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.     

Antenatal prophylaxis of Rh isoimmunization: 28-weeks'-gestation service program

Two (0.18%) of 1086 Rh-negative primigravidas or multigravidas treated similarly in all previous pregnancies, who were given a single injection of Rh immune globulin (300 μg) at 28 weeks'' gestation and subsequently were delivered of Rh-positive babies, had demonstrable Rh isoimmunization at the time of that injection and must be considered “logistic” failures of antenatal prophylaxis. The remaining 1084 (who were treated again after delivery) had no evidence of Rh isoimmunization at delivery and none of the 512 screened at 6 months after delivery appeared to be immunized. If the 28th-week injection had not been protective, one would have expected 14 of the 1084 to have been demonstrably Rh isoimmunized and evidence of Rh isoimmunization to have persisted in 6 of the 512 observed 6 months after delivery.Six of 719 Rh-negative multigravidas who had not received Rh immune globulin after previous pregnancies or had been treated only after delivery showed evidence of Rh isoimmunization despite a single injection of Rh immune globulin at 28 weeks in a subsequent pregnancy. In three of the six the cause was most likely “sensibilization” due to previous exposure to Rh-positive blood or an untreated Rh-positive pregnancy. in 3 of the remaining 716 (0.42%) there may have been true failure of antenatal Rh prophylaxis administered at the 28th week. One would have expected this figure to be 12 of 716 if antenatal Rh prophylaxis at 28 weeks'' gestation were totally unsuccessful.It is concluded that a single intramuscular injection of Rh immune globulin, 300 μg, is 88% effective in preventing Rh isoimmunization during pregnancy in Rh-negative primigravidas and in multigravidas treated antenatally in all previous pregnancies, and is 75% effective in preventing Rh isoimmunization in Rh-negative multigravidas untreated during previous pregnancies. The majority of failures are due to Rh isoimmunization during pregnancy prior to antenatal prophylaxis at 28 weeks.     

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.     

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.     

HEMATOLOGIC FEATURES WHICH MAY INFLUENCE Rh IMMUNIZATION

The biologic features which may influence Rh sensitization in the mother and hemolytic disease in the newborn are conditioned by the hereditary immunologic pattern of the subjects, the antigenic characteristic of the blood group specific substances, the character of the antibody responses, the inherent susceptibility to disease as a result of the immune mechanism, and the character and sequence of exposure to the antigenic substance. In respect to Rh-negative women, there appears to be a greater vulnerability to immunization among those of blood group A. In regard to the infant, the compatibility of the maternal-infant blood types and the part they play in the phenomenon of the competition of antigens may influence the occurrence of hemolytic disease in the newborn.     

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.     

Segregation distortion in Rh polymorphism

Segregation distortion for the Rh system is reported. Mother-infant pairs (1018 pairs) from maternity service divisions of government hospital and 216 complete families with a total of 692 children, of Visakhapatnam (Andhra Pradesh, South India) were typed for the D-d alleles of Rh system. The segregations analysis made by means of the T matrix method of ITO matrices, assuming Hardy-Weinberg equilibrium, reveals that: Rh-positive mothers produce fewer Rh-negative children with significance and Rh-negative mothers produce more Rh-positive children with less significance than expected in both the mother-child and family studies. This results in a reduction in the d allele from mothers to their children. Known Rh antigenic specificities and reproductive compensation do not explain the observed distortion. Other selectively acting forces probably linked to Rh compatibility system seem to be operating to gain d alleles to maintain Rh polymorphism.     

Effects of modulating erythrocyte membrane cholesterol on Rho(D) antigen expression

Alteration of Rh_o(D)-antigen expression in Rh-positive erythrocytes after modification of membrane fluidity has recently been demonstrated by indirect fluorescence staining. The isolation of D-antigen from Rh-negative erythrocyte membranes has also recently been claimed. We therefore attempted quantification of D-antigen sites in modified Rh-positive and Rh-negative cells by the direct radiolabelled (¹²⁵I) antibody uptake technique. The cholesterol/phospholipid molar ratio of erythrocytes was modified with resulting membrane-cholesterol enrichment or depletion. ¹²⁵I-anti-D uptake doubled in enriched Rh-positive erythrocytes, and was decreased in depleted Rh-positive erythrocytes. No change in anti-D uptake could be shown for Rh-negative erythrocytes similarly modified. If the mechanism for enhanced D-antigen expression in cholesterol enriched erythrocytes is vertical displacement of antigen, our inability to unmask the D-antigen in Rh-negative erythrocytes suggests that it is deeply buried in the lipid matrix.     

