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Biomedical subjects

C P Engelfriet

Publications and source records attributed to C P Engelfriet.

At least 127 records · Page 7Linked to original sources
PubMed1979

B-cell alloantigens in two recombinant families: prediction of a B/D recombination using B-cell-specific alloantisera.

During the VIIth Histocompatibility Workshop, 44 sera were selected that defined B-cell alloantigens showing correlation with the HLA--D antigenic determinants. The segregation of these antigens, now called DRw (HLA--D-related), was studied in a family that contained one HLA--A/B recombinant and one HLA--B/D recombinant sibling. It could be established that the DRw-1 antigenic determinants segregated with the B-D region in the A/B recombinant sibling and that the DRw-2 antigen segregated with the D region of the B/D recombinant child. In the second family, DRw typing segregated with the D region of the B/D recombinant child. In the second family, DRw typing showed that one of the children was identical with an HLA--ABC non-identical sibling. This suggested that a crossing-over had occurred. This was confirmed by mutual non-stimulation of these HLA--ABC non-identical children in the mixed lymphocyte culture. This crossing-over involved the DRw-3 alloantigen. These data confirm the assumption that serologically defined B-cell alloantigens are coded for by genes located outside the HLA--A/B region on the B-D side of chromosome. Moreover, these data suggest that, within families, serological B-cell genotype identity can predict a mutual unresponsiveness in the lymphocyte culture. However, findings in these two families indicate that discrepancies nevertheless exist between B-cell serology and mixed lymphocyte reactions and that mutual stimulation can occur despite apparent identity of serological B-cell phenotype and that B-cell phenotype identity does not necessarily predict mutual unresponsiveness in the mixed lymphocyte culture.

Adolescent↗
PubMed1979

A family with allo-immune neonatal neutropenia: group-specific pathogenicity of maternal antibodies.

A family is presented, in which the mother developed strong neutrophil granulocyte-specific antibodies with the specificity anti-NA. The first and third children, both NA1-positive, suffered from severe transient neonatal neutropenia, but the second child, NA1-negative, did not. Anti-NA1 antibodies were detectable in the serum of one affected child and the antibody level was directly related to the extent of neutropenia. The incidence of granulocyte-specific antibodies in 198 pregnant women was determined and found to be low.

Agranulocytosis↗
PubMed1979

Recognition of a non-HLA-ABC antigen present on B and T lymphocytes and monocytes only detectable with the indirect immunofluorescence test.

The serum of a 39-year-old male under long-term platelet transfusion therapy for hypoplastic anemia with thrombocytopenia was investigated for the presence of leukocyte and platelet antibodies after the patients had received platelet concentrates from more than 700 random donors. The serological studies of his serum revealed: (1) the absence of platelet-reactive antibodies; (2) the absence of agglutinating or cytotoxic antibodies against leukocytes; (3) the presence of at least two granulocyte-specific antibodies, one with the specificity anti-NA2 and the other with an undefined specificity, both only detectable by indirect immunofluorescence, and (4) the presence of cytotoxic-negative fluorescence-positive peripheral-blood-mononuclear-cell-reactive antibodies, not directed against HLA-A, B or C antigens. The significance and implications of these findings are briefly discussed.

Absorption↗
PubMed1978

The role of adherence to human mononuclear phagocytes in the destruction of red cells sensitized with non-complement binding IgG antibodies.

In patients with IgG incomplete non-complement binding warm autoantibodies, the subclass composition of the antibodies was studied in relation to the occurrence of increased haemolysis in vivo and the adherence of the patients red cells to peripheral blood monocytes (PBM) in vitro. The presence of IgG3 autoantibodies was almost always accompanied by haemolytic anaemia, but the presence of IgG1 autoantibodies only in some patients but not in others. IgG2 and IgG4 autoantibodies were not associated with increased red cell destruction. A relation identical to that between subclass composition and increased haemolysis was found between subclass composition and adherence of the patients erythrocytes to PBM and thus a strong correlation between positive adherence in vitro and increased red cell destruction in vivo. These results support an important role of adherence to mononuclear phagocytic cells in the destruction of red cells sensitized with non-complement binding IgG antibodies. Strong indications were found that IgG1 autoantibodies are of two kinds, only one of which causes adherence to phagocytes and thus increased red cell destruction.

Anemia, Hemolytic↗
PubMed1978

A simple immunofluorescence test for the detection of platelet antibodies.

Immunofluorescence tests on platelets have always been hampered by nonspecific fluorescence caused by non-immunological binding of plasma proteins to the platelet membrane. It was found that this could be easily overcome by fixation of the cells with paraformaldehyde (PFA). By using PFA-fixed platelets, a simple method for the detection of platelet antibodies, the platelet suspension immunofluorescence test (PSIFT) was developed. PFA fixation did not alter or inactivate the platelet antigens tested. Platelet-reactive antibodies detected specifically with the PSIFT included platelet-specific agglutinins of the IgM class, non-agglutinating platelet-specific antibodies of the IgG class, drug-dependent platelet antibodies, HLA antibodies, as well as anti-A and anti-B antibodies. The sensitivity of the new test was satisfactory, as was its reproducibility. Measurement of platelet immunofluorescence was possible in a continuous flow microfluorometer, making a principle, quantitation of platelet antibodies and antigens possible.

