Effects of drug therapy of visceral leishmaniasis on serum level of IFN-γ, IL-10 and IL-12 in visceral leishmaniasis patients

Background: Leishmaniosis has remained a serious public health problem in several parts of the developing world. Effective prophylacyic measurements are hampered by imprecise understanding of different aspects of the disease, including its immunoregulation. A better understanding of immunoregulation in human visceral leishmaniosis may be useful both for designing and evaluating immunoprophylaxis. Materials and Methods: This before-after interventional study investigated immunoregulatory mechanisms among 32 patients with visceral leishmaniasis in Shiraz (Iran) in 2007. The plasma cytokine (IFN-gamma, IL-10 and IL-12) levels of participants were measured before, during active disease and at different periods up to 2 months after treatment. Results: Elevated plasma levels of IFN-γ, IL-10 and IL-12 which were observed during active disease, decreased significantly after treatment. The main candidate for blunting IFN- γ activity seems to be IL-10, since the level of this cytokine which highly elevated in plasma decreased sharply after treatment (Before treatment 88.3±77.5, after treatment 25±18.3, 2months after treatment 517±1.9). difference between samples was significant (P<0/05) Discussion: Results suggest that IFN- γ and IL-10 are the molecules most likely involved in determining fate of the disease. After treatment, there is a long delay before the immune profile returns to its normal level which precludes using plasma cytokine levels as criteria for certain cure diagnosis of the disease.