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Tackling penicillin allergy delabeling with ultra-sensitive in vitro test and human-like specific IgE standards
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  • Sergi Morais,
  • Pedro Quintero-Campos,
  • Paula Segovia,
  • Ethel Ibáñez-Echevarria,
  • Dolores Hernández-Fernández de Rojas,
  • Patricia Casino,
  • Gabriel Lassabe,
  • Gualberto González-Sapienza,
  • Ángel Maquieira
Sergi Morais
Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM) Universitat Politècnica de València-Universitat de València Spain
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Pedro Quintero-Campos
Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM) Universitat Politècnica de València-Universitat de València Spain
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Paula Segovia
Cátedra de Inmunología Facultad de Química DEPBIO Instituto de Higiene Montevideo Uruguay
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Ethel Ibáñez-Echevarria
Hospital Universitari I Politènic La Fe Servicio de Alergia
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Dolores Hernández-Fernández de Rojas
Allergy Therapeutics Ibérica Av de Barcelona 115 08970 Sant Joan Despí Spain
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Patricia Casino
Group 739 of the Centro de Investigación Biomédica en Red sobre Enfermedades Raras (CIBERER) del Instituto de Salud Carlos III Spain
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Gabriel Lassabe
Cátedra de Inmunología Facultad de Química DEPBIO Instituto de Higiene Montevideo Uruguay
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Gualberto González-Sapienza
Cátedra de Inmunología Facultad de Química DEPBIO Instituto de Higiene Montevideo Uruguay
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Ángel Maquieira
Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico (IDM) Universitat Politècnica de València-Universitat de València Spain
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Abstract

Background: Penicillin allergy delabeling initiatives are now part of antibiotic stewardship programs and include the use of invasive and risky in vivo tests. Instead, the quantification of specific IgE is highly useful to confirm immediate allergy to penicillins. However, discrepant results associated to the low sensitivity of the in vitro tests have limited their routine diagnostic use for delabeling purposes. We aimed to tackle a novel diagnostic strategy for specific IgE testing based on a homologous interpolation scheme, using recombinantly produced standards. Methods: Serum samples from a cohort of allergic patients and controls were analysed by a chemiluminescence-based immunoassay, using a bispecific binanobody as standard. The novel standard targets the major antigenic determinant of penicillin G and the paratope of Omalizumab, acting as human-like specific IgE. Results: Testing a cohort of 65 human serum samples, the method achieved a good agreement and strong positive relationship, reaching a limit of detection below 0.1 IU/mL. The sensitivity of the in vitro test significantly increased (66 %), doubling that of the ImmunoCAP reference in vitro assay with an overall specificity of 100 %. Conclusions: The new diagnostic strategy compares favourably with the results obtained on the ImmunoCAP system, paving the way towards the standardization of penicillin allergy testing. The recombinant standards are potent calibrators, highly stable, easy and inexpensive to produce, and overcome the limitation associated with preparations derived from pooled human serum, expediting the production of next generation standards with different specificities to successfully tackle β-lactam allergy delabeling by in vitro tests.