Vol. 86, Iss. 4, May 2013
Is specific IgE antibody analysis feasible for the diagnosis of methylenediphenyl diisocyanate-induced occupational asthma?
Riassunto
Purpose Early recognition improves the prognosis of isocyanate asthma. A major unanswered question is whether IgE-dependent mechanisms are of diagnostic value? Our objective was to appraise serological methods using various methylenediphenyl diisocyanate (MDI)-albumin conjugates and weigh up the data versus the outcome of standardized comprehensive clinical diagnostics to evaluate the viability of immunological analysis in supportive MDI-asthma diagnosis (OAI).
Methods Specific IgE (sIgE) and IgG (sIgG) binding was measured with fluorescence enzyme immunoassay in 43 study subjects (using conjugates prepared in-vapor, in-solution and commercial preparations). The differential clinical diagnosis included standardized measurement of pulmonary function, non-specific bronchial hyper-responsiveness, specific MDI-prick test (MDI-SPT) and specific inhalation challenge (MDI-SIC).
Results Detailed diagnostic scheme allows the differential OAI and MDI-induced hypersensitivity pneumonitis (PI). The presumed OAI diagnoses were confirmed in 84 % (45 % cases having demonstrable sIgE antibodies) with RR 5.7, P > 0.001, when OAI diagnosis is correlated with MDI-SIC/MDI-SPT (RR 1.28 for MDI-SIC alone); sIgG antibodies were clinically relevant for PI and not for the OA diagnosis. MDI-specific IgE data generated with commercial ImmunoCAP preparations show high correlation with our in-vapor generated MDI conjugates.
Conclusions Isocyanate-specific IgE antibodies are not always detectable but their presence is strongly predictive of OAI and supportive for the diagnosis. MDI-SPT can be a valuable parameter differentiating OAI and PI. We have confirmed and extended published data showing that isocyanate-albumin conjugates perform better in specific antibody assays when prepared with volatile phase formulations and would like to stress additionally the necessity for further refinements and standardization in clinical diagnostics procedures.
Commento
Attualmente sono stati accertati più di 350 agenti chimici in grado di causare asma professionale. I composti chimici a basso peso molecolare rappresentano un importante sottoinsieme di questi agenti eziologici ed includono approssimativamente 100 sostanze chimiche differenti, tra cui le anidridi acide, i poliisocianati, i metalli come i sali di platino clorurati e alcuni acrilati. Una relazione qualitativa e quantitativa tra la struttura chimica di queste sostanze, la capacità di formare apteni e il loro ruolo nella patogenesi dell’asma è stata presa in considerazione in vari studi di letteratura.
La diagnosi certa di asma professionale dopo esposizione a questi composti appare però ancora di difficile realizzazione. Alcune ricerche sull’argomento hanno preso in considerazione il ruolo diagnostico dei meccanismi IgE-dipendenti e dei test immunologici specifici, ma i risultati sono ancora insufficienti.
Questa ricerca, incentrata sulla relazione tra l’esposizione a isocianati e lo sviluppo di asma professionale, fornisce ulteriori contributi ai dati pubblicati in letteratura per una diagnosi specifica tramite test con coniugati isocianato-albumina. Lo studio offre spunti per la standardizzazione delle procedure di diagnostica clinica.
Keywords
Albumin conjugates, Asthma diagnosis, Hypersensitivity pneumonitis, Immunological diagnosis, Isocyanate alveolitis, Isocyanates, MDI, methylenediphenyl diisocyanate, occupational asthma, Specific IgE antibodies, Specific IgG antibodiesArticoli correlati che potrebbero interessarti
Vol. 88, Iss. 2, February 2015
Vol. 88, Iss. 2, February 2015
Magnetic fields and leukaemia risks in UK electricity supply workers
Occupational Medicine (Oxford Journals). Vol. 64, Iss. 5, July 2014