Hereditary myeloperoxidase deficiency syndrome. Clinical and hematological data of ten cases

Ten cases with hereditary myeloperoxidase (MPO) deficiency (five total and five partial), out of 83,000 analyzed patients, were identified using a new automated flow cytochemistry screening method (Technicon H 6000). The MPO deficient neutrophils are 'large unstained cells' (LUC). Light microscopy analysis of the bloodsmears excluded the presence of blasts, large or activated lymphocytes, thus confirming the enzyme defect. Cytochemical scores, ultrastructural cytochemistry, biochemical assay, performed on the leucocytes of these subjects, provided in all cases further evidence for the MPO deficiency. Furthermore, the biochemical assay of peroxidase showed a low concentration of enzymatic activity, not previously discovered by the cytochemical analyzer but in agreement with cytochemical findings. Genetic investigation, carried out in 19 members of the probands' families, demonstrated an hereditary pattern of the disease. These subjects were not particularly susceptible to severe or pers...