Efficient Regeneration of Transgenic Rice from Embryogenic Callus via Agrobacterium-Mediated Transformation: A Case Study Using GFP and Apple MdFT1 Genes.

Genetic transformation is a critical tool for gene manipulation and functional analyses in plants, enabling the exploration of key phenotypes and agronomic traits at the genetic level. While dicotyledonous plants offer various tissues for in vitro culture and transformation, monocotyledonous plants, such as rice, have limited options. This study presents an efficient method for genetically transforming rice (Oryza sativa L.) using seed-derived embryogenic calli as explants. Two target genes were utilized to assess regeneration efficiency: green fluorescent protein (eGFP) and the apple FLOWERING LOCUS T (FT)-like gene (MdFT1). Antisense MdFT1 was cloned into a vector controlled by the rice α-amylase 3D (Ramy3D) promoter, while eGFP was fused to Cas9 under the Ubi promoter. These vectors were introduced separately into rice embryogenic calli from two Korean cultivars using Agrobacterium-mediated transformation. Transgenic seedlings were successfully regenerated via hygromycin selection using an in vitro cultivation system. PCR confirmed stable transgene integration in the transgenic calli and their progeny. Fluorescence microscopy revealed eGFP expression, and antisense MdFT1-expressing lines exhibited notable phenotypic changes, including variations in plant height and grain quality. High transformation efficiency and regeneration frequency were achieved for both tested cultivars. This study demonstrated the effective use of seed-derived embryogenic calli for rice transformation, offering a promising approach for developing transgenic plants in monocot species.

Whole-Genome Analysis of the Influenza A(H1N1)pdm09 Viruses Isolated from Influenza-like Illness Outpatients in Myanmar and Community-Acquired Oseltamivir-Resistant Strains Present from 2015 to 2019.

In this study, we describe the genetic characteristics of influenza A(H1N1)pdm09 strains detected in Myanmar from 2015 to 2019. Whole genomes from 60 A(H1N1)pdm09 virus isolates were amplified using real-time polymerase chain reaction and successfully sequenced using the Illumina iSeq100 platforms. Eight individual phylogenetic trees were retrieved for each segment along with those of the World Health Organization (WHO)-recommended Southern Hemisphere vaccine strains for the respective years. A(H1N1)pdm09 viruses from 2015 were found to belong to clade 6B, those from 2016 to 6B.1, 2017 to 6B.1A, and 2019 to 6B.1A.5a, and were genetically distinct from the Southern Hemisphere vaccine strains for the respective seasons, A/California/7/2009 and A/Michigan/45/2015. We observed one virus with intra-subtype reassortment, collected in the 2015 season. Importantly, three viruses possessed the H275Y substitution in the neuraminidase protein, appearing to be community-acquired without the prior administration of neuraminidase inhibitors. These viruses exhibited highly reduced susceptibility to oseltamivir and peramivir. This study demonstrates the importance of monitoring genetic variations in influenza viruses that will contribute to the selection of global influenza vaccines.

Detection of enterovirus D68 among children with severe acute respiratory infection in Myanmar.

BACKGROUND: Enterovirus D68 (EV-D68) is an important reemerging pathogen that causes severe acute respiratory infection and acute flaccid paralysis, mainly in children. Since 2014, EV-D68 outbreaks have been reported in the United States, Europe, and east Asia; however, no outbreaks have been reported in southeast Asian countries, including Myanmar, during the previous 10 years. METHODS: EV-D68 was detected in nasopharyngeal swabs from children with acute lower respiratory infections in Myanmar. The samples were previously collected from children aged 1 month to 12 years who had been admitted to the Yankin Children Hospital in Yangon, Myanmar, between May 2017 and January 2019. EV-D68 was detected with a newly developed EV-D68-specific real-time PCR assay. The clade was identified by using a phylogenetic tree created with the Bayesian Markov chain Monte Carlo method. RESULTS: During the study period, nasopharyngeal samples were collected from 570 patients. EV-D68 was detected in 42 samples (7.4 %)-11 samples from 2017 to 31 samples from 2018. The phylogenetic tree revealed that all strains belonged to clade B3, which has been the dominant clade worldwide since 2014. We estimate that ancestors of currently circulating genotypes emerged during the period 1980-2004. CONCLUSIONS: To our knowledge, this is the first report of EV-D68 detection in children with acute lower respiratory infections in Yangon, Myanmar, in 2017-2018. Detection and detailed virologic analyses of EV-D68 in southeast Asia is an important aspect of worldwide surveillance and will likely be useful in better understanding the worldwide epidemiologic profile of EV-D68 infection.

