Guide to Rho(D) Immune Globulin in Women With Molecularly Defined Asian-type DEL (c.1227G>A).

Rh hemolytic disease of the fetus and newborn is a potential risk for D-negative mothers who produce anti-D during pregnancy, which can lead to morbidity and mortality in subsequent pregnancies. To prevent this hemolytic disease, Rho(D) immune globulin (RhIG) is generally administered to D-negative mothers without anti-D at 28 weeks of gestation and shortly after delivery. However, current guidelines suggest that pregnant mothers with molecularly defined weak D types 1, 2, 3, 4.0, and 4.1 do not need RhIG as they are unlikely to produce alloanti-D when exposed to fetuses with D-positive red cells. This issue and the necessity of RHD genotyping have been extensively discussed in Western countries, where these variants are relatively common. Recent evidence indicates that women with Asian-type DEL (c.1227G>A) also do not form alloanti-D when exposed to D-positive red cells. We report that mothers with molecularly defined Asian-type DEL, similar to those with weak D types 1, 2, 3, 4.0, and 4.1, do not require RhIG before and after delivery. Collectively, this review could pave the way for the revision of international guidelines to include the selective use of RhIG based on specific genotypes, particularly in women with the Asian-type DEL.

Incidence of formation of anti-D between patients with and without a history of solid organ transplant.

BACKGROUND AND OBJECTIVES: Solid organ transplant surgeries including liver transplants constitute a substantial risk of bleeding complications and given frequent national blood shortages, supporting D-negative transplant recipients with D-negative red blood cell products perioperatively can be difficult for the transfusion services. This study was designed to compare the incidence of alloimmunization after D-mismatched red cell transfusions between patients with and without a history of solid organ transplant at a single tertiary care hospital. The patients undergoing solid organ transplants are on strong immunosuppressive regimens perioperatively to help reduce the risk of rejection. We hypothesized that the use of these immunosuppressive agents makes these patients very less likely to mount an immune response and form anti-D antibodies when exposed to the D-positive red blood cell products perioperatively. STUDY DESIGN AND METHODS: At our center, D-negative patients who received ≥1 unit of D-positive red blood cell products were identified using historical transfusion records. Antibody testing results were examined to determine the incidence of the formation of anti-D and any other red cell alloantibodies after transfusion and these results were compared between patients with and without a history of solid organ transplant. RESULTS: We were able to identify a total of 22 patients over 10 years with D-negative phenotype who had undergone a solid organ transplant and had received D-positive red blood cell products during the transplant surgeries. We also identified a second group of 54 patients with D-negative phenotype who had received D-positive red blood cell products for other indications including medical and surgical. A comparison of the data showed no new anti-D formation among patients with a history of D mismatched transfusion during solid organ transplant surgeries. CONCLUSION: Among our limited study population, we observed a very low likelihood of D alloimmunization among solid organ transplant recipients. A larger, prospective study could help further evaluate the need for prophylactic D matching for red cell transfusions during solid organ transplant surgeries.

A Korean family with RHD*DNT only detectable after anti-D alloimmunization.

OBJECTIVES: Identification of DNT, a rare partial D, can be challenging, as it is difficult to distinguish from D+. This study aimed to identify DNT individuals by analyzing the DNT proband's family members, characterize DNT, and propose management strategies. METHODS: Family members of the first Korean DNT proband were recruited. RHD genotyping was conducted, and weak D tests were carried out using several anti-D reagents. RESULTS: Three DNT individuals were identified among 6 family members, including 1 with an anti-D alloantibody. As DNT red cells exhibited strong reactivity with all anti-D clones, DNT was serologically indistinguishable from D+. Moreover, unusual serologic findings in DNT individuals only became apparent after anti-D alloimmunization. CONCLUSIONS: We recommend DNT individuals as candidates for Rh immune globulin prophylaxis during the perinatal period and transfusions with D- blood components. An anticipatory RHD genotyping is suggested for partial D family members to prevent potential partial D individuals from becoming alloimmunized.

Prevention of Rhesus-D Alloimmunization in the First Trimester of Pregnancy: Economic Analysis of Three Management Strategies.

