Hypogammaglobulinemia in Patients With Inflammatory Rheumatic Diseases Treated With IL-6 Receptor Inhibitors: A Retrospective Comparative Cohort Study.

This poster presents the results of a retrospective comparative cohort study evaluating hypogammaglobulinemia and serum immunoglobulin levels in patients with inflammatory rheumatic diseases treated with interleukin-6 receptor inhibitors (IL-6Ri) compared with tumor necrosis factor inhibitors (TNFi). Patients treated with IL-6Ri had lower post-treatment IgG and IgA levels and a higher prevalence of hypogammaglobulinemia than those treated with TNFi. In multivariable analysis, baseline hypogammaglobulinemia and age ≥65 years were the main factors associated with post-treatment hypogammaglobulinemia. The findings highlight the importance of assessing baseline immunoglobulin levels and considering immunoglobulin monitoring in patients treated with IL-6 receptor inhibitors, particularly those with risk factors for hypogammaglobulinemia. This poster was presented at the American College of Rheumatology (ACR) Convergence 2026.