RhD variants in Caucasians: consequences for checking clinically relevant alleles.

Background: Weak D type carriers cannot be immunized against D except when antigen density is below 400 antigens per RBC, whereas partial D carriers can produce anti-D.

Study Design And Methods: A total of 168 blood samples from Caucasian individuals were studied because of weak D expression and/or anti-D production. Serologic analysis and molecular analysis were performed.

Serological studies of monoclonal RH antibodies with RH1 (D), RH2 (C), RH3 (E) and RH5 (e) variant RBCs.

One hundred and forty five Mabs against RH antigens were tested. In this paper, we chose to detail reactivity of MoAbs directed against variant RBCs of the CNRGS collection for which we studied the molecular background. Because we developed procedures to identify variants of the RhD, RhC, RhE and Rhe antigens, we were especially interested in finding new monoclonal antibodies that could help us to characterize more accurately these variants.

Two new alleles of the RHCE gene in Black individuals: the RHce allele ceMO and the RHcE allele cEMI.

Six unrelated individuals of Afro-Caribbean origin, whose red cells have a marked reduction of the Rhe antigen expression, have been identified. All exhibited the same serological profile with anti-e monoclonal antibodies and lacked expression of the high frequency e-related antigen hrS. Transcripts and genomic analysis showed that these phenotypes resulted from the presence of two new RHCE alleles, ceMO and cEMI.

[Platelet phenotyping and study of alloantibodies using flow cytometry].

In this study, we describe a flow cytometric technic for the detection and characterization of platelet allo antibodies and for platelets grouping in the platelet group PLA. This new technique is a variant of the platelet suspension immuno fluorescence test. It is rapid, simple, sensitive and specific.

[Immunization against the ZWa (PLA1) platelet antigen: group at risk, prevention of complications. Apropos of 132 cases].

The identification of anti-ZWa (-PLA1) alloimmunisation is not very frequent. It can be observed in most perinatal alloimmune thrombocytopenias (PAT) and rare post transfusional purpuras (PTP). On the other hand, the clinical consequences of these immunisations are often dramatic, particularly for the foetuses for which there has been no prevention so far.

[Neonatal alloimmune thrombopenia].

88 families in which 84 cases of neonatal alloimmune thrombocytopenia (NAT) occurred, were studied. In 84 families, the NAT was the consequence of an incompatibility in the PLA system. Furthermore, the phenotype HLA-DR3 increases greatly the risk of immunisation (RR: 76,5).

[Neonatal alloimmune thrombopenia. Clinical and biological study of 84 cases].

Eighty-four patients with neonatal alloimmune thrombocytopenia (NAT) were investigated clinically and by biological laboratory methods. The condition appeared at birth, usually as an isolated thrombocytopenic purpura, but in about 20% of the neonates the haemorrhagic syndrome was associated with signs of infection or with jaundice and hepatosplenomegaly. Considerable variations were observed in the severity of the purpura; in 3 cases the thrombocytopenia was clinically silent.

[Activation of oxidative metabolism of granulocytes and monocytes by IGG-coated platelets from patients with thrombocytopenia].

We have previously shown that monoclonal anti-T cell antibodies bound to their specific targets can trigger the activation of monocyte/macrophage oxidative metabolism through an Fc receptor-mediated interaction. The present study demonstrates that IgG coated platelets from patients with thrombocytopenia-associated diseases can induce a similar respiratory burst activation in polymorphonuclear and mononuclear phagocytes from normal individuals. The intensity of the oxidative reaction as measured by luminol-dependent chemiluminescence is in close correlation with the level of surface-bound IgG molecules as determined by a radioactive anti-immunoglobulin assay.

An immune response gene linked to MHC in man.

With a view to finding a relationship between immune response and MHC in man, 83 D negative mothers with allo-into-D antibodies and 26 PLA1 negative mothers with allo-anti-PLA1 antibodies were investigated as regards their HLA-A, B and DR antigens. We have found that there is a highly significant relation between the DR3 antigen and an immune response to the PLA1 antigen, but none to the D antigen.

[Estimation of platelet-bound IgG by means of a test using radioactive antiglobulin].

A method of evaluation of platelet bound IgG (PA IgG) is described. This method rely upon the fixation of a radio-labelled goat anti-human IgG on platelets. Each new batch of labelling of the antiglobulin is tested with a reference system using a semi-purified anti-D IgG and O R1R1 and O rr erythrocytes.

[Neonatal thrombopenia caused by antiPLA1 and HLA-DR3 antigen alloimmunization].

The HLA typing of mothers alloimmunised against the PLA1 antigen of their thrombocytopenic neonate shows that the A1, B8, DR3 haplotype is involved. The very strong association found with DR3 (20/21) suggests that an immune response gene located in the D region of the major histocompatibility complex might be responsible for the ability to develop an anti PLA1 antibody.

Studies of platelet antibodies in patients with thrombocytopenic purpura by two different techniques.

The direct antiglobulin consumption (DAC) test, used for the detection of platelet autoantibodies, was found to be positive in 86% of a group of 150 patients with thrombocytopenic purpura. The platelet radioactive Coombs' (DRC) test was performed in 30 patients and the correlation between the two tests was statistically significant (r = 0.48, p less than 0.

Posttransfusional immunologic thrombocytopenia. A case report.

A case of posttransfusional immunologic thrombocytopenia is reported in a 75-year-od PlA1-negative woman. This was the second episode of postoperative and posttransfusion thrombocytopenia in the same patient who had had only one pregnancy. Both thrombocytopenic episodes were subclinical and discovered by systematical hematologic study.

[Glanzmann thrombasthenia, PLA1 antigen and anti-Glanzmann antibody].

Six cases of Glanzmann's thrombasthenia were studied using a platelet indirect radioactive Coombs (PIRC). In serum of two among six patients, an antibody was found, which reacted positively with all platelets except those of thrombasthenic patients. Such "anti-public" antibody which shortens the life of transfused platelets is a very serious complication of Glanzmann's thrombasthenia.

Typing and detection of antibodies in the PLA system (platelet). Application to the study of neonatal thrombopenia by feto-maternal PLA allo-immunisation.

A platelet indirect radio-active Coombs test has been described. The technique for purification and labelling the antiglobulin has been precised. This test allows the typing of platelets in the PLA system and the study of sera from mothers of thrombocytopenic child.

Platelet indirect radioactive Coombs test. Its utilization for PLA1 grouping.

A platelet indirect radioactive Coombs test (PIRC) has been described. The technique for purification and labelling the antiglobulin has been precised. This test allowed the typing of platelets in the PLA system by using an absorbed serum from a mother of a thrombocytopenic child.