Anti-D alloimmunization in the first trimester of pregnancy has long been the subject of prevention with anti-D immunoglobulins during events at risk of fetomaternal hemorrhage. Although the efficacy of preventing anti-D alloimmunization by an injection of immunoglobulin at 28 weeks of gestation (WG) is obvious, the literature provides little evidence of the effectiveness before 12+6 WG and several countries have modified their recommendations. In the presumed absence of a difference in alloimmunization risk between early and late prevention, our objective was to evaluate and compare the cost of treatment for 3 alloimmunization prevention strategies in France, the United Kingdom, and the Netherlands. This was a single-center retrospective study. Our target population included all women who received anti-D immunoglobulins (Rhophylac) in the first trimester of pregnancy before 12+6 WG at Nantes University Hospital in 2018 (N = 356). Within the target population, 2 other populations were constituted based on British (N = 145) and Dutch (N = 142) clinical practice guidelines (CPG). These 3 populations were analyzed for the comparative cost of treatment for prevention from a health system perspective. The average cost of Rhophylac alloimmunization prevention for 1 episode was €117.8 from a health system perspective. The total cost attributed to prevention in 2018 at Nantes University Hospital (N = 356) was €41,931.4 according to this perspective. If the UK CPG or Dutch CPG had been applied to the Nantes target population, a saving of around 60% would have been achieved. At the national level, the cost according to the health system perspective specifically attributable to induced abortion (N estimated = 26,916) could represent a total cost of €3,170,704. This study highlighted the high cost of the French prevention strategy in the first trimester of pregnancy compared with British or Dutch strategies. The modification of our practices would allow substantial financial savings to the French health system but would also avoid the nonrecommended exposure to a blood product at this term, would allow a faster medical management and a relief of the care system.

Application of anti-D immunoglobulin in D-negative pregnant women in China.

This article summarizes the current situation of anti-D immunoglobulin (anti-D-Ig) use in RhD-negative pregnant women at home and abroad. The article describes the concept, research and development history, and domestic and foreign applications of anti-D-Ig and points out that anti-D-Ig has not been widely used in China, mainly due to reasons such as unavailability in the domestic market and non-standard current application strategies. The article focuses on analyzing the genetic and immunological characteristics of RhD-negative populations in China. The main manifestations were that the total number of hemolytic disease of the newborn (HDN) relatively high and D variant type. In particular, there are more Asian-type DEL, the importance of clinical application of anti-D-Ig was pointed out, and its antibody-mediated immunosuppressive mechanism was analyzed, which mainly includes red blood cell clearance, epitope blocking/steric hindrance, and Fc γ R Ⅱ B receptor mediated B cell inhibition, anti-D-Ig glycosylation, etc.; clarify the testing strategies of RhD blood group that should be adopted in response to the negative initial screening of pregnant and postpartum women; this article elaborates on the necessity of using anti-D-Ig in RhD-negative mothers after miscarriage or miscarriage, as well as the limitations of its application both domestically and internationally. It also proposes a solution strategy for detecting RhD blood group incompatibility HDFN as early as possible, diagnosing it in a timely manner, and using anti-D-Ig for its prevention and treatment. If the DEL gene is defined as an Asian-type DEL, anti-D-Ig prophylaxis in women would be unnecessary. Finally, based on the specificity of RhD-negative individuals, the article looks forward to the application trend of anti-D-Ig in China. It also called for related drugs to be listed in China as soon as possible and included in medical insurance.

Autoimmune anti-D in an RhD-positive young infant: Learning from a rare case.

BACKGROUND AND OBJECTIVES: Anti-D is usually immune in nature and is formed in individuals lacking D antigen or having variants/altered D phenotypes. In the Indian population, 93.8% are RhD positive, and R1 R1 is the commonest Rh phenotype. Here we report a rare and interesting case of autoimmune anti-D in an RhD-positive 3-month-old infant leading to warm autoimmune haemolytic anaemia. STUDY DESIGN AND METHODS: Auto-anti-D was detected serologically by immunohaematological techniques such as direct antiglobulin test, antibody detection and identification, dithiothreitol, enzyme treatment, antibody titration and elution. Molecular studies were performed to rule out genetic variants of RhD. RESULTS: Anti-D was confirmed in eluate and blood group post elution was B RhD positive. On genotyping using the Indian-specific RHD genotyping assay, the sample was found to be negative for the RHD*01W.150 (most common RhD variant in Indians) but positive for RHD exon 5 and RHD exon 10 along with glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The sample was further sequenced for RHD exons 1-10 by Sanger sequencing and found to be a wild type, thus, ruling out the presence of an RhD variant. CONCLUSION: This case is of interest because of the rare occurrence of autoimmune anti-D in an RhD-positive patient of such a young age (3 months). To the best of our knowledge, only two case reports have been published on autoimmune anti-D in infancy (in 1961 and 1964).

