IL‐4 gene polymorphisms and their relation to steroid‐induced osteonecrosis of the femoral head in Chinese population

BACKGROUND: Steroid‐induced osteonecrosis of the femoral head (ONFH) is a debilitating disease characterized by the activation and infiltration of macrophages into the necrotic site. Interleukin‐4 (IL‐4) administration helped reduce the infiltration of M1 phenotypic macrophages and maintain the activation of M2 phenotypic macrophages, resulting in restriction of inflammation and decrease in osteocyte apoptosis. The aim of this study was to investigate the associations of polymorphisms of IL‐4 gene with steroid‐induced ONFH in Chinese patients. MATERIALS AND METHODS: A total of 286 steroid‐induced ONFH patients and 441 healthy controls were enrolled. We evaluated 6 single nucleotide polymorphisms of the IL‐4 gene in this case–control study. RESULTS: We identified rs2243283 in the IL‐4gene was potentially associated with an increased risk of steroid‐induced ONFH in the dominant model (p = 0.034; odds ratio [OR]: 1.40; 95% confidence intervals [CI]: 1.03–1.91) and in the log‐additive model (p = 0.04; OR: 1.31; 95% CI: 1.01–1.71) adjusted by age and gender. Furthermore, we also observed a protective effect of rs2243289 in the dominant model (p = 0.024; OR: 0.70; 95% CI: 0.51–0.95) adjusted by age and gender. CONCLUSION: These findings suggested that polymorphisms of IL‐4 gene may be associated with susceptibility to steroid‐induced ONFH.