Programmed-death-1 (PD-1) receptor plays a major physiological role in maintainance of im-mune tolerance, and, by interaction with its ligands (PD-L1 and PD-L2), prevents the develop-ment of multiple immune-mediated diseases. There is growing evidence of an important role of PD-1/PD-L1 pathway in pathogenesis of psoriasis. 84 subjects with psoriasis were included into the study, together with 29 healthy subjects as a control group. 28 of psoriatic patients were treated with biologice therapy (TNF-alpha, interleukin (IL)-12/23 or IL-17 inhibitors). Amounts of PD1 and PD-L1 positive T-cells in peripheral blood were evaluated using flow cytometry. Significantly lower levels of peripheral blood mononuclear cells (PBMCs) with the expression of PD-1 and PD-L1 were found in psoriatic patients when compared to healthy individuals, i.e. CD3/PD1, CD3/PDL1, CD4/PD1, CD4/PDL1, CD8/PDL1, CD19/PD1, CD19/PDL1 positive cells. Biologic treatment resulted in elevation of CD3/PDL1, CD8/PDL1 and decrease of CD8/PD1 posi-tive PBMCs. Our results confirm previous observations of disrupted PD-1/PD-L1 pathway in psoriasis, and that this disturbances may play an important role in development of the disease. Biologic drugs may reverse several abnormalities observed within this pathway, which may ex-plain their excellent efficacy in the treatment of psoriasis. Further research should be conducted to fully explain the results obtained.

Psoriasis is nowadays recognized as a multifactorial systemic disease with complex and still not fully understood pathogenesis. In psoriatic patients the increased cardiovascular disease (CVD) risk and frequent comorbidities like obesity are observed. The aim of this study was to investigate differences in miRNA (miR-22-3p, miR-133a-3p, miR-146a-5p, miR-369-3p and Let-7b-5p) involved in CVD risk among psoriatic patients with overweight/obesity and with normal weight. The study comprised 28 male psoriatic patients and 16 male healthy controls. miRNA isolated from peripheral blood mononuclear cells was reverse-transcribed and RT-qPCR was performed. We have found the decreased levels of miR-22, miR-133a, miR-146a, and miR-369 among the psoriatic patients. There was a statistically significant difference in miR-22 and miR-146a levels between psoriatic patients with overweight/obesity and with normal weight. There were positive correlations between miR-22 and miR-146a levels and psoriatic arthritis (PsA) in psoriatic patients with normal weight and between miR-133a level and PsA in the overweight/obese patients. The decreased levels of selected miRNA are consistent with their levels observed in CVD indicating their impact in the CVD risk in psoriatic patients. miR-22 and miR-146 may be recognized as one of the contributing factors in the obesity-CVD-psoriasis network.