Missense mutations in PIEZO1, which encodes the Piezo1 mechanosensor protein, define Er red blood cell antigens.

Despite the identification of the high-incidence red cell antigen Era nearly 40 years ago, the molecular background of this antigen, together with the other 2 members of the Er blood group collection, has yet to be elucidated. Whole exome and Sanger sequencing of individuals with serologically defined Er alloantibodies identified several missense mutations within the PIEZO1 gene, encoding amino acid substitutions within the extracellular domain of the Piezo1 mechanosensor ion channel. Confirmation of Piezo1 as the carrier molecule for the Er blood group antigens was demonstrated using immunoprecipitation, CRISPR/Cas9-mediated gene knockout, and expression studies in an erythroblast cell line. We report the molecular bases of 5 Er blood group antigens: the recognized Era, Erb, and Er3 antigens and 2 novel high-incidence Er antigens, described here as Er4 and Er5, establishing a new blood group system. Anti-Er4 and anti-Er5 are implicated in severe hemolytic disease of the fetus and newborn. Demonstration of Piezo1, present at just a few hundred copies on the surface of the red blood cell, as the site of a new blood group system highlights the potential antigenicity of even low-abundance membrane proteins and contributes to our understanding of the in vivo characteristics of this important and widely studied protein in transfusion biology and beyond.

Clinical Features of Vaccine-Induced Immune Thrombocytopenia and Thrombosis.

BACKGROUND: Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a new syndrome associated with the ChAdOx1 nCoV-19 adenoviral vector vaccine against severe acute respiratory syndrome coronavirus 2. Data are lacking on the clinical features of and the prognostic criteria for this disorder. METHODS: We conducted a prospective cohort study involving patients with suspected VITT who presented to hospitals in the United Kingdom between March 22 and June 6, 2021. Data were collected with the use of an anonymized electronic form, and cases were identified as definite or probable VITT according to prespecified criteria. Baseline characteristics and clinicopathological features of the patients, risk factors, treatment, and markers of poor prognosis were determined. RESULTS: Among 294 patients who were evaluated, we identified 170 definite and 50 probable cases of VITT. All the patients had received the first dose of ChAdOx1 nCoV-19 vaccine and presented 5 to 48 days (median, 14) after vaccination. The age range was 18 to 79 years (median, 48), with no sex preponderance and no identifiable medical risk factors. Overall mortality was 22%. The odds of death increased by a factor of 2.7 (95% confidence interval [CI], 1.4 to 5.2) among patients with cerebral venous sinus thrombosis, by a factor of 1.7 (95% CI, 1.3 to 2.3) for every 50% decrease in the baseline platelet count, by a factor of 1.2 (95% CI, 1.0 to 1.3) for every increase of 10,000 fibrinogen-equivalent units in the baseline d-dimer level, and by a factor of 1.7 (95% CI, 1.1 to 2.5) for every 50% decrease in the baseline fibrinogen level. Multivariate analysis identified the baseline platelet count and the presence of intracranial hemorrhage as being independently associated with death; the observed mortality was 73% among patients with platelet counts below 30,000 per cubic millimeter and intracranial hemorrhage. CONCLUSIONS: The high mortality associated with VITT was highest among patients with a low platelet count and intracranial hemorrhage. Treatment remains uncertain, but identification of prognostic markers may help guide effective management. (Funded by the Oxford University Hospitals NHS Foundation Trust.).

Pathologic Antibodies to Platelet Factor 4 after ChAdOx1 nCoV-19 Vaccination.

BACKGROUND: The mainstay of control of the coronavirus disease 2019 (Covid-19) pandemic is vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Within a year, several vaccines have been developed and millions of doses delivered. Reporting of adverse events is a critical postmarketing activity. METHODS: We report findings in 23 patients who presented with thrombosis and thrombocytopenia 6 to 24 days after receiving the first dose of the ChAdOx1 nCoV-19 vaccine (AstraZeneca). On the basis of their clinical and laboratory features, we identify a novel underlying mechanism and address the therapeutic implications. RESULTS: In the absence of previous prothrombotic medical conditions, 22 patients presented with acute thrombocytopenia and thrombosis, primarily cerebral venous thrombosis, and 1 patient presented with isolated thrombocytopenia and a hemorrhagic phenotype. All the patients had low or normal fibrinogen levels and elevated d-dimer levels at presentation. No evidence of thrombophilia or causative precipitants was identified. Testing for antibodies to platelet factor 4 (PF4) was positive in 22 patients (with 1 equivocal result) and negative in 1 patient. On the basis of the pathophysiological features observed in these patients, we recommend that treatment with platelet transfusions be avoided because of the risk of progression in thrombotic symptoms and that the administration of a nonheparin anticoagulant agent and intravenous immune globulin be considered for the first occurrence of these symptoms. CONCLUSIONS: Vaccination against SARS-CoV-2 remains critical for control of the Covid-19 pandemic. A pathogenic PF4-dependent syndrome, unrelated to the use of heparin therapy, can occur after the administration of the ChAdOx1 nCoV-19 vaccine. Rapid identification of this rare syndrome is important because of the therapeutic implications.

