Carboplatin-, oxaliplatin-, and cisplatin-specific IgE: cross-reactivity and value in the diagnosis of carboplatin and oxaliplatin allergy.

BACKGROUND: The diagnosis of hypersensitivity reactions (HSR) to platins is based on the characterization of the reaction and the results of skin testing. Platins can be irritants when used in skin testing; therefore, in vitro testing may offer an alternative diagnostic tool. OBJECTIVE: To evaluate sensitivity and specificity of platin specific IgE (sIgE) in patients with HSRs and in controls. METHODS: Twenty-four patients with immediate HSR to platins were included (carboplatin, 12; oxaliplatin, 12): 19 women and 5 men (mean age, 61 years). The control group included 17 patients exposed to platin and with no HSR. Skin testing was performed on 22 patients. Carboplatin sIgE and oxaliplatin sIgE were measured in 24 patients and 17 controls; carboplatin sIgE was measured in 21 patients. RESULTS: Skin test results were positive in 22 patients (carboplatin, 12/12; oxaliplatin, 10/12). Seven of 12 patients sensitive to carboplatin (59%) had positive carboplatin sIgE, 2 also had positive cisplatin sIgE, and all had negative oxaliplatin sIgE; 9 of 12 patients sensitive to oxaliplatin (75%) had positive sIgE to oxaliplatin, 8 of 12 (67%) also had positive carboplatin and cisplatin sIgE, to which they had not been exposed. All 5 carboplatin controls had negative sIgE; 3 oxaliplatin controls (25%) had positive carboplatin sIgE, and 2 had positive oxaliplatin sIgE. CONCLUSION: Carboplatin sIgE is very specific but less sensitive. In contrast, oxaliplatin sIgE had higher sensitivity but lower specificity. Analysis of our data suggests that oxaliplatin exposure was more immunogenic. This could be clinically relevant because patients sensitized to carboplatin may be able to tolerate oxaliplatin, but patients sensitized to oxaliplatin may be at risk when exposed to carboplatin and cisplatin.