Variation in baseline factor VIII concentration in a retrospective cohort of mild/moderate hemophilia A patients carrying identical F8 mutations.

Essentials Factor VIII levels vary in mild and moderate hemophilia A (MHA) patients with the same mutation. We aimed to estimate the variation and determinants of factor VIII levels among MHA patients. Age and genotype explain 59% of the observed inter-individual variation in factor VIII levels. Intra-individual variation accounted for 45% of the variation in the three largest mutation groups. SUMMARY: Background The bleeding phenotype in patients with mild/moderate hemophilia A (MHA) is inversely associated with the residual plasma concentration of factor VIII (FVIII:C). Within a group of patients with the same F8 missense mutation, baseline FVIII:C may vary, because, in healthy individuals, von Willebrand factor (VWF) levels, ABO blood group and age are also known to influence baseline FVIII:C. Our understanding of the pathophysiologic process of the causative genetic event leading to reduced baseline FVIII:C in MHA patients is still limited. Objectives To estimate the variation and determinants of baseline FVIII:C among MHA patients with the same F8 missense mutation. Methods Three hundred and forty-six patients carrying mutations that were present in at least 10 patients in the cohort were selected from the INSIGHT and the RISE studies, which are cohort studies including data of 3534 MHA patients from Europe, Canada, and Australia. Baseline FVIII:C was measured with a one-stage clotting assay. We used Levene's test, univariate and multivariate linear regression, and mixed-model analyses. Results For 59% of patients, the observed variation in baseline FVIII:C was explained by age and genotype. Compared to FVIII:C in patients with Arg612Cys, FVIII:C was significantly different in patients with eight other F8 missense mutations. Intra-individual variation explained 45% of the observed variance in baseline FVIII:C among patients with the same mutation. Conclusion Our results indicate that baseline FVIII:C levels are not exclusively determined by F8 genotype in MHA patients. Insights into other factors may provide potential novel targets for the treatment of MHA.

Prospective study of thromboembolism in 1038 children with acute lymphoblastic leukemia: a Nordic Society of Pediatric Hematology and Oncology (NOPHO) study.

UNLABELLED: ESSENTIALS: Children with acute lymphoblastic leukemia (ALL) are at risk of thromboembolism (TE). This is a prospective evaluation of the incidence, risk factors and outcomes of TE in 1038 children with ALL. TE occurred in 6.1% of children, with the highest incidence (20.5%) among those aged 15-17 years. A TE-associated case fatality of 6.4% indicates that TE is a severe complication of ALL treatment. BACKGROUND: Thromboembolism (TE) is a major toxicity in children with acute lymphoblastic leukemia (ALL) and may have a negative impact on ALL treatment. OBJECTIVES: To examine the cumulative incidence, outcomes and risk factors associated with TE in children with leukemia. PATIENTS/METHODS: We prospectively evaluated TE in 1038 Nordic children and adolescents (≥ 1 and < 18 years) diagnosed with ALL during 2008-2013 and treated according to the NOPHO (Nordic Society of Pediatric Hematology and Oncology)-ALL 2008 protocol. The cohort was followed until December 2014. Cox proportional regression was used to compute hazard ratios (HRs). RESULTS: TE events (n = 63) occurred most frequently in conjunction with asparaginase (ASP) administration (52/63). The cumulative incidence of TE was 6.1% (95% confidence interval [CI], 4.8-7.7). Being aged 15-17 years was associated with an increased risk of TE (adjusted HR of 4.0; 95% CI, 2.1-7.7). We found a TE-associated 30-day case fatality of 6.4% (95% CI, 1.8-15.5) and TE-related truncation of ASP therapy in 36.2% (21/58). Major hemorrhage occurred in 3.5% (2/58) of anticoagulated patients. Minor hemorrhage was reported in two out of 58 patients. No major bleeds occurred in children who received low-molecular-weight heparin. CONCLUSIONS: Methods to identify children and adolescents who will benefit from thromboprophylaxis during ALL treatment are called for. The truncation of ASP should be avoided. The long-term survival outcomes for ALL patients with TE require close monitoring in the future.

Complications associated with central venous access device in children with haemophilia: a nationwide multicentre study in Finland.

