Serum Rcn3 level helpful for diagnosis of connective tissue disease-associated interstitial lung disease: Study

Fangping Ding, Capital Medical University, Beijing, China, and colleagues aimed to assess Rcn3 as a potential marker in the differential diagnosis of CTD-ILD and idiopathic pulmonary fibrosis and in reflecting the disease severity in a retrospective observational pilot study.

The study included 71 ILD patients and 39 healthy controls. The patients were categorized; 39 into the IPF group and 32 in the CTD-ILD group. The ILD severity was assessed through a pulmonary function test.

The study revealed the following findings:

· In CTD-ILD patients, serum Rcn3 level was statistically higher than in IPF patients and healthy controls.

· In CTD-ILD patients, serum Rcn3 further showed a statistically negative correlation with pulmonary function indexes (DLCO% pred and TLC% pred) and a positive correlation with inflammatory indexes (ESR and CRP) (r = − 0.367; r = − 0.370; r = 0.355; r = 0.392, respectively) rather than IPF patients.

· ROC analysis showed serum Rcn3 to have superior diagnostic value for CTD-ILD. A cutoff value of 2.73 ng/mL had a specificity of 69%, a sensitivity of 69%, and an accuracy of 45% for the diagnosis of CTD-ILD.

"The study showed that serum Rcn3 levels differed remarkably between patients with CTD-ILD and IPF. In patients with CTD-ILD, serum Rcn3 levels were significantly increased and positively correlated with CTD-ILD severity reflected by pulmonary function, but not in IPF," the researchers wrote.

They conclude, "serum Rcn3 levels might be a valuable biomarker to diagnose CTD-ILD."

Reference:

Ding, F., Yang, L., Wang, Y. et al. Serum Rcn3 level is a potential diagnostic biomarker for connective tissue disease-associated interstitial lung disease and reflects the severity of pulmonary function. BMC Pulm Med 23, 68 (2023). https://doi.org/10.1186/s12890-023-02360-4