Clinical Study Assessment of Confirmed Clinical Hypersensitivity to Rituximab in Patients Affected with B-Cell Neoplasia S. Novelli , 1 L. Soto , 2 A. Caballero , 1 M. E. Moreno, 3 M. J. Lara, 1 D. Bayo, 1 A. Quintas, 1 P. Jimeno, 1 M. I. Zamora, 1 T. Bigorra, 2 J. Sierra, 1 and J. Briones 1 1 Haematology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain 2 Pneumology and Allergy Unit, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain 3 Pharmacy Deparment, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain CorrespondenceshouldbeaddressedtoS.Novelli;snovelli@santpau.cat Received 1 April 2020; Revised 16 May 2020; Accepted 25 May 2020; Published 11 June 2020 AcademicEditor:BashirA.Lwaleed Copyright©2020S.Novellietal.isisanopenaccessarticledistributedundertheCreativeCommonsAttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Rituximab hypersensitivity reactions are rare but are one of the main causes of rituximab elimination from antilymphoma immunochemotherapy treatments. While the clinical picture may be indistinguishable from other infusion-related reactions, hypersensitivityreactions(HSR)donotdisappearandinsteadbecomemoreintensewithsubsequentadministrations. Objective. Todescribetheuseofthe12-stepprotocolfordesensitizationtointravenousrituximabinclinicalpracticeandthecomplementary studyofapossibleIgE-mediatedHSRinthecontextofB-celllymphomatreatment. Methods.A12-steprituximabdesensitization protocol was performed prospectively within clinical practice in 10 patients with a history of severe infusion reactions or in patientswhohadarepeatedreactionatsubsequentdosesdespitetakingmoreintensepreventivemeasures.Skinpricktestswere performedatthetimeofreactionandatalatertimetoeliminatefalsenegativesduetopossibledruginterference. Results.Overall, withthedesensitizationprotocol,70%ofpatientswereabletocompletethescheduledimmunochemotherapy.Twopatientshadto discontinue the therapy due to clinical persistence and the third due to lymphoma progression. Intradermal tests with 0.1% rituximab were positive in only 20% of cases, demonstrating a mechanism of hypersensitivity. Conclusions. e 12-step de- sensitization protocol is very effective and assumable within healthcare practice. ere is a need to determine the mechanism underlying the infusion reaction in a large proportion of cases due to the risk of future drug exposure. 1. Introduction Rituximab is a murine/human chimeric monoclonal anti- body against CD20 that has been in use for more than 20 years for the treatment of B-cell lymphomas and autoim- mune disorders [1]. Currently, new monoclonal antibodies againsthumanizedCD20arereplacingrituximabforseveral of its indications [2, 3] and are associated with fewer infusionaladversereactions;however,thesenewoptionsare not affordable in many countries. Rituximab improves overall survival and progression- free survival in the majority of B-cell lymphomas and is therefore part of all therapeutic regimens. erefore, its elimination due to hypersensitivity reactions is detrimental to patients. e main reasons for eliminating rituximab from the therapeutic protocol of lymphoma patients are severe in- fusion reactions (IRs) that do not remit after subsequent administrations and corrective measures. Infusion-related adversereactionshavebeenreportedin84–95%ofcases,but 90%ofcasesaremild[4].IRsaredose-dependentand,inthe case of lymphomas, closely related to tumour burden, and thus, they are limited to the first-line administration. e most frequent aetiologies are cytokine release syndrome (CRS), tumour lysis syndrome (TLS), and hypersensitivity reactions (HSRs) [5]. HSRscanoccuraftervariousexposurestothedrug,and anIgEmechanismcanbedemonstratedinsomecases.e symptomscanbeindistinguishablefromthosedescribedin TLS and CRS, with the difference being that they persist Hindawi Advances in Hematology Volume 2020, Article ID 4231561, 5 pages https://doi.org/10.1155/2020/4231561