Echocardiography and strain analysis in Malaysian elite athletes versus young healthy adults.

Background: Athletes have changes that can mimic pathological cardiomyopathy. Methods: Echocardiographic study of 50 male, female athletes (MA, FA) and non-athletes (MNA, FNA) age 18 to 30 years. These athletes participate in sports with predominantly endurance component. All participants exhibit no known medical illnesses or symptoms. Results: MA have thicker wall (IVSd) than MNA. No MA have IVSd > 1.2 cm and no FA have IVSd > 1.0 cm. Left ventricle internal dimension (LVIDd), left ventricle end diastolic volume index (LVEDVi) is bigger in athletes. None have LVIDd > 5.8 cm. Right ventricle fractional area change (FAC) is lower in athletes. (MA vs MNA, p = 0.013, FA vs FNA, p = 0.025). Athletes have higher septal and lateral e' (Septal e'; MA 13.57 ± 2.66 cm/s vs MNA 11.46 ± 2.93 cm/s, p < 0.001, Lateral e'; MA 17.17 ± 3.07 cm/s vs MNA 14.82 ± 3.14 cm/s, p < 0.001), (Septal e'; FA 13.46 ± 2.32 cm/s vs FNA 12.16 ± 2.05 cm/s, p = 0.04, Lateral e'; FA 16.92 ± 2.97 cm/s vs FNA 15.44 ± 2.29 cm/s, p = 0.006).No difference in Global longitudinal (GLS), Right ventricle free wall (RVFWS) and Global circumferential strain (GCS). Left atrial reservoir (LArS) and left atrial booster strain (LAbS) is smaller in athletes. (LArS, MA 44.12 ± 9.55% vs MNA 52.95 ± 11.17%, p < 0.001 LArS, FA 48.07 ± 10.06% vs FNA 53.64 ± 8.99%, p = 0.004), (LAbS, MA 11.59 ± 5.13% vs MNA 17.35 ± 5.27%, p < 0.001 LAbS FA 11.77 ± 4.65% vs FNA 15.30 ± 4.19%, p < 0.001). Conclusion: Malaysian athletes have thicker wall and bigger left ventricle than controls. No athletes have IVSd > 1.2 cm and/or LVIDd > 5.8 cm. There is no difference in GLS, RVFWS and GCS but athletes have smaller LArS and LAbS.

The Synergistic Effects of Environmental and Genetic Factors on the Regulation of Anthocyanin Accumulation in Plant Tissues.

Anthocyanin accumulation is responsible for the coloration of apple fruit, and their accumulation depends on the expression of anthocyanin biosynthesis-related genes. Light is an environmental stimulus that induces fruit color by regulating genes involved in the anthocyanin biosynthesis pathway. In this study, the roles of light and genetic factors on fruit coloration and anthocyanin accumulation in apple fruit were investigated. Three genes in the anthocyanin biosynthesis pathway, MdCHS, MdANS, and MdUFGT1, were synthesized and cloned into a viral-based expression vector system for transient expression in 'Ruby S' apple fruits. Apple fruits were agroinfiltrated with expression vectors harboring MdCHS, MdANS, and MdUFGT1. Agroinfiltrated apple fruits were then either kept in the dark (bagged fruits) or exposed to light (exposed fruits). The agroinfiltrated fruits showed significantly different coloration patterns, transcript expression levels, and anthocyanin accumulation compared to the control fruits. Moreover, these parameters were higher in exposed fruits than in bagged fruits. For stable expression, MdCHS was introduced into a binary vector under the control of the rice α-amylase 3D (RAmy3D) promoter. The ectopic overexpression of MdCHS in transgenic rice calli showed a high accumulation of anthocyanin content. Taken together, our findings suggest that light, together with the overexpression of anthocyanin biosynthesis genes, induced the coloration and accumulation of anthocyanin content in apple fruits by upregulating the expression of the genes involved in the anthocyanin biosynthesis pathway.

