Abstract: Objective To investigate the expression of CD40/CD40L on peripheral blood mononuclear cells (PBMC) in patients with recurrent genital herpes (RGH). Methods Flow cytometric analysis was employed to identify the expression of CD40 and CD40L on PBMC and the T lymphocyte subgroups in the peripheral blood of 30 patients with RGH and 20 healthy controls. Results Percentage of the cells with either CD40 or CD40L expression in the patients with RGH was significantly lower than that in the controls (P=0.0061 and 0.041, respectively). The RGH group had a significantly lower percentages of CD3⁺ T cells (P=0.025) and CD4⁺ T cells (P=0.032) as compared to the controls. Conclusion Reduced costimulatory interaction of CD40 and CD40L in RGH patients may be one of the important factors for the recurrence.

Key words: CD40 ligand, T-lymphocytes, Herpes, genitals, Antigens, CD40