Abnormal B-cell Research Articles

Serological biomarkers for management of primary sclerosing cholangitis.

Clinical manifestations and progression of primary sclerosing cholangitis (PSC) are heterogeneous, and its pathogenesis is poorly understood. The importance of gut-liver interactions in the pathogenesis has been clinically confirmed and highlighted in different theories. Recent advances regarding biomarkers of biliary-gut crosstalk may help to identify clinically relevant PSC subgroups assisting everyday clinical work-up (e.g., diagnosis, disease stratification, or surveillance) and the exploration of potential therapeutic targets. Alkaline phosphatase produced by the biliary epithelium is consistently associated with prognosis. However, its level shows natural fluctuation limiting its use in individual patients. Inflammatory, cell activation, and tissue remodeling markers have been reported to predict clinical outcome. Elevated immunoglobulin (Ig) G4 level is associated with a shorter transplantation-free survival. IgG type atypical perinuclear anti-neutrophil cytoplasmic antibodies (P-ANCAs) are non-specific markers of various autoimmune liver diseases and may reflect an abnormal B-cell response to gut microbial antigens. IgG type atypical P-ANCA identifies PSC patients with particular clinical and genetic (for human leukocyte antigens) characteristics. The presence of IgA type anti-F-actin antibody (AAA) may predict a progressive disease course, and it is associated with enhanced mucosal immune response to various microbial antigens and enterocyte damage. IgA type anti-glycoprotein 2 (GP2) antibodies identify patients with a severe disease phenotype and poor survival due to enhanced fibrogenesis or development of cholangiocarcinoma. Elevated soluble vascular adhesion protein-1 (sVAP-1) level is associated with adverse disease outcomes in PSC. High sVAP-1 levels correlate with mucosal addressin cell adhesion molecule-1 (MAdCAM-1) expression in the liver that contributes to gut activated T-cell homing to the hepatobiliary tract. In the present paper, we review the evidence on these possible serological markers that could potentially help address the unmet clinical needs in PSC.

Health-related quality of life, fatigue and health utilities in lupus nephritis: A systematic literature review.

BackgroundSystemic lupus erythematosus (SLE) is a chronic, autoimmune disease characterized by abnormal B-cell activation and the presence of autoantibodies, which can result in organ damage. Lupus nephritis (LN) is the most common severe organ manifestation of SLE and may result in impaired kidney function. However, there is limited research on the health-related quality of life (HRQoL) burden amongst patients with LN. The objective of this systematic literature review was to assess the HRQoL, fatigue and health utilities associated with LN.MethodsA structured literature search (GSK Study 212980) of the MEDLINE and Embase databases was conducted in July 2019 and updated September 2021. Relevant international congress abstracts from 2016 to 2021 were searched, and gray literature searches and keyword-based searches in PubMed, Google, and Google Scholar were also conducted. Results were screened according to predefined criteria and data on the outcomes of interest were extracted. A quantitative analysis was conducted to supplement the narrative review, to provide 36-item Short Form survey (SF-36) estimates, and to determine variation by prognostic factors.ResultsOf 1155 articles identified, 26 studies for a total of 3440 patients were included. Patients with LN showed poorer HRQoL and more fatigue than healthy controls/the general population, although these were similar between patients with SLE with and without LN. HRQoL was worse in patients with LN Class III/IV or with active disease. Fatigue was generally reported as the most burdensome symptom and was associated with lower HRQoL and increased treatment dissatisfaction. During induction treatment, HRQoL and fatigue were improved with mycophenolate mofetil versus cyclophosphamide. HRQoL improved over time with treatment amongst patients with active LN. Very limited data were identified assigning utilities to health states for cost-effectiveness analysis. Nine studies were considered for quantitative analysis of baseline SF-36 scores. The analysis suggested that LN has a significant impact across all SF-36 domains, with the lowest scores in the general health perceptions and role-physical domains and physical component summary.ConclusionsThere is a large HRQoL burden in patients with LN, in particular regarding symptoms of fatigue. Future research should focus on investigating fatigue severity and health utilities in LN.