Detection of parechovirus-A in hospitalized children with acute lower respiratory infection in Myanmar, 2017-2018.

Parechovirus-A (PeV-A) causes emerging infection in children, and clinical presentation depends on genotype. The virus has been investigated mainly in developed countries; however, data from developing countries, especially in Asia, are sparse. This study investigated whether PeV-A circulated in children in Myanmar. This retrospective study evaluated PeV-A in nasopharyngeal samples from children aged 1 month to 12 years who were hospitalized with acute lower respiratory infection at Yankin Children Hospital, Yangon, Myanmar, during the period from May 2017 to April 2019. Real-time polymerase chain reaction (PCR) was used to detect PeV-A, and PCR-positive samples were used for genotyping and phylogenetic analysis. In total, 11/570 (1.9%) of samples were positive for PeV-A; 7 were successfully genotyped by sequencing the VP3/VP1 region, as follows: PeV-A1 (n = 4), PeV-A5 (n = 1), PeV-A6 (n = 1), and PeV-A14 (n = 1). Median age was 10.0 months (interquartile range 4.0-12.0 months), and other respiratory viruses were detected in all cases. Phylogenetic analysis showed that all detected PeV-A1 strains were in clade 1 A, which was a minor clade worldwide. Four PeV-A genotypes were detected in Myanmar. The clinical impact of PeV-A in children should be evaluated in future studies.

Whole-Genome Analysis of Influenza A(H3N2) and B/Victoria Viruses Detected in Myanmar during the COVID-19 Pandemic in 2021.

An influenza circulation was observed in Myanmar between October and November in 2021. Patients with symptoms of influenza-like illness were screened using rapid diagnostic test (RDT) kits, and 147/414 (35.5%) upper respiratory tract specimens presented positive results. All RDT-positive samples were screened by a commercial multiplex real-time polymerase chain reaction (RT-PCR) assay, and 30 samples positive for influenza A(H3N2) or B underwent further typing/subtyping for cycle threshold (Ct) value determination based on cycling probe RT-PCR. The majority of subtyped samples (n = 13) were influenza A(H3N2), while only three were B/Victoria. Clinical samples with low Ct values obtained by RT-PCR were used for whole-genome sequencing via next-generation sequencing technology. All collected viruses were distinct from the Southern Hemisphere vaccine strains of the corresponding season but matched with vaccines of the following season. Influenza A(H3N2) strains from Myanmar belonged to clade 2a.3 and shared the highest genetic proximity with Bahraini strains. B/Victoria viruses belonged to clade V1A.3a.2 and were genetically similar to Bangladeshi strains. This study highlights the importance of performing influenza virus surveillance with genetic characterization of the influenza virus in Myanmar, to contribute to global influenza surveillance during the COVID-19 pandemic.

Evolutionary Dynamics of Whole-Genome Influenza A/H3N2 Viruses Isolated in Myanmar from 2015 to 2019.

