Analysis of peripheral blood leukocytes in patients with cyclosporine A-induced gingival hyperplasia

Background: Gingival overgrowth is one of the major adverse effects of the immunosuppressive drug cyclosporine A (CsA). Although several studies have attempted to determine the immunological mechanisms of gingival hyperplasia (GO) due to CsA therapy, the pathogenesis remains unclear. In this study t he distribution of the peripheral blood leukocytes in a group of renal tran splant patients undergoing CsA therapy was analyzed and possible correlatio ns of periodontal and pharmacological variables to lymphocyte subpopulation s, natural killer cells, and monocytes investigated. Methods: Thirty-six patients were classified into 2 groups of 18 each accor ding to the degree of gingival overgrowth. The periodontal evaluation inclu ded plaque index (PI), gingival index (GI), gingival overgrowth (GO), calcu lus index (CI), and probing depth (PD). The pharmacological variables of cu rrent doses of the therapeutic serum levels of CsA were investigated. The p eripheral blood leukocytes were studied by 2-color flow cytometric analysis using anti-human CD2, CD3, CD4, CD8, CD11b, CD11c, CD16, CD19, HLA-DR, and CD3+HLA-DR+ monoclonal antibodies. Results: Statistical evaluation revealed that none of the pharmacological v ariables varied between the 2 groups. Responders (GO >30%) had significantl y higher GI, PD, and GO scores compared to nonresponders (GO less than or e qual to 30%). Of the immunological parameters studied, only CD2 was higher in the responder group. None of the clinical parameters correlated to the i mmunological values. Conclusions: The results of this study may be useful in explaining the unde rlying mechanisms of drug-induced gingival overgrowth. Several previously u nsuspected cells and accessory activation mechanisms for T lymphocytes coul d play a role in the pathogenesis.