Monitoring neutrophil engraftment in allogeneic stem cell transplantation by flow cytometric analysis of neutrophil-specific antigens NA1 and NA2.

Neutrophil-specific antigen (NA) expression on neutrophils was analysed in 18 Japanese children before and after allogeneic stem cell transplantation (allo-SCT) with myeloablative regimen. Donor-recipient NA-incompatibility was present in one of eight NA1/NA2 heterozygous patients and eight of 10 NA1/NA1 or NA2/NA2 homozygous patients. After allo-SCTs from NA-incompatible donors, a neutrophil recipient-to-donor conversion was confirmed in all cases. Conversion to donor NA type was complete before the absolute neutrophil count reached 0.1 x 10(9)/l. These observations indicate that flow cytometric analysis of NA antigens is a simple and useful method for monitoring neutrophil engraftment in NA-incompatible allo-SCT.

Significance of human neutrophil antigen-2a (NB1) expression and neutrophil number in pregnancy.

BACKGROUND: Expression of human neutrophil antigen-2a (HNA-2a) is greater in women than in men. The size of the HNA-2a-positive neutrophil population increases with pregnancy. STUDY DESIGN AND METHODS: T he relationship between HNA-2a expression on neutrophils and monocytes, and their relative numbers, was investigated. HNA-2a expression shown as the size of the HNA-2a-positive cell population and the fluorescence intensity on the cells was analyzed using flow cytometry. This investigation was done among 165 pregnant women during pregnancy and postpartum. RESULTS: In normal pregnancy, numbers of neutrophils and monocytes changed in relation to HNA-2a expression. HNA-2a was also expressed intensively on monocytes from some pregnant women in the first and second trimesters. HNA-2a expression and the number of cells markedly decreased postpartum. In threatened premature labor, the number of neutrophils decreased earlier than in normal pregnancy. CONCLUSION: HNA-2a expression may increase soon after fertilization. In this study, the results indicate that the change in the number of neutrophils and monocytes is related to HNA-2a expression.

Efficacy of prophylactic use of trimethoprim-sulfamethoxazole in autoimmune neutropenia in infancy.

PURPOSE: Most children with autoimmune neutropenia (AIN) have a benign clinical course because of the spontaneous resolution of neutropenia. The authors observed the clinical course of AIN in infancy accompanied by the prophylactic use of trimethoprim-sulfamethoxazole (TMP-SMX) during neutropenia. PATIENTS AND METHODS: Eight infants with AIN were followed by serial tests for antineutrophil antibodies and management of infectious complications. RESULTS: The spontaneous disappearance of antineutrophil antibodies that preceded the normalization of the neutrophil count was found in all patients. Until the resolution of neutropenia, TMP-SMX was administered in five patients, resulting in a reduction in the incidence of infection with no adverse effects. CONCLUSIONS: These observations demonstrate the possibility of the safety and usefulness of TMP-SMX treatment in patients with AIN.

Human neutrophil antigen-2a expression on neutrophils from healthy adults in western Japan.

BACKGROUND: Human neutrophil antigen-2a (HNA-2a)-specific MoAb, which is necessary to prepare panel neutrophils and to determine the phenotype of patients' neutrophils, has been produced in many laboratories in Japan. The frequency of the HNA-2a-positive population in western Japan is unknown. STUDY DESIGN AND METHODS: A cell line secreting an HNA-2a-specific MoAb, TAG4, was established. TAG4 was characterized by flow cytometry, and the reactivities of TAG4 and another HNA-2a-specific MoAb, 7D8, were compared in an inhibition assay and two-color flow cytometry. TAG4 was tested against granulocytes from 408 healthy adult volunteers in western Japan. RESULTS: TAG4 reacted with neutrophils, but not with the other blood cells. The reactivity of TAG4 with granulocytes treated with glycosyl-phosphatidylinositol-specific phospholipase C was markedly reduced. The reactivity of TAG4 and 7D8 was similar, but 7D8 did not prevent TAG4 from binding. A total of 406 of 408 donors were TAG4 positive. The mean percentage of HNA-2a expression of females was 70.2 percent, and that of males was 66.8 percent. CONCLUSION: TAG4 and 7D8 seem to bind to different epitopes of HNA-2a. The frequency of the HNA-2a-positive population is 99.5 percent of healthy adults in western Japan. The mean percentage of HNA-2a expression of females was greater than in males.

Significance of the detection of antineutrophil antibodies in children with chronic neutropenia.

We evaluated the clinical characteristics of 41 children with chronic neutropenia based on the quantitative analysis of antineutrophil antibodies in serum by flow cytometry. According to the strength of antineutrophil antibodies, the patients were divided into 3 groups: 12 patients presented negative antibodies, 13 patients showed weak positive antibodies, and 16 patients showed strong positive antibodies. No significant differences were seen in age of diagnosis, severity of neutropenia, and infectious complications associated with neutropenia among the 3 groups. The spontaneous resolution of neutropenia was observed in all patients with negative antibodies and in 22 of 29 patients with positive antibodies. The age of the recovery of neutropenia and the duration until spontaneous resolution of neutropenia were significantly dependent on the antibody strength at the time of diagnosis. These results demonstrate that the quantification of antineutrophil antibodies at the time of diagnosis may be useful in considering the clinical course of chronic neutropenia in childhood.