Dynamics of serum tumor markers may indicate the progression of interstitial lung disease in Sjögren's syndrome patients: new roles for old friends.

A retrospective case-control study was designed to identify the characteristics and predictors of primary Sjögren's syndrome (pSS)-associated progressive fibrosing interstitial lung disease (ILD). Patients who diagnosed pSS-ILD were enrolled from Shanghai Tongji Hospital between January 1, 2015, and September 30, 2023. Relevant clinical data, including medical history, laboratory test results, and imaging findings, were collected at baseline. Progressive pulmonary fibrosis (PPF) was defined as established standard during one year of follow-up. Multiple linear regression was used to assess the relationship between tumor markers and ILD activity status. Characteristics associated with progression were determined by COX regression analysis. Kaplan-Meier survival analysis was employed to evaluate the predictive accuracy of the model. A total of 58 patients with pSS-ILD were included. The incidence of pleuritis and baseline levels of carbohydrate antigen 50 (CA50) were significantly higher in the pSS-PPF group. No significant differences were observed in arterial blood gas analysis, tumor marker levels, or CT scores at baseline. A negative correlation was found between cancer antigen 199 (CA199) levels and forced vital capacity, while carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA125) levels were positively correlated with the severity of CT lesions. Cox regression analysis identified CEA and CA50 as significant predictors of pulmonary prognosis, and survival analysis indicated that elevated levels of CEA and CA50 were associated with disease progression. Serum tumor markers, such as CEA and CA50, may serve as potential indicators of radiographic progression and declines in lung function in pSS-ILD patients, possibly identifying individuals at higher risk of poor prognosis.