A recent study found that hypoproteinemia and serous cavity effusion were independent predictors of elevated carbohydrate antigen 125 (CA125) in patients with systemic lupus erythematosus (SLE), and that CA125 levels correlated positively with disease activity and interleukin-6 (IL-6), suggesting its potential utility as a serological marker of systemic inflammation in SLE.
Serum CA-125 is a high-molecular-weight glycoprotein commonly associated with pelvic malignancies, particularly ovarian cancer. However, because CA-125 is expressed not only by tumor cells but also by mesothelial cells, its diagnostic utility in ovarian cancer is limited by suboptimal sensitivity and specificity. Elevated CA-125 levels may arise from multiple tissues, including the peritoneum, pleura, pericardium, fallopian tube epithelium, endometrium, cervix, lungs, and breast, and can occur in both physiological and pathological states. In addition to malignant conditions, increased CA-125 levels have been reported in a wide range of non-malignant disorders, including early pregnancy, menstruation, peritonitis, nephrotic syndrome, endometriosis, leukemia, congestive heart failure, liver cirrhosis, pulmonary vascular disease, rheumatoid arthritis, and tuberculosis.
A total of 220 patients diagnosed with SLE at the Department of Rheumatology and Immunology between January 2021 and January 2025 were enrolled. Of these, 63 patients with positive CA125 formed the observation group and 157 patients with negative CA125 served as the control group. Demographic data, clinical manifestations, and laboratory parameters were collected across both groups. Univariate and binary logistic regression analyses were performed to identify factors associated with CA125 positivity and to evaluate correlations between CA125 levels and clinical indicators.
Logistic regression identified hypoproteinemia (OR 3.796, P = .034) and serous cavity effusion (OR 3.169, P = .045) as independent predictors of elevated CA125. Additional factors significantly associated with CA125 positivity included albumin (ALB; OR 1.121, P = .01), complement 3 (C3; OR 1.568, P = .048), 25-hydroxyvitamin D3 (OR 1.267, P = .013), SLE Disease Activity Index (SLEDAI; OR 0.764, P = .019), and IL-6 (OR 0.960, P = .009). Regression analysis further demonstrated that CA125 was negatively correlated with 25-hydroxyvitamin D3 and albumin, and positively correlated with SLEDAI scores and IL-6 levels.
These findings suggested that CA125 may serve as a potential serological marker reflecting disease activity and systemic inflammation in SLE, offering supportive value for clinical assessment and management. A multicenter prospective study with a larger CA125-positive cohort was recommended to validate these findings and further explore associations with related clinical indicators.
References
- Xu S, Guo X, Lu T, Zhang C. Study on the expression characteristics of CA125 in patients with SLE and its correlation with clinical indicators. Medicine (Baltimore). 2026 May 22;105(21):e48959.
- Li Q, Tian B. Case report: Three cases of systemic lupus erythematosus presenting primarily with massive ascites and significantly elevated CA-125 levels and a review of pseudo-pseudo Meigs’ syndrome in literature. Front Immunol. 2024 Jul 16;15:1423631.