Association of HLA-DRB1 alleles with anti-D alloimmunization in RhD negative pregnant women in India.

BACKGROUND: Human leukocyte antigen (HLA) restriction plays an important role in the susceptibility to alloimmunization against red blood cell (RBC) antigens. The prevalence of anti-D alloimmunization in RhD negative pregnancy is still quite high in our population. Thus, we planned this study to determine the association of HLA-DRB1 alleles with anti-D alloimmunization in RhD negative pregnant women. MATERIAL AND METHODS: RBC antibody screen (ABS) was performed for RhD negative pregnant women attending the antenatal clinic our institute. Those with a negative result were included in the 'non-alloimmunized' (NAL) group ('Control' group), while those with anti-D alloantibody on performing antibody identification were included in the alloimmunized (AL) group of the study (n = 50 each). ABS and identification were done using column agglutination technique. The HLA-DRB1 typing was done by Luminex based reverse sequence specific oligonucleotide probing (SSOP) using commercial kits. The HLA-DRB1 allele frequency was compared in both the groups. RESULTS: There was a significant difference between the two groups in terms of gravida (p < 0.001) and history of anti-D immunoprophylaxis (p < 0.001). The frequency of HLA-DRB1*03 and HLA-DRB1*04 alleles was significantly higher in the AL group than the NAL group: 40 % versus 18 % [Odds Ratio (OR): 3.04, 95 % CI: 1.21-7.6; p = 0.015] for HLA-DRB1*03 alleles and 18 % versus 4 % (OR: 5.27, 95 % CI: 1.08-25.78, p = 0.025) for HLA-DRB1*04 alleles. CONCLUSION: The frequency of HLADRB1*03 and HLADRB1*04 alleles was significantly higher in RhD negative pregnant women alloimmunized with anti-D alloantibody.

Efficacy of Rubella Vaccination after Co-Inoculation with Rhogam.

Congenital rubella syndrome is a constellation of birth defects that can have devastating consequences, impacting approximately 100,000 births worldwide each year. The incidence is much lower in countries that routinely vaccinate their population. In the US, postnatal immunization of susceptible women is an important epidemiological strategy for the prevention of rubella as the Center for Disease Control (CDC) does not recommend administering this vaccine during pregnancy due to its nature as a live attenuated virus vaccine. However, concerns that the co-administration of rubella vaccine with other immunoglobins (i.e., Rhogam) could compromise vaccine efficacy has produced warnings that can delay the administration of rubella vaccination postpartum, leaving women susceptible to the disease in subsequent pregnancies. We aimed to address whether the co-administration of the measles, mumps, and rubella (MMR) vaccine and Rhogam decreased antibody responses compared to those receiving only MMR vaccination. This retrospective cohort study utilized clinical data from 78 subjects who received the MMR vaccine and Rhogam after delivery and 45 subjects who received the MMR vaccine alone. Maternal demographics, pregnancy complications and rubella status at the start of a subsequent pregnancy were recorded for analysis. Overall, the two cohorts had similar baseline characteristics; however, lower parity was noted in the participants that received both MMR vaccination and Rhogam. Making assessments based on maternal antibody IgG index for rubella during the next pregnancy, we observed that 88% of the Rhogam + MMR vaccine group had positive serology scores, which was not significantly different from the 80% rate in the MMR-vaccine-only cohort (p = 0.2). In conclusion, no differences were observed in rubella immunity status in subsequent pregnancies in those mothers given both the MMR vaccine and Rhogam concurrently. Given these findings, warnings against co-administration of vaccines in combination with Rhogam appear unwarranted.

The exclusion of anti-D alloantibody in a suspected anti-G antibody in a pregnant 28-year-old Odiya Indian woman.

