ASSESSMENT OF HISTAMINE-RELEASE FROM BASOPHILS IN WHOLE-BLOOD BY BENZYLPENICILLOYL POLY-L-LYSINE IN PENICILLIN-SENSITIZED PATIENTS

Histamine release from basophil granulocytes in whole blood by benzylpenicilloyl poly-L-lysine (PPL) was investigated in 7 patients with penicillin allergy. All patients presented with systemic immediate hypersensitivity reactions after i.v. administration of penicillin G. Total histamine (of 7 patients) ranged from 27.5 ng/ml to 62.1 ng/ml (mean 43.2 ng/ml). The spontaneous histamine release ranged from 0.15 % to 5.1 % (mean 1.8 %) of the total content. Addition of PPL in various concentrations resulted in values between 0.8 and 9.6 %. Although PPL is a reliable allergen for prick- and intradermal testing in the diagnosis of penicillin allergy - demonstrating a histamine liberation in the skin - the in vitro experiment using the same allergen showed no histamine release above 10 %. Using a threshold of 5 % out of 7 patients, 4 (57 %) would show a positive histamine release. Therefore it might indicate that in penicillin allergy a threshold of 5 % must be used. In addition, basophils in whole blood and skin mast cells may be activated differently.