Children with haemophilia require venous access for regular infusion of coagulation factors. A central venous access device (CVAD) ensures long-term access but associates with infectious and non-infectious complications with proposed risk factors of young age at initial CVAD implantation and presence of an inhibitor. Our aim was to evaluate the incidence and risk factors for complications associated with CVAD usage in a retrospective nationwide multicentre study in five Finnish Paediatric Haemophilia Treatment Centers. Our study investigated 106 CVADs in 58 patients with 137 971 CVAD days. The median access survival was 1159 CVAD days, and most often a malfunction led to CVAD removal after a long survival (median of 1640 CVAD days). We detected a very low bloodstream infection rate (0.12/1000 CVAD days). The presence of neutralizing inhibitor was a significant risk factor for infection. Heparin vs. saline flushing did not influence the CVAD outcome. We detected a lower infection rate than previously reported, although 90% of the patients were very young (<2 years) at first insertion (median age = 1.02 year). Port access was frequent after initial implantation: six patients (10%) used the port daily for immune tolerance induction therapy and 74% at least twice weekly for prophylaxis. Young age did not increase the risk of infections, as 59% of the CVAD-related infections were recorded in children over 6 years of age. Our national experience confirms the safety of prophylactic factor concentrate administration via ports even in very young children.

Oral health care in children with haemophilia in Helsinki, Finland.

BACKGROUND: The bleeding tendency and fear of bleeds may have a negative effect on preventive dental care of patients with haemophilia both at home and at dental appointments. AIM: To describe the clinical practice of dental care in children with haemophilia in Helsinki, Finland. METHODS: This study evaluated retrospectively the medical records of 28 paediatric patients with haemophilia (aged 5.3-17.4 years) from dental visits during 2009-2010. Decayed, missing and filled teeth in the primary (dmft) and permanent dentition (DMFT), Community Periodontal Index (CPI), signs of developmental dental defects in enamel and the number of preventive and restorative procedures were gathered. Dmft + DMFT scores were compared with those of 17,079 non-haemophiliac boys. The Mann-Whitney U-test was used to compare the data between the groups of different severity of haemophilia. RESULTS: The median number of dental visits per patient was three (range 1-11). Twenty-two patients (79 %) had dmft + DMFT-scores within the 95 % reference range for age. None of the children had a CPI >2. Twelve (43 %) patients had developmental enamel defects. Half had received restorative dental care and three out of four preventive procedures. CONCLUSIONS: Dental care during hospital visits in children with haemophilia may enhance confidence in the preventive dental care and help minimise bleeding during dental procedures.

Hypercalciuria and kidney function in children with haemophilia.

Adults with haemophilia have a higher incidence of chronic kidney disease than general male population. We recently showed that children with haemophilia have higher urinary calcium excretion and lower whole body bone mineral density than controls in spite of prophylaxis with the deficient coagulation factor concentrate, serum vitamin D concentrations comparable to those of healthy children and physically active lifestyle. Persistent hypercalciuria may result in nephrocalcinosis and impact renal function. This study sought to assess persistence of urinary calcium excretion and kidney function in children with haemophilia. We investigated retrospectively urinary calcium excretion in 30 children with haemophilia (mean age 12.5 years) from consecutive urine samples over a 2-year period. Renal evaluation included blood and urine specimen, blood pressure, and renal ultrasound. High number of children with haemophilia had intermittent hypercalciuria. Hypercalciuria was not associated with age, severity of haemophilia or previous hypercalciuria. Kidney function and renal ultrasound were normal with the exception of suspected kidney stone in one patient with haemophilia and transient hypercalciuria. Vitamin D concentrations improved after the families had received information and recommendations concerning vitamin D substitution. Our findings indicate that haemophilia per se predisposes to hypercalciuria which may in turn affect bone mineral content and kidney function. Whether childhood-onset intermittent hypercalciuria contributes to hypertension and renal complications in adulthood remains to be elucidated in future studies.

Peripheral quantitative computed tomography (pQCT) reveals alterations in the three-dimensional bone structure in children with haemophilia.

