Quantitative Leukocyte Iodination

The conversion of iodide to a trichloroacetic-acid-precipitable form by phagocytizing human leukocytes was employed as the basis for a quantitative leukocyte iodination test, lodination was markedly reduced in the leukocytes of three male patients with chronic granulomatous disease, one female patient with familial lipochrome histiocytosis, and one male patient with myeloperoxidase deficiency. Leukocytes from three mothers of male patients with chronic granulomatous disease had moderately decreased iodination, whereas those from two female patients with the syndrome of recurrent cold staphylococcal abscesses had normal iodination. Iodination by leukocytes from patients with chronic granulomatous disease or familial lipochrome histiocytosis was increased by the substitution of live for heat-killed hydrogen-peroxide-generating organisms as the ingested particles. The quantitative iodination test correlates to some degree with microbicidal activity, and is therefore recommended as a simple, useful procedure for the evaluation of patients with a neutrophil dysfunction syndrome associated with impaired intraleukocytic microbicidal activity. A GROUP of conditions has been described in which a defect in intraneutrophilic microbicidal activity results in the prolonged intracellular survival of ingested organisms.^{1 2 3 4 5} Multiplication and dissemination of the sequestered organisms may cause severe and repeated infections. These conditions have focused attention on the intraneutrophilic microbicidal systems and on their evaluation in disease. Phagocytosis of micro-organisms is followed by the rupture of the leukocyte granules, with release of their contents into the phagocytic vacuole.⁶ Granular components with antimicrobial activity include lysozyme,⁷ cationic proteins⁸ and myeloperoxidase (MPO).⁹ The leukocytic metabolic burst may contribute to intracellular microbicidal activity through a fall in.