WinRho: Rh immune globulin prepared by ion exchange for intravenous use.

An Rh immune globulin [Rh IgG] for intravenous use, WinRho, has been prepared by the Winnipeg Rh Institute by a modification of the ion-exchange column method of Hoppe and colleagues. When administered to Rh-negative male and nonpregnant female volunteers WinRho was found to be nonpyrogenic, nontoxic, safe and protective against Rh alloimmunization. In a clinical trial with 240 microgram given at about 28 weeks'' gestation and 120 microgram given after delivery to Rh-negative women at risk of Rh immunization WinRho was effective in preventing Rh immunization. Of the 870 women carrying Rh-positive fetuses who were treated with WinRho during pregnancy and were not tested several months after delivery 14 would have shown evidence of Rh immunization by the time of delivery if WinRho had been ineffective; none showed such evidence. Of the 1122 women carrying Rh-positive fetuses who were retested 4 to 6 months after delivery 83 would have shown evidence of Rh immunization at that time if WinRho had been ineffective; only 1 showed such evidence. The efficiency of yield of anti-D with the modified method of production, the fct that it can be given intravenously (a route that causes the patient less discomfort and immediately results in high anti-D levels) and the lower levels of contaminating IgA and IgM make WinRho the preparation of choice for preventing Rh immunization.     

Anti-erythrocyte immunization in the pregnant woman. Apropos of the analysis of 761 cases of alloimmunized women delivered in the Paris area in 1978 and 1979

Through analysis of 760 cases of allo-immunized women delivered in the Paris area during 1978 and 1979, anti-erythrocyte immunization (ABO excluded) still appears to be a consequent perinatal risk, for the mother as for her fetus. During the considered period, general incidence in the parisian population has been of 3,78 for 1 000 livebirths, one out of four cases being a "non Rh D"immunization. Obviously, anti-D immunoglobulin prophylaxis has not proved to be as efficient as it promised to be, after more than ten years of application. Taking into account cases affecting "non ordinary" residents in the observed area, incidence of anti-D immunizations was of two out of a thousand. Anti-D immunoglobulin actual efficiency cannot be incriminated, for when correctly applied Rhesus immunization prophylaxis has demonstrated its ability to induce a twenty-fold reduction of immunization risk due to pregnancy. It must be pointed out, unfortunately, that most cases of undue immunizations are related to prophylatic omissions after delivery, miscarriage, abortion or fortuitous hetero-Rhesus blood transfusion. On another hand an important increase of "non Rh D" immunizations, which incidence, if one images that unknown cases are as frequent as known cases, could be two out of a thousand deliveries, is perhaps able to neutralize partially the decrease of Rh D immunizations. Though is underlined the absolute necessity to extend systematically anti-erythrocyte antibody screenings to all pregnant women, whatever the blood group is. A great variety of antibodies specificities can be found among "on Rh D" immunizations but anti-Kell and anti-c are by far the most frequently met. In most cases theses immunizations could easily be avoided, assessing that all female subjects aged less than 50 years are only given Kell negative and, if lacking c antigen, CC phenotyped blood.     

An immuno-haematological study among pregnant women of Patiala (India).

The present study has been conducted on 500 pregnant women belonging to Patiala city (Punjab State, India), during various stages of pregnancy, who were investigated for evidence of immunization. Incidence of immunization was found to be 1.20% in total sample and 25.00% in Rh (D) negative pregnant women. All the immunized cases were multiparae. Immunized cases were more in second trimester. Obstetrical histories of immunized cases suggest that five of them were probably immunized due to repeated pregnancies and one case was probably due to previous still births. A greater fertility was observed in the immunized group as compared to other groups. No case of immunization had previous history of blood transfusion. Rh-immunization was also studied in relation to AB0-incompatibility.     

Prevention of Rh Hemolytic Disease of the Newborn

Rh_o(D)-Immune Globulin was given to 322 Rh-negative women delivered of ABO-compatible, Rh-positive infants with no apparent failures to suppress Rh sensitization. In contrast, 32 of 305 mothers of a control group made Rh antibody during the six months following delivery. In subsequent pregnancies, 69 women administered RhoGAM had no evidence of isoimmunization after delivery while six of forty mothers of the control study produced anti-Rh. RhoGAM, given within 72 hours of delivery in the amounts employed, was effective for suppression of Rh immunization.     

