Comparison of the Detection Rate and Specificity of Irregular Red Blood Cell Antibodies Between First-Time Pregnant Women and Women With a History of Multiple Pregnancies Among 18,010 Chinese Women.

Background: There is insufficient evidence to assess the risk of the production of clinically important alloimmune irregular red blood cell (RBC) antibodies in first-time pregnant women. Methods: Using the microcolumn gel antiglobulin method, 18,010 Chinese women with a history of pregnancy and pregnant women were screened for irregular RBC antibodies, and for those with positive test results, antibody specificity was determined. The detection rate and specificity of irregular RBC antibodies in women with a history of multiple pregnancies (two or more) and first-time pregnant women were determined. Results: In addition to 25 patients who passively acquired anti-D antibodies via an intravenous anti-D immunoglobulin injection, irregular RBC antibodies were detected in 121 (0.67%) of the 18,010 women. Irregular RBC antibodies were detected in 93 (0.71%) of the 13,027 women with a history of multiple pregnancies, and antibody specificity was distributed mainly in the Rh, MNSs, Lewis, and Kidd blood group systems; irregular RBC antibodies were detected in 28 (0.56%) of the 4983 first-time pregnant women, and the antibody specificity was distributed mainly in the MNSs, Rh, and Lewis blood group systems. The difference in the percentage of patients with irregular RBC antibodies between the two groups was insignificant (χ 2 = 1.248, P > 0.05). Of the 121 women with irregular RBC antibodies, nine had anti-Mur antibodies, and one had anti-Dia antibodies; these antibodies are clinically important but easily missed because the antigenic profile of the reagent RBCs that are commonly used in antibody screens does not include the antigens that are recognized by these antibodies. Conclusion: Irregular RBC antibody detection is clinically important for both pregnant women with a history of multiple pregnancies and first-time pregnant women. Mur and Dia should be included in the antigenic profile of reagent RBCs that are used for performing antibody screens in the Chinese population.

Analysis of laboratory tests and prevention strategies for hemolytic disease of the fetus and newborn caused by anti-M / 中国输血杂志

【Objective】 To analyze the application of serological test results in the diagnosis and treatment of anti-M-induced hemolytic disease of the fetus and newborn(HDFN), and to explore HDFN prevention strategies. 【Methods】 The serological test results of 12 cases of HDFN caused by anti-M diagnosed in our laboratory from January 2017 to December 2023 were retrospectively analyzed, including blood group identification of mothers and children, serum total bilirubin/hemoglobin/antibody titer test, and three hemolysis tests in newborns. Clinical data of the children and mothers were collected, including pregnancy history, blood transfusion history, prenatal antibody testing, history of intrauterine blood transfusion and gestational week of delivery, and the prognosis of the children was followed up. 【Results】 All 12 cases of fetal neonatal hemolytic disease due to anti-M were RhD+ MN phenotype newborn born to RhD+ NN mother, with maternal- fetal incompatiblility in MN blood groups. In the ABO blood group system, ABO incompatibility between mother and child accounted for 41.7%(5/12).None of the mothers had a history of blood transfusion, and the median titer of the test at 4℃ was 32, and the median titer at 37℃ was 4. The mothers of 3 cases had a history of multiple intrauterine blood transfusions, with an incidence of 25%(3/12). One case had an abnormal first pregnancy, with an incidence of 8.3%(1/12), and seven cases had an abnormal pregnancy with a miscarriage, with an incidence of abnormal pregnancy and birth history of 58.3%(7/12). There were 6 cases of premature labor, with an incidence of 50%(6/12). The mothers in three cases underwent regular obstetric examination and the specificity of the antibodies was determined, accounting for 25%(3/12). Twelve children had free antibodies with a median titer of 6 at 4℃ and 2 at 37℃. Two children had anti-M antibodies that were not reactive at 37℃, with a negative rate of 16.7%(2/12). The positive rate of DAT and elution test was respectively 8.3%(1/12) and 16.7%(2/12) in the children. The median minimum hemoglobin value was 75 g/L, and all 12 children received blood transfusions. The median peak total bilirubin value was 157.5 μmol/L, and none of them reached the threshold for blood exchange. The rate of delayed anemia was 16.7%(2/12), the postnatal mortality rate was 8.3%(1/12), and 11 children was free of growth and neurodevelopmental delay in prognosis. 【Conclusion】 Anti-M can cause severe HDFN, which can also occur in primigravida. The intensity of antibody titer does not correlate with the severity of the disease, and it is prone to cause delayed anemia, which should be monitored regularly according to the serological characteristics of anti-M and clinical symptoms, and should be treated timely.

