Prophylactic Rh Research Articles

Blood use and alloimmunization in myelodysplastic syndrome patients: A study of a hospital transfusion experience.

Patients with myelodysplastic syndrome (MDS) are characterized by chronic anemia and most of them require transfusion making them prone to developing transfusion dependence (TD) and inducing red blood cell (RBC) alloimmunization. Little information is available regarding the status of transfusions of MDS patients in China. Clinical history and transfusion information of MDS transfusion patients from 2004 to 2023 were collected from electronic medical and laboratory records. TD patients were divided into increased blasts (IB) and non-IB group. Blood component transfusion was evaluated and compared in different groups using Mann-Whitney and chi-square tests. A total of 893 MDS patients received a median of 13 (range, 0 - 436) RBC units and 10 (range, 0 - 216) platelets (PLT) units. Seventy-one (8%) patients formed 106 RBC specific antibodies of which Rh system was the most (82/106= 77%). Twelve patients (17%) had 14 antibodies (13%) evanescence whereas 7 patients had former antibodies reemerge. Alloimmunization was more common in female, older patients and patients with larger RBC transfusions. Among 222 TD patients, RBC transfusion and alloimmunization rate in IB group were lower than those in non-IB group whilst PLT was the opposite. Prophylactic Rh system compatible transfusion can reduce the risk of RBC alloimmunization in MDS patients' especially in TD and non-IB patients and can prevent reinduction of antibody evanescence. To our knowledge this is the first study we reveal RBC antibody induction and evanescence which may related to different disease stages and classifications of MDS patients.

Rare combination of alloantibodies causing hemolytic disease of the newborn – Challenge for identification

Abstract Hemolytic disease of the newborn (HDN) refers to the destruction of the fetal and newborn red cells by maternal red cell antibodies specific for paternally inherited antigens on fetal red cells or erythroid precursors.[1] ABO-incompatibility is the most common cause of HDN. Rh-negative mothers can be alloimmunized with Rh-positive fetus. Prophylactic Rh immunoglobulin use has greatly reduced the HDN due to Rh incompatibility. Alloimmunization can also occur due to other clinically significant minor blood group antigens such as E, c, C, k, KP(a), Js(a), Js(b), Jk(a), Jk(b), Fy(a), Fy(b), S, s, and U. Multiple alloantibodies in mothers’ blood can pose a difficult challenge for identification and finding compatible blood for exchange transfusion. We report a case of HDN due to multiple antibodies and a rare combination of anti-c and anti-Jkb, challenges associated with the identification, confirmation, and finding of compatible blood units.

Non-invasive antenatal determination of fetal blood group in pregnancy care

Non-invasive prenatal testing (NIPT) using cell-free fetal DNA in maternal plasma can be used to determine the fetal blood group antigen status for a variety of blood group genes. Knowing what the fetal blood group status is, matters in two different aspects of pregnancy care. For Rh D negative women, the use of antenatal and post-natal administration of prophylactic Rh D immunoglobulin (RhD Ig) has been a game-changer in preventing Rh D allommunisation. At present in Australia, all Rh D negative women are eligible but up to 30–40% of women are in fact carrying an Rh D negative fetus and do not require antenatal RhDIg. The widespread use of NIPT for the RhD gene will allow us to target antenatal RhD Ig to women known to be carrying a D positive fetus, avoiding unnecessary administration, and preserving a scarce resource. For women embarking on pregnancy with an alloantibody capable of causing moderate to severe haemolytic disease of the fetus and newborn (HDFN), knowing the fetal antigen status matters to determine the intensity of pregnancy monitoring. Where the partner is heterozygous, there is a 50% chance of an unaffected pregnancy. In the past, CVS and amniocentesis were the only way to determine fetal antigen status, with such invasive testing likely to boost the maternal antibody response and worsening disease. NIPT enables intense pregnancy monitoring to be better targeted.

National Blood Foundation 2021 Research and Development summit: Discovery, innovation, and challenges in advancing blood and biotherapies.

National Blood Foundation 2021 Research and Development summit: Discovery, innovation, and challenges in advancing blood and biotherapies.