Serological and molecular analysis of ABO and Rh blood group chimeras

The serological examination, blood transfusion strategies and the molecular analysis to blood group chimera were conducted to demonstrate existent of chimera in blood group. The blood grouping of ABO or/and RhD, newborn red blood cells separated by capillary centrifugation. Aabsorption tests and DTT treated agglutination erythrocyte tests were implemented in four patients. Further molecular biological research was conducted on one patient''s sample. The results showed that for patient 1: ABO blood group was AB/B chimera, Rh blood cells contained the RhCE chimera gene; Patient 2: Rh blood cells contained the RhD chimera gene; Patient 3: ABO blood group was AB/B chimera, Rh blood cells contained the RhD chimera gene; Patient 4: ABO blood group was O/B chimera, Rh blood cells contained the RhCE chimera gene. The study suggests that the individuals categorized as chimeras are likely to be more common than existing literature reports. According to the serological tests, in the absence of a history of recent blood transfusion or disease to cause reduced antigen, the phenomena of hybrid aggregation of the ABO and Rh blood system were the main feature. In terms of transfusion strategy, the selection of ABO and Rh blood groups should be depended on the group of cells with more antigens.     

The Prevalence of unexpected antibodies in Saudi's plasma prior blood transfusion and their association with clinical conditions: A cross-sectional study

Unexpected antibodies, also called irregular antibodies, are not known to exist in a person's serum before testing. This research aims to assess the prevalence of unexpected antibodies and their correlation with several clinical conditions. This cross-sectional prospective study, undertaken from June 2019 to June 2020, included ABO, Rh grouping, cross-matching, and antibody screening. Antibody identification was performed only on patients who tested positive in the screening test. From a total of 9764 participants who were screened for unexpected antibodies, 107 (1.1%) tested positive. The Rh blood group system antibodies were the most frequent, particularly anti-D. There was also a significant correlation between the unexpected antibodies and history of transfusion, pregnancy, and autoimmune diseases as P ≤ 0.05. The most prominent unexpected antibodies in the study belong to the Rh system (Anti-D). Moreover, as a result of the strong correlation between the unexpected antibodies as well as the history of transfusion, pregnancy, and autoimmune diseases, the highest safety criteria must be followed during the transfusion of blood to patients with these clinical conditions.     

Incidence of Maternal Rh Immunization by ABO Compatible and Incompatible Pregnancies

The incidence of maternal Rh immunization in Rh-negative women following a single ABO compatible Rh-positive pregnancy is about 17%. This incidence was determined by following Rh-negative women through two Rh-incompatible pregnancies and analysing their sera for anti-Rh at the time of delivery of their second observed pregnancy. Maternal Rh immunization occurs almost exclusively after delivery; however, antibodies may not be detectable in the absence of further antigenic stimulation.The incidence of maternal Rh immunization when maternal-foetal ABO incompatibility is also present is 9–13% and 17% for group O and non-group O women respectively. This study emphasizes the need to offer Rh-immune prophylaxis to Rh-negative women having Rh-positive infants whether or not ABO incompatibility exists between the mother and infant.     

Rh immunization in Manitoba: progress in prevention and management.

For two decades the perinatal mortality caused by erythroblastosis has been decreasing in Manitoba. The improved management of Rh-immunized pregnancies has lowered the death rate among affected infants from 10.8% to 3.4%, while the prevention of Rh immunization has reduced its incidence from 9.1 to 2.2 per 1000 total births. In its first 6 years and 8 months Manitoba''s antenatal prophylaxis program, in which immunoglobulin is administered to Rh-negative women at 28 weeks'' gestation, reduced the incidence of Rh immunization during pregnancy by 93%. In combination with post-abortion and postpartum prophylaxis the antenatal treatment has provided a protection rate of 98.6% among primigravidas at risk. Further improvements are expected.     

BLOOD TRANSFUSIONS AND THE Rh FACTOR

When Rh-negative persons are given transfusions of Rh-positive blood, more than 50 per cent are sensitized to the Rh₀ factor. Such sensitization of female children may be the cause of hemolytic disease in their offspring many years later, while severe hemolytic reactions may follow a second transfusion of Rh-positive blood in either sex.The gross hemolysis of transfused blood may be entirely asymptomatic, however. In one case a pint of blood was completely hemolyzed within two hours without producing symptoms. The only signs were hemoglobinuria, low grade jaundice, urobilinogenuria and a rising Rh antibody titer. The patient had previously been sensitized by a single pint of Rh-positive blood.The dangers of Rh sensitization can be avoided by routine Rh typing of all prospective recipients of transfusion, whether male or female, and by giving only Rh-negative blood to those who are Rh-negative.     

Consequences of fetomaternal haemorrhage after intrauterine transfusion.

