Host responses to Epstein-Barr virus and cytomegalovirus infection in leprosy.

A study was undertaken in patients with leprosy to assess the contribution of cell-mediated immunity to the host response to Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection. Sixteen of 72 patients (22%) with lepromatous leprosy, with impaired cellular immunity, had anti-EBV titers of 1,640 or higher. Only 4 of 49 patients (8%) with tuberculoid leprosy, with intact cell-mediated immunity, attained the level of 1:640. The anti-EBV antibody titers were significantly higher in patients with lepromatous leprosy (P approximately 0.025). No significant differences were found in the level of anti-CMV antibody titers in patients with the two types of leprosy. The presence of high anti-EBV antibody titers in lepromatous leprosy suggests that cell-mediated immunity is a significant factor in host response to EBV infection. Host immune responses should be taken into consideration when assignment of an etiological role to EBV is based upon seroepidemiological data.