In the presented study the subpopulations of blood lymphocytes as well as serum concentrations of IL-6 and FAS in 20 patients with psoriasis triggered by infection and 17 healthy controls were analyzed. The flow cytometry technique and ELISA method were used. We detected statistically significant higher serum level of interleukin-6 (IL-6) in patients with active disease and tendency to the lowering of FAS level, although not statistically significant. Analysis of the correlation between the parameters showed that it was close to statistical significance for IL-6 and CD 95, p = 0.06 and R = 0.41. IL-6 level correlated positively with percentage of CD45RO+ cells (p = 0.05, R = 0.28) and negatively with percentage of CD3+ cells (p = 0.02, R = -0.34), CD4+ cells (p = 0.02, R = -0.34), CD 45RA+ cells (p = 0.04, R = -0.68).