Fatal hemolytic disease of the newborn due to anti-B Isohemagglutinin: An unfamiliar presentation of a familiar disease.

BACKGROUND: Hemolytic disease of the newborn (HDN) occurs in approximately 1 out of 3000 live births. Severe presentations are atypical but must be recognized and treated rapidly to avoid life-threatening organ dysfunction. CASE PRESENTATION: Here we report an unusual case of neonatal ABO HDN that illustrates the enormous inflammatory potential of maternal-fetal blood group mismatch. Following an uneventful delivery notable only for HDN caused by maternal anti-B IgG, our patient developed shock, DIC, and renal failure. Despite numerous interventions, she experienced a rapid clinical decline and died 10 days after birth. Treatment with whole blood exchange and a monoclonal antibody directed at complement component 5 (eculizumab) were attempted late in the disease course but were unsuccessful. Importantly, this patient had several known risk factors for severe ABO HDN, including the pentad of a group O mother with a group B neonate, high newborn red blood cell B antigen expression, presence maternal anti-B isohemagglutinin in high titer, presence of a maternal IgG anti-B isohemagglutinin, and African ancestry. CONCLUSION: Clinicians should be aware of the potential for severe ABO HDN and consider earlier diagnostic workup and more aggressive therapy in patients with high-risk features.

A study on diagnostic performance of different immunohematological diagnostic tests in assessing the prevalence of ABO Hemolytic Disease of Newborn in the antenatal O group mothers and their neonatal outcome in a tertiary care hospital in Northern India.

BACKGROUND: Hemolytic disease of the newborn (HDN) results in the decreased lifespan of the red cells. HDN related to ABO incompatibility is mostly unnoticed because routine screening is not being done. This study was done to assess the prevalence of ABO-HDN and to compare different immunohematological tests. Methods-In this study 213 O group mothers and the 122 ABO-incompatible newborns born to them were included. Quantifying the maternal IgG anti-A/anti-B antibody titer was done by Conventional Tube Technique (CTT) using Dithiothreitol (DTT) pretreated maternal serum. Hemolysin test was performed on the mothers having titer > 256. These cases were followed up and, after delivery, were monitored for ABO HDN, along with direct antiglobulin testing and elution studies. The prevalence of ABO-HDN was calculated, and the different diagnostic parameters of the tests were calculated. Results- The prevalence of ABO-HDN in our population was estimated to be 1.7%, 6.1% & 10.6% in our population, O group mothers, and O group mothers with ABOincompatible newborns, respectively. Maternal titer≥ 512 strongly correlated with ABOHDN. DAT positivity is a good predictor of ABO-HDN, especially using sensitive techniques. Maternal IgG titers have the highest sensitivity & Negative Predictive Value, while DAT has the highest specificity & Positive Predictive Value. Conclusion - Maternal ABO antibody titration may be advocated in the centers to identify high-risk groups. It can advocate institutional delivery and dedicated follow-up of newborns with ABO-HDN. Blood grouping & DAT may be performed in all newborns born to O blood group to identify high-risk cases.

Severe fetal anemia caused by anti-Jra : Burst forming unit-erythroid colony formation inhibition assay suggesting possible erythroid suppression mechanism.