Gene organization and rearrangements at the human Rhesus blood group locus revealed by fiber-FISH analysis

The human Rhesus (Rh) blood group locus is composed of two highly homologous genes, the RHD and RHCE genes on chromosome 1, encoding the D, C/c, and E/e antigens in common Rh-positive phenotypes. In general, the RHD gene is either absent or grossly deleted in Rh-negative individuals. In this study, gene organization at the RH locus of Japanese donors with different serological phenotypes was directly analyzed by two-color fluorescence in situ hybridization on DNA fibers released from their lymphocytes (fiber-FISH) and by using DNA probes of introns 3 and 7 of the RHCE and RHD genes. Six Rh-positive samples (two with the D+C-c+E+e-, two with the D+C+c-E-e+, and two with the D+C+c+E+e+ phenotype) showed the presence of two RH genes within a region of less than 200 kb on chromosome 1p36.1. Of great interest was the finding that the genes were arranged in the antidromic order of the telomere -RHCE (5'--> 3') -RHD (3'-->5') - centromere. On the other hand, two typical Rh-negative samples (D-C-c+E+e+) showed the presence of only one RHCE gene, as expected. Moreover, further analysis combined with a locus-specific assay of three Rh-negative samples (D-C+c+E+e+, D-C+c+E-e+, and D-C+c-E-e+) showed the possible presence of the RHD gene(s) and complex rearrangements, including partial deletion, duplication, and recombination, in this region; these could be responsible for the Rh-negative phenotype.     

Rh isoimmunization during pregnancy: antenatal prophylaxis.

Of 3533 Rh-negative women who began a pregnancy without detectable Rh antibodies, 62 (1.8%) demonstrated evidence of Rh isoimmunization during pregnancy or within 3 days after delivery. All denied transfusions as well as abortions or previous pregnancies not followed by the administration of Rh immune globulin. Rh isoimmunization during pregnancy or within 3 days after delivery, which will not be prevented by the administration of Rh immune globulin after delivery, is the most important cause of residual Rh isoimmunization. A clinical trial of antenatal administration of Rh immune globulin, initially at 34 weeks''s and subsequently at 28 and 34 weeks'' gestation, in 1357 Rh-negative pregnant women who were delivered of Rh-positive babies, was effective in preventing the development of Rh isoimmunization during pregnancy or within 3 days after delivery. Antenatal prophylaxis with Rh immune globulin will be necessary if the incidence of Rh isoimmunization is to be reduced to its lowest possible level. Antenatal prophylaxis at 28 weeks'' gestation is now an insured service in Manitoba.     

Demonstration of the activity of a rhesus-positive antigen in the erythrocytes of rhesus-negative donors and an increase in the expression of ABO system antigens after ultraviolet irradiation of the blood

UV irradiation (254 nm) in doses increasing erythrocyte (Er) hemolysis by 5 to 32% was found to stimulate the agglutination activity of ABO and Rhesus (Rh) system antigens. The stimulation effect was the higher the lower the antigen activity before irradiation. In the Rh-negative (Rh-)-Er, irradiation induced the Rh0(D)-like antigen specific activity suggesting that this antigen may be present in the Rh--Er membrane. Expression of Rh0(D)-antigen in Rh--Er, stimulation of its activity in Rh-positive cells, and activation of ABO system antigens may result from photo-chemical destruction of the outer membranous layer of the ER.     

Crossmatch difficulties following the prophylactic use of Rh immune globulin.

With increasing demand for platelet transfusion the need to use platelets from Rh-positive persons for Rh-negative individuals often arises. The administration of Rho(D) immune globulin (human) in this situation has been recommended, but may cause serologic difficulties owing to the recipient''s passive acquisition of antibodies other than anti-D.     

Prevention of Rh-haemolytic Disease: Final Results of the “High-risk” Clinical Trial: A COMBINED STUDY FROM CENTRES IN ENGLAND AND BALTIMORE

The final results are reported of a trial of about 1,000 μg of anti-D gammaglobulin given intramuscularly to a selected high-risk group of Rh-negative primiparae just delivered of an ABO-compatible Rh-positive baby, the aim being to prevent them becoming immunized to Rh. Six months after delivery only 1 out of 173 treated mothers had been immunized as against 38 out of 176 controls. The crucial test of the prophylactic therapy depends on the presence or otherwise of anti-D at the end of a second Rh-positive pregnancy. Of 86 treated mothers two had antibodies at this time compared with 20 out of 65 controls.The results show a high degree of protection in this group of mothers.     

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.     

ABO and Rh blood groups in relation to sex ratio, mean number and mortality of sibs.

Data are presented on the sex ratio, mean number and mortality of the sibs of 17,060 schoolchildren, and on the sex ratio and mean number of the sibs of 5,785 blood donors, in relation to the children's and donors' sex and ABO and Rh blood groups. The sex ratio is significantly higher for the sibs of AB + B than for those of A + O schoolboys, and for the sibs of Rh-negative than for those of Rh-positive male blood donors, but in both cases the mean number of sibs is exactly the same for the first-mentioned as for the second-mentioned category.     

