Supportive care in the management of patients with acute myeloid leukaemia: where are the research needs?

Supportive care for patients with acute myeloid leukaemia (AML) is defined as a broad range of interventions that ameliorate the symptoms of a disease, or the side effects caused by treatment, and which address psychological, cultural, social and spiritual factors.1 Transfusion support and infection management are key examples of supportive care that have contributed significantly to the successes of more intensive chemotherapy, delivering improvements in outcomes despite, arguably, only modest improvements in chemotherapy regimens.2 This article will review our current practice of transfusion therapy and infection management and identify research opportunities which the National Cancer Research Institute (NCRI) AML working party are supporting, alongside forthcoming national AML trials

100,000 Genomes Pilot on Rare-Disease Diagnosis in Health Care — Preliminary Report

BACKGROUND: The U.K. 100,000 Genomes Project is in the process of investigating the role of genome sequencing in patients with undiagnosed rare diseases after usual care and the alignment of this research with health care implementation in the U.K. National Health Service. Other parts of this project focus on patients with cancer and infection. METHODS: We conducted a pilot study involving 4660 participants from 2183 families, among whom 161 disorders covering a broad spectrum of rare diseases were present. We collected data on clinical features with the use of Human Phenotype Ontology terms, undertook genome sequencing, applied automated variant prioritization on the basis of applied virtual gene panels and phenotypes, and identified novel pathogenic variants through research analysis. RESULTS: Diagnostic yields varied among family structures and were highest in family trios (both parents and a proband) and families with larger pedigrees. Diagnostic yields were much higher for disorders likely to have a monogenic cause (35%) than for disorders likely to have a complex cause (11%). Diagnostic yields for intellectual disability, hearing disorders, and vision disorders ranged from 40 to 55%. We made genetic diagnoses in 25% of the probands. A total of 14% of the diagnoses were made by means of the combination of research and automated approaches, which was critical for cases in which we found etiologic noncoding, structural, and mitochondrial genome variants and coding variants poorly covered by exome sequencing. Cohortwide burden testing across 57,000 genomes enabled the discovery of three new disease genes and 19 new associations. Of the genetic diagnoses that we made, 25% had immediate ramifications for clinical decision making for the patients or their relatives. CONCLUSIONS: Our pilot study of genome sequencing in a national health care system showed an increase in diagnostic yield across a range of rare diseases. (Funded by the National Institute for Health Research and others.)

The study of DNA methylation anomalies in chronic lymphocytic leukaemia

Many haematological malignancies are associated with widespread alterations of the transcriptional and epigenetic programmes. Changes in DNA methylation provide the clearest example of epigenetic changes, but the mechanism(s) underlying such changes is unknown. To investigate this I studied DNA methylation across an ~80kb segment of the genome which is not known to be mutated in haematological malignancies. Methylation was perturbed in 35-100% of samples of DNA from individuals with a wide range of haematological malignancies but not in non-malignant haematological disorders. DNA methylation was comprehensively assessed by Southern blot analysis, classical bisulphite sequencing and using a newly developed capture bisulphite sequencing protocol. The results were also compared with analysis by MeDIP, an immunoprecipitation-based technique. These analyses provide methylation status at various levels including individual CpG resolution. This showed both gain and loss of methylation at CpG dinucleotides. Of interest, hypomethylation was most frequently seen in intergenic regions corresponding to transcription factor binding sites and areas of increased chromosome accessibility. These observations suggested that hypomethylation of the genome in haematological malignancies could arise from aberrantly expressed DNA binding proteins which, recruited to sequences in regions of open chromatin, would protect the underlying CpG dinucleotides from the methylation machinery. This, in turn, could lead to passive demethylation accumulating with increasing cell divisions. This hypothesis was tested with electrophoretic mobility shift assays using oligonucleotides representing the DNA underlying one such region. This showed that, compared to nuclear extracts from the lymphocytes of normal individuals, those from patients with CLL were enriched for a protein which binds to oligonucleotides containing the underlying sequence. Using a mass spectrometry approach, I identified a variety of proteins that may bind such regions and account for their passive demethylation in haematological malignancies

