Low immunoglobulin levels increase the risk of severe hypogammaglobulinemia in granulomatosis with polyangiitis patients receiving rituximab

• Published in: BMC Musculoskeletal Disorders
• Main Author: Besada, Emilio
• Format: Article in Journal/Newspaper
• Language: English
• Published: BioMed Central 2016
• Subjects: VDP::Medisinske Fag: 700::Klinisk medisinske fag: 750; VDP::Medical disciplines: 700::Clinical medical disciplines: 750; ANCA-associated vasculitis; Rituximab; Induction; Maintenance; Immunoglobulin; Hypogammaglobulinemia; Discontinuation; Adverse event; Principal component analysis; Correspondence analysis; Tromsø
• Online Access: https://hdl.handle.net/10037/8986; https://doi.org/10.1186/s12891-015-0860-3

License: Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/) Background: Randomized controlled trials and retrospective studies in ANCA-associated vasculitis (AAV) concurred that rituximab (RTX) is effective to induce and maintain remission. Infections and hypogammaglobulinemia during RTX were usually infrequent and uncomplicated. But in the Tromsø study cohort, 45 % of patients with granulomatosis with polyangiitis (GPA) developed hypogammaglobulinemia during RTX maintenance leading to its discontinuation in 62 %. Methods: To explain these differences in outcome when using RTX in AAV to maintain remission, we used statistical structural methods to compare the Tromsø study cohort with other published cohorts. Results: GPA patients’ characteristics of the Tromsø study cohort were not so different compared with other cohorts. Rates of hypogammaglobulinemia and discontinuation of RTX seemed closely related to the cut-off used and to the levels of immunoglobulin (Ig) at baseline. Combination of low IgG serum levels at baseline (7.7 g/L) and low cut-off to define hypogammaglobulinemia in the Tromsø study cohort explained the high rate of hypogammaglobulinemia and discontinuation of RTX. Conclusions: Patients’ characteristics in the Tromsø study cohort were not skewed, apart from IgG levels. Low IgG level at baseline seemed to contribute the most to hypogammaglobulinemia and its complications