SARS-CoV-2 symptomatic reinfection among patients with primary antibody deficiency

SARS-CoV-2 symptomatic reinfection among patients with primary antibody deficiency

Identification of a novel HOOK3-FGFR1 fusion gene involved in activation of the NF-kappaB pathway

BackgroundRearrangements involving the fibroblast growth factor receptor 1 (FGFR1) gene result in 8p11 myeloproliferative syndrome (EMS), which is a rare and aggressive hematological malignancy that is often initially diagnosed as myelodysplastic syndrome (MDS). Clinical outcomes are typically poor due to relative resistance to tyrosine kinase inhibitors (TKIs) and rapid transformation to acute leukemia. Deciphering the transcriptomic signature of FGFR1 fusions may open new treatment strategies for FGFR1 rearrangement patients.MethodsDNA sequencing (DNA-seq) was performed for 20 MDS patients and whole exome sequencing (WES) was performed for one HOOK3-FGFR1 fusion positive patient. RNA sequencing (RNA-seq) was performed for 20 MDS patients and 8 healthy donors. Fusion genes were detected using the STAR-Fusion tool. Fluorescence in situ hybridization (FISH), quantitative real-time PCR (qRT-PCR), and Sanger sequencing were used to confirm the HOOK3-FGFR1 fusion gene. The phosphorylation antibody array was performed to validate the activation of nuclear factor-kappaB (NF-kappaB) signaling.ResultsWe identified frequently recurrent mutations of ASXL1 and U2AF1 in the MDS cohort, which is consistent with previous reports. We also identified a novel in-frame HOOK3-FGFR1 fusion gene in one MDS case with abnormal monoclonal B-cell lymphocytosis and ring chromosome 8. FISH analysis detected the FGFR1 break-apart signal in myeloid blasts only. qRT-PCR and Sanger sequencing confirmed the HOOK3-FGFR1 fusion transcript with breakpoints located at the 11th exon of HOOK3 and 10th exon of FGFR1, and Western blot detected the chimeric HOOK3-FGFR1 fusion protein that is presumed to retain the entire tyrosine kinase domain of FGFR1. The transcriptional feature of HOOK3-FGFR1 fusion was characterized by the significant enrichment of the NF-kappaB pathway by comparing the expression profiling of FGFR1 fusion positive MDS with 8 healthy donors and FGFR1 fusion negative MDS patients. Further validation by phosphorylation antibody array also showed NF-kappaB activation, as evidenced by increased phosphorylation of p65 (Ser 536) and of IKBalpha (Ser 32).ConclusionsThe HOOK3-FGFR1 fusion gene may contribute to the pathogenesis of MDS and activate the NF-kappaB pathway. These findings highlight a potential novel approach for combination therapy for FGFR1 rearrangement patients.

Evaluation of immunological abnormalities in patients with rare syndromes

Recurrent infections are important problems in syndromic patients. This study aimed to evaluate immunological abnormalities in patients who presented with recurrent infections and were diagnosed with rare syndromes. This retrospective analysis included 14 patients with complaints of recurrent infections, all of whom were diagnosed with a rare syndrome. The study group consisted of patients with Aicardi syndrome, Brugada syndrome, Phelan- McDermid syndrome, trichothiodystrophy, LEOPARD syndrome, Prader-Willi syndrome, Seckel syndrome, trisomy 18 (Edwards' syndrome), Wiedemann-Steiner syndrome, West syndrome, Williams syndrome, 47,XYY syndrome, 16p13 deletion syndrome, and 13q1.3 deletion syndrome. Seven patients (50%) were girls and seven (50%) were boys (mean age, 56.7 ±32.9 months; median [range] age: 45.5 [27-153] months). There were high rates of consanguinity (50%), cesarean section delivery (71%), and hospitalization in the intensive care unit (78.5%). No patients had a family history of immunodeficiency. On admission, all patients exhibited humoral and/or cellular immune system abnormalities. During the follow-up period, all T-cell abnormalities were improved after immunoglobulin replacement therapy (IGRT), while B-cell abnormalities persisted. These findings suggested that the patients predominantly had antibody deficiencies associated with mild T-cell abnormalities because of recurrent infections. The rates of infections and hospitalizations were significantly reduced after IGRT (p < 0.001); the rate of intensive care unit admission also significantly decreased (from 78.5% to 21.4%). Two of the three oxygen-dependent patients exhibited improvement therein. IGRT was discontinued in two patients with significant clinical improvement during follow-up. An immunological evaluation should be considered in pediatric patients with rare syndromes and recurrent infections. IGRT may help to improve the prognoses of these patients.