Hemolytic diseases of the fetus and newborn caused by anti-Dib: a case report and related research / 中国输血杂志

【Objective】 To identify the specificity of alloantibody against high-frequency antigens in one case suffering with severe hemolytic diseases of the fetus and newborn (HDFN) and to screen for matching blood for transfusion. 【Methods】 The HDFN test and the antibody serological identification tests in the mother were performed. Several common high frequency antigens of maternal red blood cells (RBCs) were determined. IgG subtype coated on the RBCs of the newborn was determined. The phagocytic efficiency of the antibody was tested using the monocyte phagocytosis of sensitized erythrocyte by flow cytometry in vitro. Sanger sequencing of DI gene was performed in the mother, father and mother’s brother. The diluted maternal plasma was used for large scale screening of matching blood using IAT in Coomb’s gel card. 【Results】 Di(b-) phenotype was identified in the mother of the newborn and anti-Dib (titer: 512) related HDN was detected in the newborn. IgG1 and IgG2 subtypes of anti-Dib were detected and the rate of monocyte phagocytosis was 88.83%(74.7/84.09). The compatible blood was not detected in the maternal relatives. Subsequently, the newborn received the matching RBCs of two Di(b-) donors identified from 5 520 blood donors and discharged from the hospital. We screened out 17 Di(b-) donors out of 51 334 blood donors, indicating that the distribution frequency of Di(b-) among blood donors in Guangzhou was about 0.033% (17/51 334). 【Conclusion】 By serology and molecular biology methods, the newborn was identified with HDFN caused by anti-Dib, and an effective large-scale screening method for Di (b -) rare blood types was established to find matching blood, which supported the establishment of rare Di(b-) blood database.

Comparison of automated solid phase versus manual saline indirect antiglobulin test methodology for non-ABO antibody titration: Implications for perinatal antibody monitoring.

BACKGROUND: Accurate antibody titration is crucial in prenatal evaluations to identify patients who need clinical monitoring for hemolytic disease of the fetus and newborn (HDFN) causing fetal anemia. This study compares the established gold standard method of manual tube saline indirect antiglobulin testing (SIAT) with the newer automated solid phase (ASP) method of antibody titration and aims to establish the critical titer threshold for ASP that corresponds to the previously established SIAT critical threshold of ≥16 used in our laboratory. STUDY DESIGN AND METHODS: One hundred fifty-seven prenatal and donor plasma samples with known antibodies were tested using both SIAT and ASP methodologies and results were compared. RESULTS: The study found that ASP titers were, on average, 1.33 dilutions higher than SIAT titers. The critical titer cutoff for ASP was determined to be ≥32, which is one tube higher than the SIAT cutoff of ≥16. DISCUSSION: The ASP method for antibody titration offers greater reproducibility and efficiency compared with manual SIAT titration. This study suggests that a titer cutoff of ≥32 is appropriate for most clinically significant antibodies using ASP. However, further research is needed to determine the comparability of ASP with SIAT in samples with multiple antibodies, anti-M antibodies, and other less common antibodies. Validation of the ASP titer cutoff against HDFN clinical outcomes is required before implementing this test for routine use in perinatal antibody titration.

Fetal RHD Screening in RH1 Negative Pregnant Women: Experience in Switzerland.

RH1 incompatibility between mother and fetus can cause hemolytic disease of the fetus and newborn. In Switzerland, fetal RHD genotyping from maternal blood has been recommended from gestational age 18 onwards since the year 2020. This facilitates tailored administration of RH immunoglobulin (RHIG) only to RH1 negative women carrying a RH1 positive fetus. Data from 30 months of noninvasive fetal RHD screening is presented. Cell-free DNA was extracted from 7192 plasma samples using a commercial kit, followed by an in-house qPCR to detect RHD exons 5 and 7, in addition to an amplification control. Valid results were obtained from 7072 samples, with 4515 (64%) fetuses typed RHD positive and 2556 (36%) fetuses being RHD negative. A total of 120 samples led to inconclusive results due to the presence of maternal or fetal RHD variants (46%), followed by women being serologically RH1 positive (37%), and technical issues (17%). One sample was typed false positive, possibly due to contamination. No false negative results were observed. We show that unnecessary administration of RHIG can be avoided for more than one third of RH1 negative pregnant women in Switzerland. This reduces the risks of exposure to a blood-derived product and conserves this limited resource to women in actual need.

