Interferon gamma release assays based on M. tuberculosis-specific antigens in sarcoidosis patients.

Introduction: This study is a part of the project on interferon gamma release assays performed in the group of untreated sarcoidosis patients formerly BCG vaccinated. The aim of the study was to assess the rate of positive commercial interferon g release assays in sarcoidosis patients. We discussed the results in the context of hypothesis that M. tuberculosis antigens may play a role in the pathogenesis of sarcoidosis.

Material and methods: 151 patients, mean age 38 ± 10.3, treatment naive, with newly diagnosed pulmonary sarcoidosis were enrolled into the study. All participants underwent QFT-GIT assay. A subgroup of 81 patients underwent also T-SPOT.TB assay.

Results: QFT-GIT was positive in 7/151. T-SPOT.TB was positive in 3/81. There were no indeterminate results in both IGRAs. There was no statistically significant relationship between IGRAs results and sarcoidosis parameters such as the radiologic stage, disease duration and the presence of Löfgren's syndrome.

Conclusions: In sarcoidosis patients formerly BCG vaccinated, positive rate of IGRAs was 4.6% for QFT-GIT and 3.7% for T-SPOT. TB. We did not find the influence of the selected parameters of sarcoidosis on IGRAs results.