Active chronic sarcoidosis is characterized by increased transitional blood B cells, increased IL-10-producing regulatory B cells and high BAFF levels.

BackgroundSarcoidosis is a multisystemic disease of unknown etiology characterized by a disproportionate Th1 granulomatous immune response in the organs involved. Plasmatic hypergammaglobulinemia and B cell accumulation in granulomatous lesions suggest the possible role of humoral immune responses in the pathogenesis of sarcoidosis. The purpose of this study is to describe B cell peripheral compartment in sarcoidosis.Methodology/principal findingsWe analyzed blood B cell subsets and BAFF levels in 33 patients with chronic sarcoidosis (active sarcoidosis n = 18; inactive sarcoidosis n = 15) and 18 healthy donors. Active chronic sarcoidosis patients had significantly less circulating memory B cells (pConclusions/significanceThese data show that there is an altered B cell homeostasis in active sarcoidosis and suggest BAFF antagonist drugs as potential new treatments of this disease.