[Risk indicators of reaginic allergy. II. Presence of anti-acarian and/or anti-timothy grass pollen IgE related to birth date and family history].

One thousand three hundred and fifty-three presumed allergic children under 13 years were studied. Frequencies of biological sensitization (evaluated by PHADEBAS RAST tests) to two major antigens--Dermatophagoides pteronyssinus and timothy grass pollen--were compared. The ratio of these frequencies varies with birth season and family history. Thus it is suggested that two different physiopathologic mechanisms could play a role in the development of allergic diseases.