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

Summary. Ten cases with hereditary myeloperoxidmse (MPO) deficiency (liye total and live 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 reported by the machine as 'large unstained cells» (LUC). Light microscopy analysis of the bloodsmears excluded the presence of blasts, large or activated lymphocytes, thus confirming the enzyme defect. Cytochemica] scores, ultrastructural cytoehemistry, 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 pairticularly susceptible to severe or persistent infections, whereas they showed an high incidence of solid tumours.