Advanced Oncology Certified Nurse Practitioner (AOCNP) Certification Practice Test

Cytokine release syndrome is the most likely mechanism responsible for anaphylaxis during the first cycle of monoclonal antibody therapy. This syndrome occurs when the activation and proliferation of immune cells lead to the release of a large number of pro-inflammatory cytokines into the bloodstream. In the context of monoclonal antibody therapy, particularly against targets that are closely associated with immune function or that lead to rapid immune cell activation, this sudden release of cytokines can result in systemic reactions that mimic anaphylaxis, including hypotension, fever, and respiratory distress.

While histamine release is associated with allergic reactions, its immediate release may not fully account for the severe and systemic nature of reactions seen specifically with monoclonal antibodies. Immune complex formation and antibody-dependent cellular cytotoxicity, while relevant in different contexts of immune response and therapeutic mechanisms, are less likely to be the primary triggers for anaphylactic reactions in this specific scenario. Thus, cytokine release syndrome robustly explains the acute and severe symptoms observed during the initial treatment cycle.