Features of BAFF and APRIL receptors on circulating B cells in antineutrophil cytoplasmic antibody-associated vasculitis.

To investigate the features of circulating B cells, their expressing receptors, serum levels of B-cell activation factor of the TNF family (BAFF), and a proliferation-inducing ligand (APRIL) in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Blood samples from 24 patients with active AAV (a-AAV), 13 with inactive AAV (i-AAV), and 19 healthy controls (HC) were included in this study. The proportion of B cells and their expressing BAFF receptor (BAFF-R), transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI), and B-cell maturation antigen were analyzed via flow cytometry. Serum levels of BAFF, APRIL, and interleukin (IL)-4, IL-6, IL-10, and IL-13 were also evaluated using an enzyme-linked immunosorbent assay. The proportion of plasmablasts (PB)/plasma cells (PC) and serum levels of BAFF, APRIL, IL-4, and IL-6 were significantly higher in a-AAV than in HC. Higher serum levels of BAFF, APRIL, and IL-4 were observed in i-AAV than in HC. Lower expression of BAFF-R on memory B cells and higher expression of TACI on CD19+ cells, immature B cells, and PB/PC were demonstrated in a-AAV and i-AAV than in HC. The population of memory B cells was positively associated with serum APRIL levels and BAFF-R expression in a-AAV. In conclusion, decreased expression of BAFF-R on memory B cells and increased expression of TACI on CD19+ cells, immature B cells, and PB/PC, as well as increased serum levels of BAFF and APRIL, were sustained even in the remission phase of AAV. Persistent aberrant signaling of BAFF/APRIL may contribute to disease relapse.

Testicular vasculitis in eosinophilic granulomatosis with polyangiitis: a case-based review.

Testicular vasculitis (TV) develops when an organ is involved in systemic vasculitis. A 47-year-old man with eosinophilic granulomatosis with polyangiitis (EGPA) developed TV as the first clinical episode. The patient had bronchial asthma for 8 years and developed left testicular pain before developing arthralgia, abdominal involvement, and sensory polyneuropathy, which led to the diagnosis of EGPA. The induration of the affected testicle persisted even after initiating immunosuppressive therapy with corticosteroids and cyclophosphamide, raising concern for testicular neoplasm, while testicular pain and other symptoms resolved. The patient underwent inguinal orchiectomy, and a histology examination of the resected testicle revealed fibrinoid necrotizing vasculitis. Only three cases of biopsy-proven TV in patients with EGPA have been reported in our review of published English-language articles. Two of the three patients in the reviewed cases developed TV before being diagnosed with EGPA. Moreover, all patients underwent extirpation of the affected testicle, leading to a pathological diagnosis of TV. This report suggests that TV may develop and be the presenting condition in EGPA, although urogenital involvement is rare.

IgG4-related Disease with a Cardiac Mass Causing Cerebral Infarction.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic inflammatory disease characterized by infiltration of extensive IgG4-positive plasma cells and lymphocytes. Although IgG4-RD has been observed in almost all organs, it rarely affects the myocardium. Cardiovascular lesions of IgG4-RD appear as aortic (aortic aneurysm and aortitis) and pericardial (constrictive pericarditis) lesions as well as pseudotumors around the coronary arteries. We herein report a case of IgG4-RD with a cardiac mass in the right atrium involving a sinus node. This condition caused arrhythmia and repeated strokes. We successfully treated the patient through resection of the cardiac mass, catheter ablation and immunosuppressive therapy.

Oxidative Stress Promotes Instability of Regulatory T Cells in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

We investigated the characteristics of regulatory T cells (Tregs), focusing on the relationship between their stability and reactive oxygen species (ROS), in antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Intracellular expressions of effector cytokines, forkhead box protein 3 (FoxP3), ROS, phosphorylated mammalian target of rapamycin (mTOR), and sirtuin 1 (SIRT1) in Tregs from peripheral blood mononuclear cells (PBMCs) of patients with AAV and healthy controls (HC) were analyzed. The alterations in and functional ability of Tregs were compared before and after resveratrol (RVL) treatment of PBMCs in patients with AAV. Significantly higher expressions of interferon (IFN)-γ, interleukin (IL)-17, IL-4, ROS, and phosphorylated mTOR (pho-mTOR) and lower expression of SIRT1 in CD4+CD25+FoxP3+ cells were found in patients with AAV than in the HC. FoxP3 expression in CD4+CD25+ cells and suppressive function of Tregs were significantly lower in patients with AAV than in the HC. Tregs after RVL treatment demonstrated significant decreases in IFN-γ, ROS, and pho-mTOR levels and increases in FoxP3, SIRT1 levels, and functional activity. Conversely, the direct activation of SIRT1 by SRT1720 resulted in decreased FoxP3 expression, with no reduction in ROS levels. The pho-mTOR levels were significantly higher in Tregs after activation by SRT1720 than in those after RVL treatment. This study suggested that imbalanced changes in Tregs could be attributed to mTOR activation, in which ROS overproduction was predominantly implicated. Therefore, ROS is a key mediator for promoting Tregs instability in AAV.