Fetomaternal haemorrhage was studied after 68 consecutive fetal intravascular transfusions performed in 20 patients with Rh isoimmunisation. alpha Fetoprotein concentration was assayed in maternal blood taken before, and immediately after each transfusion and three and 24 hours later. An increase of 50% or more in the concentration in any of the samples after transfusion was considered to indicate fetomaternal haemorrhage. Fetal alpha fetoprotein concentration in blood sampled before transfusion was also assayed and the amount of fetomaternal haemorrhage calculated. Fetomaternal haemorrhage occurred in 21 of 32 patients with an anterior placenta and in six of 36 with a posterior or fundal placenta. The mean estimated volume of haemorrhage was 2.4 ml, which was on average equal to 3.1% of the total fetoplacental blood volume. When the volume of fetomaternal haemorrhage at the first transfusion was greater than 1 ml there was a greater increase in maternal Rh (D) antibody titres and a greater fall in fetal packed cell volume. Sampling of fetal blood should not be routinely done early in patients with Rh isoimmunisation, and intrauterine transfusion should be delayed as long as possible. Sampling sites other than the placental cord insertion reduces the risk of fetomaternal haemorrhage.     

Hemolytic transfusion accident due to the blood group antibody anti-Jka]

A haemolytic transfusion incident caused by anti-Jka is reported about. In a 56 year old patient suffering from chronic iron deficiency anaemia an immunization in the Kidd system has taken place within 9 days. In the course of this immunization the fourth incompatible blood transfusion caused a severe transfusion incident. The necessity of serological compatibility testing by the indirect antiglobulin or enzyme test and the significance of making a strict indication for blood transfusions are referred to.     

Molecular biology of Rh proteins and relevance to molecular medicine

The Rhesus (Rh) blood group system is expressed by a pair of 12-transmembrane-domain-containing proteins, the RhCcEe and RhD proteins. RhCcEe and RhD associate as a Rh core complex that comprises one RhD/CcEe protein and most likely two Rh-associated glycoproteins (RhAG) as a trimer. All these Rh proteins are homologous and share this homology with two human non-erythroid proteins, RhBG and RhCG. All Rh protein superfamily members share homology and function in a similar manner to the Mep/Amt ammonium transporters, which are highly conserved in bacteria, plants and invertebrates. Significant advances have been made in our understanding of the structure and function of Rh proteins, as well as in the clinical management of Rh haemolytic disease. This review summarises our current knowledge concerning the molecular biology of Rh proteins and their role in transfusion and pregnancy incompatibility.     

Functional and structural changes in the surface of human erythrocytes after irradiation with UV rays of various wave lengths. I. The expression of ABO and rhesus system antigens

UV irradiation (254 nm) in doses increasing erythrocyte haemolysis by 5, 10, 18 and 28 per cent was found to stimulate, by 2--16 times, the agglutination activity of ABO and Rh system antigens. The stimulation effect was the higher the lower the antigen activity before irradiation. In the Rh-negative (Rh-) erythrocytes, irradiation induced manifestation of the Rh0(D)-antigen specific activity suggesting that this antigen may be present in the Rh- erythrocyte membrane. The expression of Rh0(D)-antigen in Rh- erythrocytes, the stimulation of its activity in Rh-positive cells, and the activation of ABO system antigens may result from a photochemical destruction of the outer perimembraneous layer and release some of its components which stain in situ with alcian blue to be presumably glycoproteins. This effect is necessary to keep in mind when UV-irradiated blood transfusion is performed in therapeutic aims Rh- patients.     

Immunopurification of the blood group RhD protein from human erythrocyte membranes

Rh proteins are membrane proteins encoded by genes at the blood group RH locus. They are of paramount importance in transfusion medicine, but their function is still unknown. Biochemical and biophysical studies of these proteins are scarce since only minute amounts of the very hydrophobic Rh proteins, can be purified from human erythrocytes. Recently, a human monoclonal antibody (LOR-15C9) was described as having the unique property to recognize the Rh30 protein carrying the major blood group D specificity (RhD protein), either in a membrane detergent extract or when blotted on a membrane. In this report, we describe one-step purification of the RhD protein from detergent extracts of red cell membranes, based on immunoaffinity chromatography carried out with immobilized LOR-15C9 IgG. The technique yielded RhD protein with high purity which was devoid of other associated proteins (RhAG, CD47, LW and GPB) that comprise the Rh complex in the erythrocyte membrane. By contrast immunoprecipitation performed with the same antibody led to co-isolation of both RhD and RhAG.     