Hemolytic disease of the fetus and newborn: rapid review of postnatal care and outcomes.

BACKGROUND: Advances in postnatal care for hemolytic disease of the fetus and newborn (HDFN) have occurred over the past decades, but little is known regarding the frequency of postnatal treatment and the clinical outcomes of affected neonates. Most studies reporting on HDFN originate from high-income countries or relatively large centers, but important differences between centers and countries may exist due to differences in prevalence and available treatment options. We therefore aimed to evaluate the postnatal treatment landscape and clinical outcomes in neonates with Rhesus factor D (Rh(D))- and/or K-mediated HDFN and to provide recommendations for future research. METHODS: We conducted a rapid literature review of case reports and series, observational retrospective and prospective cohort studies, and trials describing pregnancies or children affected by Rh(D)- or K-mediated HDFN published between 2005 and 2021. Information relevant to the treatment of HDFN and clinical outcomes was extracted. Medline, ClinicalTrials.gov and EMBASE were searched for relevant studies by two independent reviewers through title/abstract and full-text screening. Two independent reviewers extracted data and assessed methodological quality of included studies. RESULTS: Forty-three studies reporting postnatal data were included. The median frequency of exchange transfusions was 6.0% [interquartile range (IQR): 0.0-20.0] in K-mediated HDFN and 26.5% [IQR: 18.0-42.9] in Rh(D)-mediated HDFN. The median use of simple red blood cell transfusions in K-mediated HDFN was 50.0% [IQR: 25.0-56.0] and 60.0% [IQR: 20.0-72.0] in Rh(D)-mediated HDFN. Large differences in transfusion rates were found between centers. Neonatal mortality amongst cases treated with intrauterine transfusion(s) was 1.2% [IQR: 0-4.4]. Guidelines and thresholds for exchange transfusions and simple RBC transfusions were reported in 50% of studies. CONCLUSION: Most included studies were from middle- to high-income countries. No studies with a higher level of evidence from centers in low-income countries were available. We noted a shortage and inconsistency in the reporting of relevant data and provide recommendations for future reports. Although large variations between studies was found and information was often missing, analysis showed that the postnatal burden of HDFN, including need for neonatal interventions, remains high. SYSTEMATIC REVIEW REGISTRATION: PROSPERO 2021 CRD42021234940. Available from:  https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021234940 .

Live birth prevalence of hemolytic disease of the fetus and newborn in the United States from 1996 to 2010.

BACKGROUND: Hemolytic disease of the fetus and newborn (HDFN) is mediated by maternal alloantibodies, a consequence of immune sensitization during pregnancy with maternal-fetal incompatibility with ABO, Rhesus factor (Rh), and/or other red blood cell antigens. RhD, Kell, and other non-ABO alloantibodies are the primary cause of moderate to severe HDFN, whereas ABO HDFN is typically mild. HDFN live birth prevalence owing to Rh alloimmunization among newborns in the United States was last estimated to be 106 per 100,000 births in 1986. HDFN live birth prevalence owing to all alloantibodies was estimated to be 817 to 840 per 100,000 in Europe. There is a need for updated prevalence estimates in the United States and a better understanding of disease demographics, severity, and treatments. OBJECTIVE: This study aimed to estimate the live birth prevalence of HDFN and the proportion of severe cases of HDFN in the United States, to describe the associated risk factors, and to compare the clinical outcomes and treatments among healthy newborns, newborns with HDFN, and newborns who are sick without HDFN using a nationally representative hospital discharge database. STUDY DESIGN: In this retrospective, observational cohort study, we used data from the 1996 to 2010 National Hospital Discharge Survey to identify live births, defined by inpatient visits with the newborn flag, with and without a diagnosis of HDFN across 200 to 500 sampled hospitals (≥6 beds) per year. Patient and hospital characteristics, alloimmunization status, disease severity, treatment, and clinical outcomes were evaluated. Frequencies and weighted percentages were calculated for all variables. Logistic regression was used to compare the characteristics between newborns with HDFN and other newborns using odds ratios. RESULTS: Of 480,245 live births identified, 9810 HDFN cases were recorded. When weighted to the United States population, this corresponded to a live birth prevalence of 1695 per 100,000 live births. Compared with other newborns, newborns with HDFN were more likely to be female, Black, living in the South (vs the Midwest or West), and treated at larger (>100 beds) and government-owned hospitals. ABO and Rh alloimmunization accounted for 78.1% and 4.3% of newborns with HDFN, respectively, whereas HDFN caused by other antigens, such as Kell and Duffy, accounted for 17.6% of the cases. Among newborns with HDFN, 22% received phototherapy, 1% received simple transfusions, and 0.5% received exchange transfusions or intravenous immunoglobulin. Newborns affected by HDFN caused by Rh alloimmunization were more likely to require medical interventions, including simple or exchange transfusions, and more likely to be delivered by cesarean delivery. Overall, HDFN was associated with a longer hospital length of stay in the neonatal intensive care unit when compared with healthy and other sick newborns, a higher rate of cesarean delivery, and a higher rate of nonroutine discharge than healthy newborns. CONCLUSION: Overall, the live birth prevalence of HDFN was higher than those previously reported, whereas Rh-induced HDFN live birth prevalence was similar to those previously reported. HDFN live birth prevalence owing to Rh alloimmunization decreased over time, likely because of continued Rh immune globulin prophylaxis. Treatment patterns for newborns with HDFN and the comparative clinical outcomes when compared with healthy newborns confirm the continued clinical needs of this population.

