Possible Role of Regulatory B Cells in Different Behçet’s Disease Phenotypes and Therapies: First Report from Egypt

Background and aim The data about the role of regulatory B cells (Breg) in Behcet Disease (BD) are scarce. We aimed to evaluate the frequency of total B lymphocytes and Breg cells in different BD phenotypes and therapies attempting to unravel their function. Methods This cross-sectional study included 35 BD patients and 39 healthy controls (HCs). The demographic data of the study subjects were collected including age and gender. Current medications including disease-modifying anti-rheumatic drugs (DMARDs) were recorded. All patients underwent testing for baseline laboratory investigations including full blood count, liver and kidney function tests, erythrocyte sedimentation rate (ESR) by Westergren blot and C-reactive protein (CRP). Measurement of the total B lymphocytes and their subtypes B regulatory lymphocytes by flow cytometric assay. Assessment of BD activity was done using the revised Behcet's Disease Current Activity Form (BDCAF) 2006 and Behcet's Syndrome Activity Score (BSAS) 1111111111. All participants were assessed for the presence of erectile dysfunction using the International Index of Erectile Function (IIEF-5 score), and for depression using the Beck Depression Inventory. Results A dramatic drop in the number of B cells, total and regulatory, was observed in the patients compared to the HCs. Regulatory cells (Bregs) tend to be upregulated with genital ulcers or vascular disease. Bregs but not B lymphocytes were associated with BSAS and ESR. Neither the total B lymphocytes nor the Bregs correlated with CRP or the sexual function or depression scores. Of all the used medications, low-dose aspirin was seen with markedly high Bregs proportions. Conclusion This study supports the role of B cells in BD pathogenesis and strongly suggests a possible role for Bregs in the resolution of different BD manifestations.