Lamin B-receptor mutations in Pelger-Huët anomaly

Pelger-Huët anomaly is an inherited abnormality of neutrophils, characterized by reduced nuclear segmentation and an apparently looser chromatin structure. Following linkage studies in two families, the lamin B-receptor (LBR) was sequenced and mutations found: CCG-->CTG causing proline-->leucine in codon 119 of exon 3, and IVS11-9 A-->G, disrupting the splice acceptor site. The LBR gene (LBR) was also sequenced from a single English man with Pelger-Huët anomaly and a heterozygous C-->G mutation was found in codon 569 of exon 14, predicted to cause a proline-->arginine. Our results confirm recently published findings that LBR mutations cause Pelger-Huët.

Immune tolerance therapy for haemophilia

The development of anti-factor VIII and anti-factor IX allo-antibodies in haemophilia A and B, respectively, remains a serious complication of treatment for these two X-linked haemostatic disorders, with major clinical and economic consequences. Treatment of this potentially fatal complication remains one of the greatest challenges facing haematologists at the beginning of the 21st century. Immune tolerance induction (ITI) therapy has been generally accepted as the best available treatment, extinguishing the inhibitor and permitting a resumption of standard dosing schedules. Although there have been several established protocols for ITI therapy developed over the last quarter century, the optimal scheme in terms of safety, clinical efficacy and pharmacoeconomic considerations has yet to be determined.

Hb H hydrops fetalis syndrome associated with the interaction of two common determinants of alpha thalassaemia (--MED/(alpha)TSaudi(alpha))

To date, more than 35 single or oligonucleotide mutations of the alpha genes that cause alpha thalassaemia have been described. Their interactions give rise to widely variable clinical manifestations, from a mild hypochromic, microcytic anaemia to a lethal intrauterine anaemia associated with hydrops fetalis. Understanding the molecular genetics enables accurate genotyping, genetic counselling and prenatal testing for the most severe forms of alpha thalassaemia. Here we show for the first time that the interaction between two relatively common forms of alpha thalassaemia (--MED/(alpha)TSaudi(alpha)) may be associated with a clinically severe form of alpha thalassaemia, Hb H hydrops fetalis.

Tumour lysis following hydrocortisone prior to a blood product transfusion in T-cell acute lymphoblastic leukaemia

The acute tumour lysis syndrome is a well recognised complication of chemotherapy for lymphoid malignancies. There are few reports, however, of this complication after corticosteroid therapy alone. We report a case of T-cell acute lymphoblastic leukaemia who developed the biochemical picture of tumour lysis after two doses of hydrocortisone given prior to platelet transfusion. Prophylactic corticosteroids prior to blood product infusion should be reserved for patients who have experienced febrile or allergic reactions in the past and it is suggested that they should only be administered to patients with active lymphoid malignancies with due caution.

Biopsychosocial Predictors of Quality of Life in Paediatric Patients With Sickle Cell Disease