This study aimed to analyze the genetic and evolutionary characteristics of the influenza A/H3N2 viruses circulating in Myanmar from 2015 to 2019. Whole genomes from 79 virus isolates were amplified using real-time polymerase chain reaction and successfully sequenced using the Illumina iSeq100 platforms. Eight individual phylogenetic trees were retrieved for each segment along with those of the World Health Organization (WHO)-recommended Southern Hemisphere vaccine strains for the respective years. Based on the WHO clades classification, the A/H3N2 strains in Myanmar from 2015 to 2019 collectively belonged to clade 3c.2. These strains were further defined based on hemagglutinin substitutions as follows: clade 3C.2a (n = 39), 3C.2a1 (n = 2), and 3C.2a1b (n = 38). Genetic analysis revealed that the Myanmar strains differed from the Southern Hemisphere vaccine strains each year, indicating that the vaccine strains did not match the circulating strains. The highest rates of nucleotide substitution were estimated for hemagglutinin (3.37 × 10-3 substitutions/site/year) and neuraminidase (2.89 × 10-3 substitutions/site/year). The lowest rate was for non-structural protein segments (4.19 × 10-5 substitutions/site/year). The substantial genetic diversity that was revealed improved phylogenetic classification. This information will be particularly relevant for improving vaccine strain selection.

Clinical manifestations and outcome of viral acute lower respiratory infection in hospitalised children in Myanmar.

BACKGROUND: Acute lower respiratory infection (ALRI) remains the leading cause of death in children worldwide, and viruses have been the major cause of ALRI. In Myanmar, ALRI is associated with high morbidity and mortality in children, and detailed information on ALRI is currently lacking. METHODS: This prospective study investigated the viral aetiologies, clinical manifestations, and outcomes of ALRI in hospitalised children aged 1 month to 12 years at the Yankin Children Hospital, Yangon, Myanmar from May 2017 to April 2019. The sample size was set to 300 patients for each year. Two nasopharyngeal swabs were obtained for the patients with suspected viral ALRI; one for rapid tests for influenza and respiratory syncytial virus (RSV), and the other for real-time PCR for the 16 ALRI-causing viruses. Pneumococcal colonization rates were also investigated using real-time PCR. Clinical information was extracted from the medical records, and enrolled patients were categorised by age and severity for comparison. RESULTS: Among the 5463 patients admitted with a diagnosis of ALRI, 570 (10.4%) were enrolled in this study. The median age of the patients was 8 months (interquartile range, 4-15 months). The most common symptoms were cough (93%) and difficulty in breathing (73%), while the most common signs of ALRI were tachypnoea (78%) and chest indrawing (67%). A total of 16 viruses were detected in 502 of 570 patients' samples (88%), with RSV B (36%) and rhinovirus (28%) being the most commonly detected. Multiple viruses were detected in 221 of 570 samples (37%) collected from 570 patients. Severe ALRI was diagnosed in 107 of 570 patients (19%), and RSV B and human rhinovirus were commonly detected. The mortality rate was 5%; influenza virus A (29%) and RSV B (21%) were commonly detected, and stunting and lack of immunization were frequently observed in such cases. Additionally, 45% (259/570) of the patients had pneumococcal colonization. CONCLUSIONS: Viral ALRI in hospitalised children with a median of 8 months has significant morbidity and mortality rates in Myanmar. RSV and rhinovirus were the most commonly detected from nasopharyngeal swabs, while influenza virus and RSV were the most frequently associated with fatal cases.

Epidemiology and Genetic Analysis of SARS-CoV-2 in Myanmar during the Community Outbreaks in 2020.

We aimed to analyze the situation of the first two epidemic waves in Myanmar using the publicly available daily situation of COVID-19 and whole-genome sequencing data of SARS-CoV-2. From March 23 to December 31, 2020, there were 33,917 confirmed cases and 741 deaths in Myanmar (case fatality rate of 2.18%). The first wave in Myanmar from March to July was linked to overseas travel, and then a second wave started from Rakhine State, a western border state, leading to the second wave spreading countrywide in Myanmar from August to December 2020. The estimated effective reproductive number (Rt) nationwide reached 6-8 at the beginning of each wave and gradually decreased as the epidemic spread to the community. The whole-genome analysis of 10 Myanmar SARS-CoV-2 strains together with 31 previously registered strains showed that the first wave was caused by GISAID clade O or PANGOLIN lineage B.6 and the second wave was changed to clade GH or lineage B.1.36.16 with a close genetic relationship with other South Asian strains. Constant monitoring of epidemiological situations combined with SARS-CoV-2 genome analysis is important for adjusting public health measures to mitigate the community transmissions of COVID-19.

