Type II hypersensitivity reactions after oxaliplatin rechallenge can be life threatening.

ABSTRACT

BACKGROUND: 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. CASE PRESENTATION 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. CONCLUSION: 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.