Iron-binding reactivity in mature neutrophils: relative cell content quantification by cytochemical scoring

We have developed a technique that permits evaluation and semi-quantification of iron-binding function in mature neutrophils. Neutrophil iron-binding reactivity (NFeBR) visualized using the iron nitrilotriacetate-acid ferrocyanide technique was rated 0 to 5+ in 100 segmented cells; the ratings were totaled to yield a score (NFeBRS). Males and post-menopausal females had significantly higher NFeBRS than pre-menopausal females. Neonates had low values, and a homogeneous distribution of NFeBR among neutrophils. In pregnancy and acute infection, NFeBRS were significantly increased. In a patient with congenital lactoferrin (Lf) deficiency, the NFeBRS was very low. In Ph1-positive chronic myelogenous leukemia, 13 of 17 patients had low NFeBRS due to decreased NFeBR, which was heterogeneously distributed among mature neutrophils. By ultrastructural analysis of mature neutrophils in two such patients, the stain deposits in FeBR-positive granules were of normal intensity, but the numbers of positive granules were decreased in many cells. NFeBRS were also low in 12 of 23 patients with other myeloproliferative disorders, and in seven of 15 patients with acute non-lymphoblastic leukemia, but in only seven of 63 patients with other neoplasms. NFeBRS were significantly correlated (p less than 0.008) with values of neutrophil Lf content quantified by immunologic assays in a wide variety of conditions and over a broad range of values. These results augment observations of neutrophil Lf made using immunological methods.