Screening for total and partial eosinoperoxidase deficiency by flow cytometry: prevalence in a general population, pathology and genetic implications.

The ADVIA (Bayer) haematological system differentiates leukocytes by their volume and their peroxidase (MPO and EPO) activity. It thus allows specific counting of the eosinophils and detection of totally EPO and MPO deficient individuals. EPO activity is determined by the coordinates of the eosinophil cluster on the outprint. A reliable method of quantitation by simple angle measure is suggested. It allows recognition of partial deficiencies. Among approximately 100,000 persons, 29 cases of total EPO deficiency were detected. No typical or specific pathology of the defect was noted. Family studies showed heterozygous parents and offspring to be partially deficient. The frequency of these partial deficiencies in the general population is studied. The results exclude a simple autosomal recessive monogenic transmission of the defect. A model for bigenic transmission is suggested.