The Rh-D negative pregnancy is commonly associated with alloimmunization against D-antigen. It can be prevented by anti-D prophylaxis in pregnant patients with negative results on antibody screening. Hence, it is essential to exclude alloantibody-D in the presence of multiple alloantibodies. Anti-G antibody is formed after exposure to G antigen in neonate RBCs. Blood-group discrepancy was noted in reverse grouping, and antibody-screening results were positive in our case individual, a 28-year old Odiya Indian woman. We performed antibody identification on serum specimens from this patient, which revealed the pattern of anti-D + anti-C antibody specificity. Blood-group discrepancy was solved using rr (ce/ce)-phenotype pooled cells for reverse grouping. We identified anti-G antibodies by themselves without anti-D and anti-C after performing sequential adsorption of serum with r'r' (Ce/Ce) and R2R2 (DcE/DcE) group-O RBCs in the mother, who had rr phenotype and primigravida designation. After completing antibody screening at the first antenatal check-up, we recommended prophylactic anti-D for the mother in any future pregnancies she may have.

Asian-type DEL (RHD*DEL1) with an allo-anti-D: A paradoxical observation in a healthy multiparous woman.

BACKGROUND: The DEL phenotype is the D variant expressing the least amounts of D antigen per red cell. Asian-type DEL (RHD:c:1227G > A) is the most prevalent DEL in East Asia without any anti-D alloimmunization reported before. We investigated the first observation of an anti-D in any DEL phenotype, reported in the Japanese language at a 1987 conference, only 3 years after the discovery of DEL. METHODS: We contacted the proband 35 years after the initial report. Standard hemagglutination, adsorption/elution, and flow cytometry tests were performed, as was nucleotide sequencing for the RHD, RHCE, and HLA class I and class II genes. RESULTS: The healthy multiparous Japanese woman, a regular blood donor, still had the anti-D of titer 8 representing an alloantibody by standard serologic methods. Unexpectedly, she carried an Asian-type DEL without any additional RHD gene variation. All 12 HLA alleles identified were known in the Japanese population. Interestingly, one of her HLA-DRB1 and a variant of her HLA-DQB1 alleles had previously been associated with anti-D immunization. CONCLUSION: We described an allo-anti-D, maintained for more than three decades, in an Asian-type DEL. The combination of two implicated HLA alleles were rare and could have contributed to the anti-D immunization. Continued monitoring of anti-D immunization events in patients with DEL is warranted, and we discuss possible mechanisms for further study. As only this single observation has been recognized in the last 35 years, the current recommendation is affirmed: Individuals with Asian-type DEL should be treated as Rh D-positive for transfusion and Rh immune prophylaxis purposes.

Isoinmunización Rh en bajas respondedoras: Reporte de caso / Rh Isoimmunization in Low Responders: Case Report / Isoimunização Rh em pacientes com baixa resposta: relato de caso

Introducción. La isoinmunización Rh consiste en la producción de anticuerpos maternos en una gestante Rh negativa contra los antígenos de los eritrocitos Rh positivos fetales ocasionados por una hemorragia fetomaterna. En población gestante, el 15% son Rh negativo y la severidad de la afectación fetal está relacionada con una serie de procesos inmunológicos y la historia obstétrica. Si una gestante Rh negativa con riesgo de isoinmunización no recibe profilaxis con inmunoglobulina Anti-D se inmuniza el 16% en la primera gestación, el 30% en la segunda y el 50% después de la tercera. Con este reporte de caso queremos describir el subgrupo de pacientes gestantes con isoinmunización Rh bajas respondedoras. Presentación del caso. G9P5C1A2Gem1V7 de 43 años, remitida en semana 30 de gestación por isoinmunización Rh, no recibió inmunoglobulina Anti-D durante este embarazo, ni en los anteriores ni en el posparto, reporte de Coombs indirecto de 1/4 que se eleva a 1/16, seguimiento ecográfico normal. En semana 35.3 presenta anemia fetal leve y por tratarse de un embarazo alrededor del término se finaliza por cesárea. Recién nacido con adecuado peso para la edad gestacional, quien fue dado de alta a las 72 horas con evolución satisfactoria. Discusión. Las gestantes con isoinmunización Rh bajas respondedoras se sensibilizan con altos volúmenes sanguíneos sin repercusión hemodinámica in utero, produciendo una enfermedad hemolítica fetal leve. Esta respuesta inmune es poco frecuente y está asociada a factores protectores; sin embargo, son necesarios más estudios que sustenten esta condición. Conclusiones. El control prenatal y el Coombs indirecto cuantitativo seriado son las principales herramientas para la prevención de la isoinmunización. El conocimiento de la respuesta inmunológica permite identificar el subgrupo de las bajas respondedoras que tienen una evolución clínica más leve y menor morbilidad neonatal. Palabras clave: Embarazo; Isoinmunización Rh; Eritroblastosis Fetal; Globulina Inmune RHO(D); Hidropesía Fetal.

