RESUMO
Alemtuzumab is a humanized monoclonal antibody targeting the CD52 antigen on lymphocyte surfaces. The intravenous administration of alemtuzumab provokes the depletion of lymphocytes by antibody-dependent and complement-mediated cellular cytotoxicity. Resulting cytotoxicity leads to 'first-dose infusion-related reactions in more than 90% of the patients, fewer than 3% being severe cases. We present the first successful modified rapid drug desensitization (RDD) protocol to alemtuzumab in an active relapsing-remitting multiple sclerosis (RRMS) patient. The forty-year-old female patient had an immunologically-mediated mixed-type (co-occurring IgE-mediated and cytokine release syndromes) hypersensitivity reaction (HSR) verified with a drug skin test. As the patient had severe HSR and there was no other option to treat RRMS at that time; two courses of 12 mg alemtuzumab with one-year intervals were administrated successfully using the modified 12-step intravenous RDD protocol. By experience, RDD is known as a safe and effective therapy option allowing alemtuzumab treatment targeted for the aforementioned type of MS.