Eosinophilic peroxidase deficiency. Cytochemical and ultrastructural characterization of 21 new cases

The role of peroxidasin in solid cancer progression

Peroxidasin is a heme-containing peroxidase enzyme that plays a vital role in the cross-linking of collagen IV molecules in basement membranes. Collagen IV cross-links are essential for providing structure and mechanical stability throughout tissue development, homeostasis, and wound healing. During cancer progression, the basement membrane is degraded, and proteins typically found in the basement membrane, including peroxidasin and collagen IV, can be found spread throughout the tumour microenvironment where they interact with cancer cells and alter cell behaviour. Whilst peroxidasin is reported to be up-regulated in a number of different cancers, the role that it plays in disease progression and metastasis has only recently begun to be studied. This review highlights the current literature exploring the known roles of peroxidasin in normal tissues and cancer progression, regulators of peroxidasin expression, and the reported relationships between peroxidasin expression and patient outcome in cancer.

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.

A case of eosinophil peroxidase deficiency

A case of eosinophil peroxidase deficiency is described after fortuitous detection by the H*3 Technicon hematological analyzer. From the cytochemical aspect total deficiency is admitted. The abnormality is thought to be extremely rare in a well-mixed population as exists in the Grand-Duchy of Luxembourg.