SACE and IL-2R as serum biomarkers for evaluation of multi-organ involvement and prognosis of sarcoidosis

BACKGROUND: Serum biomarkers in the evaluation of organ involvement and prognostic monitoring of sarcoidosis have not been determined. The purpose of this study was to identify common biomarkers that could be used to assess organ involvement and monitor outcomes in sarcoidosis patients. METHODS: From Mar 2013 to Sep 2021, patients with newly diagnosed pulmonary sarcoidosis were enrolled in this study in Shanghai Pulmonary Hospital. The information from medical records was retrospectively collected including diagnosis, organ involvement, laboratory tests and follow up data. Differences of continuous variables between groups were analyzed by unpaired Student’s t-test. Multivariate logistic regression model was performed to identify potential independent factors associated with multiple organ involvement. RESULTS: A total of 832 patients were included in the study. There were 339 (40.7%) patients with single organ pulmonary involvement, while 493 (59.3%) patients had two to seven organs involved. Among the routine serum tests, only the serum angiotensin converting enzyme (SACE) level was an independent factor of multiple organ involvement. Compared to those patients without involvement, SACE levels were higher in patients with extra-thoracic lymph node, skin, or spleen involvement as well as abnormal calcium metabolism. Interleukin-2 receptor (IL-2R) levels were higher in patients with extra-thoracic lymph node, spleen involvement and abnormal calcium metabolism than in those without it. The mean levels of SACE and IL-2R showed upward trends paralleling the increase on number of organs involved. In follow up, SACE and IL-2R levels were both decreased in an improved patient group, while there was no obvious difference was noticed before and after treatment in patients with persistent disease. CONCLUSION: SACE and IL-2R were useful as serum biomarkers in the initial evaluation of organ involvement as well as monitoring prognosis in sarcoidosis.