Abnormal B-Cell and Tfh-Cell Profiles in Patients With Parkinson Disease

Background and ObjectivesThere has been growing interest in potential roles of the immune system in the pathogenesis of Parkinson disease (PD). The aim of the current study was to comprehensively characterize phenotypic and functional profiles of circulating immune cells in patients with PD vs controls.MethodsPeripheral blood was collected from patients with PD and age- and sex-matched neurologically normal controls (NCs) in 2 independent cohorts (discovery and validation). Comprehensive multicolor flow cytometry was performed on whole blood leukocytes and peripheral blood mononuclear cells to characterize different immune subsets and their ex vivo responses.ResultsThe discovery cohort included 17 NCs and 12 participants with PD, and the validation cohort included 18 NCs and 18 participants with PD. Among major immune cell types, B cells appeared to be preferentially affected in PD. Proliferating B cell counts were decreased in patients with PD compared with controls. Proportions of B-cell subsets with regulatory capacity such as transitional B cells were preferentially reduced in the patients with PD, whereas proportions of proinflammatory cytokine-producing B cells increased, resulting in a proinflammatory shift of their B-cell functional cytokine responses. Unsupervised principal component analysis revealed increased expression of TNFα and GM-CSF by both B cells and T cells of patients with PD. In addition, levels of follicular T cells, an important B-cell helper T-cell population, decreased in the patients with PD, correlating with their B-cell abnormality.DiscussionOur findings define a novel signature of peripheral immune cells and implicate aberrant Tfh:B-cell interactions in patients with PD.

Relevant Characteristics Analysis Using Natural Language Processing and Machine Learning Based on Phenotypes and T-Cell Subsets in Systemic Lupus Erythematosus Patients With Anxiety

Anxiety is frequently observed in patients with systemic lupus erythematosus (SLE) and the immune system could act as a trigger for anxiety. To recognize abnormal T-cell and B-cell subsets for SLE patients with anxiety, in this study, patient disease phenotypes data from electronic lupus symptom records were extracted by using natural language processing. The Hospital Anxiety and Depression Scale (HADS) was used to distinguish patients, and 107 patients were selected to meet research requirements. Then, peripheral blood was collected from two patient groups for multicolor flow cytometry experiments. The characteristics of 75 T-cell and 15 B-cell subsets were investigated between SLE patients with- (n = 23) and without-anxiety (n = 84) groups by four machine learning methods. The findings showed 13 T-cell subsets were significantly different between the two groups. Furthermore, BMI, fatigue, depression, unstable emotions, CD27+CD28+ Th/Treg, CD27−CD28− Th/Treg, CD45RA−CD27− Th, and CD45RA+HLADR+ Th cells may be important characteristics between SLE patients with- and without-anxiety groups. The findings not only point out the difference of T-cell subsets in SLE patients with or without anxiety, but also imply that T cells might play the important role in patients with anxiety disorder.

Anti-TRIM21 antibody is associated with aberrant B-cell function and type I interferon production in systemic lupus erythematosus.

