Human leukocyte histamine release assays with whole ragweed and Alternaria antigens using Technicon autoanalyzer II

A simple and commercially available automated technique for fluorometric analysis of histamine is described. It is applicable to histamine release experiments utilizing washed leukocytes, and analyzes 15 samples/h at histamine concentrations between 1 and 1000 ng/ml with a mean variance between 0.5% and 18%. This technique is applied to a cross sectional study of leukocytes from 14 ragweed sensitive patients (7 on and 7 off immunotherapy) as well as five normals. It was also applied to 17 Alternaria-sensitive patients (4 on and 12 off immunotherapy) in addition to six normals. While antigen induced in histamine release clearly separated the sensitive group from the normals, it did not correlate with immunotherapy, and a considerable variation was seen in the sensitive patients of both the treated and untreated groups.