[Prevalence of anti-Leishmania antibodies in parenteral drug addicts. Yield value of 2 study techniques].

BACKGROUND: The prevalence of antibodies anti-Leishmania in intravenous drug addict (IVDA) patients suspect of visceral leishmaniasis (VL) and the diagnostic profitability of two tests for detecting anti-Leishmania antibodies were studied. METHODS: Serum samples corresponding to 91 healthy non IVDA individuals (group 1), 143 IVDA individuals attended in consultation for febrile illness and lymph node enlargement (group 2) with only one serum determination, and 42 IVDA individuals in whom sequential serologic study (group 3) was performed were analyzed. IgG and IgM antibodies were studied by indirect immunofluorescence (IIF). The individuals of group 1 and 90 of those of group 2 (45 with anti-Leishmania IgG antibodies and 45 without by IIF) were simultaneously studied by ELISA to analyze IgG antibodies. RESULTS: No antibodies were detected in subjects from group 1 with the two techniques used. In group 2 IgG were detected in 43.3% of the patients (titer distribution: 46.8% at 1/32, 32.3% at 1/64 and > 1/64 in 21%). In group 3 seroconversion of IgG was found in 18 cases. In 6 patients IgM was observed: 3 from group 2 (with low titers of IgG) and the remaining pertained to group 3 being accompanied by seroconversion of specific IgG. In the remaining 15 patients of group 3 seroconversion of IgG did not accompany positive IgM. No association was found in the results obtained by IIF and ELISA (p = 0.3; chi 2). CONCLUSIONS: It was found that indirect immunofluorescence and ELISA techniques are complementary methods in the indirect diagnosis of visceral leishmaniasis overall in the population of intravenous drug addicts. In this population acute disease may be manifested by IgG seroconversion with or without positive IgM although IgG seroconversion seems to be a more useful criteria given the greater number of patients in whom it is presented in this form. The high frequency of antileishmania antibodies in intravenous drug addict patients in Spain is of note.