Introduction. Rh isoimmunization consists of a Rh-negative pregnant woman producing maternal antibodies against the antigens of fetal Rh-positive erythrocytes due to fetomaternal hemorrhage. 15% of the pregnant population is Rh negative, and the severity of fetal effects is related to a series of immunological processes and the obstetric history. If a Rh-negative pregnant woman at risk of isoimmunization does not receive a prophylaxis of Anti-D immunolobulin, 16% are immunized in the first pregnancy, 30% in the second and 50% after the third. In this case report we will describe the subgroup of low responder pregnant patients with Rh isoimmunization. Case Presentation. G9P5C1A2Gem1V7, 43 years old, referred on the 30th week of pregnancy due to Rh isoimmunization. She did not receive Anti-D immunolobulin during this pregnancy, nor in her previous pregnancies, nor during postpartum. Indirect Coombs report of 1/4, which increases to 1/16. Ultrasound monitoring is normal. At week 35.3 she presented mild fetal anemia, and because the pregnancy was near its term, it was ended by cesarean section. Newborn with adequate weight considering the gestational age, who was then discharged after 72 hours with satisfactory evolution. Discussion. Low responder pregnant women with Rh isoimmunization are sensitized with high blood volumes but without hemodynamic repercussions in utero, producing a mild fetal hemolytic disease. This immune response is infrequent and is associated with protective factors; however, further studies are required to support this condition. Conclusions. Prenatal control and serialized quantitative indirect Coombs testing are the main tools for the prevention of isoimmunization. Knowledge of the immunological response enables identifying the subgroup of low responders who present a milder clinical evolution and lower newborn morbidity. Keywords: Pregnancy; Rh Isoimmunization; Erythroblastosis, Fetal; RHO(D) Immune Globulin; Hydrops Fetalis.

Introdução. A isoimunização Rh consiste na produção de anticorpos maternos em uma gestante Rh negativa contra os antígenos dos eritrócitos fetais Rh positivos causados por hemorragia fetomaterna. Na população gestante, 15% são Rh negativos e a gravidade do envolvimento fetal está relacionada a uma série de processos imunológicos e ao histórico obstétrico. Se uma gestante Rh negativa com risco de isoimunização não receber profilaxia com imunoglobulina Anti-D, imuniza-se 16% na primeira gestação, 30% na segunda e 50% após a terceira. Com este relato de caso, queremos descrever o subgrupo de pacientes gestantes com isoimunização Rh de baixa resposta. Apresentação do caso. G9P5C1A2Gem1V7, 43 anos, encaminhada na 30ª semana de gestação para isoimunização Rh, não recebeu imunoglobulina Anti-D nesta gestação, nem nas anteriores nem no puerpério, laudo de Coombs indireto de 1/4 que sobe para 1/16, acompanhamento ultrassonográfico normal. Na semana 35,3, apresentou anemia fetal leve e por se tratar de uma gestação próxima ao termo, foi interrompida por cesariana. Recém-nascido com peso adequado para a idade gestacional, que recebeu alta às 72 horas com evolução satisfatória. Discussão. Gestantes com isoimunização Rh de baixa resposta são sensibilizadas com elevados volumes sanguíneos sem repercussões hemodinâmicas in utero, produzindo doença hemolítica fetal leve. Essa resposta imune é rara e está associada a fatores protetores; no entanto, mais estudos são necessários para fundamentar esta condição. Conclusões. O controle pré-natal e o Coombs indireto quantitativo seriado são as principais ferramentas para a prevenção da isoimunização. O conhecimento da resposta imunológica permite identificar o subgrupo de pacientes com baixa resposta que apresentam evolução clínica mais branda e menor morbidade neonatal. Palavras-chave: Gravidez; Isoimunização Rh; Eritroblastose Fetal; Inmunoglobulina RHO (D), Hidropisia Fetal.