TRIM21 is a member of the tripartite motif family proteins and is one of the autoantigens which react with anti-SS-A antibody (Ab) present in sera of patients with systemic lupus erythematosus (SLE) and Sjögren's syndrome. Previous studies have shown that TRIM21 dysfunction promotes aberrant B-cell differentiation and Ab production in SLE, and anti-TRIM21 Ab may be related to the TRIM21 dysfunction in human SLE pathogenesis. Here, we examined the relationship between anti-TRIM21 Ab and clinical and immunological characteristics in SLE patients. Twenty-seven patients with SLE (23 women and four men) before immunosuppressive therapies, who fulfilled the revised 1997 American College of Rheumatology criteria for SLE, and four healthy controls (3 women and one man) were enrolled in the study. SLE patients were divided into two groups according to the seropositivity for anti-TRIM21 Ab. Serum anti-TRIM21 Ab levels were measured using enzyme-linked immunosorbent assays. The serum levels of cytokines and immunoglobulins were measured by cytometer beads arrays. The expression levels of TRIM21 protein in peripheral mononuclear cells (PBMCs) from SLE patients were evaluated by Western blotting. Sixteen and 9 patients showed seronegativity and seropositivity for anti-TRIM21 Ab, respectively. There were no significant differences in the background parameters, including female ratio, age, disease duration, SLE activity, and laboratory data between the two groups. The serum levels of interferon (IFN)-β were significantly higher in patients with anti-TRIM21 Ab as compared with those without anti-TRIM21 Ab (P = .043). The levels of IgG1 and IgA were significantly higher in SLE patients with anti-TRIM21 Ab as compared with those without anti-TRIM21 Ab (P = .0022 and .032, respectively). The PBMCs of patients with anti-TRIM21 Ab showed a significantly lower expression of TRIM21 protein as compared with those of patients without anti-TRIM21 Ab (P = .014). Anti-TRIM21 Ab seropositivity was related to B-cell abnormalities and type I IFN overproduction in SLE patients. These findings suggest that anti-TRIM21 Ab may have an inhibitory effect on TRIM21 functions and be a novel biomarker for the level of dependence on type I IFN overproduction and B-cell abnormalities.

Abnormal B-cell development in TIMP-deficient bone marrow

AbstractBone marrow (BM) is the primary site of hematopoiesis and is responsible for a lifelong supply of all blood cell lineages. The process of hematopoiesis follows key intrinsic programs that also integrate instructive signals from the BM niche. First identified as an erythropoietin-potentiating factor, the tissue inhibitor of metalloproteinase (TIMP) protein family has expanded to 4 members and has widely come to be viewed as a classical regulator of tissue homeostasis. By virtue of metalloprotease inhibition, TIMPs not only regulate extracellular matrix turnover but also control growth factor bioavailability. The 4 mammalian TIMPs possess overlapping enzyme-inhibition profiles and have never been studied for their cumulative role in hematopoiesis. Here, we show that TIMPs are critical for postnatal B lymphopoiesis in the BM. TIMP-deficient mice have defective B-cell development arising at the pro-B-cell stage. Expression analysis of TIMPless hematopoietic cell subsets pointed to an altered B-cell program in the Lineage−Sca-1+c-Kit+ (LSK) cell fraction. Serial and competitive BM transplants identified a defect in TIMP-deficient hematopoietic stem and progenitor cells for B lymphopoiesis. In parallel, reverse BM transplants uncovered the extrinsic role of stromal TIMPs in pro- and pre-B-cell development. TIMP deficiency disrupted CXCL12 localization to LepR+ cells, and increased soluble CXCL12 within the BM niche. It also compromised the number and morphology of LepR+ cells. These data provide new evidence that TIMPs control the cellular and biochemical makeup of the BM niche and influence the LSK transcriptional program required for optimal B lymphopoiesis.

Germline Mutations in CTLA4 and Spectrum of Bone Marrow Features Overlapping with Aplastic Anemia and Large Granular Lymphocyte Lymphocytosis

