Prognostic benefit of immunosuppressive agents in primary Sjögren’s syndrome patients with hypergammaglobulinemia

Objective: To elucidate the prognosis of patients with primary Sjögren's syndrome (pSS) accompanied by hypergammaglobulinemia (HG), with a particular focus on the impact of various treatments. Methods: Patients were divided into the HG group and the non-HG group, based on the presence or absence of HG [serum immunoglobulin G (IgG) level above 16 g/L]. The demographics, clinical manifestations, laboratory findings, medications and outcomes were compared between the two groups. The adverse outcome was defined as death or the increase of Sjögren's Syndrome Disease Damage Index (SSDDI) score. Results: 366 patients were included, with 225 (61.5%) in the non-HG group and 141 (38.5%) in the HG group. Compared with the non-HG group, the HG group had a greater proportion of females, higher disease activity, higher frequencies of organ involvements (excluding interstitial lung disease), and higher rates of autoantibody positivity, hypocomplementemia, and elevated erythrocyte sedimentation rate. After a follow-up of 36 (28-45) months, adverse outcomes were observed in 14 of 141 (9.9%) patients in the HG group and 23 of 225 (10.2%) in the non-HG group. In the Kaplan-Meier curve analysis, the risk of adverse outcomes did not differ between the two groups either unadjusted or corrected for conditions such as disease activity. However, compared with non-HG group, the HG group had a lower risk of poor prognosis when using immunosuppressive agents (ISA), and a trend toward a higher risk of poor prognosis when not using (adjusted P for interaction = 0.01). Conclusion: Although the prognosis of pSS patients with HG was comparable to that of non-HG patients in this study, the application of ISA may help to improve the outcome of such patients.