Short term treatment of visceral leishmaniasis of the old world with low dose interferon gamma and pentavalent antimony

Eight adult patients with visceral leishmaniasis acquired in mediterranean countries were treated in a prospective study with a combined immunomodulating and antiparasitic regimen consisting of low-dose interferon-gamma (IFN-gamma) and pentavalent antimony. The clinical outcome, hematological and parasitological parameters, the duration of treatment and number of treatment cycles as well as the cumulative dose of pentavalent antimony applied, have been evaluated. The combined treatment led to complete resolution of symptoms and parasitological cure in all cases of visceral leishmaniasis without major side effects. Combined treatment resulted in a significant reduction of duration of treatment (19 vs. 31 days, p < 0.02) and cumulative dose of pentavalent antimony (11.67 vs. 19.30 g, p < 0.02) compared to historical controls (n = 6). No relapses occurred after a median follow-up of 9 months (range: 2-28 months). We conclude that combination therapy is tolerated well and is highly effective in patients with visceral leishmaniasis. The addition of IFN-gamma to standard therapy with pentavalent antimony may reduce the cumulative dose of antimonial drugs, shortens the treatment period and probably reduces the number of relapses.