Engineering nanoallergens to investigate origins of immunogenicity and cross-reactivity in cephalosporin allergy.

Background: A major obstacle to the effective diagnosis of cephalosporin allergies is that the haptens, or segments of their molecular structures, which are responsible for the initiation of an immunogenic response, are unknown.

Objective: This study aimed to identify immunogenic moieties of cefazolin to accurately predict IgE-mediated allergy and cross-reactivity with other cephalosporin antibiotics.

Methods: Hapten immunogenicity analysis is performed using liposomal nanoallergens integrated in a cellular degranulation assay to quantify secreted allergic mediators. RBL-SX38 cells were primed with purified human monoclonal IgE or patient plasma samples before nanoallergen challenge. The monoclonal IgE priming consisted of dust mite- or peanut-specific negative controls and were compared against a cefazolin-specific monoclonal IgE. The plasma samples, in contrast, came from 3 drug allergy-negative control patients, or 2 cefazolin-allergic patients who provided 3 samples.

Results: Multiple forms of cefazolin are immunogenic when multivalently presented by nanoallergens, and there may be alternate nanoparticle formulations that can effectively diagnose IgE-mediated cefazolin allergy in patients. Additionally, common R or R groups in cephalosporin molecular structures do not singularly identify shared cross-reactivity.

Conclusion: This study highlights an innovative method to reproducibly distinguish cefazolin-allergic from nonallergic patients using finely tuned cefazolin-hapten-presenting nanoallergens in conjunction with an in vitro cellular degranulation assay.