SUMMARY: We evaluated interleukin-10 ( IL10 ) - 592 C / A, IL4 - 589 C / T, interferon gamma ( IFNG ) + 874 A / T, cytotoxic T-lymphocyte-associated antigen 4 ( CTLA4 ) + 49 A / G gene polymorphisms associated with efavirenz hypersensitivity reaction. A total of 63 human immunodeficiency virus-positive patients under treatment at a public hospital were included in the study, of whom 21 presented with efavirenz ...