Peroxisome proliferator-activated receptor gamma as modulator of inflammation in pulmonary sarcoidosis.

Peroxisome proliferator-activated receptor (PPAR) includes the family of ligand-activated transcription factors which belong to the group of nuclear hormone receptors and are connected to retinoid, glucocorticoid and thyroid hormone receptors. There are three subtypes of PPARs: PPARalpha (also known as NR1C3), PPARgamma (known as NR1C1) and PPARdelta (known as PPARbeta or NR1C2). All of them take part in the metabolism, cell proliferation and immune response. PPARgamma and PPARalpha are identified as important immunomodulators and potentially represent an anti-inflammatory target for respiratory diseases. PPARgamma deficiency in the lungs has been observed in the inflammatory diseases such as asthma, pulmonary alveolar proteinosis, fibrosis and sarcoidosis, as well as in the animal models of the lung inflammation. A small number of papers concerned with PPARgamma in sarcoidosis pointto the lowered activity of this factor in the alveolar macrophages and a lowered gene expression for the PPARgamma, while the activity is preserved in healthy individuals. At the same time, an increased activity of the nuclear factor kappa B (NF-kappaB) in the bronchoalveolar lavage has been recorded in patients with sarcoidosis. The reason for the decrease in the production of PPARgamma in sarcoidosis remains unknown. Several possible mechanisms are mentioned: genetic defect with lowered production, down-regulation due to the increased values of IFN-gamma or an increased decomposition of PPARgamma. Further investigation will explain the mechanisms regarding the decreased production of PPARgamma in sarcoidosis.

Tumor necrosis factor alpha gene polymorphism in serbian patients with sarcoidosis.

INTRODUCTION: Sarcoidosis is a multisystemic disease of unknown etiology. Genetic factors play a considerable role in the onset of the disease. Tumor necrosis factor alpha (TNF-a) is a proinflammatory cytokine which plays an important role in the pathogenesis of the disease and the formation of granuloma by regulating cellular proliferation and apoptosis. OBJECTIVE: The aim of this study was to investigate the role of TNF-alpha-308 G/A polymorphism in the development of sarcoidosis and to evaluate the association between the aforementioned type of polymorphism and the clinical course of the disease. METHODS: Seventy patients with sarcoidosis and 50 healthy volunteers were genotyped for the TNF-alpha-308G/A polymorphism. Polymorphism variants were examined by PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) on the DNA isolated from blood leukocytes. RESULTS: There were no significant differences in TNF-alpha-308A allele frequency distribution between sarcoidosis patients and the control group, but the TNF-alpha-308A allele was observed significantly more frequently in the sarcoidosis patients with Löfgren's syndrome when compared with non-Löfgren's patients. CONCLUSION: We have found that the TNF-alpha-308A variant is associated with Löfgren's syndrome in Serbian patients with sarcoidosis.