Natural history of PF4 antibodies in vaccine-induced immune thrombocytopenia and thrombosis.

The COVID-19 pandemic has resulted in the rapid development of a range of vaccines against SARS-CoV-2. Vaccine-induced immune thrombocytopenia and thrombosis (VITT) is a rare but life-threatening complication of primarily adenoviral-based vaccines associated with the presence of antibodies to a PF4/polyanion neoepitope and measured by using enzyme-linked immunosorbent assays. Presented are serial anti-PF4/polyanion antibody, platelet, and D-dimer measurements in a large cohort of patients and their relation to relapse. Overall, 51% of patients using the Stago assay had persistently positive anti-PF4/polyanion levels 100 days' postdiagnosis, whereas 94% of patients monitored by using the Immucor assay remain positive. The median duration of positivity of the PF4 assay is 87 days, with 72% of patients remaining positive after a median follow-up of 105 days. The use of plasma exchange seemed to reduce anti-PF4/polyanion levels and increase platelet counts in the acute setting more rapidly than other therapies. The rate of relapse in this study was 12.6%, with all relapsed cases exhibiting persistently positive PF4 antibodies and falling platelet counts. Only one patient had extension of their thrombosis. Overall, despite the persistence of PF4 antibodies in 72% of patients, the rate of relapse was low and did not seem to result in recrudescence of the aggressive clinical picture seen at index presentation. Monitoring of these patients in the UK cohort is ongoing and will aid in definition of the natural history of this novel condition.

Pharmacogenomic testing and prescribing patterns for patients with cancer in a large national precision medicine cohort.

Population databases could help patients with cancer and providers better understand current pharmacogenomic prescribing and testing practices. This retrospective observational study analysed patients with cancer, drugs with pharmacogenomic evidence and related genetic testing in the National Institutes of Health All of Us database. Most patients with cancer (19 633 (88.3%) vs 2590 (11.7%)) received ≥1 drug and 36 (0.2%) received genetic testing, with a significant association between receiving ≥1 drug and age group (p<0.001), but not sex (p=0.612), race (p=0.232) or ethnicity (p=0.971). Drugs with pharmacogenomic evidence-but not genetic testing-were common for patients with cancer, reflecting key gaps preventing precision medicine from becoming standard of care.

Diversity and Pathogenicity of Pythium Species Associated with Reduced Yields of Processing Tomatoes (Solanum lycopersicum) in Victoria, Australia.

Yield decline associated with poor crop establishment, stunting, wilting, and diminished root systems was reported in processing tomato crops in Victoria, Australia. During surveys between 2016 and 2018 Pythium species were isolated by soil baiting and by culturing from the diseased roots and collars of plants exhibiting these symptoms. Eleven species of Pythium were identified based on cultural characteristics and phylogenetic analysis with ITS, Cox-1, and Cox-2 gene sequences. None of the 11 Pythium species had been reported previously from processing or fresh tomatoes in Australia. Pythium dissotocum was the most abundant and widespread species isolated during surveys in each of two growing seasons. In pathogenicity tests, these Pythium species ranged from nonpathogenic to highly aggressive. P. aphanidermatum, P. ultimum, and P. irregulare were consistently the most aggressive species, causing serious damage or death at the pregermination, postgermination, and later stages of plant growth. Five processing tomato cultivars varied significantly in their susceptibility to Pythium disease. These results suggest that Pythium species could be contributing to yield loss in processing tomatoes in Victoria both in the crop establishment phase and through the season.

Aurora A Kinase (AURKA) is required for male germline maintenance and regulates sperm motility in the mouse.

