The role of tumor necrosis factor alpha G-308A polymorphisms in the course of pulmonary sarcoidosis

This study was designed to evaluate the relationship between the presence of tumor necrosis factor (TNF) polymorphisms, human leukocyte antigen (HLA)-DRB1*03 linkage and the prognosis of sarcoidosis. In a retrospective case-control study, TNF-alpha G-308A, TNF-alpha G-238A, lymphotoxin-alpha (LTA) and HLA-DRB1*03 were genotyped in 625 sarcoidosis patients. These patients were classified into 298 patients with persistent disease and 327 patients with non-persistent disease using chest X-ray (CXR) appearances and lung function parameters after at least 2 years of follow-up. The TNF-alpha -308A variant allele was observed in 25.5% of patients with persistent disease compared with 44.0% of patients with non-persistent disease. The corresponding odds ratio (OR) was 0.43 with a 95% confidence interval (CI) of 0.30-0.61. A strong linkage was found between TNF-alpha G-308A and HLA-DRB1*03 (OR = 0.03, 95% CI: 0.02-0.05). For TNF-alpha G-238A and LTA NcoI A252G, there were no statistically significant differences in the distribution of genotypes between the groups with and without persistent disease. The data indicate that presence of a TNF-alpha -308A variant allele and HLA-DRB1*03 were associated with a favorable prognosis. Because of the strong linkage between TNF-alpha G-308A and HLA-DRB1*03, genotyping of one simple and less expensive TNF-alpha single nucleotide polymorphism can be used to predict the prognosis of pulmonary sarcoidosis in clinical practice.