Genetic Polymorphisms of<i>IFNG</i>and<i>IFNGR1</i>with Latent Tuberculosis Infection

Previous studies indicated that single-nucleotide polymorphisms (SNPs) of interferon gamma (IFNG) and IFNG receptor 1 (IFNGR1) may be involved in the pathogenesis of pulmonary tuberculosis (PTB) in different populations. In order to further explore the results in a Chinese Han population, this study was designed to investigate potential associations between the polymorphisms in IFNG and IFNGR1 and susceptibility to latent tuberculosis infection (LTBI) and/or PTB in a Chinese Han population. A total of 209 PTB, 173 LTBI, and 183 healthy control subjects (HCS) were enrolled in our study. Genotyping was conducted using an improved multiplex ligase detection reaction (iMLDR). We performed a logistic regression including sex and age as covariates to test the effect of alleles/genotypes on LTBI and/or TB. All six markers studied in IFNG and IFNGR1 conformed to the Hardy–Weinberg equilibrium (HWE). The IFNG rs1861494 was significantly associated with LTBI in recessive model, and the CC+CT genotype decreased risk of LTBI by 50% (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M1"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.046</mml:mn></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M2"><mml:mtext>OR</mml:mtext><mml:mo>=</mml:mo><mml:mn>0.50</mml:mn></mml:math>, 95%CI: 0.25-0.99). The IFNGR1 rs2234711 was significantly associated with LTBI, and allele A increased the risk of LTBI by 55% (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M3"><mml:mi>P</mml:mi><mml:mo>=</mml:mo><mml:mn>0.047</mml:mn></mml:math>,<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" id="M4"><mml:mtext>OR</mml:mtext><mml:mo>=</mml:mo><mml:mn>1.55</mml:mn></mml:math>, 95%CI: 1.00-2.40). In the present study, we found that IFNG and IFNGR1 polymorphisms were associated with LTBI.