Introduction: CTLA4 haploinsufficiency due to germline heterozygous mutations in the cytotoxic T-lymphocyte antigen-4 gene (CTLA4) results in severe systemic immune dysregulation; infiltrative lymphocytic lesions of lungs (e.g. lymphocytic pneumonitis), GI tract (e.g.lymphocytic colitis), and CNS; and a spectrum of autoimmunity, immunodeficiency and peripheral blood cytopenias. We describe the hematologic, bone marrow (BM), and flow cytometry (FC) features of CTLA4 haploinsufficiency of a cohort of 14 patients, which show overlapping morphologic features with acquired aplastic anemia (acAA), and large granular lymphocyte lymphocytosis (LGL) in a subset of patients. We compared the findings to those in a separate cohort of 20 age matched patients diagnosed with acAA. There were significant differences between acAA and CTLA4 deficiency based on analysis of BM lymphocyte subsets and marrow lymphocyte infiltration patterns.Materials and Methods: Peripheral blood (PB), BM and FC analysis of patients with germline mutations in CTLA4, and acAA was performed along with review of clinical, molecular and laboratory data. Statistical comparisons were made using Mann Whitney test, with p < 0.05 for significance.Results: Median age at initial evaluation for patients with CTLA4 haploinsufficiency was 23.5 years (range 11-71 years), with a male-to-female ratio of 11:3. 11 out of 14 patients had cytopenias. Of those with cytopenias 2/11 had pancytopenia, 4/11 had bicytopenia and 5/11 had unilineage cytopenia. Hypogammaglobulinemia was common (13/14). In some cases cytopenias were recognized as autoimmune in etiology with immune thrombocytopenic purpura and autoimmune hemolytic anemia, among the most common hematologic manifestations. Three patients met criteria for a diagnosis of moderate AA, 1 for severe AA, and 1 for LGL. Overall bone marrow biopsies were hypocellular for age (10/14) with a subset (29% [4/14]) showing severe trilineage hypoplasia with ≤20% cellularity. Atypical interstitial CD8-positive T-cell infiltrates with prominent non-paratrabecular CD4-positive T-cell aggregates were evident by immunohistochemistry in most cases (10/14), accompanied by a near absence of B-cells. T-cell clonality was assessed by T-cell receptor (TCR) gamma PCR and showed abnormal oligoclonal T-cell populations in 3/8, and one case with a clonal T-cell receptor gene rearrangement. B-cell IgH PCR reactions were polyclonal. In all cases, cytogenetic studies were either negative or showed only minor abnormalities (i.e. loss of Y chromosome). Given the morphologic overlap of a subset of CTLA4 cases with acAA, we compared bone marrow flow cytometry analysis of 8 CTLA4 cases with 20 acAA cases. CTLA4 patients showed >5 fold reduction in the median percentage of B-cells in comparison to acAA (p=0.0005). While acAA cases demonstrated relative preservation the B-cell compartment with intact B-cell maturation sequence; in contrast CTLA4 cases showed abnormal B-cell maturation patterns in half of cases characterized by few detectable early B-cell precursors, and progressive loss of intermediate and mature forms. T-cell populations in CTLA4 showed inverted CD4:CD8 ratios with relatively increased CD57+ T-cells, and atypical dim expression of CD20 on T-cells. Morphologically, when the markedly hypocellular CTLA4 cases were compared to acAA on core biopsies, little difference in marrow cellularity was seen; however, the CTLA4 cases showed multiple large atypical T-cell aggregates and near total absence of B-cells, which was not seen in acAA; acAA cases showed scattered background T-cells and B-cells.Conclusions: CTLA-4 deficiency presents with cytopenias, autoimmunity, and immunodeficiency with a subset of patients that have features overlapping with bone marrow failure, specifically AA and LGL. Herein we demonstrate a combination of abnormal BM findings, previously unreported, comprising hypocellularity, CD8-positive interstitial T-cell infiltrates with atypical CD4-positive T-cell aggregates, marked B-cell lymphopenia, increased LGLs and abnormal T-cell clonality patterns by PCR. These features may help identify patients harboring CTLA4 mutations for early detection and optimal therapeutic management. DisclosuresYoung:Novartis/GSK to institute: Research Funding. Townsley:Novartis/GSK to institute: Research Funding.

B cell subset composition segments clinically and serologically distinct groups in chronic cutaneous lupus erythematosus

ObjectiveWhile the contribution of B-cells to SLE is well established, its role in chronic cutaneous lupus erythematosus (CCLE) remains unclear. Here, we compare B-cell and serum auto-antibody profiles between patients...

