HLA phenotype and exposure in development of occupational asthma.
OBJECTIVE
To review relevant scientific literature to understand the contribution of exposure to the risk of developing occupational asthma and whether HLA class 2 molecules contribute to individual susceptibility to sensitization and asthma caused by low-molecular-weight chemicals.


METHODS
The author's expert opinion was used to select relevant articles based on systematic reviews of relevant literature.


RESULTS
Studies during the past decade have shown that intensity of exposure is an important determinant of asthma induced by inhaled respiratory sensitizers, both proteins and low-molecular-weight chemicals. There is evidence that HLA class 2 alleles contribute to the risk of sensitization and asthma caused by low-molecular-weight chemical sensitizers. HLA-DR3 is associated with an increased risk of developing specific IgE to trimellic anhydride (TMA) and complex platinum salts such as ammonium hexachloroplate (ACP). In those exposed to ACP and possibly also to TMA, risk is greater in those who have experienced lower intensity of exposure.


CONCLUSIONS
Exposure intensity is an important determinant of sensitization and asthma caused by respiratory sensitizers. HLA class 2 alleles contribute to individual susceptibility to low-molecular-weight chemicals. For some chemicals, the contribution of HLA class 2 alleles is greater in those less exposed at work to the relevant chemical.
Taylor
A J Newman
AJ
Imperial College School of Medicine, National Heart and Lung Institute, London, England. a.newmant@rbh.nthames.nhs.uk
D000818:Animals; D001249:Asthma / Q000209:etiology* / Q000276:immunology; D004198:Disease Susceptibility; D006684:HLA-DR Antigens / Q000032:analysis* / Q000235:genetics; D006801:Humans; D006967:Hypersensitivity / Q000150:complications; D007073:Immunoglobulin E / Q000276:immunology; D007509:Irritants / Q000009:adverse effects; D009784:Occupational Diseases / Q000209:etiology* / Q000276:immunology; D016273:Occupational Exposure; D010641:Phenotype
D006684:HLA-DR Antigens; D007509:Irritants; D007073:Immunoglobulin E