Sarcoidosis is associated with a wide range of disease outcomes including spontaneous remission and progressive courses. It is necessary to identify patients with spontaneous remission without corticosteroid treatment. This study aimed to identify the markers for predicting spontaneous remission in patients with sarcoidosis.

453 patients diagnosed with sarcoidosis at the Shanghai Pulmonary Hospital between Jan 2013 and Aug 2017 and were followed-up for more than 2 years were enrolled. Patients were divided into spontaneous remission group and non-remission group. Differences of variables between groups were analyzed by chi-square test or unpaired Student's t-test. The cumulative spontaneous remission rate was analyzed using the Kaplan-Meier method.

Of the 173 patients (stage I/II/III/IV, 53/110/6/4) without medication, 117 (67.6%) achieved spontaneous remission. The serum level of soluble interleukin-2 (IL-2) receptor (sIL-2R) and the ratio of CD4/CD8 was significantly lower and CD8⁺ T cell was significantly higher in spontaneous remission group when compared with non-remission group (P < 0.001, P = 0.042 and P = 0.048). Multivariate logistic regression model showed sIL-2R level was an independent predictor of spontaneous remission (P = 0.021). In stage I subgroup, a cut-off value of 1129.5U/ml was obtained from the ROC curve, which yielded a sensitivity of 50% and a specificity of 94.4%. In stage II subgroup, a cut-off value of 1026.5U/ml was obtained with a sensitivity of 66.7% and a specificity of 68.7%.

This study provided useful information that sIL-2R level could be used as a maker for spontaneous remission in determining the treatment strategies for patients with pulmonary sarcoidosis.