Tocilizumab in the management of posttransfusion hyperhemolysis syndrome in sickle cell disease: The experience so far.

BACKGROUND: Posttransfusion hyperhemolysis syndrome is a rare but life-threatening form of delayed hemolytic transfusion reaction with lysis of both transfused and autologous red cells, seen predominantly in patients with sickle cell disease. Macrophage activation is thought to play a major role in its pathophysiology. Standard treatment is with intravenous immunoglobulin and steroids but refractory cases pose a major clinical problem. Tocilizumab is a humanized monoclonal antibody against the IL-6 receptor that can inhibit IL-6 induced macrophage activation. METHODS AND MATERIALS: We describe the case of a 33-year-old woman with sickle cell anemia and posttransfusion hyper hemolysis syndrome refractory to standard therapy, treated with Tocilizumab. We also review all cases reported in the literature where Tocilizumab was used for posttransfusion hyperhemolysis. RESULTS: Treatment with Tocilizumab was well tolerated with no observed adverse events. There was no further drop in Hb after day 2 of treatment with subsequent continuous gradual improvement. Her bilirubin dropped significantly after the first dose and continued to improve, while ferritin and LDH reduced significantly after day 2 of treatment with Tocilizumab and continued to drop thereafter. Like in our case, all other cases in the literature where Tocilizumab was used for posttransfusion hyperhemolysis led to rapid clinical responses and no adverse events. DISCUSSION: Even though the number of cases of posttransfusion hyper hemolysis syndrome treated with Tocilizumab are few, they have all been associated with rapid clinical responses with no observed adverse events suggesting that the role of Tocilizumab in this context needs to be further explored.

Epidemic of influenza A(H1N1)pdm09 analyzed by full genome sequences and the first case of oseltamivir-resistant strain in Myanmar 2017.

A community outbreak of human influenza A(H1N1)pdm09 virus strains was observed in Myanmar in 2017. We investigated the circulation patterns, antigenicity, and drug resistance of 2017 influenza A(H1N1)pdm09 viruses from Myanmar and characterized the full genome of influenza virus strains in Myanmar from in-patients and out-patients to assess the pathogenicity of the viruses. Nasopharyngeal swabs were collected from out-patients and in-patients with acute respiratory tract infections in Yangon and Pyinmana City in Myanmar during January-December 2017. A total of 215 out-patients and 18 in-patients infected with A(H1N1)pdm09 were detected by virus isolation and real-time RT-PCR. Among the positive patients, 90.6% were less than 14 years old. Hemagglutination inhibition (HI) antibody titers against A(H1N1)pdm09 viruses in Myanmar were similar to the recommended Japanese influenza vaccine strain for 2017-2018 seasons (A/Singapore/GP1908/2015) and WHO recommended 2017 southern hemisphere vaccine component (A/Michigan/45/2015). Phylogenetic analysis of the hemagglutinin sequence showed that the Myanmar strains belonged to the genetic subclade 6B.1, possessing mutations of S162N and S164T at potential antigenic sites. However, the amino acid mutation at position 222, which may enhance the severity of disease and mortality, was not found. One case with no prior history of oseltamivir treatment possessed H275Y mutated virus in neuraminidase (NA), which confers resistance to oseltamivir and peramivir with elevated IC50 values. The full genome sequence of Myanmar strains showed no difference between samples from in-patients and out-patients, suggesting no additional viral mutations associated with patient severity. Several amino acid changes were observed in PB2, PB1, and M2 of Myanmar strains when compared to the vaccine strain and other Asian strains. However, no mutations associated with pathogenicity were found in the Myanmar strains, suggesting that viral factors cannot explain the underlying reasons of the massive outbreak in Myanmar. This study reported the first detection of an oseltamivir-resistant influenza virus in Myanmar, highlighting the importance of continuous antiviral monitoring and genetic characterization of the influenza virus in Myanmar.