BACKGROUND: The Jr blood group system includes a single, high-prevalence antigen, Jra , encoded by the ABCG2 gene. The impact of anti-Jra in pregnancy is variable, ranging from no clinical effect to severe anemia including some fetal deaths. Case reports have postulated that anti-Jra mediated fetal anemia is poorly hemolytic, suggesting other mechanisms of anemia may be involved. STUDY DESIGN AND METHODS: We describe the case of severe anti-Jra mediated fetal anemia. At Canadian Blood Services laboratories, maternal anti-Jra was tested for phagocytic activity via a monocyte monolayer assay (MMA) and erythroid suppression via inhibition of burst forming unit-erythroid (BFU-E) colony formation assays. The New York Blood Center sequenced exons 4 and 7 of the ABCG2 gene. RESULTS AND DISCUSSION: Sequencing of exons 4 and 7 of the ABCG2 gene revealed maternal compound heterozygosity for two nonsense mutations at exon 7 (c.706 C > T and c.784G > T). Fetal sequencing revealed the c.706C > T polymorphism. The MMA showed a borderline phagocytic index (around the cutoff of five for both donor segments tested [5 ± 1 and 7 ± 3]). The BFU-E colony formation inhibition assay suggested a dose-dependent inhibition of BFU-E colony formation with inhibition percentages of 4%, 11%, and 43% at maternal serum concentrations of 2%, 5%, and 10%, respectively. Our findings support the hypothesis that anti-Jra may impair erythropoiesis leading to clinically significant fetal/neonatal anemia. A referral to maternal fetal medicine is recommended if anti-Jra is detected in pregnancy, regardless of the titer.

Evaluation of the effectiveness of the human-baited double net traps and BG traps compared with the human landing catches for collecting outdoor Aedes albopictus in China.

Dengue fever is one of the biggest threats to public health in China, causing huge disease burden and economic loss. Aedes-mosquito surveillance could be a cornerstone for predicting the risk of Aedes-borne diseases and evaluating the effect of vector management during diseases outbreaks. The human landing catch (HLC) method is regarded as the "gold standard" for catching Aedes mosquitoes, but it potentially exposes field professionals to vectors of known or unknown pathogens. Human-baited double net (HDN) was recommended to replace HLC for emergency monitoring in China when Aedes-borne diseases break out, but it had been reported with low efficiency for capturing Aedes mosquitoes. In this study, we compared HLC with HDN and BG traps for field Aedes albopictus monitoring, with the aim of evaluating the effectiveness of HDN replacing HLC and finding an effective and safe alternative to the HLC for monitoring Aedes albopictus. Six sites in Hangzhou, Shaoxing, and Yiwu, Zhejiang Province, China, were chosen to conduct outdoor HLC, HDN, and BG trap catches from June to October 2021. The tests were performed 3 h apart: 8:30-9:30 AM, 16:30-17:30 PM, and 17:30-18:30 PM. A total of 2330 adult mosquitoes were collected, and Aedes albopictus was the most abundant species in all three catches with 848(98.95%), 559(97.39%) and 867 (96.44%) caught in HLC, HDN and BG traps respectively. Compared to HLC, HDN collected significantly less Ae. albopictus and Ae. albopictus females per trapping period (P < 0.001, P < 0.001), whereas no statistical differences were found between the HLC and BG trap (P = 0.970, P > 0.05). Statistically significant positive spatial correlations for Ae. albopictus sampling was found between HLC and HDN traps (r = 0.543, P < 0.001) and HLC and BG traps (r = 0.658, P < 0.001). In conclusion, both the BG trap and HDN have a significant positive spatial correlation with HLC, making them safer alternatives to HLC for Ae. albopictus monitoring in China. However, with better a sampling efficiency, being less labor intensive, and no human-baited attraction bias, the BG trap could be a better choice than the HDN trap.

Extending the Structural Diversity of Labdane Diterpenoids from Marine-Derived Fungus Talaromyces sp. HDN151403 Using Heterologous Expression.

Heterologous biosynthesis has become an effective means to activate fungal silent biosynthetic gene clusters (BGCs) and efficiently utilize fungal genetic resources. Herein, thirteen labdane diterpene derivatives, including five undescribed ones named talarobicins A-E (3-7), were discovered via heterologous expression of a silent BGC (labd) in Aspergillus nidulans. Their structures with absolute configurations were elucidated using extensive MS and NMR spectroscopic methods, as well as electronic circular dichroism (ECD) calculations. These labdanes belong to four skeleton types, and talarobicin B (4) is the first 3,18-dinor-2,3:4,18-diseco-labdane diterpene with the cleavage of the C2-C3 bond in ring A and the decarboxylation at C-3 and C-18. Talarobicin B (4) represents the key intermediate in the biosynthesis of penioxalicin and compound 13. The combinatorial heterologous expression and feeding experiments revealed that the cytochrome P450 enzymes LabdC, LabdE, and LabdF were responsible for catalyzing various chemical reactions, such as oxidation, decarboxylation, and methylation. All of the compounds are noncytotoxic, and compounds 2 and 8 displayed inhibitory effects against methicillin-resistant coagulase-negative staphylococci (MRCNS) and Bacillus cereus.

