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

OBJECTIVES: 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) levels during 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 University Hospitals, 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. RESULTS: Thirty patients (median age, IQR 56 (42-66); 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. CONCLUSIONS: Hypogammaglobulinaemia 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.

Relapses of idiopathic inflammatory myopathies after vaccination against COVID-19: a real-life multicenter Italian study.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccination plays a crucial role as pivotal strategy to curb the coronavirus disease-19 (COVID-19) pandemic. The present study described the clinical status of patients affected by idiopathic inflammatory myopathies (IIM) after COVID-19 vaccination to assess the number of relapses. We included all patients affected by IIM and followed by Myositis Clinic, Rheumatology and Respiratory Diseases Units, Siena University Hospital, Bari University Hospital, Policlinico Umberto I, Sapienza University, Rome, and Policlinico Paolo Giaccone, Palermo. They underwent a telephone survey. A total of 119 IIM patients (median, IQR 58 (47-66) years; 32males; 50 dermatomyositis, 39 polymyositis and 30 anti-synthetase syndrome) were consecutively enrolled. Except four patients who refused the vaccination, 94 (81.7%) received Comirnaty, 16 (13.9%) Spikevax, 5 (4.4%) Vaxzevria. Seven (6.1%) patients had flare after vaccination. One of them had life-threatening systemic involvement and died two months after second dose of COVID-19 vaccination. From logistic regression analysis, Chi2-log ratio = 0.045,the variable that most influences the development of flare was the number of organs involved (p = 0.047). Sixty-eight patients received the third dose of COVID-19 vaccination: 51(75%) Comirnaty and 17 (25%) Moderna. No patients had flares after third dose. Our study represents the largest cohort of IIM patients in which the incidence of recurrence after anti-SARS-CoV-2 vaccine was assessed. In line with real-life data from other diseases, we found a clinical non-statistically significant risk of relapse in our patients, which occurred seldom, usually mild and in patients with a more severe and aggressive course of disease.