Interventions for chronic kidney disease in people with sickle cell disease

Background Sickle cell disease (SCD) is one of the commonest severe monogenic disorders in the world, due to the inheritance of two abnormal haemoglobin (beta-globin) genes. SCD can cause severe pain, significant end-organ damage, pulmonary complications, and premature death. Kidney disease is a frequent and potentially severe complication in people with SCD. Chronic kidney disease is defined as abnormalities of kidney structure or function, present for more than three months. Sickle cell nephropathy refers to the spectrum of kidney complications in SCD. Glomerular damage is a cause of microalbuminuria and can develop at an early age in children with SCD, and increases in prevalence in adulthood. In people with sickle cell nephropathy, outcomes are poor as a result of the progression to proteinuria and chronic kidney insufficiency. Up to 12% of people who develop sickle cell nephropathy will develop end-stage renal disease. Objectives To assess the effectiveness of any intervention in preventing or reducing kidney complications or chronic kidney disease in people with SCD (including red blood cell transfusions, hydroxyurea and angiotensin-converting enzyme inhibitor (ACEI)), either alone or in combination with each other. Search methods We searched for relevant trials in the Cochrane Library, MEDLINE (from 1946), Embase (from 1974), the Transfusion Evidence Library (from 1980), and ongoing trial databases; all searches current to 05 April 2016. We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register: 13 April 2017. Selection criteria Randomised controlled trials comparing interventions to prevent or reduce kidney complications or chronic kidney disease in people with SCD. There were no restrictions by outcomes examined, language or publication status. Data collection and analysis Two authors independently assessed trial eligibility, extracted data and assessed the risk of bias. Main results We included two trials with 215 participants. One trial was published in 2011 and included 193 children aged 9 months to 18 months, and compared treatment with hydroxyurea to placebo. The second trial was published in 1998 and included 22 adults with normal blood pressure and microalbuminuria and compared ACEI to placebo. We rated the quality of evidence as low to very low across different outcomes according to GRADE methodology. This was due to trials having: a high or unclear risk of bias including attrition and detection bias; indirectness (the available evidence was for children aged 9 months to 18 months in one trial and a small and select adult sample size in a second trial); and imprecise outcome effect estimates of significant benefit or harm. Hydroxyurea versus placebo We are very uncertain if hydroxyurea reduces or prevents progression of kidney disease (assessed by change in glomerular filtration rate), or reduces hyperfiltration in children aged 9 to 18 months, mean difference (MD) 0.58 (95% confidence interval (CI) -14.60 to 15.76 (mL/min per 1.73 m²)) (one study; 142 participants; very low-quality evidence). In children aged 9 to 18 months, hydroxyurea may improve the ability to concentrate urine, MD 42.23 (95% CI 12.14 to 72.32 (mOsm/kg)) (one study; 178 participants; low-quality evidence). Hydroxyurea may make little or no difference to SCD-related serious adverse events including: incidence of acute chest syndrome, risk ratio (RR) 0.39 (99% CI 0.13 to 1.16); painful crisis, RR 0.68 (99% CI 0.45 to 1.02); and hospitalisations, RR 0.83 (99% CI 0.68 to 1.01) (one study, 193 participants; low-quality evidence). No deaths occurred in the trial. Quality of life was not reported. ACEI versus placebo We are very uncertain if ACEI reduces proteinuria in adults with SCD who have normal blood pressure and microalbuminuria, MD -49.00 (95% CI -124.10 to 26.10 (mg per day)) (one study; 22 participants; very low-quality evidence). We are very uncertain if ACEI reduce or prevent kidney disease as measured by creatinine clearance. The authors state that creatinine clearance remained constant over six months in both groups, but no comparative data were provided (very low-quality evidence). All-cause mortality, serious adverse events and quality of life were not reported. Authors' conclusions In young children aged 9 months to 18 months, we are very uncertain if hydroxyurea improves glomerular filtration rate or reduces hyperfiltration, but it may improve young children's ability to concentrate urine and may make little or no difference on the incidence of acute chest syndrome, painful crises and hospitalisations. We are very uncertain if giving ACEI to adults with normal blood pressure and microalbuminuria has any effect on preventing or reducing kidney complications. This review identified no trials that looked at red cell transfusions nor any combinations of interventions to prevent or reduce kidney complications. Due to lack of evidence this review cannot comment on the management of either children aged over 18 months or adults with any known genotype of SCD. We have identified a lack of adequately-designed and powered studies, and no ongoing trials which address this critical question. Trials of hydroxyurea, ACEI or red blood cell transfusion in older children and adults are urgently needed to determine any effect on prevention or reduction kidney complications in people with SCD