Aurora A kinase (AURKA) is an important regulator of cell division and is required for assembly of the mitotic spindle. We recently reported the unusual finding that this mitotic kinase is also found on the sperm flagellum. To determine its requirement in spermatogenesis, we generated conditional knockout animals with deletion of the Aurka gene in either spermatogonia or spermatocytes to assess its role in mitotic and postmitotic cells, respectively. Deletion of Aurka in spermatogonia resulted in disappearance of all developing germ cells in the testis, as expected, given its vital role in mitotic cell division. Deletion of Aurka in spermatocytes reduced testis size, sperm count, and fertility, indicating disruption of meiosis or an effect on spermiogenesis in developing mice. Interestingly, deletion of Aurka in spermatocytes increased apoptosis in spermatocytes along with an increase in the percentage of sperm with abnormal morphology. Despite the increase in abnormal sperm, sperm from spermatocyte Aurka knockout mice displayed increased progressive motility. In addition, sperm lysate prepared from Aurka knockout animals had decreased protein phosphatase 1 (PP1) activity. Together, our results show that AURKA plays multiple roles in spermatogenesis, from mitotic divisions of spermatogonia to sperm morphology and motility.

Characterization and treatment of congenital thrombotic thrombocytopenic purpura.

Congenital thrombotic thrombocytopenic purpura (cTTP) is an ultra-rare thrombomicroangiopathy caused by an inherited deficiency of a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13). There are limited data on genotype-phenotype correlation; there is no consensus on treatment. We reviewed the largest cohort of cTTP cases, diagnosed in the United Kingdom, over the past 15 years. Seventy-three cases of cTTP were diagnosed, confirmed by genetic analysis. Ninety-three percent were alive at the time of review. Thirty-six percent had homozygous mutations; 64% had compound heterozygous mutations. Two presentation peaks were seen: childhood (median diagnosis age, 3.5 years) and adulthood, typically related to pregnancy (median diagnosis age, 31 years). Genetic mutations differed by age of onset with prespacer mutations more likely to be associated with childhood onset (P = .0011). Sixty-nine percent of adult presentations were associated with pregnancy. Fresh-frozen plasma (FFP) and intermediate purity factor VIII concentrate were used as treatment. Eighty-eight percent of patients with normal blood counts, but with headaches, lethargy, or abdominal pain, reported symptom resolution with prophylactic therapy. The most common currently used regimen of 3-weekly FFP proved insufficient for 70% of patients and weekly or fortnightly infusions were required. Stroke incidence was significantly reduced in patients receiving prophylactic therapy (2% vs 17%; P = .04). Long-term, there is a risk of end-organ damage, seen in 75% of patients with late diagnosis of cTTP. In conclusion, prespacer mutations are associated with earlier development of cTTP symptoms. Prophylactic ADAMTS13 replacement decreases the risk of end-organ damage such as ischemic stroke and resolved previously unrecognized symptoms in patients with nonovert disease.

Using informatics to guide public health policy during the COVID-19 pandemic in the USA.

BACKGROUND: Current and future pandemics will require informatics solutions to assess the risks, resources and policies to guide better public health decision-making. METHODS: Cross-sectional study of all COVID-19 cases and deaths in the USA on a population- and resource-adjusted basis (as of 24 April 2020) by applying biomedical informatics and data visualization tools to several public and federal government datasets, including analysis of the impact of statewide stay-at-home orders. RESULTS: There were 2753.2 cases and 158.0 deaths per million residents, respectively, in the USA with variable distributions throughout divisions, regions and states. Forty-two states and Washington, DC, (84.3%) had statewide stay-at-home orders, with the remaining states having population-adjusted characteristics in the highest risk quartile. CONCLUSIONS: Effective national preparedness requires clearly understanding states' ability to predict, manage and balance public health needs through all stages of a pandemic. This will require leveraging data quickly, correctly and responsibly into sound public health policies.

Presenting ADAMTS13 antibody and antigen levels predict prognosis in immune-mediated thrombotic thrombocytopenic purpura.

