Immunophenotyping of T cells in the peripheral circulation in psoriasis

Psoriasis is a T-helper (Th)-1/Th17-mediated chronic inflammatory disease. Cytokine mediated interaction between T lymphocytes and keratinocytes lead to keratinocyte hyper-proliferation, which leads to further inflammation in the psoriatic plaques. There is an increased population of T-helper cells in the skin lesions as well as in the peripheral circulation in psoriasis. However, the relative percentage of each T-cell phenotype in the disease pathogenesis is understudied. Our aim was to study the immune-phenotype of the different T-helper/T-reg cell subsets in patients with psoriasis, with respect to healthy controls.A total of 189 cases of psoriasis and 189 age- and gender-matched healthy controls were recruited in this cross-sectional study. Disease severity was determined by psoriasis area severity index (PASI) scoring. Peripheral blood mononuclear cells were isolated by Ficoll-Paque density centrifugation, and T-cell immunophenotyping was done by flow cytometric analysis.In psoriasis, we observed an imbalance in T-cell immunophenotype, characterised by an increase in Th1/Th17 cells and a relative decrease in Th2/T-reg cells, as compared to the healthy controls. We also found that the percentage of Th1/Th17 cells showed a linear trend, increasing with increasing disease severity (PASI).Our results suggest an immune-dysregulation in psoriasis associated with a predominance of Th1/Th17 phenotype, especially with increasing severity of the disease.