Substituent Effects of the Nitrogen Heterocycle on Indole and Quinoline HDN Performance: A Combination of Experiments and Theoretical Study.

Hydrodenitrogenation (HDN) experiments and density functional theory (DFT) calculations were combined herein to study the substituent effects of the nitrogen heterocycle on the HDN behaviors of indole and quinoline. Indole (IND), 2-methyl-indole (2-M-IND), 3-methyl-indole (3-M-IND), quinoline (QL), 2-methyl-quinoline (2-M-QL) and 3-methyl-quinoline (3-M-QL) were used as the HDN reactant on the NiMo/γ-Al2O3 catalyst. Some key elementary reactions in the HDN process of these nitrogen compounds on the Ni-Mo-S active nanocluster were calculated. The notable difference between IND and QL in the HDN is that dihydro-indole (DHI) can directly convert to O-ethyl aniline via the C-N bond cleavage, whereas tetrahydro-quinoline (THQ) can only break the C-N single bond via the full hydrogenation saturation of the aromatic ring. The reason for this is that the -NH and C=C groups of DHI can be coplanar and well adsorbed on the Ni-Mo-edge simultaneously during the C-N bond cleavage. In comparison, those of THQ cannot stably simultaneously adsorb on the Ni-Mo-edge because of the non-coplanarity. Whenever the methyl group locates on the α-C or the ß-C atom of indole, the hydrogenation ability of the nitrogen heterocycle will be evidently weakened because the methyl group increases the space requirement of the sp3 carbon, and the impaction of the C=C groups on the Ni-S-edge cannot provide enough space. When the methyl groups are located on the α-C of quinoline, the self-HDN behavior of 2-M-QL is similar to quinoline, whereas the competitive HDN ability of 2-M-QL in the homologs is evidently weakened because the methyl group on the α-C hinders the contact between the N atom of 2-M-QL and the exposed metal atom of the coordinatively unsaturated active sites (CUS). When the methyl group locates on the ß-C of quinoline, the C-N bond cleavage of 3-methyl-quinoline becomes more difficult because the methyl group on the ß-C increases the steric hindrance of the C=C group. However, the competitive HDN ability of 3-M-QL is not evidently influenced because the methyl group on the ß-C does not evidently hinder the adsorption of 3-M-QL on the active sites.

Routine noninvasive prenatal screening for fetal Rh D in maternal plasma-A 2-year experience from a single center in Belgium.

BACKGROUND: Hemolytic disease of the fetus and newborn (HDFN) due to rhesus D (RhD) immunization is a potentially life-threatening situation for which use of Rh Immunoglobulin (RhIg) has decreased risk drastically. Determination of fetal RHD on maternal plasma can be used to restrict prenatal RhIg administration to women carrying an RhD-positive child, avoiding unnecessary administration of blood-derived products. STUDY DESIGN AND METHODS: The aim of this study is to determine the performance of fetal RHD typing in our center. We prospectively collected 205 fetal RHD and 127 serological cord blood RhD data from RhD-negative women starting at 11 weeks of pregnancy (from October 2019 to October 2021). Real-time polymerase chain reaction targeting RHD exon 5 and 7 was used, similar to the screening program in The Netherlands, supplemented with an amplification control (beta-actin; ACTB) and a sex determination marker located on the Y-chromosome (SRY gene). RESULTS: Fetal RHD testing reached a sensitivity and specificity of 100%. No false-negative nor false-positive results were reported. Inconclusive results (6%, 13/205) were due to weak amplification in 10 cases, a maternal RHD variant in 2 cases (RHD*01N.71 and partial DVI), and a fetal RHD variant (partial DVI) in 1 case. Unnecessary administration of RhIg prophylaxis was avoided in 33% of cases and on the other hand was administered in one case (fetal partial DVI) which would have been missed with cord blood serology. DISCUSSION: This study demonstrates the high accuracy of routine prenatal fetal RHD gene screening after 11 weeks of pregnancy, encouraging routine clinical practice.