Immune-mediated thrombotic thrombocytopenic purpura (TTP) is a life-threatening disorder caused by antibodies against ADAMTS13. From the United Kingdom TTP registry, we undertook a prospective study investigating the impact of the presenting anti-ADAMTS13 IgG antibody and ADAMTS13 antigen on mortality. A total of 312 episodes involving 292 patients over 87 months were included; 68% were female, median age 46 (range, 11-88 years), and median presenting ADAMTS13 of <5% (range, <5%-18%). The mortality rate was 10.3% (n = 32); 68% of patients had a raised troponin at presentation conferring a sixfold increase in mortality compared with those with normal troponin levels (12.1% vs 2.0%, P = .04). Twenty-four percent had a reduced Glasgow Coma Score (GCS) at presentation with a ninefold increase in mortality (20% vs 2.2% for normal GCS at presentation, P < .0001). Mortality increased with higher anti-ADAMTS13 antibody levels and lower ADAMTS13 antigen levels. Those with antibody levels in the upper quartile (antibody >77%) had a mortality of 16.9% compared with 5.0% for the lowest quartile (antibody <20%) (P = .004). Those with an antigen level in the lowest quartile (antigen <1.5%) had a mortality of 18% compared with 3.8% for the highest quartile (antigen >11%) (P = .005). The synergistic effect of anti-ADAMTS13 IgG antibody in the upper quartile and ADAMTS13 antigen in the lowest quartile had the highest mortality of 27.3%. We conclude that both anti-ADAMTS13 IgG antibody and ADAMTS13 antigen levels correlate with outcome in TTP with increased cardiac and neurological involvement and increased mortality.

Utilization of increased risk for transmission of infectious disease donor organs in solid organ transplantation: Retrospective analysis of disease transmission and safety.

The inadequate supply of transplantable organs necessitates new approaches to organ availability. Serologies and nucleic acid testing (NAT) for hepatitis C virus (HCV), hepatitis B virus (HBV), and human immunodeficiency virus (HIV) are used in microbiologic screening of potential organ donors. Organs from donors considered at "high risk" (Centers for Disease Control and Prevention, CDC 1994) or "increased risk" (U.S. Public Health Service, PHS 2013) for transmission of viral infection to recipients may provide an expanded source of organs for transplantation. We review a single-center experience with 257 adult organ recipients of organs from donors meeting either CDC 1994 or PHS 2013 risk criteria between 2011 and 2016. Tracking these transplants required modification of the Transplant Center electronic database to identify all recipients of increased-risk donor (IRD) organs, documentation of informed consent, and microbiologic testing data. No transmissions of HIV, HBV, or HCV were identified by NAT or clinically. Nine patients developed positive serologic assays for one of the tested viruses; all recipients were retested and remain negative by NAT. Notably, post-transplant HBV core serologies reverted to negative on re-testing; these positive serologies are likely false positives caused by receipt of blood products. Use of IRD organs can be performed safely with appropriate informed consent and rigorous pre- and post-transplant microbiological testing.

Thrombotic thrombocytopenic purpura and pregnancy: presentation, management, and subsequent pregnancy outcomes.

Pregnancy can precipitate thrombotic thrombocytopenic purpura (TTP). We present a prospective study of TTP cases from the United Kingdom Thrombotic Thrombocytopenic Purpura (UK TTP) Registry with clinical and laboratory data from the largest cohort of pregnancy-associated TTP and describe management through pregnancy, averting fetal loss and maternal complications. Thirty-five women presented with a first TTP episode during pregnancy: 23/47 with their first congenital TTP (cTTP) episode and 12/47 with acute acquired TTP in pregnancy. TTP presented primarily in the third trimester/postpartum, but fetal loss was highest in the second trimester. Fetal loss occurred in 16/38 pregnancies before cTTP was diagnosed, but in none of the 15 subsequent managed pregnancies. Seventeen of 23 congenital cases had a missense mutation, C3178T, within exon 24 (R1060W). There were 8 novel mutations. In acquired TTP presentations, fetal loss occurred in 5/18 pregnancies and 2 terminations because of disease. We also present data on 12 women with a history of nonpregnancy-associated TTP: 18 subsequent pregnancies have been successfully managed, guided by ADAMTS13 levels. cTTP presents more frequently than acquired TTP during pregnancy and must be differentiated by ADAMTS13 analysis. Careful diagnosis, monitoring, and treatment in congenital and acquired TTP have assisted in excellent pregnancy outcomes.

Quantum Monte Carlo Study of the Reactions of CH with Acrolein: Major and Minor Channels.

