The expression of human leukocyte antigen-DR and CD25 on circulating T cells in cutaneous lupus erythematosus and correlation with disease activity.

BACKGROUND: Lupus erythematosus (LE) is a chronic autoimmune disease with a broad clinical spectrum reaching from primarily cutaneous manifestations [cutaneous LE (CLE)] up to systemic disease [systemic LE (SLE)]. In patients with SLE, the expression of activation markers on circulating T cells reflects disease activity. Here, we investigated whether this also holds true for patients with CLE. PATIENTS AND METHODS: The expression of the activation markers human leukocyte antigen (HLA)-DR and CD25 on circulating T lymphocytes was measured by flow cytometry in 24 patients suffering from different types of active CLE. Simultaneously, the disease activity was assessed clinically using a CLE activity index. Eighteen healthy donors were analyzed for control purposes.
RESULTS: HLA-DR was expressed on a significantly elevated percentage of both CD4+ and CD8+ circulating T cells in active CLE patients when compared with healthy controls. The percentage of HLA-DR-expressing T lymphocytes closely correlated with the disease activity. Interestingly, in disseminated scarring chronic discoid LE, a significantly increased percentage of CD25+ cells was observed only in the subset of skin-homing cutaneous lymphocyte antigen (CLA)+CD4+ and CD8+ T cells.
CONCLUSION: Our results provide evidence that activation markers on peripheral blood T cells might help to objectively assess the disease activity in CLE. Furthermore, a significant population of CD25+CLA+CD8+ T cells can only be detected in a subgroup of patients with disseminated scarring CLE and might reflect the systemic expansion of activated cytotoxic T lymphocytes involved in destruction of epidermal tissue.