patients with these distortions, high IFN scores, and high levels of IgG and BAFF may be at risk for progression to SLE.

Prolonged Impairment of Immunological Memory After Anti-CD20 Treatment in Pediatric Idiopathic Nephrotic Syndrome.

Anti-CD20 therapy is effective in idiopathic nephrotic syndrome (INS). However, transient or sustained hypogammaglobulinemia predisposing to an increased risk of infectious diseases can follow treatment in some patients. We analyzed the long-term effects of anti-CD20 therapy on immunological memory in 27 frequently-relapsing/steroid-dependent INS pediatric patients after more than 4 years from the first and at least 2 years from the last anti-CD20 infusion. Twenty-one INS children, never treated with anti-CD20 and under an intense oral immunosuppression with prednisone, mycophenolate mofetil, and calcineurin inhibitors were also included as control group. Levels of circulating B-cell subpopulations, total serum immunoglobulins and IgG and memory B cells directed against hepatitis B virus (HBV) and tetanus were determined and correlated with clinical characteristics. Nine patients never relapsed after more than 2 years from the last anti-CD20 administration (5 after the first, 3 after the second, and 1 after the fifth infusion). At last follow-up, most patients showed a complete recovery and normalization of total (27/27), transitional (27/27), and mature-naïve B cells (25/27). However, a sustained and significant reduction of total memory (20/27) and switched memory (21/27) B cells was found in most patients. 11/27 patients showed hypogammaglobulinemia at last follow-up and, among these, four presented with a severe hypogammaglobulinemia (IgG < 160 mg/dl). In contrast, no patient in the control group developed a severe hypogammaglobulinemia. Age at the time of first anti-CD20 administration was positively associated with IgG levels at last follow-up (p = 0.008); accordingly, younger patients had an increased risk of hypogammaglobulinemia (p = 0.006). Furthermore, severe hypogammaglobulinemia and delayed switched memory B-cell reconstitution were more frequent in non-relapsing patients. Reduced IgG levels against HBV and tetanus were observed at baseline and further declined at last follow-up. Antigen-specific memory B-cells were induced by re-immunization, but specific IgG titers remained low. In conclusion, anti-CD20 therapy can be disease-modifying in some INS patients. However, a prolonged impairment of immunological memory occurs frequently, independently from the number of anti-CD20 infusions, particularly in younger patients. Re-immunization may be necessary in these patients.