Not as "D"eadly as once thought - the risk of D-alloimmunization and hemolytic disease of the fetus and newborn following RhD-positive transfusion in trauma.

The use of blood products to resuscitate injured and massively bleeding patients in the prehospital and early in-hospital phase of the resuscitation is increasing. Using group O red blood cells (RBC) and low titer group O whole blood (LTOWB) avoids an immediate hemolytic reaction from recipient's naturally occurring anti-A and - B, but choosing the RhD type for these products is more nuanced and requires the balancing of product availability and survival benefit against the risk of D-alloimmunization, especially in females of childbearing potential (FCP) due to the possible future occurrence of hemolytic disease of the fetus and newborn (HDFN). Recent models have estimated the risk of fetal/neonatal death from HDFN resulting from D-alloimmunization of an FCP during her trauma resuscitation at between 0-6.5% depending on her age at the time of the transfusion and other societal factors including trauma mortality, her age when she becomes pregnant, frequency of different RHD genotypes in the population, and the probability that the woman will have children with different fathers; this is counterbalanced by an approximately 24% risk of death from hemorrhagic shock. This review will discuss the different models of HDFN outcomes following RhD-positive transfusion as well as the results of recent surveys where the public was asked about their preferences for urgent transfusion in light of the risks of fetal/neonatal adverse events.

Blood immunological analysis of hemolytic disease of the fetus and newborn caused by Rh deletion type D-- / 中国输血杂志

【Objective】 To analyze the causes of a case of hemolytic disease of the fetus and newborn (HDFN),and investigate the genetic background of maternal Rh deletion D--formation. 【Methods】 Blood samples of maternal and fetus were collected, and ABO blood typing, Rh blood typing, antibody screening and identification test were performed to explore the blood group serological characteristics of Rh deletion type D--, and Rh gene sequence was performed on parturient. 【Results】 The maternal blood group was identified to be O type, D--, and the anti-Hr0 antibody against Rh high-frequency antigen was suspected to be caused by multiple pregnancies which passes through the placental barrier and enable fetus to obtain anti Hr0 antibody, leading to HDFN, with genetic testing result as RH RHCE* Ce/RHCE* Ce. 【Conclusion】 In-depth research on the formation mechanism of Rh D-- in parturient should be conducted to provide clinical value for HDFN blood exchange treatment and blood transfusion in special blood group population.

Analysis of ABO system hemolytic disease of the fetus and newborn in 1 040 cases and its influencing factors / 中国输血杂志

