Background
Interleukin-18 (IL-18) and interferon-γ (IFN-γ) are cytokines of crucial role in inflammation
and immune reactions. There is a growing evidence supporting important roles for IL-18 and
IFN γ in tuberculosis (TB) infection and anti-tuberculosis immunity.
Objective
To evaluate the role of polymorphisms in IL-18-607 and -137 and INF-γ +874 in susceptibility to TB infection among Egyptian patients.
Methods
A case control study was conducted to investigate the polymorphism at IL-18-607, -137 and
INF-γ+874 by sequence specific primer-polymerase chain reaction (SSP- PCR) in 105
patients with pulmonary and extra pulmonary tuberculosis and 106 controls.
Results
A significant protective effect against TB was found in homozygous CC genotype at IL-18
-137G/C, in addition to a 7-fold risk with GG and GC genotypes in the recessive model.
Apart from a decreased risk with the AC genotype, no association was detected between
the susceptibility to TB and different genotypes or alleles at the IL-18 -607A/C site. The
homozygous AA genotype in INF-γ+874 showed a significant higher risk to TB than the
homozygous TT or heterozygous AT genotypes with nearly a 2-fold risk of TB infection with
the A allele. Regarding haplotype association, the GC haplotype was strongly associated
with TB infection compared to other haplotypes