Ann. occup. Hyg., Vol. 46, No. 7, pp. 645, 2002
© 2002 British Occupational Hygiene Society
Published by Oxford University Press
Letters to the Editor |
Natural Rubber Latex Aeroallergen Exposure
1 Business Healthcare Ltd, Occupational Health Solutions, Leeming Lane South, Mansfield Woodhouse, Nottinghamshire NG19 9AQ; 2 Health and Safety Laboratory, Broad Lane, Sheffield S37HQ, UK
Received 16 April 2002;
We read with interest the account by Sri-Akajunt et al. (2000) of their measurement of personal exposure to latex airborne allergens in three occupational exposure groups. We were, however, surprised to note that in citing Swanson et al. (1994) and Liss et al. (1997) they misquoted the units of exposure. Swanson recorded a range of 8978 ng/m3; this is reported as 8978 µg/m3 by Sri-Akajunt et al. Similarly, Liss gives a range of 5616 ng/m3 and this is reported by Sri-Akajunt et al. as µg/m3. The levels reported by Sri-Akajunt et al. (1002740 ng/m3) were also significantly higher than previous reports in healthcare workers. Baur et al. (1998) reported a range of 0.4205 ng/m3, and not having found any cases of latex allergy above a level of 0.6 ng/m3 suggest that this figure should be the threshold limit value for latex. One possible explanation for the variation in ranges found by these different studies is that all used a RAST inhibition assay for measurement of airborne latex allergen. The difficulty inherent in this method is that it is dependent on the avidity of the pooled patient sera, and that once this supply has been exhausted, it is not readily reproducible. Furthermore, these observations highlight the need for inter-centre comparison of methods and standardization of latex extracts for use as reference standards in these assays.
Hence, although exposureresponse relationships are indeed important in establishing occupational standards, Baur is incorrect in identifying a level produced by this method as being sufficiently reproducible to use in standard setting. A method which could be used to overcome this deficiency is by the development of an ELISA method using monoclonal antibodies against major latex allergens, as described for airborne flour exposure (Wiley et al., 1997) and for fungal alpha amylase (Elms et al., 2001).
REFERENCES
Baur X, Chen Z, Allmers H. (1998) Can a threshold limit value for natural rubber latex airborne allergens be defined? j allergy clin immunol; 101: 247.[Web of Science][Medline]
Elms J, Denniss S, Smith M, et al. (2001) Development and validation of a monoclonal based immunoassay for the measurement of fungal alpha-amylase: focus on peak exposures. Ann Occup Hyg; 45: 8995.
Liss GM, Sussman GL, Deal K, et al. (1997) Latex allergy: epidemiological study of 1351 hospital workers. Occup Environ Med; 54: 33542.
Sri-Akajunt N, Sadhra S, Jones M, Burge PS. (2000) Natural rubber latex aeroallergen exposure in rubber plantation workers and glove manufacturers in Thailand and health care workers in a UK hospital. Ann Occup Hyg; 44: 7988.
Swanson MC, Bubak ME, Hunt LW, Yunginger JW, Warner MA, Reed CE. (1994) Quantification of occupational latex aeroallergens in a medical center. J Allergy Clin Immunol; 94: 44551.[Web of Science][Medline]
Wiley K, Smith MM, Allan LJ, Griffin P. (1997) Measurement of airborne flour exposure with a monoclonal antibody-based immunoassay. Int Arch Allergy Immunol; 114: 27884.[Medline]
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