【Objective】 To analyze ABO system hemolytic disease of the fetus and newborn (HDFN) and its influencing factors in Obstetrics Department of our hospital. 【Methods】 The blood samples of 1 040 neonates and their mothers in the obstetric department of our hospital were retrospectively analyzed from September 2022 to January 2023, including ABO and RhD blood group of the neonates and mothers, as well as 3 tests of HDFN, Hb, total bilirubin (TBIL) and indirect bilirubin(IBIL) of the neonates. Relevant clinical data of the neonates and mothers were collected, including maternal and neonatal age, neonatal sex, maternal pregnancy history, gestational age and delivery mode, and their influences on ABO-HDFN were analyzed. 【Results】 Among 1 040 HDFN samples, 298 were ABO incompatibility, among which 113 were HDFN positive, with a positive rate of 37.9% (113/298); the positive rate of HDFN in neonates born to mothers with type O was significantly higher than that in neonates born to mothers with type A and B (71.4% vs 8.2%, P<0.05); the positive rate of HDFN in neonates with antigen-A incompatibility was significantly higher than that in neonates with antigen-B incompatibility (48.7%vs 26.7%, P<0.05), which was the highest in neonates with O-A incompatibility [83.6% (61/73)], followed by O-B incompatibility [58.2% (39/67)]. There was no significant difference in Hb and bilirubin among the other groups except for the difference of Hb between the O-A incompatibility HDFN positive group and the HDFN negative group [(145.0±16.0) vs(153.4±13.2), P<0.05)]. The levels of Hb, TBIL and IBIL in the "direct antiglobulin test+ indirect antiglobulin test+release test+" group were significantly different from those in the HDFN negative group[(144.9±21.6) vs (153.3±13.2), P <0.05; (36.9±11.8) vs (29.6±6.1), P<0.05; (30.6±12.7) vs (23.0±6.9), P<0.05, respectively]. Logistic regression analysis showed that maternal delivery frequency, mother-neonate incompatible antigen and maternal blood type were independent risk factors for HDFN. 【Conclusion】 ABO-HDFN occurred mainly in neonates born to O-type mothers, and the positive rate was the highest in neonates with O-A incompatibility. The severity of HDFN had little relationship with the mother-neonate blood type, but had relationship with the result of 3 tests of HDFN. Maternal delivery frequency, mother-neonate incompatible antigen and maternal blood type were independent risk factors for HDFN.

Polyhydramnios as a sole ultrasonographic finding for detecting fetal hemolytic anemia caused by anti-c alloimmunization.

OBJECTIVE: The prenatal course of a rare case with fetal anemia caused by maternal anti-c alloimmunization was reported. CASE REPORT: A 39-year-old female with anti-c and anti-E antibodies against red cells had previously experienced a stillbirth. At her present pregnancy, titers of maternal antibodies and fetal middle cerebral artery peak systolic velocity (MCA-PSV) were frequently monitored to investigate the severity of fetal hemolytic anemia. Rather than manifesting as an increase in MCA-PSV, the anemic fetus was delivered at 32 weeks and one day of gestation with a sole presentation: polyhydramnios. Neonatal hospitalization course were compatible with hemolytic anemia. The baby was discharged at 48 days of age. CONCLUSION: This case illustrated the complexities of dealing with maternal red cell alloimmunization during pregnancy and the limitations of noninvasive diagnostic modalities for detecting fetal anemia, and highlighted that obstetricians should refer all available clinical parameters in order to offer appropriate perinatal care.

Hemolytic Disease of the Fetus and Newborn: Historical and Current State.

Hemolytic disease of the fetus and newborn (HDFN) is an immune-mediated disorder affecting neonates globally, with a range of clinical presentations from severe and life threatening to mild or even asymptomatic. Historically, HDFN has been responsible for a large proportion of perinatal mortality, and, despite advances in diagnosis and management, this morbidity and mortality has not been eradicated. Blood banking techniques and blood transfusion have contributed to improved prophylaxis and management, drastically improving the outcome of newborns with HDFN over the last century.

A case of mild HDFN caused by anti-C, anti-D, and anti-G: Diagnostic strategy and clinical significance of distinguishing anti-G from anti-D and anti-C.

Anti-G is commonly present with anti-D and anti-C and can confuse serological investigations. The differentiation of anti-G from anti-D and anti-C is particularly essential for the accurate diagnosis of hemolytic disease of the fetus and newborn (HDFN) and appropriate administration of anti-D immunoglobulin prophylaxis in Rhesus (Rh) negative women. We reported a rare case of anti-G together with anti-D and anti-C in a pregnant woman and her female neonate. The titers of IgG anti-D, anti-C, and anti-G in the woman were 256, 128, and 32, respectively. While the titers of IgG anti-D, anti-C, and anti-G in the neonate were 16, 8, and 4, respectively. The neonate experienced mild HDFN and only received phototherapy during hospitalization. This report discusses the diagnostic strategy and clinical significance of differentiating anti-G from anti-D and anti-C.