Posttransfusion hyperhemolysis is arrested by targeting macrophage activation with novel use of Tocilizumab.

BACKGROUND: Hyperhemolysis syndrome (HHS) is a posttransfusion complication most frequently seen in sickle cell disease (SCD), characterized by rapid destruction of transfused and autologous red blood cells (RBCs), resulting in reticulocytopenia and a decrease in hemoglobin to below pretransfusion levels. Additional RBC transfusion can be life threatening. Most patients improve with intravenous immune globulin and steroids, but in refractory cases, hyperhemolysis may result in multiorgan failure and death in the absence of salvage therapy. The exact pathophysiology of HHS remains uncertain, yet new insights suggest that RBC destruction is driven by activated macrophages. Therefore, we propose that antimacrophage therapy may represent an effective treatment. CASE REPORT: A case of life-threatening HHS, refractory to intravenous immune globulin and steroids, in a patient with SCD is presented. Marked elevation in ferritin, an indirect marker of macrophage activation, a negative direct antiglobulin test, and the absence of RBC alloantibodies was noted. A hemoglobin nadir of 2.1 g/dL and resultant hypoxemia-induced organ failure prompted the use of tocilizumab, an interleukin-6 receptor monoclonal antibody. Hemoglobin-based oxygen carrier-201, a cell-free polymerized bovine hemoglobin, was used to support the patient during critical anemia. RESULTS: Hemolysis resolved and ferritin dramatically decreased after administration of tocilizumab, which was well tolerated. A full recovery was achieved. CONCLUSION: This case highlights both a novel and successful approach to managing refractory transfusion-induced hyperhemolysis with tocilizumab and provides further evidence supporting the role for macrophage activation in the destruction of RBCs in antibody-negative HHS. We propose that tocilizumab is an effective and rapid salvage therapy for refractory HHS.

Characterization of Fruit Quality Attributes and Cell Wall Metabolism in 1-Methylcyclopropene (1-MCP)-Treated 'Summer King' and 'Green Ball' Apples During Cold Storage.

This study aimed to elucidate whether 1-methylcyclopropene (1-MCP) treatment delays the fruit softening mechanism associated with the fruit quality of the newly released apple cultivars "Summer King" and "Green Ball" during cold storage. For both cultivars, the fruit treated with 1-MCP exhibited lower internal ethylene concentration, higher firmness, and higher titratable acidity relative to the control fruit, in association with less fruit softening. In addition, the treated fruit significantly delayed fresh weight loss and reduction of soluble solids content, especially in "Green Ball." Moreover, slower degradation of cell wall components (water-soluble pectin, sodium carbonate-soluble pectin, hemicellulose, and cellulose) was also observed in the treated fruit in comparison to the control fruit. Similarly, the enzymatic activities (of polygalacturonase, pectin methylesterase, cellulase, ß-galactosidase, and α-L-arabinofuranosidase) that cause cell wall degradation were relatively lower in the treated fruit than in the control fruit for both cultivars, which was further proved by transcriptional analysis of the genes encoding the enzymes. Overall, the results suggested that the usage of 1-MCP is useful to delay fruit softening of the two cultivars during cold storage by delaying the degradation of cell wall components and enzymatic activities of cell wall hydrolysis.

Two more new species of the Cyrtodactylus peguensis group (Squamata: Gekkonidae) from the fringes of the Ayeyarwady Basin, Myanmar.

Two new species of Bent-toed Geckos of the Cyrtodactylus peguensis group are described from foothill areas occurring on opposite sides of the Ayeyarwady Basin. Cyrtodactylus nyinyikyawi sp. nov. from the Shwe Settaw Wildlife Sanctuary, Magway Region in the east and C. pyadalinensis sp. nov. from the Panluang-Pyadalin Wildlife Sanctuary, Shan State in the west bear unique suits of morphological and color pattern character states separating them from all species in the peguensis group. Additionally, a molecular phylogeny based on the mitochondrial gene ND2 indicates that neither species is nested within, nor sister to any known species in the group. This study augments recent and ongoing studies showing that the Ayeyarwady Basin is herpetologically more diverse than previously considered and should be incorporated into ongoing discussions concerning conservation efforts in Myanmar.

