Predictive Value of Serum sIL-2R Levels and Th17/Treg Immune Balance for Disease Progression in Patients With Rheumatoid Arthritis-Associated Interstitial Lung Disease.

Background: This article analyzed the relationship between serum sIL-2R levels and Th17/Treg immune balance in patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and their prognostic value.

Methods: RA patients (n = 311) were retrospectively selected for research and then allocated to the RA and RA-ILD groups. Baseline data and 3-year follow-up records of all patients were attained to assess disease progression. Serum sIL-2R levels were examined with ELISA, and Th17 and Treg cell clusters were tested with flow cytometry, followed by the calculation of the Th17/Treg ratio. The correlation of serum sIL-2R with Th17/Treg and related cytokines (IL-17, IL-6, IL-10, and TGF-β1) in RA-ILD patients were analyzed with Spearman's analysis. ROC curves were plotted for analyzing the performance of serum sIL-2R levels and the Th17/Treg ratio for predicting disease progression in RA-ILD patients. A multivariate Cox regression model was developed to screen independent risk factors for disease progression in RA-ILD patients.

Results: RA-ILD patients had elevated serum levels of sIL-2R, Th17 cells, IL-17, and IL-6 and an increased ratio of Th17/Treg, accompanied by a decreased Treg cell population and IL-10 and TGF-β1 levels. Serum sIL-2R levels were correlated positively with IL-17 levels and the Th17/Treg ratio in RA-ILD patients and negatively with IL-10 levels. DAS28 scores, serum sIL-2R levels, and an elevated Th17/Treg ratio were independent risk factors for disease progression in RA-ILD patients, and increased FEV1 and FEV1/FVC were protective factors.

Conclusion: Serum sIL-2R levels in conjunction with Th17/Treg immune balance can assist in predicting 3-year disease progression in RA-ILD patients.