[Serum IgE in patients suffering from IgA deficiency with or without atopy]

Numerous studies, based upon the frequency of allergic and auto-immune disorders in association with selective deficiency in IgA, as well as the abnormally high proportion of IgA deficiency in atopic patients, have led to the hypothesis that allergy results from a deficiency in IgA during the first months of life. Thus subjects with an initial transient deficiency in IgA (followed by normal or greater than average production) produce an excess of IgE. The aim of this study, carried out by multifactorial data analysis, was to determine whether serum IgE levels were related to those of IgA. Comparison of the serum Ig levels of 4 groups of individuals, with or without IgA deficiency, showed that the production of IgE was more closely related to the respiratory condition responsible than to IgA levels. According to IgA and E levels, the 4 groups differ distinctly, atopic patients without asthma constituting a "bridge" between the control group and those with asthma. In the presence of an apparently identical situation, i.e. an IgA deficiency, individuals may react in two different ways: some produce an abundance of IgE whilst others fail to do so and are more susceptible to recurrent infective episodes. The role of the genetic control of IgE as well as environmental factors in the pathogenesis of allergic manifestations is discussed.