Increased Circulating HLA‐DR+CD4+ T Cells in Systemic Lupus Erythematosus: Alterations Associated with Prednisolone Therapy

Patients with active systemic lupus erythematosus (SLE) in the circulation have a selective increase of a subset of the CD4+ helper/inducer T cells bearing HLA‐DR+, major histocompatibility complex class II antigens. We studied prednisolone‐induced alterations of HLA‐DR+, CD4+, and CD8+ T‐cell subsets in three patients with active SLE. Prednisolone therapy was accompanied by a drastic reduction in circulating HLA‐DR+, CD4+ T‐cell subsets, serum anti‐DNAtitre, normalization of the serum immunoglobulin profile, and CD4+ T‐cell responses to phytohaemagglutinin and concanavalin A. These changes in immune functions were associated with eventual improvement in the clinical condition of active SLE. A low precentage of HLA‐DR+, CD8+ T‐cell subsets was present in the circulation, which was not changed by prednisolone therapy. These results suggest that HLA‐DR+, CD4+ T‐cell subsets play a major role in the pathogenesis of active SLE, and that prednisolone‐induced immunosuppression in this disease is mediated by changes in the HLA‐DR+, CD4+ T‐cell subsets in circulating blood.