ABSTRACT
Objective To investigate the distribution and proportion of CD8α+α + T cells in lesions and peripheral blood of patients with psoriasis,and to assess their roles in the pathogenesis of psoriasis.Methods An immunofluorescence assay was performed to observe the distribution of CD8α+α+ T cells in lesions of 5 patients with progressive psoriasis vulgaris and normal skin of 5 healthy human controls.Flow cytometry was conducted to determine the proportion of CD8α+α+ T cells,and to measure the expressions of interferon (IFN)-γ and tumor necrosis factor (TNF)-α in peripheral blood from 10 patients with progressive psoriasis vulgaris and 8 healthy human controls.Statistical analysis was carried out by t test with GraphPad Prism software.Results A massive infiltrate mainly composed of CD8α+α+ T cells but not CD8α+β+ T cells was observed in the upper dermis of lesions from the 5 patients with psoriasis,while there was no infiltrate of CD8α+β+ or CD8α+α+ T cells in the normal skin of 5 healthy human controls.Flow cytometry revealed that the proportion of CD8α+α+ T cells was significantly higher in peripheral blood from 10 patients with psoriasis than in that from 8 healthy human controls (26.47％ ± 12.99％ vs.9.12％ ± 4.80％,t =3.96,P＜ 0.001).Significant differences were also noted between the psoriatic patients and healthy human controls in the percentage of cells secreting IFN-γ (47.36％ ± 19.38％ vs.13.44％ ± 9.21％,t =4.54,P ＜ 0.001) and cells secreting TNF-α (54.14％ ± 21.14％ vs.34.03％ ± 17.22％,t =2.17,P ＜ 0.05) in peripheral blood CD8α+α+ T cells.Conclusions Both the distribution and proportion of CD8α+α+ T cells are increased in lesions and peripheral blood from patients with psoriasis,suggesting that CD8α+α+ T cells may be the main subgroup of CD8+ T cells that contribute to the pathogenesis of psoriasis.