Detection of T cells and melanocytes in skin of patients with psoriasis and their clinical significance

Abstract

Objective To investigate the relationship of CD4+ and CD8+ T cells with melanocytes in skin of patients with psoriasis, and to study their clinical significance. Methods Tissue specimens were obtained from both lesional and nonlesional skin of 29 patients with progressive psoriasis and 5 patients with regressive psoriasis, as well as from normal skin of 6 healthy individuals. Immunohistochemical staining was performed to determine the quantity and distribution of CD4+ T and CD8+ T cells, as well as the quantity of melanocytes and proportion of cells containing pigment granules in the basal layer of these specimens. Statistical analysis was carried out with the software SPSS 18.0 by one-way analysis of variance (ANOVA), least significant difference (LSD) test and Pearson correlation analysis. Results In patients with psoriasis, the mean number of CD4+ T cells per high-power (× 200) field was significantly larger in lesional skin than in nonlesional skin (epidermis: 5.29±4.66 vs. 0, P 0.05). The mean number of melanocytes was significantly higher in regressive psoriatic lesions than in white patches arising in subsided psoriatic lesions (P 0.05), while the proportion of pigment granule-containing cells was insignificantly lower in regressive psoriatic lesions than in white patches (P>0.05), and significantly lower in regressive psoriatic lesions and white patches than in normal control skin (both P 0.05), while the number of both CD4+ T cells and CD8+ T cells was positively correlated with that of melanocytes (r=0.46 and 0.56, respectively, both P 0.05). Conclusions In progressive psoriatic lesions, there is a significant increase in the number of CD4+ and CD8+ T cells as well as melanocytes in the basal layer, but a significant decrease in the proportion of pigment granule-containing cells. After subsidence of psoriatic lesions, both the number of melanocytes and proportion of pigment granule-containing cells gradually reach the levels in normal skin of healthy individuals. Key words: Psoriasis; T-lymphocytes; Melanocytes; CD8-positive T-lymphocytes; CD4-positive T-lymphocytes