Correlation between serum IgG levels and labial gland pathological grading in patients with suspected Sjögren's syndrome: a cross-sectional analysis
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Published on: October 13, 2023
Lishi Yu1, Andi Xu1, Suhua Hu1
1Department of Rheumatology, The Fifth Affiliated Hospital of Wenzhou Medical University, Lishui, Zhejiang Province, 323000, China.
Objective:
To investigate the clinical association between serum immunoglobulin G (IgG) levels and labial gland pathological grading in patients with suspected Sjögren's syndrome (SjD).
Methods:
This retrospective cross-sectional study included hospitalized patients with suspected SjD who underwent labial gland biopsy between December 2023 and December 2025. Smoothing curve fitting and logistic regression models were used to assess the association between serum IgG levels and labial gland pathological grade. Sensitivity and subgroup analyses were performed to evaluate the robustness of the results.
Results:
A total of 169 patients were enrolled. Compared with the low-IgG group (<15.03 g/L), the high-IgG group ( 15.03 g/L) had significantly higher odds of an elevated labial gland pathological grade (adjusted odds ratio [OR], 3.06; 95% confidence interval [CI], 1.43-6.54; P = 0.004). Serum IgG modeled as a continuous variable was independently associated with higher pathological grades (adjusted OR per 1-g/L increase, 1.12; 95% CI, 1.04-1.20; P = 0.002), and the relationship was linear. Sensitivity and subgroup analyses confirmed the consistency and stability of these findings.
Conclusion:
This study provides evidence supporting a positive, linear association between serum IgG levels and labial gland pathological grade in patients with suspected SjD, suggesting that elevated IgG levels may reflect greater labial gland inflammatory involvement.
Key Points:
This cross-sectional study identified a linear, positive association between serum IgG levels and labial gland pathological grade in patients with suspected primary Sjögren's syndrome. Patients with serum IgG levels 15.03 g/L had a higher odds of a positive labial gland biopsy (FS 1) compared to those with lower IgG levels (adjusted OR: 3.06; 95% CI: 1.43-6.54). The association between IgG levels and pathological grade remained consistent across subgroups stratified by sex, age, autoantibody status, and clinical manifestations. Serum IgG levels may serve as a non-invasive correlate of labial gland inflammatory involvement in patients with suspected primary Sjögren' s syndrome.