Rh alloimmunization in chronically transfused patients with thalassemia receiving RhD, C, E, and K matched transfusions

AbstractChronically transfused patients with thalassemia are at risk for red cell alloimmunization. No studies have specifically examined alloimmunization after implementation of prophylactic Rh (D, C, E) and K matched red cells in a racially diverse population of thalassemia patients and donors. This retrospective study examined Rh antibodies among 40 chronically transfused patients (Asian, White, Black, Indian, Middle Eastern) with thalassemia receiving a mean of 174 serologic prophylactic RhD, C, E, and K matched red cell units. We examined the patients' RH genotype, as well as donor race and Rh phenotypes over 3 transfusion events preceding antibody detection. Eighteen alloantibodies were detected in 13 of 40 patients (32.5%), with an alloimmunization rate of 0.26 antibodies per 100 units transfused. Thirteen antibodies (72.2%) were directed against Rh (5 anti-D, 4 anti-C, 2 anti-E, 1 anti-e, 1 anti-V), despite donor phenotypes that confirmed lack of transfusion of D, C, or E antigens to patients lacking the corresponding antigen(s). Ten of 40 patients had an altered RH genotype, but the Rh antibodies were not associated with patients with variant RH. Black donors with a known high frequency of RH variants provided 63% of the units transfused in the 3 visits preceding unexplained anti-Rh detection. Rh alloimmunization not explained by the thalassemia patients' RH genotype or the donors' serologic phenotype suggests more precise matching is needed, and the role of donor RH genotypes on alloimmunization should be explored. Extending Rh D, C, and E matching to include c and e would result in better-matched units and further minimize Rh alloimmunization.

Challenges in providing compatible blood with Rh genotype-matching in Brazilian patients with sickle cell disease.

The aim of this study was to verify the possibility of performing prophylactic Rh genotype-matching in Brazilian patients with sickle cell disease (SCD) and identify the genotypes that are lacking or insufficient in our donor cohort. Rh alloimmunisation is still a challenge in transfused patients with SCD. Rh genotype-matching may mitigate Rh alloimmunisation. We examined the transfusion requests for antigen-matched donor units in SCD patients with Rh variants and compared the Rh altered alleles in the patients to the Rh allele frequency in a selected donor population. For each patient and donor, RBC antigen genotyping was performed using HEA, RHD and RHCE BeadChip arrays. Sequencing was used to clarify inconclusive results. Twenty-one patients and 956 Brazilian blood donors were genotyped. According to our matching strategies, 47·6% of patients filled most of their unit requests, but 52·4% of patients had insufficient donors to fill their annual transfusion needs. We found different combinations of RHCE variant alleles in patients and donors, but the most frequent genotypes that are lacking or insufficient in our donor cohort are those associated with the lack of hrB and hrS high prevalence antigens and those co-inherited with altered RHD alleles. Our study shows that the provision of compatible blood with Rh genotype-matching in Brazilian patients with SCD can be feasible but challenging and, efficient strategies of recruitment of African-Brazilian donors must be developed.

RH genotype matching for transfusion support in sickle cell disease

AbstractRh alloimmunization remains a challenge for patients with sickle cell disease (SCD) despite transfusion of serologic Rh C, E, and K antigen-matched red cells. Inheritance of altered RH alleles contributes to the prevalence of Rh antibodies after blood transfusion in patients with SCD and explains approximately one-third of cases. The remainder seem to be stimulated by altered Rh proteins on African American donor red cells. Matching patients with donors on the basis of RH genotype may mitigate Rh alloimmunization, but the feasibility and resources required are not known. We compared RH allele frequencies between patients with SCD (n = 857) and African American donors (n = 587) and showed that RH allele frequencies are similar. Overall, 29% of RHD and 53% of RHCE alleles are altered in patients and African American donors. We modeled RH genotype matching compared with serologic Rh D, C, and E, along with K antigen matching, and found that approximately twice the number of African American donors would be required for RH genotype vs Rh serologic matching at our institution. We demonstrated that African American donor recruitment is necessary to maintain an adequate supply of C-, E-, and K-negative donor units to avoid depleting the Rh-negative (RhD−) blood supply. Our results suggest that prophylactic RH genetic matching for patients with SCD is feasible with a donor pool comprised primarily of African-Americans and would optimize the use of our existing minority donor inventory. The current cost of RH genotyping all minority donors and management of the data remain limiting factors.

