Elevated rate of Thelper1 (TH1) lymphocytes and serum IFN-γ levels in psoriatic patients

Several disorders are known to be associated with altered Thelper1/Thelper2 (T(H)1/T(H)2) cytokine balance. Psoriasis is characterized by increased systemic and local production of T(H)1 and pro-inflammatory cytokines. Furthermore recent data indicate the dominant presence of T(H)1 lymphocytes in the circulation and T(H)1 and Tcytotoxic1 (T(C)1) cells in lesional skin of psoriatic patients. In order to assess the systemic T(H)1/T(H)2 imbalance in psoriasis most of the studies so far tested isolated peripheral mononuclear cells. As a new approach we applied a whole blood flow cytometric assay to determine the rate of circulating T(H)1/T(H)2 and T(C)1/Tcytotoxic2 (T(C)2) lymphocytes based on their intracellular IFN-gamma, IL-4 and IL-10 expression. Besides, serum levels of these cytokines were determined in healthy controls and psoriatic patients by commercial ELISAs. In psoriatic patients we found significantly (P < 0.02) increased rates of CD4(+)/IFN-γ(+) lymphocytes (30.3+/-8.8%) while the percent of CD4(+)/IL-4(+) cells (0.37+/-0.31%) were significantly (P < 0.03) lower compared to healthy controls (CD4(+)/IFN-gamma(+): 20.1+/-7.3% and CD4+/IL-4+/-0.78+/-0.44%). The IL-10-positive CD4(+) and CD8(+) cells also had higher rate in psoriasis, but the difference between patients and controls was not significant, similarly to the rate of CD8(+)/IFN-gamma(+) and CD8(+)/IL-4(+) lymphocytes. Beside cellular expression, serum IFN-gamma levels were also significantly higher (control: 4.9+/-6.4 pg/ml; psoriatic patients: 35.9+/-47.0 pg/ml; P < 0.05). Our results provide further evidence for an altered T(H)1/T(H)2 balance in psoriasis measured in non-separated whole blood T cells. (C) 2003 Elsevier Science B.V. All rights reserved.