Histopathological evidence for macrophage activation driving post-transfusion hyperhaemolysis syndrome.

Post-transfusion hyperhaemolysis syndrome (PTHS) is a rare life-threatening transfusion complication reported mainly in sickle cell patients. Its pathogenesis is poorly understood. Antibody-mediated haemolysis and bystander effect have been proposed as putative mechanisms, but in half of cases, red cell antibodies are undetectable, and PTHS develops despite transfusion of cross-matched compatible RBC. An alternate hypothesis proposes activated macrophages as the main drivers of red cell destruction through direct phagocytosis. We report the histopathological findings of two patients with PTHS showing extensive macrophage expansion and erythrophagocytosis, supportive of macrophage activation driving PTHS. This supports a possible role for novel therapies that target macrophage activation.

Prevention of hemolytic transfusion reactions with intravenous immunoglobulin prophylaxis in U- patients with anti-U.

BACKGROUND: The U- phenotype is extremely rare and is found predominantly in black African populations at a frequency of between 0.2 and 1.7%. In European populations, U- units are therefore rare, with limited availability in the United Kingdom. Anti-U is clinically significant and is known to cause hemolytic transfusion reactions (HTRs) and hemolytic disease of the fetus and newborn. It has been suggested that intravenous immunoglobulin (IVIG) may be considered as an option among supportive therapy for urgent transfusion when clinically significant antigen-matched units are not available. We report three cases with anti-U transfused with least-incompatible RBC units, their outcomes, and their clinical management. STUDY DESIGN AND METHODS: Intravenous immunoglobulin was prescribed when least-incompatible units must be issued in patients with anti-U to ameliorate acute HTR and prevent the development of delayed HTR. We report the outcome of these cases. RESULTS: Of the case reports described, one patient with weak anti-U developed a delayed HTR after transfusion with incompatible units due to an anamnestic response. Two additional patients are described, with the use of IVIG as a precautionary measure to prevent the development of HTRs when transfused with antigen-positive incompatible units. No acute HTRs or delayed HTRs were noted upon follow-up. CONCLUSION: U- units are not always readily available and transfusion support requires close collaborative working among a multidisciplinary team. Transfusion with antigen-positive incompatible units with IVIG cover both ameliorates acute HTRs and prevents the development of delayed HTRs.

Bombay phenotype (Oh ) and high-titer anti-H in pregnancy: two case reports and a review of the literature.

BACKGROUND: Antenatal cases of Bombay-phenotype (Oh ) individuals and hemolytic disease of the fetus and newborn (HDFN) are not well described in the literature. We present two case reports of high-titer anti-H in pregnant Oh individuals and their serologic investigation, clinical management, and subsequent outcomes. We describe current published cases detailing pregnancy in Oh individuals, to add to the evidence base for clinical decision making and management of pregnancy. STUDY DESIGN AND METHODS: We describe two case reports of high-titer anti-H in pregnancy in Oh individuals. We summarize published cases to date, to inform clinical decision making and antenatal management in individuals with the Bombay phenotype. RESULTS: Of the case reports described, neither were affected by HDFN due to anti-H. Antibody titers were high in both cases (immunoglobulin G titer scores, 512 and 4000, respectively) and would be expected to cause some degree of HDFN, a surprising finding. Regular mean cerebral artery Doppler ultrasound was normal. Patient blood management (PBM) techniques ensured that the patient's hemoglobin (Hb) levels were monitored and maintained. Transfusion intervention was not required, with minimal blood loss recorded at birth in both cases. CONCLUSION: High-titer anti-H in Oh pregnancies may, in rare cases, cause HDFN, but evidence suggests that this may not be the case in all pregnancies. We recommend a multidisciplinary approach, with prompt referral to a fetomaternal medicine unit, combined with PBM strategies, and a planned delivery with the provision of rare-phenotype units (if available and if indicated) on standby.