High incidence of IgG class of Epstein-Barr virus capsid antibody in Indian patients of lepromatous leprosy.

Low levels of Epstein-Barr virus capsid (EBVC) antibody of the IgG class were detected in the sera of 19 of 23 (82.6%) lepromatous leprosy patients and six of 38 (16%) healthy controls. In contrast, heterophile antibody was found in only six of 43 (14%) lepromatous patients and three of 41 (7%) normal subjects. Overlap of the two types of antibody occurred only in one normal serum. It is inferred that the presence of EBVC antibody against an unbiquitous virus in lepromatous patients who often suffer from impairment of cell-mediated immunity might be due to past infection leading to persistence of the virus in their lymphoid cells and subsequent production of specific anti-viral antibody. Further, the striking finding of low incidence and titre of EBVC antibody in the normal Indian adults is consistent with the rarity of EB virus-associated disease, such as Burkitt's lymphoma, nasopharyngeal carcinoma and infectious mononucleosis in India.