Prevalence of “unexpected antibodies” in the antenatal women attending the Government Maternity Hospital, Tirupati

Background: All antibodies to red cell antigens, other than naturally occurring anti-A and anti-B are considered unexpected. They can be either alloantibodies or auto antibodies. In pregnant women, these antibodies may cross the placenta and cause haemolytic disease of the foetus and newborn (HDFN). Timely detection of such antibodies in antenatal women is essential for early management of HDFN. Methods: A prospective cross-sectional study was carried out on 2060 multiparous pregnant women attending the Government Maternity Hospital, Tirupati to detect prevalence of unexpected antibodies. The women were grouped and typed for ABO and rhesus (Rh) D antigens by tube method and screened for alloantibodies by column agglutination technology. The medical and detailed obstetric history of these women were reviewed. Results: The overall prevalence of alloantibodies was 1.1%. There was a statistically significant difference between alloimmunization rates in the Rh D-antigen negative and D-antigen positive women (12.8% versus 0.3%). The antibodies detected in this study were, anti-D (63.8%), anti-D+C (13.7%), anti-C, anti-E, anti-M, anti-Lea, and anti-Leb (4.5% each). Anti-D contributed to 77.3% of total alloimmunization in this study. Conclusions: In spite of the introduction of prophylactic Rh- immunoglobulin, anti-D (77.3%) is still a common antibody identified in the antenatal women of our region. In developing countries like India, universal antenatal antibody screening, though desirable may not be justified at present as the cost and infrastructure required would be immense. However, it is necessary to impose properly formulated protocols to screen at least the pregnant women with adverse obstetric history.

Prophylactic Rh and Kell Antigen Matching Significantly Decreases Rates of Alloimmunization in Transfusion Dependent MDS Patients

Background: 40-80 % of patients with myelodysplastic syndrome (MDS) become transfusion dependent during their disease course and are at risk for the development of alloimmunization. Red blood cell (RBC) alloantibodies can make finding compatible blood for transfusion more difficult, expensive and time consuming. Allommunization rates of approximately 30-47% have been reported in patients with sickle cell disease and the transfusion of RBCs prophylactically matched for Rh antigens E and C, and K antigens reduced the rate of alloimmunization from 3% to 0.5% per unit (Vichinsky et al, 2001). In 2007, our hospital instituted a policy of transfusing prophylactic Rh and K matched blood to MDS patients. The objectives of this study were to compare the rates of alloimmunization in MDS patients who received prophylactic Rh and K matched blood compared to those that did not and identify potential risk factors for alloimmunization. Methods: 193 Transfusion dependent MDS patients were identified out of 387 patients registered and prospectively followed in a local MDS registry. Transfusion dependence was defined as the receipt of at least 1 unit of PRBC every 8 weeks for a minimum of 16 weeks. Records of transfusions received up to May 1, 2014 were collected from blood bank databases of the hospitals at which patients were transfused. Patients were classified according to whether phenotyping had been performed, the location of transfusions (transfused only at our institution, transfused only at an outside institution or transfused at both sites) and whether prophylactic Rh (E, C antigens) and K matched blood was transfused. Data were descriptively analyzed and we conducted univariate and multivariate logistic regression using p< 0.05 as statistically significant to identify risk factors for alloimmunization.Results: 176 MDS patients with complete transfusion records are included, 73 transfused at Sunnybrook, 92 transfused in community hospitals and 11 at both. The median age was 72 yrs (range 22-89), 60% were male, and 8%, 43% and 27% had very low, low and intermediate risk R-IPSS scores respectively. Median follow up was 2.9 years (IQR 1.6-5) 3.49 SD). Blood groups O, A, B, AB and O were 45%, 38%, 15% and 2% respectively, while 85% were RhD+. The median time from diagnosis until first transfusion was 4 months (IQR: 0.2-14), with 51 patients having received at least 1 transfusion prior to diagnosis at a median time of 0.9 months. 4.5% had a pre-existing allo-antibody at time of MDS diagnosis. With a median follow up from diagnosis of 3 years (IQR:1.6-5)), the median number of RBC units transfused was 38 (IQR: 15-98)) and 36 (20%) patients developed new alloantibodies (median 2 (IQR (1-2.5) alloantibodies). The median number of RBC units until first allo antibody was 13.5 units (range 0-121) and 1.25 years from diagnosis (95% CI:0.4-2.1). The majority of the alloantibodies were in the Rh (n=28) and K (n=14) groups (80%) and co-existed 27% of the time. More patients transfused at our hospital received prophylactic Rh K matched blood sometimes or always (60% versus 26%) and rates of allo-immunization were decreased by 65% (absolute rate of alloimmunization 10% versus 29%). By multivariate analysis analysis, number of rbc transfused (p<.0001), receiving prophylactic phenotype matched blood (p=.0008) and location of transfusions (Sunnybrook versus elsewhere (p=.03)) were independent risk factors for alloimmunization.Conclusions: 20-30% of RBC transfusion dependent MDS patients will become allo-immunized to clinically significant blood group antigens, the majority being Rh and K antigens. The practice of phenotyping at baseline and prophylactically transfusing Rh and Kell matched blood decreases rates of alloimmunization up to 65% and should be strongly considered for routine transfusion practice in centres that treat MDS.Table 1All Patients (n=176)Sunnybrook (n=73)Community(n=92)Ever phenotyped45%64%28%Phenotyped before 1st transfusion20%38%8%Developed allo-antibodies20%10%29%Received prophylactic Rh K matched blood(developed alloantibodies)NeverSometimesAlways58% (16%)24% (42%)18% (6%)40% (3%)23% (23%)37% (7%)74% (22%)22% (60%)4% (0%) [Display omitted] DisclosuresWells:Celgene: Honoraria, Other, Research Funding; Novartis: Honoraria, Research Funding; Alexion: Honoraria, Research Funding. Buckstein:Celgene: Research Funding.

