Cashew oral immunotherapy for desensitizing cashew-pistachio allergy (NUT CRACKER study).

Abstract

Oral immunotherapy (OIT) is a treatment option for patients with milk, egg, and peanut allergy, but data on the efficacy and safety of cashew OIT are limited. A cohort of 50 cashew-allergic patients aged ≥4years, who were consecutively enrolled into cashew OIT (target dose 4000mg protein) between 4/2016 and 12/2019. Fifteen cashew-allergic patients who continued cashew elimination served as observational controls. Co-allergy to pistachio and walnut was determined. Full desensitization rate and associated immunological changes in both groups were compared. Patients fully desensitized to cashew were instructed to consume a dose of 1200mg cashew protein for 6months and were then challenged to a full dose. Patients with co-allergy to pistachio or walnut were challenged to the respective nut. Forty-four of 50 OIT-treated patients (88%) compared to 0% in controls tolerated a dose of 4000mg cashew protein at the end of the study (odds ratio 8.3, 95% CI 3.9-17.7, p<0.001). An additional three patients were desensitized to 1200mg cashew protein, and three patients stopped treatment. Three patients (6%) were treated with injectable epinephrine for home reactions. Desensitized patients had decreased SPT, sIgE, basophil reactivity, and increased sIgG4, following treatment. Following cashew desensitization, all pistachio (n=35) and four of eight walnut co-allergic patients were cross-desensitized to the respective nut. All (n=44) patients consuming a low cashew dose for ≥6months following desensitization passed a full-dose cashew OFC. Cashew OIT desensitizes most cashew-allergic patients and cross-desensitizes to pistachio. Safety is similar to OIT for other foods.