Sickle cell disease (SCD) refers to a group of inherited blood disorders with considerable morbidity that causes severe pain, reduces life expectancy, and requires significant self-management. Acute painful episodes are the hallmark of SCD, but persistent daily pain is also highly prevalent in this population. Characterising the impact and experience of SCD-related morbidity (i.e., sleep disruption, frequent emergency department visits, cognitive dysfunction) on health-related quality of life (HRQOL) requires multiple assessment methods to best capture the underlying mechanisms. To gain a greater understanding of the effect of common symptom categories on HRQOL and to determine potential pain coping targets, the present study investigated whether demographic, socioeconomic, sleepiness, pain burden, frequency of emergency department (ED) visits, and cognition predicted HRQOL in a paediatric sample of patients with SCD. Our study was a secondary analysis of baseline assessment data of children with SCD aged 8-15 years (n = 30) in the Prevention of Morbidity in Sickle Cell Anaemia Phase 2b (POMSb2) randomised controlled clinical trial of auto-adjusting continuous positive airways pressure. Patients completed cognitive testing (IQ, Processing Speed Index, Delis-Kaplan Executive Function Scale (DKEFS) Tower, Conner's Continuous Performance Test), sleepiness (Epworth Sleepiness Scale), and HRQOL (PedsQL Sickle Cell Module) at baseline. Patients reported pain burden (Sickle Cell Pain Burden Inventory-Youth) each month over 8 visits. Caregivers provided demographic information and reported their child's executive function (Behavioural Rating Inventory of Executive Function) at baseline. Data from our analysis demonstrated that demographic factors (i.e., age, gender, level of neighbourhood deprivation) and treatment variables (i.e., hydroxyurea use) did not independently predict HRQOL, and laboratory values (i.e., haemoglobin, haematocrit, mean oxygen saturation) were not significantly correlated with HRQOL (ps > 0.05). However, sleepiness, pain burden, ED visits, and executive dysfunction independently predicted HRQOL (R ² = 0.66) with large effects (η² = 0.16 to 0.32). These findings identify specific, measurable symptom categories that may serve as targets to improve HRQOL that are responsive to change. This knowledge will be useful for multimodal interventions for paediatric patients with SCD that include sleep management, pain coping strategies, and executive function training.

Heterogeneity of respiratory disease in children and young adults with sickle cell disease

To detect and characterise different phenotypes of respiratory disease in children and young adults with sickle cell disease (SCD), 11 lung function and haematological biomarkers were analysed using k-means cluster analysis in a cohort of 114 subjects with SCD aged between 5 and 27 years. Three clusters were detected: cluster 1 had elevated pulmonary capillary blood volume, mixed obstructive/restrictive lung disease, hypoxia and moderately severe anaemia; cluster 2 were older patients with restrictive lung disease; and cluster 3 were younger patients with obstructive lung disease, elevated serum lactate dehydrogenase and bronchodilator reversibility. These results may inform more personalised management strategies to improve outcomes.

Acute myelomonocytic leukemia with t(10;11)(p13;q23): heterogeneity of breakpoints at 11q23 and association with recombinase activation

The human trithorax homolog gene (MLL) is directly involved in over 90% of cases of acute leukemia with abnormalities of 11q23. However, involvement of other genes at 11q23 both centromeric and telomeric of MLL has been identified in different subtypes of leukemia and lymphoma. We describe a case of acute myelomonocytic leukemia (AMML; FAB type M4) with t(10;11)(p13;q23) in which the breakpoint at 11q23 was centromeric to the MLL gene and distinct from the breakpoint seen in promyelocytic leukemias with t(11;17)(q23;q22), thus providing further evidence of heterogeneity of breakpoints in 11q23 in acute leukemia. Rearrangements of immunoglobulin (IG) and T-cell receptor (TCR) genes were also observed, with no immunophenotypic evidence for commitment to the lymphoid lineages, indicating that inappropriate activation of the recombinases may be a feature of this particular variant translocation.

Airway and alveolar nitric oxide production, lung function, and pulmonary blood flow in sickle cell disease

BACKGROUND

Children with sickle cell disease (SCD) often have obstructive lung function abnormalities which could be due to asthma or increased pulmonary blood volume; it is important to determine the underlying mechanism to direct appropriate treatment. In asthmatics, exhaled nitric oxide (FeNO) is elevated. FeNO, however, can also be raised due to increased alveolar production. Our aim, therefore, was to determine if airway or alveolar NO production differed between SCD children and ethnic and age-matched controls.

METHODS

Lung function, airway NO flux and alveolar NO production, and effective pulmonary blood flow were assessed in 18 SCD children and 18 ethnic and age-matched controls.

RESULTS

The SCD children compared to the controls had a higher respiratory system resistance (P = 0.0008), alveolar NO production (P = 0.0224), and pulmonary blood flow (P < 0.0001), but not airway NO flux. There was no significant correlation between FeNO and respiratory system resistance in either group, but in the SCD children, there were correlations between alveolar NO production (P = 0.0006) and concentration (P < 0.0001) and pulmonary blood flow.

