IFNG and congestive heart failure: Fifty-six Iranian patients with CHF were enrolled in this study as the case group and compared with 139 healthy subjects, using polymerase chain reaction with sequence-specific primers method, so as to determine the frequency of alleles, genotypes and haplotypes of IFN-γ (+874 A/T) and IL-2 (-330 G/T, +166 G/T) SNPs.