Anti-TRIM21 antibody seropositivity is related to B-cell abnormalities in systemic lupus erythematosus

Abstract Background/Purpose TRIM21 is one of the autoantigens which react with anti-SS-A antibody (Ab). Previous studies have shown that TRIM21 dysfunction promotes aberrant B-cell differentiation in systemic lupus erythematosus (SLE). Here we examined the relationship between anti-TRIM21 Ab and clinical and immunological characteristics in SLE patients. Methods Twenty-seven patients with SLE before immunosuppressive therapies and four healthy controls (HC) were enrolled in the study. Serum anti-TRIM21 Ab levels were measured using enzyme-linked immunosorbent assays. The serum levels of cytokines and immunoglobulins were measured using cytometer beads arrays. The protein expression levels of TRIM21 in peripheral blood mononuclear cells (PBMCs) were evaluated by western blotting. Results Nineteen and 8 patients showed seronegativity and seropositivity for anti-TRIM21 Ab, respectively. There were no significant differences in the background parameters, including SLE activity and laboratory data. The serum levels of interferon (IFN)-α2 were significantly higher in patients with anti-TRIM21 Ab as compared with those without anti-TRIM21 Ab (p = 0.03). The levels of IgG1, IgG2, and IgA were significantly higher in patients with anti-TRIM21 Ab as compared with those without anti-TRIM21 Ab (p = 0.005, 0.04 and 0.01, respectively). The PBMCs of patients with anti-TRIM21 Ab showed a significantly higher expression of TRIM21 protein as compared with those of patients without anti-TRIM21 Ab. Conclusion Anti-TRIM21 Ab seropositivity is related to B-cell abnormalities and type I IFN overproduction in SLE patients, which may be due to the inhibitory effect of anti-TRIM21 Ab on TRIM21 functions.

Bach2 overexpression represses Th9 cell differentiation by suppressing IRF4 expression in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by abnormal activation of T cells and caused by an imbalance in the production and clearance of apoptotic cells. We previously showed that the transcription regulator Bach2 regulated abnormal B-cell activation in SLE. Here, we investigated whether Bach2 was also involved in Th9 cell differentiation in SLE. We found that the proportion of Th9 cells was enhanced in the peripheral blood mononuclear cells (PBMC) of SLE patients. The PBMC and CD4+ T cells of SLE patients exhibited a decrease of Bach2 expression and an increase of IL-9 expression. Furthermore, Bach2 overexpression significantly repressed the levels of PU.1, IRF4, IL-9, and Th9 cells in the CD4+ T cells of SLE patients and healthy volunteers. In addition, Bach2 overexpression inhibited the levels of IL-9 and Th9 cells, whereas IRF4 upregulation enhanced the levels of IRF4 and IL-9 and Th9 cells in the CD4+ T cells of SLE patients and healthy volunteers. The effect of IRF4 up-regulation was abolished by Bach2 overexpression. In summary, our work suggests that Bach2 overexpression represses Th9 cell differentiation by suppressing IRF4 expression in SLE, and thus, Bach2 may be a novel potential target for SLE treatment.

Abstract PO-42: TBL1XR1 mutations drive extranodal lymphomagenesis by inducing a protumorigenic memory B-cell fate

Abstract The most aggressive B-cell lymphomas frequently manifest extranodal distribution and carry somatic mutations in the poorly characterized gene TBL1XR1. Here, we show that TBL1XR1 mutations skew the humoral immune response towards generating abnormal immature memory B-cells (MB), while impairing plasma cell differentiation. At the molecular level, TBL1XR1 mutants co-opt SMRT/HDAC3 repressor complexes towards binding the MB cell transcription factor (TF) BACH2, at the expense of the germinal center (GC) TF BCL6, leading to pre-memory transcriptional reprogramming and cell-fate bias. Upon antigen recall, TBL1XR1 mutant MB cells fail to differentiate into plasma cells and instead preferentially reenter new GC reactions, providing evidence for a cyclic re-entry lymphomagenesis mechanism. Ultimately, TBL1XR1 alterations lead to a striking extranodal immunoblastic lymphoma phenotype that mimics the human disease. Both human and murine lymphomas feature expanded MB-like cell populations, consistent with a MB-cell origin and delineating an unforeseen pathway for malignant transformation of the immune system. Citation Format: Leandro Venturutti, Matt Teater, Andrew Zhai, Amy Chadburn, Leena Babiker, Daleum Kim, Louis Staudt, Michael Green, Pedro Farinha, Andrew Weng, Christian Steidl, Ryan Morin, David Scott, Gil Privé, Ari Melnick. TBL1XR1 mutations drive extranodal lymphomagenesis by inducing a protumorigenic memory B-cell fate [abstract]. In: Proceedings of the AACR Virtual Meeting: Advances in Malignant Lymphoma; 2020 Aug 17-19. Philadelphia (PA): AACR; Blood Cancer Discov 2020;1(3_Suppl):Abstract nr PO-42.

