ASTHMA IN TANTA, EGYPT - SEROLOGIC ANALYSIS OF TOTAL AND SPECIFIC IGE ANTIBODY-LEVELS AND THEIR RELATIONSHIP TO PARASITE INFECTION

The relationship between asthma, IgE and parasite infection was compared in 68 randomly selected patients with asthma and 37 nonasthmatic controls living in Tanta, Egypt. Sera were assayed for total IgE and for IgE antibodies to inhaled allergens (mite, cat, cockroach, ryegrass, ragweed and 3 fungi) and to parasite antigens (Schistosoma mansoni and Brugia malayi). Parasite infection was determined by microscopic examination of stool specimens. Total IgE levels were significantly higher in patients with asthma (geometric mean 909 IU/ml), than in controls (geometric mean 145 IU/ml, p < 0.001). The high IgE levels correlated with parasite infection and the presence of IgE antibodies to S. mansoni antigens, which were also elevated compared to controls. The prevalence of allergen-specific IgE antibodies among Egyptian asthmatics was low by comparison with 'Western' asthmatics, but nonetheless higher than among Egyptian controls. A radioallergosorbent test (RAST) values of > 40 U/ml to any allergen was found in 19/68 (28%) sera from the asthma group, as compared to only 1/37 (3%) sera from controls (p < 0.001). The highest RAST values were to dust mite (Dermatophagoides pteronyssinus and D. farinae) allergens, followed by rye grass and ragweed allergens. The results suggest that in this area of Egypt, several factors may influence the development of asthma, including nonspecific activation of IgE and/or inflammatory mechanisms by helminth parasites and sensitisation to environmental allergens.