Lack of significant cross-reactivity between Leishmania serology and mycobacteriosis in patients infected with HIV-1.

OBJECTIVE: To determine the existence of cross-reactions between Leishmania serology and mycobacteriosis in patients infected with HIV-1. PATIENTS AND METHODS: HIV-positive individuals, with culture-proven episodes of tuberculosis or disseminated Mycobacterium avium complex (MAC) infection, were identified from the data files of our microbiology laboratory. Patients were included if leishmania serology had been performed within a period of 2 months before and 1 month after the diagnosis of mycobacterial disease. RESULTS: We identified 106 cases of tuberculosis and 38 of disseminated MAC infection with concomitant leishmania serology in HIV-infected individuals. Among them, only two cases (1.8%), both with tuberculosis and without visceral leishmaniasis, showed positive leishmania serology. The two cases are discussed. CONCLUSIONS: We conclude that, in spite of its low sensitivity, serology is a useful diagnostic tool in co-infected patients, mainly because of its high specificity and the low rate of cross-reactivity with two of the most frequent causes of fever of unknown origin in HIV-positive patients from our area.