The immune response in patients with cutaneous leishmaniasis and the influence of zinc supplementation

Cutaneous leishmaniasis triggers a varied immune response depending on parasite and host factors, which in turn can be influenced by nutrients. The resistance to the infection is associated with the Th1 type of cytokine production. The Th1 type can be reduced as a consequence of zinc deficiency, which may increase the risk for chronicity of the infection. Using in vitro and ex vivo models, we studied the influence of zinc supplementation on the immune response in patients with cutaneous leishmaniasis treated with antimony and the data were also compared to those of matched controls. Twenty-nine patients with cutaneous leishmaniasis (n = 14 in zinc-supplemented group [45 mg/day] and n = 15 in placebo group) were treated by intramuscular injections of antimony for 20 days and took supplements for 60 days. Immunoglobulins in plasma and cell proliferation, IFN-γ production and CD markers of isolated peripheral blood mononuclear cells (PBMC) were measured. It was found that the cellular immune response of the patients maintained its activity as assessed by the ability of the PBMC to proliferate and produce IFN-γ in response to concanavalin A. Moreover, there was no difference in these variables between the zinc-supplemented and placebo groups after 60 days. The addition of zinc sulphate in vitro to PBMC reduced the IFN-γ production in the placebo group only. It is concluded that the cellular immune response of the cutaneous leishmaniasis patients remained active during treatment by antimony when compared to that of controls. It was not possible to document an additional effect of zinc supplementation for 60 days on the immune response.