Antibodies↗
PubMed1978

Autoimmune granulocytopenia: the detection of granulocyte autoantibodies with the immunofluorescence test.

Neutropenia may be caused by neutrophil autoantibodies. The detection of such antibodies has always been difficult. Recently, we developed a sensitive indirect immunofluorescence technique applicable to granulocytes which proved to be of value in the detection of granulocyte alloantibodies. We have now used this method to investigate the serum and cells of 29 patients with idiopathic or secondary neutropenia. In four patients neutrophil-antigen-specific autoantibodies were detected in the serum and the patient's own granulocytes showed direct fluorescence. Furthermore, differences in the immunoglobulin composition and the temperature of optimal activity of the autoantibodies were found. Direct fluorescence was also demonstrated with the granulocytes from five other neutropenic patients and with the granulocytes from five non-neutropenic patients mainly with infectious disease. However, no granulocyte antibodies could be eluted or shown to be present in the serum. This indicates that a positive direct granulocyte fluorescence test may not be considered as proof that autoantibodies are present.

Adult↗
PubMed1978

Destruction of IgG-sensitized erythrocytes by human blood monocytes: modulation of inhibition by IgG.

The in vitro interaction between monocytes and erythrocytes sensitized with non-complement binding IgG antibodies (i.e. the Rh antibody anti-D:EAIgG anti-D) is completely inhibited by low concentrations of IgG (E.G. 30--100 microgram/ml). However, the interaction between monocytes and erythrocytes sensitized with IgG anti-A (EAIgG anti-A) is not inhibited by IgG. The findings presented in this paper indicate that this difference is probably due to the difference in the number of IgG antibody molecules per EAIgG. Thus, the higher the number of IgG antibody molecules per EAIgG, the less the interaction between EAIgG and monocytes is inhibited by IgG. A second factor which proved to have a strong influence on inhibition by IgG was the number of EAIgG per monocyte. When the number of EAIgG per monocyte was increased from 1 to 32, the percentage of inhibition by a fixed amount of IgG (50 microgram/ml) decreased significantly. This in vitro effect is only evident when relatively weakly sensitized erythrocytes are used and, in vivo, destruction of these weakly sensitized red cells (e.g. EAIgG anti-D) is confined to the spleen. Since a considerable haemoconcentration occurs in this organ, it is conceivable that a high EAIgG:macrophage ratio is accomplished. The latter data are an indication that this high ratio may allow interaction between weakly sensitized erythrocytes and splenic macrophages despite the presence, in vivo, of a high concentration of IgG, and that, in this way, in the spleen, the inhibitory effect of IgG is overcome.

Cell Adhesion↗
PubMed1978

Monocyte-induced increase in osmotic fragility of human red cells sensitized with anti-D alloantibodies.

The mechanism by which human monocytes increase the osmotic fragility of red cells sensitized with Rhesus alloantibodies anti-D was studied in vitro. Both the increase in osmotic fragility and the lysis of red cells by monocytes were enhanced by cytochalasin B and were inhibited by hydrocortisone. These effects were similar to the effects of these agents on lysosomal enzyme release by monocytes. However, hydrocortisone was completely ineffective when added 1 h after mixing monocytes and sensitized red cells. This indicates that the damage responsible for the fragility increase and lysis is completed within 1 h and suggests that it is due to lysosomal enzymes released by the monocytes. Since for the full expression of the osmotic fragility increase and lysis an incubation time much longer than 1 h is required, it appears that the latter phenomena are the non-specific sequelae of damage inflicted upon the red cell by released lysosomal enzymes.

Cytochalasin B↗
PubMed1978

Destruction of sensitized erythrocytes by human monocytes in vitro: effects of cytochalasin B, hydrocortisone and colchicine.

The purpose of this study was to characterize the destruction of sensitized erythrocytes by human blood monocytes in vitro. The incubation in vitro of human monocytes with 51Cr-labelled human erythrocytes sensitized with IgG rhesus alloantibodies anti-D (EAIgG anti-D) resulted in release of 51Cr from the erythrocytes (lysis) as well as uptake of 51Cr-labelled erythrocytes by the monocytes (phagocytosis). The lysis of EAIgG anti-D by monocytes was not dependent on phagocytosis, because cytochalasin B, which inhibited phagocytosis of EAIgG, enhanced lysis. In contrast, hydrocortisone and colchicine inhibited lysis, but had no effect on phagocytosis. These agents did not affect binding of EAIgG anti-D to monocytes. The effect of these agents on lysis corresponded to their effect on release of lysosomal enzymes by monocytes. The release of lysosomal enzymes, when induced by EAIgG anti-D, was, likewise, enhanced by cytochalasin B and inhibited by hydrocortisone and colchicine. A significant correlation was found between lysosomal enzyme release and lysis. Together, these results strongly suggest that lysosomal enzymes, released by the monocytes when incubated with anti-D-sensitized erythrocytes, are responsible for the cytotoxic activity of these cells towards sensitized erythrocytes. The action of these enzymes only occurs over a short range, probably at the site of attachment of the erythrocyte, because only erythrocytes that were bound to the monocytes were lysed. The finding of other investigators that removal of monocytes from suspensions of human mononuclear leucocytes results in a strong reduction in the cytotoxic activity of these leucocytes towards sensitized erythrocytes in vitro. was confirmed.