The RHD variants in Chinese population

The Rhesus (Rh) blood group system is the most important blood group system in hemolytic disease of the fetus and newborn (HDFN). In clinical transfusions, the D antigen in the Rh blood group system comes third, behind antigens A and B which from ABO blood group system. Over the past decade, molecular technologies have been used to investigate the RHD allele in different ethnic groups. This review first introduces the basic structure of RhD protein and coding genes, then focuses on D-negative, weak D, partial D, DEL, RhD_null variants reported in the Chinese population. To date, more than 460 RHD variants have been reported around the world, but less than 70 RHD variants have been reported in the Chinese population. Further research is needed to identify more RHD polymorphism and establish criteria for blood detection and transfusion guidelines for RHD variants. Only in this way can we better guarantee the safety of blood transfusion and prevent the occurrence of HDFN. With the accumulation of research and clinical data, we should be clearer which RHD variants are to be regarded as RhD negative and which need to be regarded as RhD positive.     

Ten homozygous-D-individuals in one Italian village

A large inbred Italian kindred with 10 members homozygous for the rare Rh gene complex-D-is described. The propositus has immune antibody to a high-incidence Rh antigen: her baby required exchange transfusion. None of the other 9-D-/-D- individuals has made antibody even though 2 were women with children. This kindred supports previous observations of the excess of consanguinity among the parents of -D-homozygotes. 40.9% (instead of the 25% expected) of the offspring of -D-heterozygous parents are -D-homozygotes.     

Characterization of the Mouse Rh Blood Group Gene

The Rh blood group system is of clinical importance in blood transfusion and as the cause of hemolytic disease of the newborn. Other than their role as carriers of Rh antigens, very little is known about the function of the Rh polypeptides. As a first step to generate an animal model system in which to study the structure and function of Rh, and to extend the phylogenetic analysis of RH genes, the Rh homologue from Mus musculus was characterized. Comparison of RH from humans and mice revealed 71 and 58% sequence identity at the nucleotide and amino acid levels, respectively. Mouse Rh mRNA encodes a protein which is 1 amino acid longer (418 aa) than that of human (417 aa). Rh protein was detected in mouse erythrocyte membranes and was comparable in size to human Rh. Mouse erythrocytes do not show serologic reactivity with human Rh antibodies, probably because the greatest divergence between the mouse and the human genes was seen in the predicted extracellular loops, while the transmembrane regions were more conserved. The mouse RH locus consists of only one gene, which is important for future genetic manipulation and which also indicates that the RH gene duplication seen in humans has occurred since the mammalian radiation.     

Clinical Evaluation of Rh0(D) Immune Globulin (Human) in Canada

—During 1966, clinical trials were conducted in three Canadian centres to determine the safety and efficacy of Rh₀(D) immune globulin (human) in preventing isoimmunization by the Rh₀(D) antigen in Rh-negative women delivering ABO-compatible Rh-positive infants.The candidates were randomly divided into control and treated groups; the treated mothers received an intramuscular injection of 300 μg. of anti-Rh₀(D) within 72 hours of delivery. Follow-up antibody screening tests were conducted on the sera of all patients six to nine months post partum.Of the 175 control patients, 11 or 6.2% became actively immunized to the Rh antigen, whereas complete protection against maternal Rh immunization was observed in the 191 treated patients.     

Mechanism of Rh prophylaxis: an experimental study on specificity of immunosuppression.

The mechanism by which Rh immunization is prevented by IgG anti-D was investigated by studying the specificity of immunosuppression. 62 D-negative Kell(K)-negative male volunteers were given two successive stimuli of 1 ml D-positive K-positive red cells. Thirty-one of the volunteers were also given 13-14 mug of IgG anti-K immediately after each stimulus, the others acting as controls. Anti-D developed in 11 of the 31 controls and in one of the 31 volunteers who had received anti-K. This marked suppression of the anti-D response by IgG anti-K was accompanied by the rapid clearance of the injected red cells to the spleen. This shows that the predominant mechanism that must be operating when IgG anti-D prevents Rh immunization is not antigen specific but is one that must involve the whole red cell, probably through destruction within splenic macrophages.     

Effect of ABO Incompatibility on Pregnancy-Induced Rh Isoimmunization

The protective effect of ABO incompatibility between mother and fetus in respect of pregnancy-induced Rh isoimmunization has been recognized for approximately 20 years. Many have tacitly assumed that this protection was absolute and that when an infant was born with Rh hemolytic disease of the newborn, who was also ABO-incompatible with its mother, there must have been a previous ABO-compatible pregnancy in which the mother was initially sensitized. It has also been assumed that pregnancy-induced Rh isoimmunization could not occur if the father was AB and the mother O. Data are presented to show that both of these assumptions are not universally true. In a detailed study of a large number of families with pregnancy-induced Rh iso-immunization, nine families were found in which sensitization occurred and in which ABO incompatibility was present in every pregnancy. In addition, three families are documented in which pregnancy-induced Rh immunization had occurred and in which the father was AB and the mother O.