CD3+CD56+ NK T cells are significantly decreased in the peripheral blood of patients with psoriasis
Psoriasis is a chronic, inflammatory, hyperproliferative skin disease, in which autoimmunity plays a great role. Natural killer T cells (NK T cells), are suggested to be involved in the pathogenesis of different autoimmune diseases. To examine the involvement of CD3+CD56+ NK T cells in the pathogenesis of psoriasis, we investigated the lymphocyte subpopulations obtained from blood samples of psoriatic patients before and after treatment, and of healthy controls, using two‐colour flow cytometry. We found no significant differences between total T cells, total B cells, T helper cells, T cytotoxic cells and NK cells in patients with psoriasis before and after treatment and in controls. Increased percentage of memory T cells and decreased percentage of naive T cells was detected in psoriatic patients compared to controls, but these changes were not statistically significant. The CD3+CD56+ cells of psoriatic patients were significantly decreased relative to controls. The percentage of CD3+CD56+ cells increased after different antipsoriatic therapies, but remained significantly lower than those found in controls. CD3+CD56+ cells of healthy controls were capable of rapid activation, while in psoriatic patients activated NK T cells were almost absent. The decrease in the number of CD3+CD56+ cells may represent an intrinsic characteristic feature of patients with psoriasis, which is supported by the fact that after treatment NK T cells do not reach the values found in controls. In conclusion our results suggest that CD3+CD56+ NK T cells could be actively involved in the development of Th1 mediated autoimmune diseases.