A cross-sectional study of haemolytic disease of the newborn in Uganda.

BACKGROUND AND OBJECTIVES: Haemolytic disease of the newborn (HDN) is an immune haemolytic anaemia from maternal alloantibodies. Rh immunoglobulin (RhIg) prophylaxis can prevent alloimmunization to the D antigen. However, RhIg is not universally available in Uganda. ABO incompatibility also causes HDN. We determined the prevalence of HDN among newborn infants with jaundice in Uganda. MATERIALS AND METHODS: We conducted a prospective cross-sectional study at Kawempe National Referral Hospital, Kampala, Uganda. Infants aged 0-14 days with neonatal jaundice (or total bilirubin >50 µmol/L) were enrolled. Clinical evaluation and laboratory testing, including ABO, RhD typing and maternal antibody screen, were performed. RESULTS: A total of 466 babies were enrolled. The mean (SD) age was 3.4 (1.5) days. Of newborn babies with jaundice, 17.2% (80/466) had HDN. Babies with HDN had lower haemoglobin (SD); 15.7 (2.7) compared with those without HDN; 16.4 (2.4) g/dL, p = 0.016; and a higher bilirubin (interquartile range); 241 (200-318) compared with those without HDN; 219 (191-263) µmol/L, p < 0.001. One baby had anti-D HDN, while 46/466 had HDN from an ABO incompatibility (anti-A 43.5% and anti-B 56.5%); 82% of babies with HDN also had suspected neonatal sepsis or birth asphyxia. About 79.2% (57/72) of mothers did not have ABO/Rh blood group performed antenatally. All infants with HDN survived except one. CONCLUSION: Among newborn infants with jaundice, HDN is not rare. The majority is due to ABO HDN affecting group A and group B babies equally. Ensuring routine ABO/Rh grouping for all pregnant women is an area for improvement.

Retrospective analysis of direct antiglobulin test positivity at tertiary academic hospital over 10 years.

BACKGROUND: Hemolytic disease of the fetus and newborn (HDFN) is a clinically significant problem that may potentially affect any pregnancy. Direct antiglobulin test (DAT) is considered to be an important test in identifying newborns who are suspected to have HDN. This study aims in reviewing data regarding a positive DAT result concerning etiology and the development of HDN over a period of 10 years. STUDY DESIGN AND METHODS: A retrospective study of all neonates with a positive DAT result between January 2011 and December 2020 was performed. Data were obtained from patients' electronic hospital files, transfusion medicine databases, and medical birth records. Laboratory parameters along with clinical interventions in neonates with a DAT-positive result and a comparison group of DAT-negative neonates were performed. RESULTS: 36,000 deliveries were registered in this period. 176 (2.65 %) neonates had a positive DAT result. ABO-incompatibility was the most common cause with 59.1 %; Rh incompatibility 13.8 %, minor blood group incompatibility, and other RBC-related antibodies 10.1 %, and unspecified etiology in 17 % of cases. Among DAT-positive cases, 32.7 % of neonates were diagnosed with HDN. ABO-incompatibility was the major reason as well. Initial mean total bilirubin levels were higher in the DAT-positive group than the control group (p < 0.001), and these neonates also had a lower initial hemoglobin level (p < 0.001). The need for therapeutic interventions was significantly higher in DAT-positive neonates (p < 0.001) as 86.8 % underwent phototherapy, with 32.7 %, and 17.6 % receiving exchange transfusion (ET) and intravenous immunoglobulin (IVIG), respectively. CONCLUSION: In conclusion, ABO incompatibility was the most common cause for neonatal DAT positivity. Besides the common causes of DAT positivity, there would be rare but important conditions that may lead to a positive result, such as antibodies passively acquired from mothers in the context of alloimmunizations or using drugs. In addition, as a high rate of therapeutic intervention was identified among neonates with a DAT-positive result, there is a crucial need for increasing awareness regarding early diagnosis of the condition, careful monitoring, and the employment of prenatal alloimmunization screening tests.

