Transforming growth factor-{beta} gene polymorphisms in different phenotypes of sarcoidosis.

The aetiology of sarcoidosis is unclear. Single nucleotide polymorphisms (SNPs) in transforming growth factor (TGF)-β2 and -β3 have been reported to be associated with the development of lung fibrosis in patients with sarcoidosis. SNPs in TGF-β2 (rs1891467) and TGF-β3 (rs3917200) were investigated in 296 patients with sarcoidosis (acute/self remitting, n = 70 (including 62 patients with Löfgren's syndrome); chronic, n = 168; acute/chronic, n = 58) by real-time PCR. 32 patients showed radiological signs of lung fibrosis. The genotype frequencies were compared among the sarcoidosis groups as well as to 377 healthy controls. We found a significant association with the G-allele in rs1891467 in TGF-β2 and an acute/self remitting course of sarcoidosis compared to a chronic course (p = 0.001). The results were even more evident for patients with Löfgren's syndrome (p<0.001). Moreover, we could demonstrate a borderline significance between TGF-β3 (rs3917200) and lung fibrosis (p = 0.050). Carriers of the G-allele in rs1891467 might be protected from developing a chronic course. Moreover, there is evidence that rs3917200 is involved in the development of lung fibrosis in sarcoidosis. This study is the first in sarcoidosis patients to suggest a genetic implication of TGF-β2 as a protective factor in the course of sarcoidosis.