Catalytic activity of neutrophil and eosinophil peroxidase. Cytochemical and biochemical study in total hereditary myeloperoxidase deficiency.

We studied myeloperoxidase and eosinophil peroxidase activity in healthy subjects and in four totally myeloperoxidase deficient subjects using cytochemical and biochemical methods. Cytochemical tests demonstrated a pH dependent, enzymatic differentiated affinity of myeloperoxidase and eosinophil peroxidase for the chromogens used. The eosinophil peroxidase/myeloperoxidase ratio varied from 1.5 to 4. Biochemical assays, using MBTH-AA or o-dianisidine methods, produced eosinophil peroxidase/myeloperoxidase ratios of 1.98 and 1.72.