# A correlation study of serum tumor markers with systemic lupus erythematosus-associated interstitial lung disease

## TL;DR

This study explores how certain tumor markers in the blood correlate with lung disease in patients with systemic lupus erythematosus.

## Contribution

The study identifies specific tumor markers that may serve as potential biomarkers for diagnosing SLE-associated interstitial lung disease.

## Key findings

- SLE-ILD patients had higher levels of CEA, CA125, CA15-3, CA19-9, SCC, CYFRA21-1, and FER compared to SLE patients without ILD.
- CA15-3 and CA19-9 showed significant diagnostic value for SLE-ILD, with combined AUC of 0.80.
- SCC and CYFRA21-1 levels correlated with kidney function in SLE-ILD patients.

## Abstract

Systemic lupus erythematosus-associated interstitial lung disease (SLE-ILD) is a pulmonary manifestation of SLE. Currently, serum biomarkers for early identification of SLE-ILD are lacking. Our study aimed to investigate the correlation and clinical significance of serum tumor markers (TMs) in patients with SLE-ILD.

We conducted a retrospective analysis of medical records from SLE patients between January 2017 and November 2023. We compared the differences in serum levels of TMs including carcinoembryonic antigen (CEA), carbohydrate antigens (CA125, CA15-3, and CA19-9), squamous cell carcinoma antigen (SCC), cytokeratin-19-fragment (CYFRA21-1), neuron-specific enolase (NSE) and ferritin (FER), between SLE-ILD and SLE patients.

A total of 386 SLE patients were enrolled in this study, comprising 64 individuals with SLE-ILD. Compared with SLE group, SLE-ILD group exhibited higher serum levels of CEA, CA125, CA15-3, CA19-9, SCC, CYFRA21-1, and FER. Multivariate regression indicated that age (OR = 1.038, 95% CI = [1.004, 1.074]), CA15-3 (OR = 1.099, 95% CI = [1.039, 1.162]), and CA19-9 (OR = 1.032, 95% CI = [1.005, 1.059]) were associated factors for SLE-ILD (p < 0.05). Serum levels of CA15-3 demonstrated good diagnostic value with an area under the receiver operating characteristic curve (AUC) = 0.72; furthermore, combining age with serum levels of CA19-9 and CA15-3 presented enhanced diagnostic performance as reflected by an AUC = 0.80 (95% CI = [0.73, 0.86]). Serum levels of SCC and CYFRA21-1 moderately positively correlated with serum creatinine levels (r = 0.562 and 0.713, respectively).

Serum levels of CA125, CA15-3, and CA19-9 could act as associated markers for SLE-ILD. Serum SCC, CYFRA21-1 and FER levels may also be linked to kidney involvement in SLE-ILD.