Acrolein is an important unsaturated hydrocarbon, containing both C═O and C═C bonds, and responsible for atmospheric pollution. A recent study of major reactions of CH with acrolein has been supplemented with computations of other reactions of the system. Similar to the previous approach, the quantum Monte Carlo (QMC) method in the accurate diffusion Monte Carlo (DMC) method was implemented. Single determinant wave functions were used as trial functions for the random walks. Rate coefficients and product branching ratios were computed by solving master equations using the MultiWell software suite. At room temperature, the dominant product channels are 2-methylvinyl + CO (P6), 1,3-butadienal + H (P2), and furan + H (P1). At elevated temperatures, 2,3-butadienal + H (P10) is also a major product. The chain decomposition pathway to form C3H4 + HCO was not competitive with the cyclization pathway at any of the temperatures studied. The DMC branching fractions of the products formed in the subject reaction are in reasonable accord with previous experimental and theoretical values. The computed rate coefficients were found to be independent of pressure at temperatures relevant to combustion (1500-2500 K).

Sex-specific patterns and differences in dementia and Alzheimer's disease using informatics approaches.

The National Institutes of Health Office of Research on Women's Health recently highlighted the critical need for explicitly addressing sex differences in biomedical research, including Alzheimer's disease and dementia. The purpose of our study was to perform a sex-stratified analysis of cognitive impairment using diverse medical, clinical, and genetic factors of unprecedented scale and scope by applying informatics approaches to three large Alzheimer's databases. Analyses suggested females were 1.5 times more likely than males to have a documented diagnosis of probable Alzheimer's disease, and several other factors fell along sex-specific lines and were possibly associated with severity of cognitive impairment.

A quantum Monte Carlo study of the reactions of CH with acrolein.

To assist understanding of combustion processes, we have investigated reactions of methylidyne (CH) with acrolein (CH2CHCHO) using the quantum Monte Carlo (QMC) and other computational methods. We present a theoretical study of the major reactions reported in a recent experiment on the subject system. Both DFT and MP2 computations are carried out, and the former approach is used to form the independent-particle part of the QMC trial wave function used in the diffusion Monte Carlo (DMC) variant of the QMC method. In agreement with experiment, we find that the dominant product channel leads to formation of C4H4O systems + H with leading products of furan + H and 1,3-butadienal + H. Equilibrium geometries, atomization energies, reaction barriers, transition states, and heats of reaction are computed using the DFT, MP2, and DMC approaches and compared to experiment. We find that DMC results are in close agreement with experiment. The kinetics of the subject reactions are determined by solving master equations with the MultiWell software suite.

Interval prediction of molecular properties in parametrized quantum chemistry.

The accurate evaluation of molecular properties lies at the core of predictive physical models. Most reliable quantum-chemical calculations are limited to smaller molecular systems while purely empirical approaches are limited in accuracy and reliability. A promising approach is to employ a quantum-mechanical formalism with simplifications and to compensate for the latter with parametrization. We propose a strategy of directly predicting the uncertainty interval for a property of interest, based on training-data uncertainties, which sidesteps the need for an optimum set of parameters.

Pathways to soot oxidation: reaction of OH with phenanthrene radicals.

Energetics and kinetics of the oxidation of possible soot surface sites by hydroxyl radicals were investigated theoretically. Energetics were calculated by employing density functional theory. Three candidate reactions were selected as suitable prototypes of soot oxidation by OH. The first two, OH + benzene and OH + benzene-phenol complex, did not produce pathways that lead to substantial CO expulsion. The third reaction, OH attack on the phenanthrene radical, had multiple pathways leading to CO elimination. The kinetics of the latter reaction system were determined by solving the master equations with the MultiWell suite of codes. The barrierless reaction rates of this system were computed using the VariFlex program. The computations were carried out over the ranges 1500-2500 K and 0.01-10 atm. At higher temperatures, above 2000 K, the oxidation of phenanthrene radicals by OH followed a chemically activated path. At temperatures lower than 2000 K, chemical activation was not sufficient to drive the reaction to products; reaction progress was impeded by intermediate adducts rapidly de-energizing before reaching products. In such cases, the reaction system was modeled by treating the accumulating adducts as distinct chemical species and computing their kinetics via thermal decomposition. The overall rate coefficient of phenanthrene radical oxidation by OH forming CO was found to be insensitive to pressure and temperature and is approximately 1 × 10(14) cm(3) mol(-1) s(-1). The oxidation of phenanthrene radicals by OH is shown to be controlled by two main processes: H atom migration/elimination and oxyradical decomposition. H atom migration and elimination made possible relatively rapid rearrangement of the aromatic edge to form oxyradicals with favorable decomposition rates. The reaction then continues down the fastest oxyradical pathways, eliminating CO.