Previous immunophenotyping studies have shown that the number and proportion of CD4+ T cells are increased in active skin lesions; approximately 30% of patients are classified into the BT, BB, and BL forms.[31,44] This kind of immune response in type 1 reactions can be reversed (reversal, pseudo-exacerbation, or ascending reactions) or worsened (degradation or descending reactions).[43,45] They are the critical reasons for nerve damage in leprosy.[37] The innate and adaptive immune responses are involved in the pathogenesis of type 1 reactions. This evidence concerns the gene CD4 and leprosy.