Prediction of late asthmatic responses to inhaled allergen
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SummaryRelationships between cutaneous and bronchial responses to allergen were examined in nineteen atopic asthmatics. Allergen inhalation tests elicited an isolated early asthmatic response (EAR) in ten subjects and a dual asthmatic response (DAR) in nine subjects. Ragweed IgE RAST, performed with the sera of those patients tested with ragweed antigen, yielded higher values in all but one patient who experienced DAR than any of the patients with EAR. In one patient with annual symptoms in the ragweed season, positive skin tests with ragweed antigen and DAR to inhaled ragweed extracts, the IgE RAST was entirely negative and the serum IgE concentration was low. Dilutions of the allergen used in each individual for inhalation were also used in skin‐prick tests. Early cutaneous allergic response (ECAR) mean wheal diameters were obtained at 10 min and late cutaneous allergic response (LCAR) mean diameters at 6‐8 hr. Early asthmatic response (EAR) subjects differed modestly from DAR subjects in the relationships between ECAR and LCAR; in the EAR group, a significantly larger wheal diameter (P < 0.01) was required before an LCAR ensued, however there was some overlap. Once LCAR developed, there was no difference between EAR and DAR groups in the magnitude of the LCAR. There was a trend (not significant) towards a requirement for a higher antigen concentration in the EAR group to elicit an LCAR.In conclusion, correlates of an isolated EAR from inhaled antigen include: (i) a low positive IgE RAST result with the antigen, (ii) ECAR 6 mm or greater with the antigen which does not proceed to a LCAR, and (iii) a high concentration of antigen is needed in skin tests to elicit an LCAR. Correlates of a DAR include:(i) a high IgE RAST result with the antigen, (ii) an ECAR wheal diameter less than 5 mm with the antigen proceeds to a LCAR, and (iii) a low antigen concentration in skin tests elicits an LCAR.The observed correspondence between the tendency to late skin and late airway responses is evidence of a common immunologic basis.
