Comparison of myeloperoxidase activity in leukocytes from normal subjects and patients with chronic granulomatous disease.

A study was undertaken to compare myeloperoxidase (MPO) activity in leukocytes from normal subjects and those with chronic granulomatous disease (CGD) and to eliminate further consideration of MPO as the oxidase responsible for the post-phagocytic respiratory burst and subsequent oxidase microbicidal sequence lacking in leukocytes from patients with CGD. With use of granule fractions isolated from a number of samples, MPO activity in several MPO-mediated biochemical systems (peroxidase assays, protein iodination, and amino acid decarboxylation) was measured. No difference was demonstrated between granule fraction preparations from normal subjects and those with CGD. These data show that MPO activity is normal in CGD leukocytes and are inconsistent with a role for MPO in initiating the post-phagocytic respiratory burst.