Lucio’s phenomenon is a type of leprosy reaction found in Mexico and Caribbean countries. But uncommonly seen in India and seems to be an emergency for patients. Leprosy reactions are commonly classified as T1R (Type 1 Reaction) and T2R (Type 2 Reaction). T1R is characterized by the alternation in the T cells function and T2R is considered an acute event mediated by immune complex deposition. Th1 andTh17 cells shown protective role in localized leprosy and associated with immunopatology in reactions patients. Other hand FOXP3+ Treg cells associated with gernaliezed lepromatous leprosy and showed progression of leprosy. . The aim of our study was to analyze their role in a patient who had suffered lucio phenomenon. Flowcytometry were used to cell phenotypes and the percentage of cytokines in 48 hours MLSA (M. leprae sonicated antigen) stimulated PBMC cultures in patients with lepromatous disease and lucio’ phenomenon. Th17 cells showed increase Th17 in lucio’s phenomenon. Although Th1 and Treg cells have not show any difference.