Background:Psoriasis is regarded as a Th1-cell type disease. Interleukin-4, a Th2 type cytokine, is diminished in psoriatic skin. It has been postulated that switching the cytokine profile from Th1 to Th2 may be of great help in the treatment of psoriasis. Some recent reports demonstrate a favorable role of IL-4 in the treatment of psoriasis. Therefore we decided to evaluate how IL-4 plasma levels fluctuate in the case of favorable treatment outcome observed in patients with clinically active and stable disease.Material/Methods: 17 patients with active psoriasis vulgaris, 17 with stable disease, and 22 age- and sex-matched healthy controls were included in the study. IL- 4 plasma levels were evaluated by the ELISA method twice – before treatment implementation and 4 weeks thereafter.Results: We observed statistically significant higher IL-4 plasma levels in the active psoriasis group both before treatment implementation (1[sup]st[/sup] examination) and after 4 weeks of treatment (2[sup]nd[/sup] examination) compared with both the control group (p<0.001) and the stable psoriasis group (1st examination: p<0.001, 2nd examination: p<0.01). There was no statistically significant difference in IL-4 plasma levels between the stable psoriasis and control groups in both examinations (p>0.05).
Conclusions: Our data seem to support the hypothesis of the existence of immunologically distinct psoriasis subtypes.

Keywords: Anthralin - therapeutic use, Ficusin - therapeutic use, Interleukin-4 - blood, Methotrexate - therapeutic use, Phototherapy, Psoriasis - blood, Psoriasis - therapy, Severity of Illness Index, Anthralin - therapeutic use, Ficusin - therapeutic use, Interleukin-4 - blood, Methotrexate - therapeutic use, Phototherapy, Psoriasis - therapy, Severity of Illness Index