Interleukin-10 gene polymorphism is associated with patients on multi-drug resistant tuberculosis during the intensive phase of standard chemotherapy

Abstract

Background and objective. To study interleukin-10 (IL-10) gene polymorphism is associated with patients on multi-drug resistant tuberculosis (MDR TB) during the intensive phase of standard chemotherapy. Methods. The study comprised 170 individuals in Kharkiv region of Ukraine including 74 patients with pulmonary MDR TB (group1), 66 patients without – MDR TB (group 2) and 30 healthy donors (group 3). Serum level of IL-10 was evaluated by ELISA (pg/L). Measurements on serum samples of patients were conducted prior or during first days after admission to the hospital and after 2 months on therapy. Investigations of gene polymorphism of IL-10 were performed using restriction analysis of the amplification products of specific regions of the genome. The method of investigation (for the sets real-time) — an allele-specific PCR using intercalating coloring Sybr Green. G1082A — IL-10 rs1800896 were genotyped with amplification-refractory mutation system-polymerase chain reaction. Results. In the 1stgroup, the level of IL-10 was (38.01±0.78), 2nd – (43.88±0.70) while in the 3rd group this value was (50.25±1.26) (p<0.05 between the groups). In patients with MDR TB the heterozygous GA genotype (75.68±4.99 % (N=56) ) was higher than: 14.86±4.14 % (N=11) of patients who had homozygote AA and GG (9.46±3.40 % (N=7)) genotype. In patients of the 2nd group, the homozygote AA genotype (62.12±5.97 % (N=41)) was higher than: 25.76±5.38 % (N=17) of patients who had heterozygous GA and homozygote GG genotype who had 12.12±4.02 % (N=8). In contrast, most of healthy donors had homozygous GG genotype with 56.67±9.05 % (N=17) and a low frequency of heterozygous GA 23.33±7.72 % (N=7) and AA genotype 20.00±7.30 % (N=6) (p<0.05 between the groups). Following a 2 month treatment, there was a significant increase of cytokine levels in the IL-10: 1st group (44.58±0.78) and 2nd group (50.59±0.99) (p<0.05 between the groups), when compared to the beginning of therapy and after 2 months (p<0.001). Conclusion. Compared to healthy control-group, patients with tuberculosis had significantly low level of IL-10. This coincided with a greater frequency of heterozygous GA genotype in the 1stgroup and homozygote АА genotype in the 2ndgroup’s polymorphism G1082A genes of IL-10. Further studies are warranted on whether a higher rate of patients without MDRTB has a causal immunogenetic relationship to polymorphism of genes encoding for IL-10 than patients with MDR TB. Standard 2-month TB therapy results in reversal of inflammation characterized by increase in IL-10 to the level comparable to healthy donors. IL-10 are immune correlates of treatment outcome and can help to identify better strategy for TB management. TB chemotherapy may have immunomodulatory effect of anti-inflammatory nature.