01550nas a2200205   4500000000100000008004100001260001200042653002700054653001500081653001200096653002200108653002600130100001200156700002800168700001300196245002700209300000900236520108500245022001401330       2020                            d  c11/202010a Mycobacterium leprae 10aImmunology10aleprosy10aleprosy reactions10alymphocyte activation1 aFroes L1 aBianconcini Trindade MA1 aSotto MN00aImmunology of leprosy.  a1-213 a<p>Leprosy is a disease caused by  (ML) with diverse clinical manifestations, which are strongly correlated with the host's immune response. Skin lesions may be accompanied by peripheral neural damage, leading to sensory and motor losses, as well as deformities of the hands and feet. Both innate and acquired immune responses are involved, but the disease has been classically described along a Th1/Th2 spectrum, where the Th1 pole corresponds to the most limited presentations and the Th2 to the most disseminated ones. We discuss this dichotomy in the light of current knowledge of cytokines, Th subpopulations and regulatory T cells taking part in each leprosy presentation. Leprosy reactions are associated with an increase in inflammatory activity both in limited and disseminated presentations, leading to a worsening of previous symptoms or the development of new symptoms. Despite the efforts of many research groups around the world, there is still no adequate serological test for diagnosis in endemic areas, hindering the eradication of leprosy in these regions.</p>  a1563-5244