Metabolic activities and molecular investigations of the ameliorative impact of some growth biostimulators on chilling-stressed coriander (Coriandrum sativum L.) plant.

BACKGROUND: Priming of seed prior chilling is regarded as one of the methods to promote seeds germination, whole plant growth, and yield components. The application of biostimulants was reported as beneficial for protecting many plants from biotic or abiotic stresses. Their value was as important to be involved in improving the growth parameters of plants. Also, they were practiced in the regulation of various metabolic pathways to enhance acclimation and tolerance in coriander against chilling stress. To our knowledge, little is deciphered about the molecular mechanisms underpinning the ameliorative impact of biostimulants in the context of understanding the link and overlap between improved morphological characters, induced metabolic processes, and upregulated gene expression. In this study, the ameliorative effect(s) of potassium silicate, HA, and gamma radiation on acclimation of coriander to tolerate chilling stress was evaluated by integrating the data of growth, yield, physiological and molecular aspects. RESULTS: Plant growth, yield components, and metabolic activities were generally diminished in chilling-stressed coriander plants. On the other hand, levels of ABA and soluble sugars were increased. Alleviation treatment by humic acid, followed by silicate and gamma irradiation, has notably promoted plant growth parameters and yield components in chilling-stressed coriander plants. This improvement was concomitant with a significant increase in phytohormones, photosynthetic pigments, carbohydrate contents, antioxidants defense system, and induction of large subunit of RuBisCO enzyme production. The assembly of Toc complex subunits was maintained, and even their expression was stimulated (especially Toc75 and Toc 34) upon alleviation of the chilling stress by applied biostimulators. Collectively, humic acid was the best the element to alleviate the adverse effects of chilling stress on growth and productivity of coriander. CONCLUSIONS: It could be suggested that the inducing effect of the pretreatments on hormonal balance triggered an increase in IAA + GA3/ABA hormonal ratio. This ratio could be linked and engaged with the protection of cellular metabolic activities from chilling injury against the whole plant life cycle. Therefore, it was speculated that seed priming in humic acid is a powerful technique that can benefit the chilled along with non-chilled plants and sustain the economic importance of coriander plant productivity.

HDN-1 induces cell differentiation toward apoptosis in promyelocytic leukemia cells depending on its selective effect on client proteins of Hsp90.

Heat Shock Protein 90 (Hsp90) is frequently upregulated in many cancers, and its inhibition simultaneously blocks multiple signaling pathways, resulting in cell differentiation or apoptosis. However, the complexity of Hsp90 in differentiation and its relation with apoptosis have remained unsettled. In this study, we demonstrated that HDN-1, a C-terminal inhibitor of Hsp90, induced the differentiation of HL-60 cells toward apoptosis. HDN-1 induced the differentiation of cells containing mutant AML1-ETO into mature granulocytes, which was related to its selective effect on client proteins of Hsp90. HDN-1 destabilized AML1-ETO and preserved C/EBPß at the same time, thereby induced a total increase in C/EBPß levels because of AML1-ETO negative regulation to C/EBPß expression. Neither HDN-1 nor 17-AAG (an N-terminal inhibitor of Hsp90) led to the differentiation of NB4 cells because mutant PML-RARα was not affected as a client protein of Hsp90; thus, no additional expression of C/EBPß was induced. 17-AAG did not affect the differentiation of HL-60 cells due to decreased AML1-ETO and C/EBPß levels. These results indicate that HDN-1 drives cell differentiation toward apoptosis depending on its selective influence on client proteins of Hsp90, establishing the relationship between differentiation and apoptosis and uncovering the mechanism of HDN-1 in promyelocytic leukemia cell differentiation. Moreover, HDN-1 is very promising for the development of anticancer agents with the induction of differentiation.

