Clinical diagnostic value of serum soluble IL-2 receptor for stage I sarcoidosis in benign isolated mediastinal and hilar lymphadenopathy

Abstract

Background: Serum soluble interleukin-2 receptor (sIL-2R) is recognized as a marker of T-cell activation and is abnormally elevated in sarcoidosis. However, its value for stage I sarcoidosis in benign granulomatous diseases is unclear.

Methods: We enrolled 33 stage I sarcoidosis patients, 17 lymph node tuberculosis patients, 15 reactive lymphadenopathy patients, and 11 healthy controls. Serum biomarkers concentrations were collected and collated.

Results: Serum sIL-2R concentrations were the highest in stage I sarcoidosis. The AUC of serum sIL-2R for stage I sarcoidosis was 0.7452 in all subjects and 0.6861 in granulomatous diseases. The AUCs of two combined diagnostic forms, sIL-2R with angiotensin-converting enzyme (ACE) and sIL-2R with ACE, erythrocyte sedimentation rate (ESR), and lactate dehydrogenase (LDH) were 0.7994 and 0.891 in all subjects, respectively. In granulomatous disease groups for ROC analysis, the best cut-off value of sIL-2R was 745.00 U/ml with 48.50% sensitivity and 84.40% specificity. The combination of four parameters increased the diagnostic accuracy for stage I sarcoidosis in granulomatous diseases (74.10% sensitivity and 100% specificity). Serum sIL-2R concentrations were positively correlated with serum ACE (r = 0.4652, P = 0.0126).

Conclusion: Serum sIL-2R appeared to be valuable in identifying stage I sarcoidosis in a group of benign granulomatous disorders.

Keywords: Angiotensin Converting Enzyme; Lymphadenopathy; Serum soluble IL-2 receptor; Stage I sarcoidosis.