TNF and pulmonary tuberculosis: Previously also, positive association of TNF- 238 A/G was reported among Iranian pulmonary tuberculosis cases.22,30 TNF 238 A/G polymorphism has been extensively studied in TB cases of various ethnic groups.8,9,10 However, studies that were conducted in Turkey, India and Columbia demonstrated no association of specific allele of TNF-α gene with susceptibility to TB.8,9,31 There are also considerable variations in genotype frequencies of TNF 857 polymorphisms in different populations.