Terminating Routine Cord Blood RhD Typing of the Newborns to Guide Postnatal Anti-D Immunoglobulin Prophylaxis Based on the Results of Fetal RHD Genotyping.

INTRODUCTION: Targeted routine antenatal prophylaxis with anti-D immunoglobulin (Ig) only to RhD-negative pregnant women who carry RhD-positive fetuses (determined by fetal RHD genotyping) has reduced D-alloimmunization significantly when administered in addition to postnatal prophylaxis. Achieving high analysis sensitivity and few false-negative fetal RHD results will make RhD typing of the newborn redundant. Postnatal prophylaxis can then be given based on the result of fetal RHD genotyping. Terminating routine RhD typing of the newborns in cord blood will streamline maternity care. Accordingly, we compared the results of fetal RHD genotyping with RhD typing of the newborns. METHODS: Fetal RHD genotyping was performed, and antenatal anti-D Ig was administered at gestational week 24 and 28, respectively. Data for 2017-2020 are reported. RESULTS: Ten laboratories reported 18,536 fetal RHD genotypings, and 16,378 RhD typing results of newborns. We found 46 false-positive (0.28%) and seven false-negative (0.04%) results. Sensitivity of the assays was 99.93%, while specificity was 99.24%. CONCLUSION: Few false-negative results support the good analysis quality of fetal RHD genotyping. Routine cord blood RhD typing will therefore be discontinued nationwide and postnatal anti-D Ig will now be given based on the result of fetal RHD genotyping.

Antibody-mediated antigen loss switches augmented immunity to antibody-mediated immunosuppression.

Antibodies against fetal red blood cell (RBC) antigens can cause hemolytic disease of the fetus and newborn (HDFN). Reductions in HDFN due to anti-RhD antibodies have been achieved through use of Rh immune globulin (RhIg), a polyclonal antibody preparation that causes antibody-mediated immunosuppression (AMIS), thereby preventing maternal immune responses against fetal RBCs. Despite the success of RhIg, it is only effective against 1 alloantigen. The lack of similar interventions that mitigate immune responses toward other RBC alloantigens reflects an incomplete understanding of AMIS mechanisms. AMIS has been previously attributed to rapid antibody-mediated RBC removal, resulting in B-cell ignorance of the RBC alloantigen. However, our data demonstrate that antibody-mediated RBC removal can enhance de novo alloimmunization. In contrast, inclusion of antibodies that possess the ability to rapidly remove the target antigen in the absence of detectable RBC clearance can convert an augmented antibody response to AMIS. These results suggest that the ability of antibodies to remove target antigens from the RBC surface can trigger AMIS in situations in which enhanced immunity may otherwise occur. In doing so, these results hold promise in identifying key antibody characteristics that can drive AMIS, thereby facilitating the design of AMIS approaches toward other RBC antigens to eliminate all forms of HDFN.

Genotipificación del gen RHD en ADN fetal libre en plasma de embarazadas RhD negativo / Genotyping of the RHD gene in free fetal DNA in plasma of RhD negative pregnant women

Objetivo: Determinar el grupo RhD fetal a través del estudio del gen RHD en ADN fetal que se encuentra libre en plasma de embarazadas RhD negativo. Método: Se analizó la presencia de los genes RHD, SRY y BGLO en ADNfl obtenido de plasma de 51 embarazadas RhD negativo no sensibilizadas, utilizando una qPCR. Los resultados del estudio genético del gen RHD se compararon con el estudio del grupo sanguíneo RhD realizado por método serológico en muestras de sangre de cordón, y los resultados del estudio del gen SRY fueron cotejados con el sexo fetal determinado por ecografía. Se calcularon la sensibilidad, la especificidad, los valores predictivos y la capacidad discriminativa del método estandarizado. Resultados: El gen RHD estaba presente en el 72,5% de las muestras y el gen SRY en el 55,5%, coincidiendo en un 100% con los resultados del grupo RhD detectado en sangre de cordón y con el sexo fetal confirmado por ecografía, respectivamente. Conclusiones: Fue posible deducir el grupo sanguíneo RhD del feto mediante el estudio del ADN fetal que se encuentra libre en el plasma de embarazadas con un método molecular no invasivo desarrollado y validado para este fin. Este test no invasivo puede ser utilizado para tomar la decisión de administrar inmunoglobulina anti-D solo a embarazadas RhD negativo que portan un feto RhD positivo.