Targeting the neonatal Fc receptor (FcRn) to treat autoimmune diseases and maternal-fetal immune cytopenias.

FcRn, a non-classical Fc gamma (γ) receptor (FcγR) with near ubiquitous expression, plays key roles in disease pathogenesis and progression though immunoglobulin G (IgG) transport, IgG recycling, and IgG-immune complex clearance. FcRn function can be inhibited using IgG-based and non-IgG-based antagonists, by exploiting the pH-dependent binding affinity of FcRn for the IgG Fc region. FcRn therapeutics have shown promise in murine models and human clinical trials for autoimmune diseases and maternal-fetal immune cytopenias; they appear safe, well-tolerated, and reduce circulating IgG levels. Compared to traditional therapeutics, inhibiting FcRn has fewer adverse side effects and represents a new approach that is less invasive, time-consuming, and costly.

Clinical Implication of Immunohaematological Tests in ABO haemolytic disease of newborn: Revisiting an old disease.

OBJECTIVE: We aimed to assess the frequency distribution of of ABO haemolytic disease of newborn (ABO-HDN) and to know the predictive value of immunohaematological tests in identifying at risk neonates. BACKGROUND: ABO incompatibility, although a common cause of haemolytic disease of newborn, has several unaddressed issues related to it. MATERIAL AND METHODS: A prospective study over 20 months was carried out in a tertiary care centre in South India. Blood grouping, Direct Antiglobulin test (DAT) and elution studies were performed on neonatal samples, whereas blood grouping, antibody screening and antibody titration were performed on maternal samples. In suspected cases, ABO-HDN was diagnosed after excluding other possible causes for haemolysis. The laboratory results were correlated with the clinical details to assess the predictive value of the tests. RESULTS: Of the total 2856 pregnancies, 34% had ABO incompatibility. On testing with columnagglutination test (CAT), the overall DAT positivity and that among ABO-incompatible cases were 3.8% and 11.2%, respectively,) whereas by conventinal tube technique (CTT) it was 0.6% and 2.4% respectively. CAT was found to have higher sensitivity, and the predictive value was higher for CTT. Maternal IgG titre showed a positive linear relationship with the DAT strength and the rise in indirect bilirubin levels. The positive predictive value of combination of tests such as DAT, elution and titation was 94.12%, which was much higher than that of the individual tests. CONCLUSION: DAT positivity is a predictor of early rise in serum bilirubin level, and a combination of tests has a better predictive value than individual tests towards development of clinically significant hyperbilirubinemia in ABO-HDN.

A novel silent RHCE allele in Chinese population.

OBJECTIVES: We aimed to analyse the molecular backgrounds of the family in which an eight-day-old baby was confirmed to have hemolytic disease of the newborn (HDN) and phenotype observed for the baby did not conform to the expected phenotype. BACKGROUND: The silent RHCE allele is rare in the Rh system. METHODS: To determine the antibody specificity, her family members' blood samples were collected and tested using routine serological methods. The Rh C + c-e + E- phenotype observed for the baby did not conform to the expected phenotype based on the maternal RhC-c + E + e- phenotype. The RH genes of the family members were further analysed by sequencing. RESULTS: The Rh phenotypes of the baby, her brother, her mother and father were CCDee, CcDEe, ccDEE and CCDee, respectively. IgG anti-e was confirmed to cause the HDN in the case. A heterozygous silent RHCE * 03(c.1059G > A) mutation in exon 7 was found in the baby and her mother, which is a novel nonsense allele caused by a premature termination codon (Trp353stop). CONCLUSION: The silent RHCE * 03(c.1059G > A) variant was observed in a heterozygous state in mother and baby. We predict that, had this occurred in the homozygous state, it would give rise to the rare D-- phenotype. To enhance the safety of transfusion, considerable attention should be paid to the RHCE gene in the Chinese population.

Molecular characterization and multidisciplinary management of Gerbich hemolytic disease of the newborn.

