Introduction: Regulatory T cells (Treg) play a central role in the immunopathogenesis of psoriasis. Immunoregulatory T cells (Tregs) are involved in important homeostatic mechanism for maintaining tolerance and preventing autoimmunity, and autoimmune diseases. The aim of this study was to examine the role of Tregs cells in the pathogenesis of psoriasis, and determine the range value for Treg cells (CD4+ CD25+) in the peripheral blood of patients with psoriasis compared to the severity of disease.
Material and methods: The study included 51 patients diagnosed with psoriasis and 25 healthy individuals. Phenotype profile of peripheral blood lymphocytes was determined by flow cytometry, and assessment of severity of disease was determined on the basis of PASI score (e.g. Psoriasis Area and Severity Index).
Results: Proportion of CD4+CD25+T cells in the control group was significantly higher than in the patients with psoriasis [6,4% ±(5,4-7,6) vs. 4,1% (3,1 -5,8)-Mann-Whitney U test, p <0.001]. In the present study we did not find a statistically significant correlation between the levels of CD4+CD25+cells, in patients with psoriasis, compared to the severity of disease-PASI. (i.e. Pearson correlation, r = 0.197, p = 0.194).
Conclusion: The stratification of patients, according to the severity of the clinical course was not possible on the basis of Treg cells' level. ROC curve analysis of the optimal cutoff (PASI=10) and the CD4+CD25+, which distinguishes between patients and healthy individuals was 5% of CD4+CD25+ of the total number of CD4+ lymphocytes with specificity of 69% and sensitivity of 84%.
Keywords: CD4 + CD25 +; PASI; flow cytometry; psoriasis; regulatory T cells.