Histamine release from peripheral blood leucocytes in egg-allergic patients.

Twelve egg-allergic patients were selected on the basis of a clinical history of egg allergy and a positive skin-prick test (SPT) to whole egg. A study was then carried out on the ability of the patients' washed leucocytes to release histamine in the presence of whole egg, ovomucoid, ovalbumin and ovotransferrin. Histamine release (HR) from washed leucocytes was demonstrated in ten out of twelve patients, but only four out of ten released over 40% of their total histamine. Spontaneous HR ranged from 2.1-14.5% with a mean of 7.5%. There was good agreement between positive and negative HR, skin test and radioallergosorbent test (RAST) results. Concordance between the HR and skin test was found in 83%, HR and RAST in 71% and skin test and RAST in 78% of patients. However there was poor quantitative agreement between these three tests. When skin-prick tests and HR thresholds were compared, ovomucoid elicited the greatest skin test sensitivity in five out of six patients, whereas five of the same six were more sensitive to ovalbumin when judged by HR.