Detection Of The Levels Of The Peripheral CD4~+CD25~+Foxp3~+ And CD4~+CD25~+HLA-DR~+T Cells In Patients With Vitiligo

Background and objectivesVitiligo is a depigmenting disorder characterized by the loss of melanocytes from the epidermis. The pathogenesis of vitiligo are still not fully elucidated.However,accumulating evidences suggest that autoimmune pathogenesis may be involved in vitiligo[1].Some scholar consider that the breakdown of immunological tolerance may play an important role in vitiligo pathogenesis[2].The relationship between the level of CD4~+CD25~+ regulatory T cells(Tregs) expressed in human beings and autoimmune diseases has become a hot spot in the research nowadays.CD4~+CD25~+ Tregs are a flock of cells functioning in immunological regulation or immune suppression, which could inhibit the proliferation of initial and memory T cells.There have been reports about the role of CD4~+CD25~+Tregs in psoriasis, atopic dermatitis and skin immunosuppression induced by UV[3]. However,there are few reports about the relationship between the expre- ssion of CD4~+CD25~+Tregs and vitiligo.In the previous study, we examined the proportion of CD4~+CD25~+Tregs in the peripheral lymphocytes from patients with progressing vitiligo and found that the number of CD4~+ CD25~+Tregs was lower than the normal controls obviously, suggesting that the decrease of CD4~+CD25~+Tregs may be correlated with the development of vitiligo.Forkhead transcription factor p3(Foxp3) plays an important role in the formation of CD4~+CD25~+Tregs.It is the most specific mark of CD4~+CD25~+Tregs.CD4~+CD25~+T cells have heterogeneity,with 20–30% of them coexpressing HLA-DR.In the present study, we detected the percentages of peripheral CD4~+ T cells expressing CD25 and Foxp3 and CD25 and HLA-DR in patients with vitiligo,in order to study the role of CD4~+CD25~+Tregs in vitiligo.Methods:26 patients with vitiligo from out-patient clinic were enrolled in this study,including 14 patients with progressing vitiligo and 12 patients with stable vitiligo.The ratios of the peripheral CD4~+CD25~+Foxp3~+ and CD4~+ CD25~+HLA-DR~+T cells to CD4~+T cells in patients with stable vitiligo and progressing vitiligo were detected by flow cytometry and compared with that of 20 normal controls.Results:1. The ratio of CD4~+CD25~+Foxp3~+T cells to CD4~+T cells in patients with progressing vitiligo(1.78±0.13)% was lower than the normal controls(2.81±0.22)% and the patients with stable vitiligo(2.23±0.16)% in peripheral blood,the differences were with statistical significance (P<0.05).2. No significant difference was found between the ratios of peripheral CD4~+CD25~+HLA-DR~+T cells to CD4~+T cells in patients with progressing vitiligo(1.52±0.14)% and the normal controls(1.73±0.20)% and the patients with stable vitiligo(1.60±0.21)%(P>0.05).Conclusions:1. The ratio of peripheral CD4~+CD25~+Foxp3~+T cells to CD4~+T cells in patients with progressing vitiligo was obviously lower than that in patients with stable vitiligo and that of normal control. There was no significant difference between the percentage of the peripheral CD4~+CD25~+Foxp3~+T cells in CD4~+T cells in patients with stable vitiligo and that of normal control.2. There was no significant difference between the percentage of the peripheral CD4~+CD25~+HLA-DR~+T cells in CD4~+T cells in patients with both progressing vitiligo and stable vitiligo and normal control.3. CD4~+CD25~+Foxp3~+Tcells are reduced in peripheral blood of the patients with vitiligo,supporting the autoimmune theory of the disease and providing a new way to targeted therapy.