IMMUNOLOGICAL DETERMINANTS OF DISEASE EVOLUTION IN LOCALIZED CUTANEOUS LEISHMANIASIS DUE TO LEISHMANIA-MAJOR

Localized cutaneous leishmaniasis caused by Leishmania major is polymo rphic in its clinical presentation and evolution. Clinical and parasit ologic features and disease evolution of 112 Tunisian patients was eva luated. The expression of interleukin (IL)-4, IL-6, IL-10, IL-12 (p40) , interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha mRNA w as analyzed by reverse transcription-polymerase chain reaction in 73 b iopsies. Cytokine mRNA expression varied individually over a wide rang e; TNF-alpha, IL-6, and IFN-gamma were detectable in >90% of lesions, IL-12 and IL-10 in 40% and 70%, respectively, and IL-4 in only 9%. Sta tistical analysis demonstrated positive association between the level of IL-12 and IFN-gamma and the presence of parasites in the lesions. U nfavorable evolution of the lesions was positively associated with hig h IL-10, IL-12, and IFN-gamma mRNA expression. These results indicate that an unfavorable clinical outcome was not related to an inadequate Th1 cell response and suggest that the macrophage-activating effect of IFN-gamma may be inhibited by the concomitant expression of IL-10.