Minimizing
allergen concentration in
latex goods to prevent sensitization to
natural rubber latex (NRL) and thereby the development of clinical
allergy is acknowledged as of mutual interest for rubber manufacturers and regulatory health authorities. However, measuring total
protein, the principal currently available method, cannot be deemed a satisfactory regulatory measure to control
allergen content. Specific methods based on human
IgE-containing
reagents, such as radioallergosorbent test (RAST) inhibition, have been available in certain laboratories for demonstrating NRL
allergens in rubber products but the methods lack standardization. Currently, one commercial test has become available for measuring individual NRL
allergens by capture ELISA-based assays using
monoclonal antibodies and purified or recombinant
allergens. Such methods are specific, they can be properly standardized, and they are of sufficient sensitivity and reproducibility. Results from medical gloves collected in two national market surveys in Finland in 1995 and 1999, respectively, show that Hev b 6.02 and Hev b 5, the two major
allergens for NRL-allergic adults, are the most abundant
allergens regularly detectable in high- and moderate-
allergen gloves. In addition, Hev
b 3 and Hev b 1, the two major
allergens for children with
spina bifida, are also commonly found. In general, when the sum of the four
allergens exceeded 1 microg/g, most NRL-allergic patients showed positive skin prick test reactions against them. Using these new methods assessment of threshold levels that could in due course become guidelines for the rubber industry and regulatory health authorities is becoming possible. Eventually, this progress is expected to lead to a declining incidence of
latex allergy.