TOTAL IgE, SPECIFIC IgE AND ASCARIS INFECTION AND THE EXPRESSION OF SKIN-TEST POSITIVITY AND ATOPIC DISEASES IN AFRICA

摘要

Studies show rising rates of allergies and asthma in Africa, with increasing prevalence of allergic diseases in all communities, especially in rural and black African subjects. There is a complex interplay between environmental and genetic factors that affect the manifestation of allergies in Africa. The African setting is a wonderful 'natural experiment' where black African populations have co-evolved with parasites and micro-organisms, possibly leading to pro-allergic genetic potential, which has, however, been mitigated by continued exposure to factors in a traditional rural environment that downregulate manifestation of that potential. This complex situation leads to differences in presentation and diagnosis of allergy in Africa from those in First World settings. For example, rural to urban migration may lead to the lack of allergic family history in black African subjects, and parasite infestation may be an important factor in dictating total IgE levels, and may also have an effect on reducing skin reactivity.