Therefore, peripheral CVID memory B cells are prompted to die from apoptosis due to a constitutive Bcl-2 family protein imbalance and defective protection from activation-induced apoptosis.
Our finding of a normal mutation frequency of the BCL-6 gene in two hypomutated CVID point to a defect of the Ig targeting of hypermutation machinery in these cases.
The CD21(low) V(H)1-69(+) B cells of MC patients, like those of CVID and HIV patients, are anergic to BCR and TLR9 stimulation and display deregulation of several anergy-related genes; proliferative anergy is also observed in CD21(high) MZ-like V(H)1-69(+) B cells, that over-express the antiproliferative transcriptional repressor Stra13.
The CD21(low) B cells have been shown to be profoundly anergic, and defects of BCR-mediated calcium signaling and of T cells have been described in CVID 1a.
The CD21(low) V(H)1-69(+) B cells of MC patients, like those of CVID and HIV patients, are anergic to BCR and TLR9 stimulation and display deregulation of several anergy-related genes; proliferative anergy is also observed in CD21(high) MZ-like V(H)1-69(+) B cells, that over-express the antiproliferative transcriptional repressor Stra13.
B-cells expressing L3P-BLK showed accelerated destruction of BCR-internalized antigen and reduced ability to elicit CD40L-expression on antigen-specific CD4(+) T-cells.In conclusion, we found a novel BLK gene variant in CVID-patients that causes suppressed B-cell proliferation and reduced ability of B-cells to elicit antigen-specific CD4(+) T-cell responses.
To explore the dysregulated networks in these subjects, we applied whole blood transcriptional profiling to 91 CVID subjects, 47 with inflammatory conditions and 44 without, in comparison to subjects with XLA and healthy controls.
To examine the possibility that sporadic male cases with X-linked agammaglobulinaemia (XLA), which is caused by mutations in the Bruton's tyrosine kinase (Btk) gene, might be misregistered as having CVID, we employed a flow cytometric test to identify XLA in hypogammaglobulinaemic males registered as CVID in the Japanese Immunodeficiency Registry.
The pathogenic origins of these two diseases are different; agammaglobulinemia is a group of inherited disorders that usually are caused by mutations in the gene encoding Bruton Tyrosine Kinase (BTK) protein while CVID is a heterogeneous disorder mainly without monogenic cause.
Viruses and bacteria in bronchoalveolar lavage fluids, protected specimen brush samples, and bronchial biopsies from 14 patients with primary hypogammaglobulinemia (11 patients with common variable immunodeficiency [CVID] and three patients with X-linked agammaglobulinemia [XLA]) were analyzed.
Seven known genetic defects, including Bruton tyrosine kinase (Btk), CD4OL, and signaling lymphocyte activation molecule-associated protein (SAP) (all X-linked) and inducible costimulator molecule (ICOS), transmembrane activator and calcium-modulator and cytophilin ligand interactor (TACI), B-cell-activating factor of the tumor necrosis family receptor (BAFFR), and CD19 (all autosomal recessive), were found in patients with the phenotype of common variable immunodeficiency (CVID).
Transmembrane activator and calcium-modulating cyclophilin ligand interactor mutations in common variable immunodeficiency: clinical and immunologic outcomes in heterozygotes.
We found increased basal levels of Bax and Bim in CVID B cells that correlated with low viability and high Caspase-3 activation only in CD27<sup>+</sup> B cells, particularly in a subgroup of apoptosis-prone CVID (AP-CVID) patients with low peripheral B cell counts and high autoimmunity prevalence (mostly cytopenias).
The main findings were: (i) CVID patients have raised serum levels of CCL19 and CCL21 independently of features of chronic inflammation; (ii) CCL19 and CCR7 have similar expression in spleens from CVID patients and controls, while CCL21 is variably down-regulated in spleens from patients; (iii) T cell expression of CCR7 is particularly low in patients characterized by chronic inflammation in vivo; and (iv) PBMC from CVID patients had attenuated cytokine response to stimulation with CCL19 and CCL21.
The main findings were: (i) CVID patients have raised serum levels of CCL19 and CCL21 independently of features of chronic inflammation; (ii) CCL19 and CCR7 have similar expression in spleens from CVID patients and controls, while CCL21 is variably down-regulated in spleens from patients; (iii) T cell expression of CCR7 is particularly low in patients characterized by chronic inflammation in vivo; and (iv) PBMC from CVID patients had attenuated cytokine response to stimulation with CCL19 and CCL21.
Our observations indicate that a predominance of CCR7(-) T cells with effector-memory cell features and with reduced proliferative capacity may characterize a subgroup of CVID.