034 Impaired frequency and function of transitional B cells in patients with pemphigus vulgaris

Pemphigus vulgaris (PV) is an autoimmune disease clinically characterized by blisters on the skin and/or mucosa. Pathophysiologically, PV mediated close interaction of B cells and autoreactive T cells, inducing proliferation, differentiation, production autoantibodies targeting desmosomal adhesion proteins, namely desmoglein 3 1. To elucidate cell changes at different stages PV, canonical populations, like naïve, memory, transitional, non-switched, switched plasmablasts were monitored in peripheral blood. Our results revealed that transitional which represent a crucial link between immature bone marrow mature significantly decreased active patients, i.e. newly diagnosed chronic, compared to remittent patients healthy controls. Moreover, after depletion therapy, their frequencies recovered levels controls, suggesting deficit this population may contribute pathophysiology. As regulatory role under inflammatory conditions was suggested other diseases, we determined capacity via TGF-β, IL-10, IL-35 secretion but also pro-inflammatory IL-6. Interestingly, from refractory further stimulation CpG CD40L, resulting diminished cytokines. Thus, our findings indicate both frequency render them unable effectively inhibit processes PV.