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

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.

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 Behçet's Disease Current Activity Form (BDCAF) 2006 and Behçet'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.

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.

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.