CONCLUSION

Airway NO flux was not elevated in the SCD children nor correlated with airways obstruction, suggesting that airways obstruction, at least in some SCD children, is not due to asthma.

Ruxolitinib treatment in an infant with JAK2+ polycythaemia vera-associated Budd-Chiari syndrome

Budd-Chiari syndrome (BCS) is caused by hepatic venous outflow obstruction commonly seen with myeloproliferative neoplasms (MPNs). Polycythaemia vera (PV) is a very rare MPN in childhood. This is the youngest reported patient diagnosed with PV and BCS secondary to JAK V617F mutation.A 26-month-old girl was admitted with a 5-month history of abdominal distension, hepatosplenomegaly and ascites. Imaging studies revealed occlusion of the right hepatic vein and marked attenuation of the middle and left hepatic veins. BCS was diagnosed after excluding other causes of chronic liver disease. Mandatory prothrombotic workup revealed underlying PV.Partial recanalisation of hepatic veins occurred following anticoagulation therapy and PV was well controlled by pegylated interferon and hydroxycarbamide until she developed nephrotic syndrome, likely secondary to pegylated interferon. Therefore, treatment was modified to ruxolitinib, a novel-JAK-2 inhibitor; the therapy has been effective for almost 20 months with a good response and has no side effects.

The presence of alpha-thalassaemia trait blunts the response to hydroxycarbamide in patients with sickle cell disease

Hydroxycarbamide (HC), although a key drug therapy in sickle cell disease (SCD), does not result in a clinical response in all patients. Increases in fetal haemoglobin (HbF) and mean corpuscular volume of erythrocytes are standard clinical measures of HC efficacy in SCD. Genetic studies have determined that the majority of HbF regulation occurs outside the beta-globin locus. Approximately 30% of SCD patients have co-inherited alpha-thalassaemia resulting in hypochromic and microcytic erythrocytes. We provide data from 30 SCD patients (10 with alpha-thalassaemia) demonstrating that co-existing alpha-thalassaemia significantly affects several standard measures of HC efficacy in SCD.

Clinical management of sickle cell liver disease in children and young adults

Liver involvement in sickle cell disease (SCD) is often referred to as sickle cell hepatopathy (SCH) and is a complication of SCD which may be associated with significant mortality. This review is based on a round-table workshop between paediatric and adult hepatologists and haematologists and review of the literature. The discussion was prompted by the lack of substantial data and guidance in managing these sometimes very challenging cases. This review provides a structured approach for the diagnosis and management of SCH in children and young adults. The term SCH describes any hepatobiliary dysfunction in the context of SCD. Diagnosis and management of biliary complications, acute hepatic crisis, acute hepatic sequestration and other manifestations of SCH are discussed, as well as the role of liver transplantation and haemopoietic stem cell transplantation in the management of SCH.

Successful treatment of mixed-type autoimmune hemolytic anemia with rituximab in a child following liver transplantation

Development of a severe form of mixed-type AIHA after orthotopic liver transplantation is a rare, but a life-threatening event. We report a case of mixed-type AIHA that developed in a child after hepatocyte and living-related orthotopic liver transplantation for factor VII deficiency.

Disturbances in T-cell subpopulations in B-cell chronic lymphocytic leukaemia

The relative proportions of immunoregulatory T-cell subpopulations defined by OKT monoclonal antibodies are disturbed in chronic lymphocytic leukaemia (CLL) patients (even early mild cases) compared with normal subjects in the same age range. The mean ratio OKT4+:OKT8+ (helper:suppressor/cytotoxic) is reversed from the normal 1.6:1 to 1:1.9. The absolute concentration of each OKT population in the circulation is slightly higher than normal, the increase in OKT8+ being the most significant. The E-rosette-forming cells did not always correlate with OKT+ cells and, in four cases, the discrepancy between the size of the OKT3+ population and the sum of OKT4+ and OKT8+ suggested the presence of T cells with an immature (thymic) phenotype in peripheral blood. These abnormalities may account for the depressed immune function of CLL patients.

