Lymphoproliferative response after stimulation with soluble leishmania antigen (SLA) as a predictor of visceral leishmaniasis (VL) relapse in HIV+ patients

The introduction of HAART resulted in the decrease of Leishmania/HIV co-infection cases; nevertheless, the number of relapses remains high and secondary prophylaxis is recommended. However, secondary prophylaxis is not necessary in all patients, and presents a high risk of toxicity and an elevated cost. Our aim was to study whether specific cellular response to Leishmania infantum (measured by cell proliferation response after stimulation with soluble Leishmania antigen (SLA)), could be a useful tool to attempt a secondary prophylaxis withdrawal. In June 2009 an outbreak of leishmaniasis by Leishmania infantum was declared in the southeast of Madrid, and since January 2013, we recruited 10 HIV+ patients that had been treated for visceral leishmaniasis. 6 patients had positive SLA-cell proliferation test. The mean CD4 cell counts of those patients with positive SLA were 140 cel/mm3 and 40 cel/mm3 in those with negative SLA test. 3 patients with positive SLA-cell proliferation test (CD4 count: 336, 307, 625) were not on prophylaxis, and the other 3 patients (CD4 count: 152, 189, 359) were on secondary prophylaxis that was withdrawn after the positive SLA-cell proliferation test with no posterior relapses (mean follow up 60 weeks). From the 4 patients, which had negative SLA-cell proliferation test and continued on prophylaxis, 3 had positive PCR for Leishmania at the end of the follow-up and 2 presented clinical relapses. The performance of SLA-cell proliferation test can be a useful tool that can permit us to try withdrawal of the prophylaxis in Leishmania/HIV co-infected patients with low CD4⁺ counts under clinical supervision, diminishing risk of toxicity and cost.