RhD Immunization Despite Adequate Immunoprophylaxis: Role of Fc Gamma Receptor Gene Polymorphisms

▪Introduction: One of the most effective immunological interventions in clinical medicine is the prevention of hemolytic disease of the newborn by prophylactic Rh immune globulin (Rh-Ig) therapy. The administration of ante- and postnatal Rh-Ig has reduced the risk of RhD immunization in the Netherlands from 17% to a mere 0.31%, yet its mechanism of action is still unknown. To gain more insight into the possible working mechanism of the Rh-Ig prophylaxis we analyzed potential risk factors and genotyped all known IgG-Fc receptor (protein FcγR, gene FCGR) variants known to date, on a cohort of Dutch women who failed Rh-Ig prophylaxis and developed anti-D antibodies. Adequate Rh-Ig immunoprophylaxis was defined as an antenatal and postnatal prophylaxis of 1,000 IU (200 µg) in both current and previous pregnancies, according to the Dutch guidelines.Material and Methods: Between 1999 and 2013 we identified 274 women who produced anti-D antibodies. Through a structured questionnaire we collected information about Rh-Ig prophylaxis and additional clinical data for potential risk factors. In 122 cases, adequate Rh-Ig prophylaxis was given, and clinical risk factors for fetal maternal hemorrhage (FMH) could be collected. Their clinical circumstances were compared to a control group of 339 randomly selected pregnant women. The Rh-Ig therapy failure of 57 of those women could not be explained through our risk factor analysis. From these 57 cases, DNA was obtained, and used for the FcγR-specific multiplex ligation-dependent probe amplification (MLPA) assay, identifying both single nucleotide polymorphisms and copy number variations in the FCGR locus. The results were compared to a control group of 200 healthy donors.Results: A history of red blood cell transfusion (p=0.05) and caesarean section (p<0.0001) were identified to be independent risk factors for RhD immunization. All other described risk factors for FMH such as miscarriage, termination of pregnancy, or invasive diagnostic procedures, requiring an additional Rh-Ig dose according to the guidelines, were not found to increase the risk of immunoprophylaxis failure. RhD-immunization due to caesarian section or red blood cell transfusion accounted for 53% of our cohort, suggesting an alternative explanation for the production of Rh-Ig alloantibodies in the remaining 47% of the cases - despite adequate amount of prophylaxis given in current and previous pregnancies. We therefore postulate the existence of a genetic variation that puts women at increased risk for RhD immunization during pregnancy. To test this hypothesis we analyzed the genetic variation in the FCGR locus and found a significantly (p=0.02) increased prevalence of the FCGR2 -ORF, expressing a functional copy of the activating FcγRIIc, which is otherwise a pseudogene. Strikingly, the prevalence of the 2B.4-promotor haplotype of the FCGR2B gene, associated with a 1.5 fold increase of the inhibitory FcγRIIb, was strongly (p=0.0001) increased.Conclusion: Caesarian section and red blood cell transfusion are risk factors that increase RhD immunization during pregnancies, accounting for about half failed Rh-Ig prophylactic cases. Genetic variation in the FCGR-gene might be a possible explanation for increased immunization risk. In our cohort we encountered a significantly increased frequency of individuals expressing FcγRIIc, along with a polymorphism encoding for a higher expression of the inhibitory receptor FcγRIIb, suggesting these genes to influence immune responses to RBC in a manner previously unrecognized. DisclosuresNo relevant conflicts of interest to declare.

