Background: FOXP3 is a critical regulator of the development and function of regulatory T (Treg) cells, which are capable of suppressing immune responses. A recent study showed that the presence of the (GT) n microsatellite polymorphism in the FOXP3 gene was associated with enhancer activity, resulting in an effect on type I diabetes mellitus. Furthermore, sarcoidosis reportedly increases the prevalence of Treg cells in bronchoalveolar lavage fluid and peripheral blood. Because Treg cells may play roles in immune responses in sarcoidosis, in this study we investigated whether the FOXP3 gene polymorphism affects sarcoidosis.
Methods: One hundred and eight sarcoidosis patients and 100 healthy control subjects were studied. PCR-based fragment analysis combined with fluorescent technology were used to determine the FOXP3 (GT)n genotype.
Results: We found that the genotype distribution did not differ between sarcoidosis patients and healthy controls. Among sarcoidosis patients, the prevalence of the (GT)15 allele was higher in patients without skin lesions than in patients with skin lesions (p = 0.037, odds ratio = 2.96, 95% confidence interval: 1.07-8.24).
Conclusions: Although the FOXP3 gene polymorphism has no effect on susceptibility to sarcoidosis, the (GT)15 allele may exert protective effects against skin involvement.