Rh-immunization by Pregnancy: Results of a Survey and Their Relevance to Prophylactic Therapy

A series of Rh-negative primiparae has been studied in order to gain further insight into the process of immunization by pregnancy. The distribution of foetal cell counts in blood samples taken after delivery was determined for 2,029 mothers giving birth to ABO-compatible babies and for 417 mothers with ABO-incompatible babies.A total of 760 mothers were tested for the development of Rh antibodies six months after the delivery of an ABO-compatible Rh-positive baby and 236 were further followed up through a second Rh-positive pregnancy. The incidence of anti-D six months after delivery is estimated to be 8.5%, and there is evidence of a direct relation between the count of foetal cells after delivery and the risk of developing antibodies. A further 8.5% of mothers were estimated to develop anti-D by the end of the second pregnancy, and it is postulated that these individuals had been primed by the first pregnancy. There is some evidence that the larger stimuli of Rh-positive blood in the first pregnancy are more likely to result in overt antibody formation, while the smaller stimuli are more likely to prime, antibodies not being detected until a second stimulus occurs during the second pregnancy.These findings are relevant to the programme for preventing Rh-immunization by injecting anti-D gammaglobulin.     

Molecular definition of red cell Rh haplotypes by tightly linked SphI RFLPs.

The Rh blood group system of human red cells contains five major antigens D, C/c, and E/e (the latter four designated "non-D") that are specified by eight gene complexes known as Rh haplotypes. In this paper, we report on the mapping of RH locus and identification of a set of SphI RFLPs that are tightly linked with the Rh structural genes. Using exon-specific probes, we have localized the SphI cleavage sites resulting in these DNA markers and derived a comprehensive map for the RH locus. It was found that the SphI fragments encompassing exons 4-7 of the Rh genes occur in four banding patterns or frameworks that correspond to the distribution and segregation of the common Rh haplotypes. This linkage disequilibrium allowed a genotype-phenotype correlation and direct determination of Rh zygosity related to the Rh-positive or Rh-negative status (D/D, D/d, and d/d). Studies on the occurrence of SphI RFLPs in a number of rare Rh variants indicated that Rh phenotypic diversity has taken place on different haplotype backgrounds and has arisen by diverse genetic mechanisms. The molecular definition of Rh haplotypes by SphI RFLP frameworks should provide a useful procedure for genetic counseling and prenatal assessment of Rh alloimmunization.     

The experience and effectiveness of the Nova Scotia Rh program, 1964-84.

A program to reduce the incidence of erythroblastosis fetalis was started in Nova Scotia in 1964. Up to the end of 1984, 120 fetuses received 247 intrauterine transfusions. The survival rate was 45.6% in the first 10 years of the program and 66.7% in the next 11 years. For fetuses at or over 26 weeks'' gestation the figures were 51.5% and 73.7% respectively. Postpartum prevention was started in 1968, with administration of Rh immune globulin (RhIG) to Rh-negative unimmunized women within 72 hours after the birth of an Rh-positive infant. Antepartum prevention, started in 1979, consisted of administration of RhIG at 28 weeks'' gestation to Rh-negative unimmunized women. The effectiveness of the prevention program was evaluated by enumerating the known cases of Rh(D) alloimmunization in the province from 1982 to 1984: 55 cases were identified, a rate of 1.5 per 1000 births instead of the expected rate of about 10 per 1000.     

新生溶血病患儿红细胞上致敏抗体对Rh 血型检测的影响

目的:探讨新生溶血病患儿红细胞致敏抗体对其Rh血型鉴定的影响。方法:采用抗球蛋白法、盐水法、微柱凝胶法(Rh血型测定型)、凝聚胺法和抗血清微柱凝胶法(Ig G型)五种方法对近三年来我院收集的163例新生溶血病患儿红细胞进行Rh血型检测,对五种检测结果不一致的患儿红细胞进行0.2 M 2-巯基乙醇抗体放散,比较放散后五种方法检测结果并验证其准确性。结果:29例直接抗体试验阳性患儿的五种Rh血型检测结果不一致,经0.2 M 2-巯基乙醇抗体放散后检测结果均一致。Rh血型准确性验证表明,红细胞放散测定的Rh血型完全符合临床现象。结论:患儿红细胞的致敏抗体达一定数量后,会影响抗球蛋白法、盐水法、微柱凝胶法(Rh血型测定型)、凝聚胺法和抗血清微柱凝胶法(Ig G型)对Rh血型鉴定,0.2M 2-巯基乙醇抗体放散法是一种正确鉴定新生儿Rh血型的简单可行的方法。