350 Myelodysplastic syndrome and alloimmunization: The impact of prophylactic Rh and Kell matching for red cell transfusion

350 Myelodysplastic syndrome and alloimmunization: The impact of prophylactic Rh and Kell matching for red cell transfusion

D+ platelet transfusions in D– patients: cause for concern?

Abstract Patients whose RBCs are D– may produce anti-D if they are exposed to D on donor RBCs. Except in emergency situations, patients whose RBCs lack D are transfused with only D– RBCs. Platelets carry no Rh antigens, but platelet units may be contaminated by RBCs that could carry D when these units are collected from D+ donors. The purpose of this study was to determine whether our policy of allowing D+ platelets to be transfused to patients whose RBCs type as D–, without the use of prophylactic Rh immunoglobulin (RhIG), results in D alloimmunization. The transfusion records of all patients who received platelet transfusions from December 2004 to March 2007 were reviewed. Transfusion recipients were evaluated with pretransfusion ABO and D typings, and an antibody screen. Recipients were reevaluated in the same manner before subsequent transfusions. Transfusion records of 114 D– patients were analyzed. Overall, 104 patients received D+ platelets; 67 had repeat antibody screening after transfusion. No patients were shown to make anti-D after platelet transfusion. There was no evidence of D alloimmunization as a result of transfusion of D+ platelets in any D– patient during this study. The data do not support the practice of restricting D– patients to receiving only D– apheresis platelets, even among patients with chronic transfusion requirements. Prophylactic use of RhIG for D+ apheresis platelet transfusions in D– patients also appears to be unnecessary. Immunohematology 2009;25:5–8.

Implementation of Antenatal Prophylaxis: A Midwife’s Perspective

In July 2003, The Royal Women’s Hospital, Melbourne implemented the use of Prophylactic Rh D Immunoglobulin in obstetrics to help reduce the incidence of Haemolytic Disease of the Newborn (HDN), as recommended by the Chief Medical Officer in December 2002. Successful implementation required the coordinated efforts of a large working party including haematologists, laboratory staff, blood bank, product technicians, CSL, clinical managers, midwives, obstetricians, clerical staff and educators. New practice guidelines, system processes, procedures and staff education needed to be developed and coordinated to support the successful implementation across the Royal Women’s Hospital complex maternity care programme sites. This talk firstly outlines how this implementation was achieved across a complex organisation as is The Royal Women’s Hospital, and the tools that were invaluable in contributing to its consistent success. Examples of materials developed to support staff, from discussion guidelines to materials developed to aid pregnant women to make an informed choice will be shown. The second part of this talk offers an insight into the concerns that pregnant women raise regarding the offering of prophylactic Anti – D, from a midwifery perspective. What does the consumer think and how can we best serve their needs? What are the practical considerations that help Rh D negative women choose what is best for themselves and their babies? It is hoped that this talk contributes practical information to anyone involved in the delivery of prophylactic Anti-D to pregnant women for the prevention of HDN.

A rapid gel agglutination test for the determination of fetomaternal haemorrhage

Determination of fetomaternal haemorrhage (FMH) remains an area of difficulty. In most cases, prophylactic Rh immunoglobulin is usually administered to affected women without testing for foetal red blood cells (RBC). Here, we describe a new particle gel immunoassay (PaGIA) for the determination FMH (FMH-PaGIA). Superparamagnetic particles were coated with monoclonal anti-D and mixed with ethylenediaminetetraacetic acid-anticoagulated blood samples from D-negative pregnant women. The particles were isolated using a magnetic particle concentrator and then placed into the reaction chamber of a gel card. Agglutinated particles on top or dispersed through the gel matrix indicated the presence of D-positive cells. After the test was adapted to detect >or=0.3% D-positive RBC, randomly selected postpartum samples from 208 women were analysed in parallel with the Kleihauer-Betke test (KBT). In addition, all discrepancies were further analysed by flow cytometry. A total of 203 of the 208 postpartum samples were negative in both tests. One sample reacted positive with both assays. Two samples were strongly positive in the new FMH-PaGIA, but negative in the KBT. A serological re-examination revealed that both women were D positive. The KBT gave a false-positive result in two cases because of hereditary persistence of haemoglobin F. The new test is specific, easy to perform and can be done at any time in all laboratories.