Gerbich (Ge) antigens are high frequency red cell antigens expressed on glycophorin C (GYPC) and glycophorin D. Hemolytic disease of the fetus and newborn (HDFN) due to Gerbich antibody is rare and presents a clinical challenge, as Gerbich negative blood is scarce. We report a case of HDFN due to maternal Ge3 negative phenotype and anti-Ge3 alloimmunization, successfully managed by transfusion of maternal blood. Molecular testing revealed that the mother has homozygous deletion of exon 3 of GYPC, the father is homozygous wildtype for GYPC, and the infant is obligate heterozygote expressing Ge3.

Unexpected Diversity and High Abundance of Putative Nitric Oxide Dismutase (Nod) Genes in Contaminated Aquifers and Wastewater Treatment Systems.

It has recently been suggested that oxygenic dismutation of NO into N2 and O2 may occur in the anaerobic methanotrophic "Candidatus Methylomirabilis oxyfera" and the alkane-oxidizing gammaproteobacterium HdN1. It may represent a new pathway in microbial nitrogen cycling catalyzed by a putative NO dismutase (Nod). The formed O2 enables microbes to employ aerobic catabolic pathways in anoxic habitats, suggesting an ecophysiological niche space of substantial appeal for bioremediation and water treatment. However, it is still unknown whether this physiology is limited to "Ca Methylomirabilis oxyfera" and HdN1 and whether it can be coupled to the oxidation of electron donors other than alkanes. Here, we report insights into an unexpected diversity and remarkable abundance of nod genes in natural and engineered water systems. Phylogenetically diverse nod genes were recovered from a range of contaminated aquifers and N-removing wastewater treatment systems. Together with nod genes from "Ca Methylomirabilis oxyfera" and HdN1, the novel environmental nod sequences formed no fewer than 6 well-supported phylogenetic clusters, clearly distinct from canonical NO reductase (quinol-dependent NO reductase [qNor] and cytochrome c-dependent NO reductase [cNor]) genes. The abundance of nod genes in the investigated samples ranged from 1.6 × 107 to 5.2 × 1010 copies · g-1 (wet weight) of sediment or sludge biomass, accounting for up to 10% of total bacterial 16S rRNA gene counts. In essence, NO dismutation could be a much more widespread physiology than currently perceived. Understanding the controls of this emergent microbial capacity could offer new routes for nitrogen elimination or pollutant remediation in natural and engineered water systems. IMPORTANCE: NO dismutation into N2 and O2 is a novel process catalyzed by putative NO dismutase (Nod). To date, only two bacteria, the anaerobic methane-oxidizing bacterium "Ca Methylomirabilis oxyfera" and the alkane-oxidizing gammaproteobacterium HdN1, are known to harbor nod genes. In this study, we report efficient molecular tools that can detect and quantify a wide diversity of nod genes in environmental samples. A surprisingly high diversity and abundance of nod genes were found in contaminated aquifers as well as wastewater treatment systems. This evidence indicates that NO dismutation may be a much more widespread physiology in natural and man-made environments than currently perceived. The molecular tools presented here will facilitate further studies on these enigmatic microbes in the future.

Anti-D alloimmunisation in pregnant women with DEL phenotype in China.

OBJECTIVES: To analyse anti-D alloimmunisation in pregnant women with D-elute (DEL) phenotype in China, for developing a predictive model to evaluate whether a person with the DEL phenotype can receive RhD-positive blood. BACKGROUND: Alloanti-D acquired by pregnancy or transfusion is one of the major causes of both haemolytic disease among newborns and haemolytic transfusion reactions. To date, there is little data available about the antigenic properties and immunogenicity of extremely weak D variants known as DEL. METHODS: RHD genotyping and D epitope mapping were performed using gene sequencing and comprehensive immunohaematological methods, respectively. DEL pregnant women carrying an RhD-positive fetus were tested for the presence of alloanti-D. RESULTS: A total of 130 of 142 (91·5%) pregnant women with a DEL phenotype were confirmed to carry the RHD (K409K) allele. Among 12 DEL women who appeared to have RHD-CE-D hybrid alleles, there were 1 RHD-CE (4-7)-D, 7 RHD-CE(4-9)-D, and 4 RHD-CE (2-5)-D alleles. Alloanti-D antibodies were detected in 6 of 142 DEL women, and all the six women had the partial DEL phenotype. CONCLUSION: The data indicate that partial DEL women appear at risk of alloimmunization to the D antigen. RhD immune globulin prophylaxis is necessary for partial DEL women. Partial DEL patients should receive only RhD-negative RBCs, whereas DEL patients with complete expression of antigen can safely receive RhD-positive RBCs.

