Long-term monitoring of visceral leishmaniasis in patients with AIDS - Relapse risk factors, value of polymerase chain reaction, and potential impact on secondary prophylaxis

Background: Molecular methods have become essential in the diagnosis of visceral leishmaniasis (VL) in patients who have AIDS. The present study aimed at (1) identifying relapse risk factors for VL and (2) assessing the value of long-range routine polymerase chain reaction (PCR) monitoring in such patients, (3) with a view to proposing decision-making elements for discontinuing specific secondary prophylaxis. Methods: A cohort of 27 HIV-positive patients was prospectively followed up during a period of 5 months to 9 years (median = 51 months) after a first episode of VL. The clinical and biologic follow-up protocol included routine Leishmania detection using peripheral blood and a previously validated PCR method. Quantitative and qualitative variables were statistically analyzed. Results: Sixteen patients relapsed, for a total of 38 relapses. CD4 counts <100 cells/mu L and absence of highly active antiretroviral therapy at primary diagnosis and CD4 counts <100 cells/mu L during follow-up were the major predictive factors for relapse. No relapse occurred when CD4 counts were >200 cells/mu L. The Leishmania PCR assay was positive in all clinical relapses, and its negative predictive value was 100%. Conclusions: The PCR assay used here proved extremely useful for routine follow-up of VL in patients who had AIDS. Considering CD4 cell counts and Leishmania PCR assays, these results allow defining proposals for discontinuing secondary prophylaxis, and thus optimizing the clinical care of VL in these patients.