Type II hypersensitivity reactions after oxaliplatin rechallenge can be life threatening

Rechallenge with oxaliplatin is common in the treatment of colorectal cancer and increases the risk of a detrimental oxaliplatin-induced immune reaction. Allergic reactions to oxaliplatin may be partially avoided by desensitization protocols involving immune suppressive drugs, slow administration and gradually increasing chemotherapeutic doses. However, non-IgE-mediated immunopathologic reactions to oxaliplatin remain challenging and may be potentially life-threatening.

Here we report two potentially fatal cases of type II hypersensitivity to oxaliplatin in metastatic colorectal cancer patients. Both patients manifested with severe thrombocytopenia, intravascular haemolysis, and acute kidney injury 4-6 h after oxaliplatin administration in a rechallenge setting. Serology revealed that the reactive entity for immune haemolysis was an IgG oxaliplatin-induced antibody. The course of anti-cancer treatment and severe adverse event after oxaliplatin rechallenge including diagnostic dilemma and the results of detailed routine clinical chemistry and hematology testing are described. Extended immunohaematology/serology testing revealed that the oxaliplatin-induced IgG antibody was present in the circulation prior to the onset of hypersensitivity, persisted for months and elicited cross-reactivity with other platinum agents.

Development of type II hypersensitivity reaction manifesting as a sudden onset of severe thrombocytopenia and immune haemolysis must be considered in patients treated with oxaliplatin, especially those on long-term therapy or when rechallenged. Step-wise diagnosis involves clinical presentation, detection of haemolysis in patient's blood and/or urine, evaluation of platelet count, and direct anti-globulin Coombs test.