Immune Responses in Cutaneous Leishmaniasis: In vitro Thelper1/Thelper2 Cytokine Profiles Using Live Versus Killed Leishmania major.

Background: Recovery from cutaneous leishmaniasis (CL) leads to protection against further lesion development. In contrast, vaccination using killed parasites does not induce enough protection; the reason(s) is not currently known but might be related to different immune response induced against live versus killed parasites. In this study, Th1/Th2 cytokine profiles of CL patients were evaluated against live versus killed Leishmania major.

Methods: In this study peripheral blood mononuclear cells (PBMC) of the volunteers with active CL lesion (CL), history of CL (HCL) and healthy volunteers were cultured and stimulated with live or killed Leishmania major, the supernatants were collected and levels of IFN-γ, IL-5 and IL-10 were titrated using ELISA method.

Results: The results showed that IFN-γ levels in CL patients (p< 0.001) and HCL volunteers (p< 0.005) are significantly higher when stimulated with live than stimulated with killed L. major. IFN-γ production in PBMC volunteers with CL and HCL stimulated with live or heat-killed L. major was significantly (p< 0.001) higher than in unstimulated ones. The level of IL-5 in CL patients (p< 0.005) and HCL volunteers (p< 0.001) are significantly lower when stimulated with live than killed L. major. There was no significant difference between the levels of IL-10 in PBMC stimulated with either live or killed L. major.

Conclusion: It is concluded that using live Leishmania induces a stronger Th1 type of immune response which justify using leishmanization as a control measure against CL.