PURPOSE: The aims of the present case-control study were to examine polymorphisms in the interleukin-6 (IL-6), IL-10, transforming growth factor (TGF)-β 1, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ genes in patients with ILD, compared to healthy controls.
METHODS: We included patients diagnosed with idiopathic pulmonary fibrosis (IPF), nonspecific interstitial pneumonia (NSIP), and pulmonary fibrosis associated with collagen disease (PF/CD).
RESULTS: Among 78 patients with ILD (IPF, n=44; NSIP, n=13; PF/CD, n=21) analyzed in the present study, the mean age was 56.4 ± 12.9 years and 42 (53.8%) were male. Our normal control healthy population consisted of 135 individuals (65 male, 70 female) with a mean age of 31.2 ± 9.5 years. In TGF-β 1, the T/T G/G genotype was more frequent in the ILD group compared to control subjects (44.9% vs. 30.4%; p=0.033), but after Bonferroni correction, the difference was not significant (Pcorr=0.26). With respect to IFN-γ, the T/A genotype was more frequently seen in healthy controls than in the ILD group, but, again, the difference was not significant after appropriate correction (49.6% vs. 34.6%, p=0.03, Pcorr=0.08). Furthermore, after adjusting for gender, the frequency of the T/T G/G genotype in TGF-β 1 was higher for males than for females in the ILD group, compared to control subjects. However, after correction, the difference again did not attain statistical significance (ILD: males 50% vs. females 35%; healthy controls: males 29.2% vs. females 31.4%, p=0.02, Pcorr=0.16). With respect to IFN-γ, the T/A was more frequent, with statistical significance, in females compared to males of the ILD group, and the p-value remained significant after Bonferroni correction (50% vs. 26%; healthy controls: females 48.5% vs. males 50.7%, p=0.007, Pcorr=0.02). No significant genotype differences in IL-6, IL-10, or TNF-α were seen between ILD patients and healthy controls.
CONCLUSION: Gender differences were apparent in IFN-γ polymorphisms of ILD individuals compared to healthy controls.
CLINICAL IMPLICATIONS: Gender differences in IFN-γ gene polymorphisms may suggest that such polymorphisms may serve as markers of disease susceptibility in the Arab world.
DISCLOSURE: Esam Alhamad, No Financial Disclosure Information; No Product/Research Disclosure Information