TY - JOUR T1 - Are there differences in the functional polymorphism of <em>FCGR3A</em> gene between sarcoidosis and tuberculosis?: Preliminary study JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - 3065 AU - Piotr Klimont AU - Marlena Typiak AU - Krzysztof Rebala AU - Maria Dudziak AU - Anna Dubaniewicz AU - Bartlomiej Rekawiecki Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/3065.abstract N2 - Because of similarities in clinical and histopathological pattern of sarcoidosis (SA) and tuberculosis (TB), mycobacterial antigens are considered in an etiopathogenesis of SA, especially in a chronic course of the disease in Stage II. We have recently found an increased level of circulating immune complexes (ICs) with mycobacterial heat shock proteins in SA compared to TB and healthy individuals, however a slight increase of these ICs concentration was found in TB vs controls. This immunocomplexemia may result from a dysfunction of receptors for Fc fragment of immunoglobulin G (FcγR), especially FcγRIIIa, encoded by FCGR3A gene due to its V158F polymorphism, which causes lower affinity of FcγRIIIa to ICs with their following decreased clearance. Therefore, we genotyped 77 SA, 105 TB patients and 143 healthy controls using PCR-SSP. We found a significant increase in the frequency of 158FF genotype in Stage I of SA vs TB and controls. In Stage I of SA vs TB and controls we revealed a significantly higher occurrence of 158F allele. In Stage II of SA and TB there was a significantly increased presence of 158V allele than in Stage I. No differences were showed between allele or genotype frequency between TB and Stage II of SA. Thus, V158F polymorphism of FCGR3A may cause the immunocomplexemia in our SA patients. Furthermore, the obtained results suggest different pathomechanisms of both stages of sarcoidosis and may imply a common mycobacterial background of TB and chronic Stage II of SA. Analysis of this polymorphism may serve as a biomarker in the discrimination of sarcoidosis from tuberculosis. Funding: grant 5160/B/P01/2010/39 and MN-31. ER -