83 Pilotstudy: Combination of Delayed Cord Clamping and Recombinant Erythropoietin (Rhepo) for The Prevention of Anaemia of Prematurity

Background/Aim: The optimal management of anaemia of prematurity is still unknown. Therapeutic approaches include delayed cord clamping and early treatment with protein and iron supplements and prophylactic rh Epo. We investigated the possible benefit of delayed cord clamping (45 s) combined with rh Epo 750 IU/kg/week from day 8–10 with early cord clamping and rh Epo.

Karl landsteiner and his major contributions to haematology

Karl landsteiner and his major contributions to haematology

Testing the Mother's Blood to Determine Fetal Rh Type

Rh-negative pregnant women can become sensitized to Rh antigens on the surface of fetal red blood cells that cross into the maternal circulation. Despite the use of prophylactic Rh immunoglobulin, an estimated 10.6 of 10,000 live births …

Development of a flow cytometric test for the detection of D-positive fetal cells after fetomaternal hemorrhage and a survey of the prevalence in D-negative women

Abstract A sensitive test for the presence of D-positive fetal red blood cells (RBCs) in the maternal circulation of D-negative women has been developed. It was used to investigate the possibility that the occasional failure in preventing alloimmunization might be due to the administration of inadequate amounts of prophylactic anti-D Rh immune globulin. The standard dose in Australia contains 125μg of antibody, and can suppress immunization by an estimated 6 mL of packed D-positive RBCs. A fetomaternal hemorrhage (FMH) of this volume is detectable in the maternal circulation as approximately 0.25 percent of the total RBCs. Our test utilizes a commercially available human monoclonal IgG anti-D that has been biotinylated and used with a dye-conjugated streptavidin. Flow cytometry is used to quantitate fluorescing D-positive RBCs. To date, 2,288 tests have been performed on blood samples from D-negative women attending local antenatal clinics or at the time of delivery. Evidence for an FMH has been obtained in six cases (0.26%). In one case, the FMH was only 0.1 percent, and in another (confirmed by the Kleihauer-Betke method), fetal cells constituted only 0.2 percent. Additional Rh immune globulin was not given to these patients. In the other four cases, the D-positive fetal cells were estimated to be 0.7, 0.5, 0.5, and 0.4 percent, and additional prophylactic Rh immune globulin was administered. Although the prevalence of FMH is low, screening D-negative women at risk of alloimmunization has proved to be simple, fast, and inexpensive.

Effectiveness of prophylactic Rh immunosuppression after transfusion with D-positive blood

In a published investigation 42 D-negative men were transfused with single units of D-positive R1r (CDe/cde) blood to mimic the D-incompatible transfusion accidents occasionally seen in young D-negative women. Twenty-two men received no therapy and 20 were treated with Rh immunoglobulin in a calculated dose of 20 μg of anti-Rh per milliliter of infused red cells. The reported incidence of serologic D alloimmunization was 81.8 per cent in control and zero per cent in treated recipients. Posttransfusion 51Cr clearance studies with a challenge with the use of 5 ml. of D-positive cells from the same donor at five months in these identical subjects vary from the results based upon the presence of circulating anti-D active antibody. Exponential immune clearance curves occurred in two control and nine treated recipients. As the first evidence of D alloimmunization is an immune Cr clearance curve followed at some later time by circulating active anti-D antibodies, these data could suggest that Rh immunization actually was 90.9 per cent in untreated control subjects and 45 per cent in treated men. The dose of passive Rh immunoglobulin effective in prophylaxis of transfusion Rh immunization of a D-negative person is still not definitely established, but apparently it is greater than 20 μg of anti-Rh per milliliter of D-positive erythrocytes received.

THE RISK OF RH ISOIMMUNIZATION IN RUPTURED TUBAL PREGNANCY

In 9 (24%) out of 38 African women who had suffered a ruptured tubal pregnancy significant numbers of fetal erythrocytes (5 or more per 150,000 maternal cells) were found in the maternal circulation. This is a higher incidence than occurs after abortion and indicates that rupture of a tubal pregnancy is a potential source of Rh isoimmunization. The finding of fetal cells in the peritoneal cavity suggests that this is the main source of the fetal blood found in the maternal circulation. At operation on Rh-negative patients with ruptured tubal pregnancies, therefore, complete removal of the peritoneal blood should be attempted and the blood recovered should never be transfused into the patient, who should always receive prophylactic Rh immunoglobulin.