Objective: To determine the fetal RhD group through the study of the RHD gene in fetal DNA found free in plasma of RhD negative pregnant women. Method: The presence of the RHD, SRY and BGLO genes in fetal DNA obtained from plasma of 51 non-sensitized RhD negative pregnant women was analyzed using qPCR. The results of the genetic study of the RHD gene were compared with the RhD blood group study performed by serological method in cord blood samples, and the results of the SRY gene study were compared with the fetal sex determined by ultrasound. Sensitivity, specificity, predictive values and discriminative capacity of the standardized method were calculated. Results: The RHD gene was present in 72.5% of the samples and the SRY gene in 55.5%, coinciding 100% with the results of the RhD group detected in cord blood, and with the fetal sex confirmed by ultrasound, respectively. Conclusions: It was possible to deduce the RhD blood group of the fetus through the study of fetal DNA found free in the plasma of pregnant women with a non-invasive molecular method developed and validated for this purpose. This non-invasive test can be used to make the decision to administer anti-D immunoglobulin only to RhD-negative pregnant women carrying an RhD-positive fetus.

Rh(D) immune globulin administration in pregnancy: Retrospective audit of patient safety events followed by targeted educational intervention with Bayesian analysis.

OBJECTIVES: To examine local patient safety events related to the administration of anti-Rh(D) immune globin (RhIG) during pregnancy, and to follow-up with targeted educational intervention to improve knowledge of this process. BACKGROUND: Administration RhIG is established treatment for the prevention of haemolytic disease of the foetus and newborn (HDFN). However, patient safety events in relation to its correct use continue to occur. METHODS: A retrospective audit of patient safety events related to RhIG administration during pregnancy was performed. Targeted educational intervention in the form of PowerPoint® presentation were given to nursing staff, laboratory staff and physicians and evaluated with pre- and post-tests using multiple-choice questions given immediately before and after the presentation. RESULTS: An annual incidence of 0.24% of patient safety events related to the administration of RhIG during pregnancy was found. These events were mostly in the preanalytical phase, for example mislabelled samples or samples for D-rosette/Kleihauer-Betke testing drawn from the baby, not the mother. Using Bayesian analysis, the probability of positive effect for the targeted educational intervention was 100% with a median improved score of 29%. This was compared with a control group using standard curriculum education intervention based on the current curriculum for nursing, laboratory and medical students which showed a median improved score of only 4.4%. CONCLUSIONS: Administration of RhIG during pregnancy is a multistep process involving health care professionals of several disciplines providing opportunities to enhance the curriculum for nursing, laboratory and medical students and to ensure on-going education.

Cases of RhD variants RhD*DAU2/DAU6 and RhD*weak D type 4.1 in pregnant women in Saudi Arabia.

The D antigen is one of the most immunogenic and clinically significant antigens of the Rh blood group system due to its various genotypes that encode for more than 450 different variants. Accurate RhD typing and D variant identification is crucial specially in prenatal screening during pregnancy. Women with RhD -ve phenotype are eligible to Rh immune globulin (RhIG) prophylaxis for the prevention of anti-D alloimmunization and hemolytic disease of the fetus and newborn (HDFN). However, there are some women who possess RhD variant alleles, who are mistakenly grouped as RhD positive and considered not eligible for RhIG prophylaxis, putting them at risk of anti-D alloimmunization and consequently leading to HDFN during subsequent pregnancies. Here, we describe  two cases of RhD variants DAU2/DAU6 and Weak D type 4.1 in obstetric patients who were grouped as RhD +ve with negative antibody screening during routine serologic  testing. Weak/Partial D molecular analysis using genomic DNA Red Cell Genotyping (RCG) revealed that both patients had RhD variants, one of which DAU2/DAU6 allele associated with anti-D alloimmunization. According to routine testing neither patients received RhIG or transfusion. In this case report we document to our knowledge the first reported cases of RhD variants among pregnant women in Saudi Arabia.