Is there a correlation of serum and tissue T helper-1 and -2 cytokine profiles with psoriasis activity and severity? A cross-sectional study.

Abstract

Previous studies correlating Th1 and Th2 cytokine profiles with psoriasis activity provided inconsistent results. Correlation of tissue cytokine levels with psoriasis severity has not been studied till now. To compare serum and tissue Th1 and Th2 cytokine profiles of patients with active and stable psoriasis as well as healthy controls, and to correlate them with psoriasis severity. This was a cross-sectional study involving adult patients with 'active' psoriasis (untreated progressive chronic plaque psoriasis, guttate psoriasis, and erythrodermic psoriasis), 'stable' psoriasis (stable plaque psoriasis or those with completely resolved lesions) and healthy subjects with non-inflammatory skin lesions as controls. Mean levels of Th1 and Th2 cytokines in serum [interleukin 2 (IL-2), interferon-gamma (IFN-γ), IL-4, IL-10] and tissue mRNA expression (IFN-γ, IL-4) were compared among these three groups. There were 30 patients each in active and stable psoriasis groups, and 15 in the control group. Mean serum IL-2, IFN-γ, and IL-10 levels of patients with psoriasis patients were significantly higher than the controls (P < 0.001 for both active and stable psoriasis), whereas mean serum IL-4 level of patients was significantly lower than the controls (P < 0.001). However, there was no statistically significant difference of serum cytokine levels between active and stable psoriasis groups. Mean quantitative tissue mRNA expression of IFN-γ and IL-4 of patients with active and stable psoriasis were significantly lower than the controls (P < 0.001 and <0.01, respectively), but were not significantly different between active and stable psoriasis groups. Serum and tissue cytokines showed weak correlation with psoriasis area and severity index. Small sample size and heterogenous nature of patients with psoriasis in terms of disease activity, morphology and treatment are limitations of this study. There is no significant change in the serum or tissue levels of Th1 and Th2 cytokines with activity or severity of psoriasis.