Study of montelukast in children with sickle cell disease (SMILES): a study protocol for a randomised controlled trial

Background

Young children with sickle cell anaemia (SCA) often have slowed processing speed associated with reduced brain white matter integrity, low oxygen saturation, and sleep-disordered breathing (SDB), related in part to enlarged adenoids and tonsils. Common treatments for SDB include adenotonsillectomy and nocturnal continuous positive airway pressure (CPAP), but adenotonsillectomy is an invasive surgical procedure, and CPAP is rarely well-tolerated. Further, there is no current consensus on the ability of these treatments to improve cognitive function. Several double-blind, randomised controlled trials (RCTs) have demonstrated the efficacy of montelukast, a safe, well-tolerated anti-inflammatory agent, as a treatment for airway obstruction and reducing adenoid size for children who do not have SCA. However, we do not yet know whether montelukast reduces adenoid size and improves cognition function in young children with SCA.

Methods

The Study of Montelukast In Children with Sickle Cell Disease (SMILES) is a 12-week multicentre, double-blind, RCT. SMILES aims to recruit 200 paediatric patients with SCA and SDB aged 3–7.99 years to assess the extent to which montelukast can improve cognitive function (i.e. processing speed) and sleep and reduce adenoidal size and white matter damage compared to placebo. Patients will be randomised to either montelukast or placebo for 12 weeks. The primary objective of the SMILES trial is to assess the effect of montelukast on processing speed in young children with SCA. At baseline and post-treatment, we will administer a cognitive evaluation; caregivers will complete questionnaires (e.g. sleep, pain) and measures of demographics. Laboratory values will be obtained from medical records collected as part of standard care. If a family agrees, patients will undergo brain MRIs for adenoid size and other structural and haemodynamic quantitative measures at baseline and post-treatment, and we will obtain overnight oximetry.

Discussion

Findings from this study will increase our understanding of whether montelukast is an effective treatment for young children with SCA. Using cognitive testing and MRI, the SMILES trial hopes to gain critical knowledge to help develop targeted interventions to improve the outcomes of young children with SCA.

Trial registration

ClinicalTrials.govNCT04351698. Registered on April 17, 2020. European Clinical Trials Database (EudraCT No. 2017-004539-36). Registered on May 19, 2020

What is the role of chest X-ray imaging in the acute management of children with sickle cell disease?

Children with sickle cell disease (SCD) frequently present to hospital acutely unwell and are often exposed to diagnostic chest X-rays (CXRs). Little evidence exists to determine when CXRs are clinically useful. Using electronic hospital records, we audited CXR use in children aged 0-18 who presented to hospital over the past 10 years in both an inpatient and emergency department setting. From a total of 915 first CXRs, only 28·2% of CXRs (n = 258) had clinically significant findings that altered management or final diagnosis. Of these abnormalities, consolidation represented 52·3%, effusion 8·9%, cardiomegaly 8·4% and sickle cell-related bone changes 6·3%. Indications for CXR of respiratory distress (OR = 3·74, 95% CI 2·28-6·13), hypoxia (OR = 1·86, 95% CI 1·50-2·31) and cough (OR = 1·64, 95% CI 1·33-2·02), were more likely to have significant CXR findings. Patients who had higher peak fever (38·4°C vs. 37·4°C, P = 0·001), higher peak CRP (156·4 vs. 46·1, P < 0·001) and higher WCC (20·2 vs. 13·6, P < 0·001) were more likely to have clinically significant abnormalities on CXR. We found a decision tool using either hypoxia, cough, respiratory distress, T > 38°C, CRP > 50 or WCC > 15 × 10⁹ /l as indications for CXR, to have a sensitivity of 88% (with 95% CI 0·78-0·95) and specificity of 46% (95% CI 0·43-0·50) for clinically significant findings.

