Cytokines in leprosy, II. Effect of treatment on serum cytokines in leprosy.
BACKGROUND: Multidrug therapy (MDT) causes a decrease in the bacterial burden in leprosy patients. Does the decrease in the antigenic stimulation of the immune system have an effect on cytokine production?
METHODS: The effect of treatment on serum cytokines was evaluated in 36 leprosy patients and 35 reactional leprosy patients and compared with that in 20 age- and sex-matched healthy individuals. The enzyme-linked immunosorbent assay (ELISA) technique was used to measure serum levels of interleukin-2 receptor (IL-2R), interleukin-10 (IL-10), and interleukin-1beta (IL-1beta) before and after treatment. These cytokines represent T-helper 1 (TH1), T-helper 2 (TH2), and macrophage cytokines, respectively.
RESULTS: The studied serum cytokines were significantly reduced after 1 year of treatment in leprosy patients. The degrees of reduction were significantly positively correlated with a reduction in the bacterial index (BI) and morphologic index (MI). After 1 year of MDT (but not 6 months), paucibacillary (PB) patients showed a significant reduction in all the studied serum cytokines to levels comparable with those of healthy controls. Multibacillary (MB) patients also showed a significant reduction in all the studied serum cytokines, but the levels were still significantly higher than those of healthy controls. Leprosy patients with high levels of serum IL-1beta were more susceptible to the development of reactions after the initiation of treatment. Corticosteroid therapy of reactional patients resulted in a significant reduction in the studied serum cytokines to levels similar or lower than those of nonreactional leprosy patients. The dose of steroids showed a significant positive correlation with the amount of decrease in IL-1beta.
CONCLUSIONS: MDT caused a reduction in serum cytokines correlated with a reduction in the bacterial burden. It is advisable to continue MDT for PB patients for 1 year. Serum IL-1beta levels may have a prognostic value for the susceptibility of leprosy patients to the development of reactions.