The prevalence of immunoglobulin E antibodies to the proteins of rubber (Hevea brasiliensis) latex and grass (Phleum pratense) pollen in sera of British blood donors.

BACKGROUND: Although there have been many studies of the prevalence of latex allergy in populations deemed to be at risk, little is known of the potential allergic susceptibility to latex products prevailing in the general population. OBJECTIVE: To assess the possible prevalence of allergy to latex goods in a population of blood donors by measurement of specific antilatex immunoglobulin (Ig) E in blood, to relate this to prevalence of antigrass IgE in the blood donations, and to assess the prevalence of antibodies to grass, house dust mite and cat allergens in those donors having antilatex IgE antibodies. METHODS: Sera from two groups of donations obtained in the English West Midlands were assayed. A group of 2000 donations obtained in midwinter was assayed for antilatex and antigrass pollen IgE. A group of 5000 midsummer donations was assayed for total IgE, and antilatex IgE and the sera giving a positive reaction, assayed for antigrass pollen, antihouse dust mite and anticat IgE. The nature of the principal latex and grass pollen polypeptides reacting with IgE in the sera was assessed by immunoblotting. RESULTS: Anti-latex IgE was detected in approximately 4% of the winter and 7% of the summer donations. The prevalence of antigrass IgE in the winter donations was approximately 20% and amongst the latex-positive sera approximately 84% contained antigrass IgE. Of the summer donations of latex-positive sera, 96% contained antigrass, 48.6% antimite IgE and 34% anticat IgE. The prevalence of both antilatex and antigrass IgE was age and sex related. Inhibition studies indicated cross-reactivity of IgE with latex and grass pollen proteins. CONCLUSIONS: Whilst 4-7% of the population may have serum IgE reacting with latex, the levels are low compared with those reacting with the aeroallergens studied. The apparent cross-reactivity of some serum IgE with both latex and grass pollen taken with other evidence suggests that, in some individuals, allergy to latex may arise from an initial sensitization by grass pollen.

IgE antibodies to foods are not a feature of cystic fibrosis.

It has been suggested that patients with cystic fibrosis have abnormal immune responses to foods. We have measured IgE antibodies to inhalants and foods (by RAST) in 105 patients with cystic fibrosis aged between 8 months and 28 years. Serum IgE was elevated (greater than 180 kU/l) in 21 patients. In 43, IgE antibodies were detected in serum. The majority of positive results were with house-dust mite, grass pollen or Aspergillus. Only four of the patients had a positive RAST to a food--one to milk, one to wheat and two to egg. On the basis of high serum IgE or positive RAST results, 44.8 per cent of the patients were atopic and the frequency of atopy was age-related, being higher in patients aged 4 years or more. However, the presence of food antibodies was unrelated to age. This study confirms the high prevalence of atopy in patients with cystic fibrosis but unequivocally demonstrates that the presence of IgE antibodies to foods in their serum is rare.

A community survey of IgG4 antibody levels.

Precise and specific radioimmunoassays have been developed to quantify IgG4 and IgG4 antibodies. A community survey has demonstrated that men have significantly higher total serum IgG4 levels than women: geometric mean values of 0.581 mg/ml versus 0.302 mg/ml. This sex difference was extended to total IgE values. Circulating levels of IgG4 antibodies against foods, especially egg and milk, were normally higher than those against the three most common U.K. inhalant allergens--grass pollen, house dust mite and cat epithelium.

RAST atopy screen.

A single in vitro screening test for atopic allergy is described. It uses the radioallergosorbent test (RAST) principle, and has been applied to screening sera from U.K. patients with possible atopic symptoms. When compared with the Phadebas RAST, the test sensitivity was 97% and the specificity 100%, and these results suggest that it is useful in any preliminary allergy investigation.

Allergy and parasites: the measurement of total and specific IgE levels in urban and rural communities in Rhodesia.

Eighty adult asthmatics living in an African city had a significantly higher serum IgE level (799 u/ml) than the control group (350 u/ml). A high proportion (78.7%) of the asthmatics had demonstrable circulating mite-specific IgE antibodies. The rural population of a filariasis endemic region was investigated and although no allergic subjects were identified, the group had a significantly higher IgE level (1613 u/ml) than the asthmatics and also showed a relatively high incidence of grass pollen-specific IgE antibodies (35%). The discrepancy between clinical history and laboratory results supports the mast cell saturation hypothesis and suggests: (a) an explanation for the susceptibility to allergy of African and Asian immigrants to Great Britain, and (b) a practical approach for preventing allergic reactions in vivo.