Single-cell O2 exchange imaging shows that cytoplasmic diffusion is a dominant barrier to efficient gas transport in red blood cells

Disorders of oxygen transport are commonly attributed to inadequate carrying capacity (anemia) but may also relate to inefficient gas exchange by red blood cells (RBCs), a process that is poorly characterized yet assumed to be rapid. Without direct measurements of gas exchange at the single-cell level, the barriers to O2 transport and their relationship with hematological disorders remain ill defined. We developed a method to track the flow of O2 in individual RBCs by combining ultrarapid solution switching (to manipulate gas tension) with single-cell O2 saturation fluorescence microscopy. O2 unloading from RBCs was considerably slower than previously estimated in acellular hemoglobin solutions, indicating the presence of diffusional barriers in intact cells. Rate-limiting diffusion across cytoplasm was demonstrated by osmotically induced changes to hemoglobin concentration (i.e., diffusive tortuosity) and cell size (i.e., diffusion pathlength) and by comparing wild-type cells with hemoglobin H (HbH) thalassemia (shorter pathlength and reduced tortuosity) and hereditary spherocytosis (HS; expanded pathlength). Analysis of the distribution of O2 unloading rates in HS RBCs identified a subpopulation of spherocytes with greatly impaired gas exchange. Tortuosity imposed by hemoglobin was verified by demonstrating restricted diffusivity of CO2, an acidic gas, from the dissipative spread of photolytically uncaged H+ ions across cytoplasm. Our findings indicate that cytoplasmic diffusion, determined by pathlength and tortuosity, is a major barrier to efficient gas handling by RBCs. Consequently, changes in RBC shape and hemoglobin concentration, which are common manifestations of hematological disorders, can have hitherto unrecognized and clinically significant implications on gas exchange

Whole-genome sequencing of patients with rare diseases in a national health system

Most patients with rare diseases do not receive a molecular diagnosis and the aetiological variants and causative genes for more than half such disorders remain to be discovered. Here we used whole-genome sequencing (WGS) in a national health system to streamline diagnosis and to discover unknown aetiological variants in the coding and non-coding regions of the genome. We generated WGS data for 13,037 participants, of whom 9,802 had a rare disease, and provided a genetic diagnosis to 1,138 of the 7,065 extensively phenotyped participants. We identified 95 Mendelian associations between genes and rare diseases, of which 11 have been discovered since 2015 and at least 79 are confirmed to be aetiological. By generating WGS data of UK Biobank participants, we found that rare alleles can explain the presence of some individuals in the tails of a quantitative trait for red blood cells. Finally, we identified four novel non-coding variants that cause disease through the disruption of transcription of ARPC1B, GATA1, LRBA and MPL. Our study demonstrates a synergy by using WGS for diagnosis and aetiological discovery in routine healthcare

Significant haemoglobinopathies: A guideline for screening and diagnosis. A British Society for Haematology Guideline

Antenatal screening/testing of pregnant women should be carried out according to the guidelines of the National Health Service (NHS) Sickle Cell and Thalassaemia Screening Programme. Newborn screening and, when necessary, follow-up testing and referral, should be carried out according to the guidelines of the NHS Sickle Cell and Thalassaemia Screening Programme. All babies under 1 year of age arriving in the United Kingdom should be offered screening for sickle cell disease (SCD). Preoperative screening for SCD should be carried out in patients from ethnic groups in which there is a significant prevalence of the condition. Emergency screening with a sickle solubility test must always be followed by definitive analysis. Laboratories performing antenatal screening should utilise methods that are capable of detecting significant variants and are capable of quantitating haemoglobins A2 and F at the cut-off points required by the national antenatal screening programme. The laboratory must ensure a provisional report is available for antenatal patients within three working days from sample receipt