Deletions and rearrangement of CDKN2 in lymphoid malignancy

Recurrent abnormalities of the short arm of chromosome 9, including translocations and interstitial deletions, have been reported in both leukemia and lymphoma. The pathologic consequences of these abnormalities remain unknown. The cyclin-dependent kinase 4 inhibitor (CDKN2) gene, which maps to 9p21, has been implicated by the finding of a high frequency of biallelic deletions in leukemic cell lines. We have determined the incidence of structural abnormalities affecting CDKN2 by DNA blot in a panel of 231 cases of leukemia and lymphoma and 66 cell lines derived from patients with lymphoid malignancies with defined cytogenetic abnormalities. Structural alterations of CDKN2 were seen in 20 (8.3%) of all fresh cases and 10 (15.1%) of all cell lines. Biallelic CDKN2 deletions were seen in 11 of 53 (21%) cases of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). There was no association with any particular cytogenetic abnormality. Biallelic deletions were also found in high-grade and transformed non-Hodgkin's lymphoma (NHL) of both B- and T-cell lineages. In two cases of transformed NHL, analysis of sequential samples showed loss of CDKN2 with transformation. Neither deletions nor rearrangements of the CDKN2 gene were seen in any of the 119 leukemias of mature B or T cells analyzed. Biallelic deletions of CDKN2 were observed in 6 of 13 NHL cell lines. Three of the 6 cases had undergone transformation from low- to high-grade disease: in 2 of these cases it was possible to show that the CDKN2 deletions were present in fresh material from the patient and were therefore not an artifact of in vitro culture. Rearrangements of CDKN2 were seen in 2 cases (4%) of BCP-ALL, in 1 case of B-NHL, and in 1 Burkitt's lymphoma cell line and suggest the presence of a "hot spot" for recombination in the vicinity of the CDKN2 gene. These data indicate that the loss of CDKN2 expression may be involved in the pathogenesis of a subset of BCP-ALL, some high-grade NHL, and in the transformation of NHL from low- to high-grade disease. CDKN2 deletions and rearrangements occurred in the absence of detectable cytogenetic changes of chromosome 9p in 25 of 30 (83%) cases. Finally, of 10 cases of BCP-ALL that produced overt, transplantable leukemia in mice with severe combined immunodeficiency (SCID), seven showed biallelic CDKN2 deletions. In contrast, none of 11 cases that failed to engraft showed biallelic CDKN2 deletions. BCP-ALL cases that lack CDKN2 expression may have a particular propensity to grow in SCID mice.

Advanced epithelioid haemangioendothelioma in a child presenting as deep vein thrombosis

Venous thromboembolism (VTE) is a rare event in children and does not usually trigger investigation for malignancy. We report the case of a previously healthy female teenager presenting with unilateral leg swelling. Colour-Doppler ultrasound confirmed deep vein thrombosis (DVT), and the thrombophilia workup was negative. Cross-sectional imaging identified multiple liver and lung lesions, diagnosed as epithelioid haemangioendothelioma (EHE) at biopsy. Lifelong anticoagulation was commenced; the patient was initially observed and then started on sirolimus at disease progression. We describe the first published case of EHE presenting with DVT in a child. Clinicians need to be mindful of the association between cancer and thrombosis, even in paediatric patients.

