Neutrophil research relies largely on studies with highly purified cells. Yet the isolation procedures induce changes in surface expression of several proteins. We used a large panel of monoclonal antibodies (MoAbs) to characterize in detail the phenotypic changes during isolation and stimulation of human neutrophils. Centrifugation on density gradients appears to be the crucial step that causes an increase in expression of antigens not detectable on neutrophils in whole blood samples (cytochrome b558 recognized by MoAb 7D5; and CD10) or expressed at significantly lower levels (CD11a, CD11b, CD11c, CD13, CD16, CD45, and CD67). Other antigens were unaffected by the density gradient centrifugation step (CD32, CD54, CD58, Leu-8, HLA class I). Upregulation of antigens was also determined by stimulation of purified neutrophils. Upregulation of CD63 was an excellent marker for release from azurophil granules. We subsequently related the surface antigen expression to functional activities of purified neutrophils. From these experiments, we concluded that 7D5-as “early activation” marker--does not necessarily discriminate between primed or resting neutrophils with respect to NADPH oxidase activity.

Background Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is a potentially devastating disease, which may lead to intracranial haemorrhage (ICH), with neurological damage as a consequence. In the absence of screening, FNAIT is only diagnosed after bleeding symptoms, with preventive options limited to a next pregnancy.Objectives To estimate the population incidence of FNAIT and its consequences to prepare for study design of a screening programme.Search strategy An electronic literature search using MEDLINE, EMBASE and Cochrane database, and references of retrieved articles. No language restrictions were applied.Selection criteria Prospective studies on screening for human platelet antigen 1a (HPA-1a) alloimmunisation in low-risk pregnant women.Data collection and analysis Two reviewers independently assessed studies for inclusion and extracted data. Main outcome data were prevalence of HPA-1a negativity, HPA-1a immunisation, platelet count at birth and perinatal ICH. We aimed to compare outcome with and without intervention.Main results HPA-1a alloimmunisation occurred in 294/3028 (9.7%) pregnancies at risk. Severe FNAIT occurred in 71/227 (31%) immunised pregnancies, with perinatal ICH in 7/71 (10%). True natural history data were not found because interventions were performed in most screen-positive women.Authors' conclusions Screening for HPA-1a alloimmunisation detects about two cases in 1000 pregnancies. The calculated risk for perinatal ICH of 10% in pregnancies with severe FNAIT is an underestimation because studies without interventions were lacking. Screening of all pregnancies together with effective antenatal treatment such as intravenous immunoglobulin may reduce the mortality and morbidity associated with FNAIT.

Paroxysmal nocturnal hemoglobinuria (PNH) is a disease that affects not only red cells, but other blood cells as well. The common defect is supposed to be an acquired deficiency of glycosyl-phosphatidylinositol (GPI)-anchored membrane proteins, which may be present already at the hematopoietic stem cell level. Recently, a panel of monoclonal antibodies (MoAbs) has become available directed against various GPI- linked membrane proteins. This makes it possible to study various cell lineages for the deficiency of such proteins in PNH in more detail. Using cytofluorography, we could show that the granulocytes of 20 different PNH patients miss not only GPI-linked FcRIII (CD16 antigen), but also three other GPI-linked proteins, ie, CD24 antigen, CD67 antigen and a granulocyte-specific 50 to 80 Kd antigen. The affected granulocytes were not only neutrophils but also eosinophils, as was found in a more detailed analysis of three patients. Moreover, in all 10 PNH patients tested, the monocytes were found to be deficient for the GPI-linked CD14 antigen, and we found with CD24 and CD55 (DAF) antibodies that lymphocytes may be involved as well. However, abnormal B and T lymphocytes were detected only in a subset of patients (2 of 10 tested). The uniform deficiency of GPI-linked proteins of granulocytes allows the introduction of a new diagnostic cytofluorometric assay for PNH with MoAbs against GPI-linked granulocytic antigens. This test was positive in all PNH patients studied and not in a group of 40 control patients or 50 normal donors, with the exception of three of 16 aplastic anemia (AA) patients. In the three AA patients, subpopulations (10% to 20%) of PNH granulocytes could be detected, whereas these patients had a negative acidified serum (Ham) test. This indicates that the new test is more sensitive than the Ham test and allows the early diagnosis of PNH in AA. An advantage of the neutrophil assay is that, in contrast to the Ham test, it is not influenced by recent red-cell transfusions. Moreover, it is possible to quantify the number of affected cells by single cell analysis.

Paroxysmal nocturnal hemoglobinuria (PNH) is a disease that affects not only red cells, but other blood cells as well. The common defect is supposed to be an acquired deficiency of glycosyl-phosphatidylinositol (GPI)-anchored membrane proteins, which may be present already at the hematopoietic stem cell level. Recently, a panel of monoclonal antibodies (MoAbs) has become available directed against various GPI- linked membrane proteins. This makes it possible to study various cell lineages for the deficiency of such proteins in PNH in more detail. Using cytofluorography, we could show that the granulocytes of 20 different PNH patients miss not only GPI-linked FcRIII (CD16 antigen), but also three other GPI-linked proteins, ie, CD24 antigen, CD67 antigen and a granulocyte-specific 50 to 80 Kd antigen. The affected granulocytes were not only neutrophils but also eosinophils, as was found in a more detailed analysis of three patients. Moreover, in all 10 PNH patients tested, the monocytes were found to be deficient for the GPI-linked CD14 antigen, and we found with CD24 and CD55 (DAF) antibodies that lymphocytes may be involved as well. However, abnormal B and T lymphocytes were detected only in a subset of patients (2 of 10 tested). The uniform deficiency of GPI-linked proteins of granulocytes allows the introduction of a new diagnostic cytofluorometric assay for PNH with MoAbs against GPI-linked granulocytic antigens. This test was positive in all PNH patients studied and not in a group of 40 control patients or 50 normal donors, with the exception of three of 16 aplastic anemia (AA) patients. In the three AA patients, subpopulations (10% to 20%) of PNH granulocytes could be detected, whereas these patients had a negative acidified serum (Ham) test. This indicates that the new test is more sensitive than the Ham test and allows the early diagnosis of PNH in AA. An advantage of the neutrophil assay is that, in contrast to the Ham test, it is not influenced by recent red-cell transfusions. Moreover, it is possible to quantify the number of affected cells by single cell analysis.