Rituximab-induced hypogammaglobulinaemia in patients affected by idiopathic inflammatory myopathies: a multicentre study

Abstract

Objective Rituximab (RTX) is an anti-CD20 chimeric monoclonal antibody recommended as off-label treatment in patients with idiopathic inflammatory myopathies (IIM). The present study aimed to evaluate changes in immunoglobulin (Ig) levelsduring RTX-treatment and their potential association with infections in a cohort of IIM patients. Methods Patients evaluated in the Myositis clinic belonging to the Rheumatology Units of Siena, Bari and Palermo UniversityHospitals, and treated for the first time with RTX were enrolled. Demographic, clinical, laboratory and treatment variables, including previous and concomitant immunosuppressive drugs and glucocorticoid (GC) dosage were analysed before (T0) and after 6 (T1) and 12 (T2) months of RTX treatment. (median age,; 22 female) were selected. During the observational period, low levels of IgG (<700 mg/dl) and IgM (<40 mg/dl) occurred in 10% and 17% of patients, respectively. However, no one showed severe (IgG<400 mg/dl) hypogammaglobulinaemia. IgA concentrations were lower at T1 than T0 (p=0.0218), while IgG concentrations were lower at T2 compared to those at baseline (p=0.0335). IgM concentrations were lower at T1 and T2 than T0 (p<0.0001), as well at T2 than T1 (p=0.0215). Three patients suffered major infections, two others had paucisymptomatic COVID-19, one suffered from mild zoster. GC dosages at T0 were inversely correlated with IgA T0 concentrations (p=0.004, r=-0.514). No correlation was found between demographic, clinical and treatment variables and Ig serum levels. Results Thirty patients ConclusionHypogammaglobulinaemia following RTX is uncommon in IIM and is not related to any clinical variables, including GC dosage and previous treatments. IgG and IgM monitoring after RTX treatment does not seem useful in stratifying patients who require closer safety monitoring and prevention of infection, due to the lack of association between hypogammaglobulinaemia and the onset of severe infections.

Pyomyositis Secondary to Localized Cellulitis in a Dermatomyositis Patient: A Case Report and Review of Infectious Complications in Dermatomyositis

“…Patients No. Infections Mean Age Male% Study IIM GCs/ISD/BT 1026 7(0.7%) In years 61.8 33.4% R Shirley 2021 13 GCs/ISD/BT 214 121(56.5%) At diagnosis 38.7 20.9% Cohort study Naveen 2021 14 CYC 14 7(50.0%) In years 51.1 – R Sangmee 2018 15 GCs/ISD/BT 204 13(6.4%) – – R Redondo 2018 16 – 106 56(52.8%) – – R Xiao 2017 17 RTX 30 8(26.7%) In years 52.5 30.0% R Marion 2011 18 RTX 30 3(10.0%) In years 56.0 26.7% R Edoardo 2023 19 CTX 11 2(18.2%) – – Clinica...…”