Concomitant Chronic Lymphocytic Leukemia and Mantle Cell Lymphoma Discovered by Flow Cytometry

Abstract Casestudy: Chronic lymphocytic leukemia (CLL) accounts for about 30% of all lymphoid neoplasms and is the most common adult blood cancer in the Western world. Mantle cell lymphoma (MCL) accounts for only about 6% of all B-cell lymphomas in Western countries. MCL and CLL are both CD5 positive B-cell lymphoproliferative disorders. It is necessary to distinguish these two entities as MCL is a more aggressive disease, and requires specific treatment. MCL and CLL can occur in one patient at the same time and is often termed a composite lymphoma. We present an 84-year-old female with a history of endometrial cancer who was found to have splenomegaly and lymphadenopathy. Flow cytometry was performed upon her peripheral blood specimen which demonstrated two distinct populations of abnormal light chain restricted B-cell populations. One population demonstrated kappa light chain restriction and was positive for CD45, CD19, CD20, CD5, CD38, FMC-7, and CD22, representing MCL. The other population showed dim lambda light chain restriction that was also positive for CD45, CD19, dim CD20, CD5, and CD23, representing CLL. FISH studies demonstrated t(11;14), and four common deletions or chromosome aneuploidy associated with CLL. These findings confirmed the dual populations of CLL and MCL. This is an interesting case because it is a very rare combination with only a few cases having been reported with two distinct cell populations in one patient at the same time.

Concomitant Chronic Lymphocytic Leukemia and Mantle Cell Lymphoma Discovered by Flow Cytometry

Abstract Casestudy: Chronic lymphocytic leukemia (CLL) accounts for about 30% of all lymphoid neoplasms and is the most common adult blood cancer in the Western world. Mantle cell lymphoma (MCL) accounts for only about 6% of all B-cell lymphomas in Western countries. MCL and CLL are both CD5 positive B-cell lymphoproliferative disorders. It is necessary to distinguish these two entities as MCL is a more aggressive disease, and requires specific treatment. MCL and CLL can occur in one patient at the same time and is often termed a composite lymphoma. We present an 84-year-old female with a history of endometrial cancer who was found to have splenomegaly and lymphadenopathy. Flow cytometry was performed upon her peripheral blood specimen which demonstrated two distinct populations of abnormal light chain restricted B-cell populations. One population demonstrated kappa light chain restriction and was positive for CD45, CD19, CD20, CD5, CD38, FMC-7, and CD22, representing MCL. The other population showed dim lambda light chain restriction that was also positive for CD45, CD19, dim CD20, CD5, and CD23, representing CLL. FISH studies demonstrated t(11;14), and four common deletions or chromosome aneuploidy associated with CLL. These findings confirmed the dual populations of CLL and MCL. This is an interesting case because it is a very rare combination with only a few cases having been reported with two distinct cell populations in one patient at the same time.

Elevated STAT1 expression but not phosphorylation in lupus B cells correlates with disease activity and increased plasmablast susceptibility

SLE is characterized by two pathogenic key signatures, type I IFN and B-cell abnormalities. How these signatures are interrelated is not known. Type I-II IFN trigger activation of Janus kinase (JAK) - signal transducer and activator of transcription (STAT). JAK-STAT inhibition is an attractive therapeutic possibility for SLE. We assess STAT1 and STAT3 expression and phosphorylation at baseline and after IFN type I and II stimulation in B-cell subpopulations of SLE patients compared with other autoimmune diseases and healthy controls (HD) and related it to disease activity. Expression of STAT1, pSTAT1, STAT3 and pSTAT3 in B and T cells of 21 HD, 10 rheumatoid arthritis (RA), seven primary Sjögren's (pSS) and 22 SLE patients was analysed by flow cytometry. STAT1 and STAT3 expression and phosphorylation in PBMCs (peripheral blood mononuclear cells) of SLE patients and HD after IFNα and IFNγ incubation were further investigated. SLE patients showed substantially higher STAT1 but not pSTAT1 in B- and T-cell subsets. Increased STAT1 expression in B-cell subsets correlated significantly with SLEDAI and Siglec-1 on monocytes, a type I IFN marker. STAT1 activation in plasmablasts was IFNα dependent while monocytes exhibited dependence on IFNγ. Enhanced expression of STAT1 by B-cell candidates as a key node of two immunopathogenic signatures (type I IFN and B-cells) related to important immunopathogenic pathways and lupus activity. We show that STAT1 is activated upon IFNα exposure in SLE plasmablasts. Thus, Jak inhibitors, targeting JAK-STAT pathways, hold a promise to block STAT1 expression and control plasmablast induction in SLE.

