Association of serum tumor markers with serous effusion in systemic lupus erythematosus

The objective of this study was to investigate the relationship between serum tumor markers and serous effusion in systemic lupus erythematosus (SLE) patients, thereby contributing preliminary data on the utility of these tumor markers in diagnosing serous effusion. In this retrospective analysis, clinical data of SLE patients were extracted from electronic medical records. This included the levels of serum tumor markers, including pro-gastrin-releasing peptide, neuron-specific enolase (NSE), cytokeratin-19 fragments (CYFRA 21-1), various carbohydrate antigens (CA 153, CA 125, CA 19-9), along with carcinoembryonic antigen, and alpha-fetoprotein. Positivity of tumor markers was established based on serum levels surpassing the upper threshold of the respective reference ranges. This study included 149 eligible patients with SLE, of whom 38 (25.50%) had serous effusion, and the prevalence of pleural, pericardial, and peritoneal effusions was 11.41%, 14.77%, and 6.71%, respectively. The analysis revealed that patients with serous effusion had higher scores on the SLE Disease Activity Index 2000 (SLEDAI 2000) than those without serous effusion. Notably, this disparity remained significant when the serositis score was excluded from the SLEDAI 2000 calculation. The positivity rate and serum levels of CA 125 were higher in patients with serous effusion and pleural effusion. Patients with pericardial effusion demonstrated an elevated CYFRA 21-1 positivity rate and serum CA 125 and CYFRA 21-1 levels compared to patients without pericardial effusion. CA 125 and NSE were higher both in terms of positivity rate and serum levels for patients with peritoneal effusion. Through receiver operating characteristic curve analysis, a moderate relationship was discerned between the conjoined levels of CYFRA 21-1 and CA 125 and the occurrence of pericardial effusion. Additionally, CA 125, NSE, and their combination revealed the moderate diagnostic ability of peritoneal effusion. In summary, this study observed elevated serum levels of various tumor markers in SLE patients exhibiting serous effusion, which is likely attributable to lupus-induced inflammation. These findings suggest that serum tumor markers can be valuable in diagnosing pericardial and peritoneal effusions.