Colchicine↗
PubMed1978

Subdivisions of the HLA-B5 and Bw35 complex.

Population studies in 579 individuals, previously phenotyped to be B5 or Bw35, were carried out with 23 HLA antisera defining the B5-Bw35 complex. The inheritance of five subdivisions in this complex, B5.1, B5.2, B5.y, Bw35 and BHR were tested in 23 families. Differing frequencies of these specificities were observed in American Indians, Blacks, Caucasians, Chinese, Filipinos, Japanese and Mexican Americans.

Epitopes↗
PubMed1978

Serological, immunochemical and immuoncytological properties of granulocyte antibodies.

The immunochemical characteristics of granulocyte allo- and autoantibodies can easily be studied with indirect immunofluorescence techniques. The correlation of these properties with the serological behavior of the antibodies and the clinical condition in which they were found was studied. The investigations included the determination of immunoglobulin class, subclass, light-chain composition, as well as optimal temperature of activity. Complement fixation in vitro was also investigated. Striking differences were found between IgG and IgM antibodies in their serological properties, especially in the granulocytotoxicity and leukoagglutination tests at different temperatures. Differences in light-chain and IgG subclass compositions of the antibodies did not seem to play a role. In studying the distribution of granulocyte-specific antigens on normal granulocytes and granulocytes in all stages of development, it was found that, while NA1, NA2 and ND1 are present in the same quantity on the cells of an individual, the NB1 antigen is unequally distributed, both over ripe granulocytes and granulocyte precursors.

Agglutination Tests↗
PubMed1977

Mechanisms of red cell destruction mediated by non-complement binding IgG antibodies: the essential role in vivo of the Fc part of IgG.

F(ab')2G anti-D was prepared by limited digestion of IgG anti-D with pepsin. Conditions of digestion were chosen in order to obtain a nearly complete conversion of the anti-D antibody molecules as tested by immunochemical and serological techniques. The F(ab')2G anti-D was not capable of inducing adherence of rhesus D positive red cells to monocytes in vitro or of eliminating such cells in vivo in normal volunteers. These findings are compatible with a role of the Fc-receptor-mediated adherence to cells of the macrophage system in vivo in the destruction of erythrocytes by non-complement binding IgG antibodies.

Cell Survival↗
PubMed1977

The detection of granulocyte alloantibodies with an indirect immunofluorescence test.

An indirect immunofluorescence technique for the detection of alloantibodies against granulocytes was developed. A major problem was the unspecific fluorescence of granulocytes, due to unspecific adherence of immunoglobulins to the cell membrane. This could be suppressed by the prefixation of the granulocytes with paraformaldehyde. The developed test proved to be specific and sensitive and to have a high reproducibility. Strongly positive reactions were obtained with antisera containing granulocyte-specific agglutinins or granulocyte-cytotoxins, but also with some sera that did not react in either the agglutination or the cytotoxicity test. HLA antisera also gave positive reactions, but strong anti-A, anti-B or anti-D sera did not react. With this technique leucocyte antibodies can be detected in a higher percentage of patients with febrile transfusion reactions.

Cytotoxicity Tests, Immunologic↗
PubMed1977

A comparative study of the production of antibodies against human blood cells in animals of various species.

In view of the importance of the species of animals used for the preparation of specific heteroantisera against human blood cells, comparative immunization experiments were carried out in goats, rabbit, chickens, guinea pigs, and rats, using lysates of leukocytes, granulocytes, lymphocytes, monocytes, and thrombocytes. The antisera obtained were tested by the indirect immunofluorescence technique. The strongest antisera were obtained in goats, but these antisera required extensive absorptions to make them specific for the immunizing cell, whereas rabbit antisera needed only few absorptions. Antisera from both of these animals could be rendered specific for lymphocytes, granulocytes and platelets. In the guinea pig only immunization with monocytes and granulocytes resulted in useful antisera, which were all specific for granulocytes after appropriate absorptions. Antisera obtained from rats could be rendered specific for granulocytes and lymphocytes by absorption. Antibodies against platelets could not be detected in any of the rat antisera. Chickens, however, produced strong anti-platelet antibodies. A specific anti-granulocyte antiserum could also be obtained in these animals. Specific anti-monocyte antisera could not be prepared from any of the animal sera. Immunizations with leukocyte lysate resulted in granulocyte-specific antisera in most animals but not in chickens. All antisera produced in chickens were specific for platelets. It can be concluded from these results that animals of different species may react very differenly to the antigens of some human blood cells.

Animals↗