Interferon-γ production and Leishmanin skin test in non-healing cutaneous Leishmaniasis compared with healed individuals

Background: Cutaneous leishmaniasis (CL) is a self-healing disease, but due to unknown causes, a few cases of CL could get a chronic or non-healing course. These cases of chronic and recurrent leishmaniasis are defined as non-healing. Objectives: Comparison of the production of interferon-γ (IFN-γ) and Leishmanin skin test (LST) between non-healing and healed patients of CL. Patients and Methods: Fifteen patients with non-healing CL suffering for more than two years, and eight individuals cured from CL were enrolled in this study. The rate of IFN-γ production by peripheral blood mononuclear cells assessed by ELISA and results of LST were compared in both groups. Results: The mean level of the IFN-γ production in non-healing patients and cured individuals were 729 pg/ml, and 4229 pg/ml, respectively (T- test, P<0.01). Four patients in non-healing group had negative LST and all cured patients had positive LST. Conclusion: The low level of the IFN-γ in non-healing patients and high level of IFN-γ in healed individuals are in favour of the lack of TH1 response, which is usually seen in healed patients. Comparing the results of LST between two groups is not conclusive.