IL-10 producing Bregs are impaired in psoriatic arthritis and psoriasis and inversely correlate with IL-17- and IFNγ-producing T cells

Our aim was to study CD19(+)CD27(+)CD24(high) memory and CD19(+)CD24(high)CD38(high) transitional and IL-10 + Breg cells, known to inhibit Th1 and Th17 cells in experimental arthritis, in psoriatic arthritis (PsA) and psoriasis (Ps). Peripheral blood Breg cells from 60 patients with PsA, 50 patients with Ps and 23 healthy controls were analyzed by flow cytometry. IL-17A-producing CD3(+) T cells and IFNγ-producing CD3(+) T cells and activation of p38 MAPK and STAT3 were also studied. CD19(+)CD27(+)CD24(high) and CD19(+)CD24(high)CD38(high) Breg cells were decreased in PsA and Ps. In Ps patients, CD19(+)CD27(+)CD24(high) Breg cells inversely correlated with PASI score. IL-10 + Bcells were also decreased and inversely correlated with IL-17A + CD3 + and IFN-γ + CD3 + T cells. B cells from patients exhibited impaired activation of p38 MAPK and STAT3. In conclusion, IL-10 + Breg cells are decreased PsA and Ps and inversely correlated with the severity of psoriasis and IL-17A + and IFNγ + T cells.