Quantitation by myeloperoxidase assay of neutrophil accumulation at the site of in vivo allergic reactions.

Skin window techniques to investigate neutrophil inflammatory reactions in human skin have been limited by cellular distortion and difficulties in quantitation. We have developed a quantitative approach based on the assessment of the myeloperoxidase (MPO) released from sonicated membrane filters to which exuding inflammative cells had adhered. Our studies have shown that (1) a standard curve can be derived for each subject from the linear relationship between amounts of MPO released and designated numbers of blood neutrophils which have been aspirated onto such filters; (2) the number of neutrophils adhering to filters appended to skin window sites can then be reliably estimated by comparing the amount of MPO released by sonication of such filters with the standard curve; and (3) neutrophil accumulation is greater at pollen-challenged than control sites in sensitive subjects.