Alterations of B Cells in Immunosuppressive Phase of Septic Shock Patients.

Septic shock is a subset of sepsis related to acute circulatory failure characterized by severe immunosuppression and high mortality. Current knowledge about B-cell status in the immunosuppressive phase of septic shock is sparse. The aim of this study was to investigate the alterations of B Cells in the immunosuppressive phase of septic shock. Prospective cohort study. Adult ICUs at a university hospital. Adult septic shock patients without any documented immune comorbidity. None. The absolute counts of lymphocytes and B cells of 81 patients and 13 healthy controls, and serum immunoglobulin levels of 64 patients and 10 healthy controls were determined by clinical laboratory. The percentages and counts of B-cell subsets of 33 patients and 10 healthy controls and the immunoglobulin M expression on B-cell subsets of 20 patients and five healthy controls were quantified by flow cytometry. Immunoglobulin levels produced by B cells after stimulation in vitro of 20 patients and five healthy controls were tested by enzyme-linked immunosorbent assay. Redistribution and selective depletion of B-cell subsets in septic shock patients were discovered, and a decrease in immunoglobulin M levels was associated with a reduction in resting memory B-cell counts. These alterations were more pronounced in nonsurvivors compared with survivors. Additionally, receiver operating characteristic curve analysis showed that the data of B-cell subsets had the best predictive value for mortality risk. Severe B-cell abnormalities are present in the immunosuppressive phase of septic shock and are associated with prognosis.

Identification of Novel Genetic Variants in CVID Patients With Autoimmunity, Autoinflammation, or Malignancy.

Common variable immunodeficiency (CVID) is a primary immunodeficiency characterized by recurrent bacterial infections and defined by reduced levels of IgG, IgA, and/or IgM, insufficient response to polysaccharide vaccination, and an abnormal B-cell immunophenotype with a significantly reduced fraction of isotype-switched memory B cells. In addition to this infectious phenotype, at least one third of the patients experience autoimmune, autoinflammatory, granulomatous, and/or malignant complications. The very heterogeneous presentation strongly suggests a collection of different disease entities with somewhat different pathogeneses and most likely diverse genetic etiologies. Major progress has been made during recent years with the advent and introduction of next-generation sequencing, initially for research purposes, but more recently in clinical practice. In the present study, we performed whole exome sequencing on 20 CVID patients with autoimmunity, autoinflammation, and/or malignancy from the Danish CVID cohort with the aim to identify gene variants with a certain, possible, or potential disease-causing role in CVID. Through bioinformatics analyses, we identified variants with possible/probable disease-causing potential in nine of the patients. Of these, three patients had four variants in three different genes classified as likely pathogenic (NFKB1, TNFAIP3, and TTC37), whereas in six patients, we identified seven variants of possible pathogenic potential classified as variants of unknown significance (STAT3, IL17F, IRAK4, DDX41, NLRC3, TNFRSF1A, and PLCG2). In the remaining 11 patients, we did not identify possible genetic causes. Genetic findings were correlated to clinical disease presentation, clinical immunological phenotype, and disease complications. We suggest that the variants identified in the present work should lay the ground for future studies to functionally validate their disease-causing potential and to investigate at the mechanistic and molecular level their precise role in CVID pathogenesis. Overall, we believe that the present work contributes important new insights into the genetic basis of CVID and particular in the subset of CVID patients with a complex phenotype involving not only infection, but also autoimmunity, autoinflammation, and malignancy.

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.