Myeloperoxidase Deficiency

The potent myeloperoxidase-hydrogen-peroxide-halide (MPO-H 2 O 2 -halide) system created by activated neutrophils represents an extremely efficient microbicidal system. Nonetheless, hereditary deficiency of MPO is extremely common and only rarely associated with clinically significant immune dysfunction. In addition, acquired deficiency of MPO is seen in some forms of myeloid leukemia. The structure and function of MPO are reviewed in this context, and recent data regarding the biosynthesis of MPO are presented. Current studies employing recently isolated cDNA probes for MPO will provide insight into the underlying genetic defect in hereditary MPO deficiency, as well as clarification of the link between MPO gene expression and myeloid differentiation.