{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T13:30:10Z","timestamp":1774445410679,"version":"3.50.1"},"reference-count":37,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2026,3,24]],"date-time":"2026-03-24T00:00:00Z","timestamp":1774310400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Children"],"abstract":"<jats:p>Background\/Objectives: Severe infusion-related reactions to rituximab are rare; we aim to extend our knowledge about them in children, focusing on rituximab-induced serum sickness (RISS) and anaphylaxis. Methods: We conducted a monocentric retrospective study on children and adolescents who received rituximab. Patients were defined as having RISS if they had fever and at least rash and\/or arthralgia, 1 to 30 days following infusion, and without another diagnosis to explain symptoms. Anaphylaxis was defined according to the diagnostic criteria proposed by the World Allergy Organization. Results: 1534 rituximab infusions in 391 patients were analyzed. Seven patients developed RISS; all received rituximab for an autoimmune disease, including four for immune thrombocytopenia (ITP). Six patients had fever, rash, and arthralgia. C-reactive protein or sedimentation rate was increased in all patients, and complement was decreased in 83%. Evolution was favorable within a few days with corticosteroids and\/or intravenous immunoglobulins. Rituximab was reinfused in one patient, which resulted in an immediate anaphylactoid reaction. Lower doses of rituximab were less likely to induce RISS. RISS was associated with a greater chance of achieving ITP remission. Seven patients developed anaphylaxis; five successfully received further infusions using desensitization protocols. Conclusions: RISS in children is a severe complication of rituximab infusion. Our study suggests that it may be more frequent in individuals treated for autoimmune conditions, especially ITP. The classical triad of fever, rash, and arthralgia appeared to be frequently present, and biological inflammation and\/or low complement can further support the diagnosis. In contrast to anaphylaxis, where rituximab may be safely rechallenged upon desensitization protocol, treatment alternatives should be pursued in patients experiencing RISS, given the higher risk of severe RISS recurrence.<\/jats:p>","DOI":"10.3390\/children13040442","type":"journal-article","created":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T10:07:13Z","timestamp":1774433233000},"page":"442","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Severe Reactions to Rituximab in Children: A Cohort Study of Rituximab-Induced Serum Sickness and Anaphylaxis"],"prefix":"10.3390","volume":"13","author":[{"given":"Camille","family":"Feltesse","sequence":"first","affiliation":[{"name":"Department of Pediatric Hematology and Oncology, Centre Hospitalier Universitaire de Sherbrooke, University of Sherbrooke, Sherbrooke, QC J1H 5H3, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jean-Fran\u00e7ois","family":"Delisle","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Centre Hospitalier Universitaire Sainte Justine, University of Montreal, Montreal, QC H3T 1C5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3448-2098","authenticated-orcid":false,"given":"Roxane","family":"Labrosse","sequence":"additional","affiliation":[{"name":"Division of Allergy and Immunology, Department of Pediatrics, Centre Hospitalier Universitaire Sainte Justine, University of Montreal, Montreal, QC H3T 1C5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Colette","family":"Deslandres","sequence":"additional","affiliation":[{"name":"Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Centre Hospitalier Universitaire Sainte Justine, University of Montreal, Montreal, QC H3T 1C5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7463-1233","authenticated-orcid":false,"given":"Nadia","family":"Roumeliotis","sequence":"additional","affiliation":[{"name":"Department of Pediatric Intensive Care, Centre Hospitalier Universitaire Sainte Justine, University of Montreal, Montreal, QC H3T 1C5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6026-6861","authenticated-orcid":false,"given":"Jean Jacques","family":"De Bruycker","sequence":"additional","affiliation":[{"name":"Division of Allergy and Immunology, Department of Pediatrics, Centre Hospitalier Universitaire Sainte Justine, University of Montreal, Montreal, QC H3T 1C5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5391-1578","authenticated-orcid":false,"given":"V\u00e9ronique","family":"Phan","sequence":"additional","affiliation":[{"name":"Division of Nephrology, Department of Pediatrics, Centre Hospitalier Universitaire Sainte Justine, University of Montreal, Montreal, QC H3T 1C5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9412-333X","authenticated-orcid":false,"given":"Thomas","family":"Pincez","sequence":"additional","affiliation":[{"name":"Department of Pediatric Hematology and Oncology, Centre Hospitalier Universitaire Sainte Justine, University of Montreal, Montreal, QC H3T 1C5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8567-3308","authenticated-orcid":false,"given":"Yves","family":"Pastore","sequence":"additional","affiliation":[{"name":"Department of Pediatric Hematology and Oncology, Centre Hospitalier Universitaire Sainte Justine, University of Montreal, Montreal, QC H3T 1C5, Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,24]]},"reference":[{"key":"ref_1","first-page":"832","article-title":"Indications for Rituximab Use in an Integrated Health Care Delivery System","volume":"26","author":"Delate","year":"2020","journal-title":"J. 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