Neutrophil function and diagnosis of pre-leukaemic states

Defective neutrophil function and microbicidal mechanisms in the myelodysplastic disorders

Neutrophil function studies have been carried out in a series of 44 patients with primary myelodysplastic syndromes (MDS). In vitro tests of phagocytosis and killing of Candida guilliermondii and Staphylococcus aureus identified 13 patients with abnormal neutrophil function at presentation and a further 10 who developed abnormalities during the course of their disease. The incidence of defective function in the five disease categories in this series was: refractory cytopenia (RC) 8/17; refractory cytopenia with sideroblastic change (RC + SC) 5/8; acquired idiopathic sideroblastic anaemia (AISA) 2/4; refractory anaemia with excess blasts (RAEB) 7/11; chronic myelomonocytic leukaemia (CMML) 1/4. Eleven of 23 patients with defective neutrophil function experienced severe infective complications; in only three of these patients were neutrophil counts less than 1 X 10(9)/l and susceptibility to infection was considered to reflect, at least partially, qualitative neutrophil abnormalities. There was no correlation between absolute neutrophil count and defective function. Abnormal overall neutrophil microbicidal activity was equally associated with impaired and normal phagocytosis. Some patients with intracellular killing defects had reduced myeloperoxidase (MPO) activities and one had reduced hexose monophosphate shunt (HMPS) activity. In two patients, whose neutrophils showed markedly impaired candidacidal activity, levamisole corrected function when added in vitro at 10(-7) M and also when administered in therapeutic dosage. It is suggested that deranged function, probably reflecting abnormalities in maturation of the granulocyte series, occurs across the myelodysplastic spectrum and that several microbicidal mechanisms may be defective.

Partial myeloperoxidase deficiency in preleukemia

In seven subjects with partial and apparently acquired form of myeloperoxidase (MPO) deficiency, some functional properties of neutrophils (PMNs) were studied. Five patients suffered from preleukemia, one from diabetes mellitus and one from carcinoma of the breast with bone marrow metastases. Intracellular bactericidal activity, oxygen consumption and superoxide radical production were within normal limits. In three patients with preleukemia, the serum opsonic activity was markedly reduced (less than m-3SD) in an autologous system, but normal in the presence of pooled normal serum. Decreased opsonic activity was also found when these patient's sera were assayed in the presence of normal PMNs. Since the levels of IgG and C3 were comparable in the patients' sera and the pooled serum, a deficiency of another unknown opsonin or the presence of an opsonization inhibitor has to be postulated. The partial MPO defect apparently doesn't decrease the intracellular killing of Staphylococcus aureus by PMNs. The known susceptibility to bacterial infections in preleukemia may be explained by the reduction of serum opsonization conducing to a secondary decrease of the ingestion and killing of bacteria by the PMNs.

A comparison of the cytotoxic potential in polymorphonuclear leukocytes obtained from normal donors and cancer patients

Human polymorphonuclear leukocytes (PMNs) obtained from both normal donors and cancer patients kill human tumor cells in vitro. Furthermore, the PMNs were shown to exert a greater cytotoxic effect on malignant targets than they did on nonmalignant targets. In addition, colon and breast cancer patients with stage I disease were found to possess PMN cells which were less effective in killing the tumor cells than were the PMN cells from normal donors. In contrast, the colon and breast cancer patients with stage IV disease possessed PMN cells which were more effective than normal cells in killing the tumor targets. No clear cut trend was found for PMN cells obtained from breast and colon cancer patients diagnosed with stage II and III disease. However, it must also be noted that individual patients did not always conform to the group pattern.

A new neutrophil candida killing test: chromium-51 release from Candida guilliermondii

Neutrophil candidacidal function was measured by a chromium-51 (51Cr) release technique, using Candida guilliermondii as the test organism. The effect of varying the neutrophil:candida ratio, the time course of 51Cr release, the effect of different serum concentrations, and the reproducibility of the technique were investigated. Results from 33 experiments, using neutrophils from 35 normal donors and six patients with known neutrophil defects, show the technique to be a reliable and reproducible assay of candida killing. The chromium release assay has the advantage of being easy to perform and not liable to subjective errors.