The Bayer-Technicon hematological devices differentiate leukocytes by their peroxidase activity and their volume, displaying them as separate clusters. Peroxidase deficiencies are manifested by the irregular location of these clusters. This makes it possible to identify persons totally or partially lacking myeloperoxidase. The deficiency is quantified by the myeloperoxidase index, which is expressed for every routine analysis and for which normal values were determined. Values of the myeloperoxidase index confirm varying degrees of deficiency and prevalence. Family studies using these degrees show that the hereditary pattern must be more complicated than the classical autosomal-recessive mode. A bigenic mode is suggested. While about half of the totally deficient individuals detected were free of typical symptoms, in the other half we found infectious complications that were sometimes life-threatening. The hematological devices allow the identification of persons suffering from eosinoperoxidase deficiency and from MPO deficiency of the monocytes. The latter symptom seems to indicate immaturity of these cells and may lead to unexpected diagnosis of malignancy.
