IFNG and leprosy: Serological and gene approaches had not proven satisfactory for the purpose of diagnosing leprosy [56]; although these and other test methods are continually being refined and evaluated, in particular: details of new M. leprae antibodies [97], [98], new approach in the application of M. leprae specific DNA polymerase chain reaction [99]–[101], and cell-mediated immune response assays primarily based on IFN-γ release [102], [103].