Analysis of clonal rearrangements of the Ig heavy chain locus in acute leukemia

Clonal rearrangements of the Ig heavy chain (IGH) locus occur in nearly all cases of B-cell precursor acute leukemia (BCP-ALL). Some of these rearrangements may be detected by polymerase chain reaction (PCR) using VH gene framework III (FRIII) and JH consensus primers. However, about 20% of BCP-ALLs fail to amplify with this technique. To determine the causes of these PCR failures and to investigate any possible association with specific subgroups of disease, we analyzed 72 acute leukemias of defined immunophenotype and cytogenetics, comparing FRIII with VH-family leader-specific PCR methods and Southern blotting. Of 37 BCP-ALL cases, 6 (16.2%) failed totally to amplify with FRIII and JH primers. None of these cases amplified with VH leader primers. Additionally, all cases retained germline VH6 genes and 5 of 11 rearranged alleles amplified with a consensus DH primer, indicating that these rearrangements represented biallelic DH-JH recombinations. Among the 6 FRIII and VH leader PCR-negative BCP-ALL cases, there was no common immunophenotype or consistent cytogenetic abnormality, although all showed structural chromosomal abnormalities and 3 of 5 successfully karyotyped had abnormalities of chromosome 12p. 13 cases with t(9;22)(q34;q11) Philadelphia chromosome-positive [Ph+]) and IGH rearrangements (9 BCP-ALL and 4 biphenotypic cases) were also analyzed. Of 23 rearranged IGH alleles, 19 (82%) were positive by FRIII PCR, and all 4 remaining alleles were amplified by VH leader primers. Use of the leader primers in these Ph+ cases also detected 3 additional clonal rearrangements that were not anticipated from Southern blotting; such unexpected bands were not observed in 21 other Ph- cases. The additional bands represented "new" and unrelated VH rearrangements rather than VH-VH replacement events. We conclude that biallelic DHJH rearrangements occur in a subgroup of BCP-ALL; in these cases, the activation of the full VHDHJH recombination mechanism had not occurred. Therefore, these cases of BCP-ALL were arrested at an early stage of B-cell differentiation. In contrast, all Ph+ BCP-ALLs and biphenotypic acute leukemias, which may represent the transformation of multipotent hemopoietic stem cells, had undergone VHDHJH recombination. Of 9 Ph+ BCP-ALL cases, 3 also showed ongoing VHDHJH rearrangement, reflecting the persistent expression of the VHDHJH recombinase. Finally, sequence analysis of 33 rearranged VHDHJH genes showed that only 3 including 2 Ph+ BCP-ALL maintained an intact open-reading frame. Loss of the open-reading frame occurred not only because of out-of-frame VHDH and DHJH joining, but also because of VH gene mutation and deletion. These data show that most BCP-ALLs may represent the neoplastic transformation of BCPs destined to die in the bone marrow.

High Prevalence of Hemophagocytic Lymphohistiocytosis in Acute Liver Failure of Infancy

OBJECTIVES

To investigate the prevalence of hemophagocytic lymphohistiocytosis (HLH) syndrome in pediatric acute liver failure (PALF) of infancy and assess the diagnostic role of rapid immunologic tests, genotype/phenotype correlations, and clinical outcomes.

STUDY DESIGN

We retrospectively analyzed 78 children with PALF aged <24 months referred over almost 2 decades. The studied patients with a phenotype of HLH syndrome had a comprehensive immunologic workup, including additional genetic analysis for primary immunologic causes.

RESULTS

Thirty of the 78 children had the HLH phenotype and underwent genetic assessment, which demonstrated positive findings in 19 (63.3%), including 9 (30%) with biallelic primary HLH mutations and 10 (33.3%) with heterozygous mutations and/or polymorphisms. The most common form of primary HLH was familial hemophagocytic lymphohistiocytosis (FHL)-2, diagnosed in 6 children, 4 of whom had a c.50delT (p.Leu17ArgfsTer34) mutation in the PRF1 gene. Three patients with primary HLH received genetic diagnoses of FHL-3, Griscelli syndrome, and LRBA (lipopolysaccharide-responsive vesicle trafficking, beach- and anchor-containing) protein deficiency. Overall mortality in the series was 52.6% (10 of 19), and mortality in children with a documented biallelic pathogenic HLH mutation (ie, primary HLH) was 66.6% (6 of 9). Two children underwent liver transplantation, and 4 children underwent emergency hematopoietic stem cell transplantation; all but 1 child survived medium term.

CONCLUSIONS

Primary HLH can be diagnosed retrospectively in approximately one-third of infants with indeterminate PALF (iPALF) who meet the clinical criteria for HLH, often leading to their death. The most common HLH type in iPALF is FHL-2, caused by biallelic mutations in PRF-1. The clinical relevance of observed heterozygous mutations and variants of uncertain significance requires further investigation. Prompt hematopoietic stem cell transplantation could be life-saving in infants who survive the liver injury.