comparison of genetic polymorphisms of tnf-α and il-10 genes between tuberculosis patients and healthy blood donors

background almost one-third of the world's population is infected with mycobacterium tuberculosis, but only 10% of them develop tuberculosis. tnf-α/il-10 balance has key roles in controlling latent/activation stages of tuberculosis. objectives the objective of this study was to determine an association between polymorphic variants of the tnf-α and il-10 genes and tuberculosis. patients and methods this case-control study was performed on 100 patients with tuberculosis (tb) and 194 healthy blood donors. there was no significant difference among the groups regarding gender and race (p > 0.05). the patients were diagnosed at boo-ali hospital in sistan-baluchestan province, iran. polymerase chain reaction (pcr) was performed using commercially available cts-pcr-ssp tray kit (university clinic heidelberg) for single nucleotide polymorphisms (snps) at il-10 -1082 a/t, -819 c/t and -592 a/c; tnf-a-308 g/a and -238 g/a. analysis of the specific amplicons was done by electrophoresis on 2% agarose gel containing 0.5 μg/ml ethidium bromide. results were analyzed using the statistical software package spss 17.0 for windows (spss inc.). results a total number of 100 patients (50 with pulmonary tb [ptb] and 50 with extrapulmonary tb [eptb]) and 194 healthy blood donors were genotyped. the results showed significantly increased frequency of aa genotype of il-10 (c/a-592). also, polymorphism was observed in eptb patients compared to normal human subjects (nhs) and ptb patients (p = 0.05). the genotype frequency of il-10 (c/t-819), il-10 (g/a-1082) tnf-α (g/a-308) and tnf-α (g/a-238) did not show any significant difference. frequency of high producing il-10 (-819) t allele was significantly over-represented in eptb group in comparison to both healthy blood donor and ptb groups (47.7% vs. 36.9%, p = 0.035; 47.7% vs. 31.8%, p = 0.03; respectively). frequency of il-10(-592) a allele was significantly increased in eptb patients compared to nhs and ptb patients (51% vs. 37%, p = 0.01; 51% vs. 33%, p = 0.01; respectively). conclusions results of the present study showed il-10 gene polymorphism (c/t –819, c/a –592) plays a key role in susceptibility to or protection against eptb development in the iranian population.