Metabolomics-based study on the significance of differential metabolite binding IgG isoforms in Hemolytic disease of newborn.

BACKGROUND: Hemolytic disease of the newborn (HDN) is a common condition that can have a severe impact on the health of newborns due to the hemolytic reactions it triggers. Although numerous studies have focused on understanding the pathogenesis of HDN, there are still many unanswered questions. METHODS: In this retrospective study, serum samples were collected from 15 healthy newborns and 8 infants diagnosed with hemolytic disease. The relationship between different metabolites and various IgG subtypes in Healthy, HDN and BLI groups was studied by biochemical technique and enzyme-linked immunosorbent assay (ELISA). Metabolomics analysis was conducted to identify the differential metabolites associated with HDN. Subsequently, Pearson's correlation analysis was used to determine the relation of these differential metabolites with IgG isoforms. The relationship between the metabolites and IgG subtypes was observed after treatment. RESULTS: The study results revealed that infants with hemolytic disease exhibited abnormal elevations in TBA, IgG1, IgG2a, IgG2b, IgG3, and IgG4 levels when compared to healthy newborns. Additionally, differences in metabolite contents were also observed. N, N-DIMETHYLARGININE showed negative correlations with TBA, IgG1, IgG2a, IgG2b, IgG3, and IgG4, while 2-HYDROXYBUTYRATE, AMINOISOBUTANOATE, Inosine, and ALLYL ISOTHIOCYANATE exhibited positive correlations with TBA, IgG1, IgG2a, IgG2b, IgG3, and IgG4. Through metabolomics-based research, we have discovered associations between differential metabolites and different IgG isoforms during the onset of HDN. CONCLUSION: These findings suggest that changes in metabolite and IgG isoform levels are linked to HDN. Understanding the involvement of IgG isoforms and metabolites can provide valuable guidance for the diagnosis and treatment of HDN.

The Severity of Direct Antiglobulin Test Negative ABO Hemolytic Disease of Newborn: A Retrospective Analysis at a Tertiary Children's Hospital.

This study aimed to evaluate the severity of ABO hemolytic disease of newborn (ABO-HDN) with negative direct antiglobulin test (DAT), which was identified by elution test. We retrospectively reviewed the clinical records of all neonates admitted with the diagnosis of neonatal hyperbilirubinemia requiring phototherapy or exchange transfusion. Neonates were divided into four groups according to their immunohematology test results. Then their essential laboratory results, magnetic resonance image (MRI), brainstem auditory evoked potential (BAEP) findings, and rate of exchange transfusion were compared between different groups. We found that neonates in ABO-HDN with negative DAT group developed jaundice faster and anaemia more severely than those in the non-HDN group. Although they might get less severe anaemia than neonates in ABO-HDN with positive DAT group and the Rh-HDN group, neonates in ABO HDN with negative DAT group might develop jaundice as quickly as the latter two groups. As to MRI and BAEP findings, there were no significant differences among the four groups. The rate of exchange transfusion in ABO-HDN with negative DAT group was higher than that in the non-HDN group but lower than that in ABO-HDN with positive DAT group, though without statistical significance. It suggested that in the presence of clinical suspicion of ABO-HDN with negative DAT result, the elution test should be added to rule out or confirm the diagnosis to help prevent the morbidity from hyperbilirubinemia.