Children with haemophilia are at risk of suboptimal bone mass accrual and low bone mineral density (BMD). We recently demonstrated that although BMD in Finnish children with haemophilia was within the normal range, their whole body BMD was significantly lower and hypercalciuria more prevalent than in controls. This study sought to determine the bone structure and strength in physically active children with haemophilia. To investigate the underlying mechanisms in this group, we conducted a case-control study to assess bone structure and strength by peripheral quantitative computed tomography (pQCT) at the radius. The study group comprised 29 patients (mean age 12.2 years) and 46 age-matched controls. Children with haemophilia had decreased total BMD Z-score at the distal radius (P ≤ 0.001), but increased cortical bone density at the proximal radius (P ≤ 0.001). Total bone area at the proximal radius was significantly lower in children with haemophilia (P = 0.002), whereas there were no differences in cortical bone area or in polar Strength-Strain Index, a parameter of bone strength, between the patients and controls. Patients with mild to moderate haemophilia and on-demand treatment had inferior bone strength compared to those with moderate to severe haemophilia and prophylaxis. Our findings suggest altered skeletal development in patients with haemophilia in the radius, resulting in smaller bone size and higher cortical bone density. Importantly, bone strength at the radius appears equal to healthy children. Prophylactic treatment seems to have a beneficial effect on bone health.

MRI after removal of central venous access device reveals a high number of asymptomatic thromboses in children with haemophilia.

Central venous access devices (CVADs) are often required in children with haemophilia to secure venous access for prophylactic treatment or immune tolerance therapy. Complications of CVADs include infections, thrombosis and mechanical problems. This study sought to determine the outcome of the vessels by magnetic resonance imaging (MRI) in children with haemophilia and to assess risk factors for development of catheter-related deep venous thrombosis (DVT). After the removal of CVAD an MRI of the chest and neck was performed to 20 boys with haemophilia who each had 1-3 (total number 27) CVADs placed. MRI revealed DVT in five children (25%). As their CVADs were functional at the time of the removal, the DVTs were clinically silent. However, there had been suspicion of DVT leading to replacement of the CVAD in one case. All the children with DVT had their CVADs inserted initially below the age of 1 year. The clinical signs of mild post-thrombotic syndrome (PTS) were common: dilated chest wall veins were observed in 11 (55%) children and were associated with DVT in three cases. Arm circumference discrepancy was observed in one child with DVT. No correlation between the duration or number of CVADs and DVT was detected. None of the patients had subjective symptoms of PTS. Silent DVT is a common complication of CVAD. Catheter insertion at a young age seems to predispose to thrombosis. The long-term consequences of the DVTs remain unknown.

Long-term FEIBA prophylaxis does not prevent progression of existing joint disease.

Activated prothrombin complex concentrates have been used to treat bleeding episodes for patients who have developed an inhibitor to factor VIII (FVIII). FEIBA-Vh (FVIII bypassing activity, FEIBA) has been used since 1970 for this purpose and with FVIII for immune tolerance programmes. Studies have not been presented to show the safety and efficacy of FEIBA when given over a long period of time to prevent haemophilic arthropathy with bleeding into the joints of these patients. This study was undertaken to ascertain the outcome of haemophilic arthropathy with FEIBA prophylaxis. Data were collected on seven patients with known long-standing high-titre FVIII inhibitors given FEIBA prophylaxis for 3-6(1/2) years. Patients were given 50-100 units of FEIBA three to four times weekly. A functional joint evaluation revealed some degree of arthropathy already present in all patients at time of prophylaxis initiation. Safety was measured by medical status, evidence of thrombosis, life-threatening bleeding and inhibitor titre. Efficacy was measured for joint outcome by a functional physical therapeutic scale. At the conclusion of the study, efficacy was mixed as all of the joints for which the patients were placed on prophylaxis had progressed and developed synovitis. Two patients had a functional improvement in their arthropathy, and all were functional enough to attend regular school. The product was deemed safe for long-term use, as there were no complications of therapy with no thrombosis, no life-threatening bleeding episodes and no anamnesis caused by FEIBA alone. Inhibitor titres fell in all patients over the course of the study. Total product usage ranged from approximately 9373-15,571 U kg(-1) year(-1). FEIBA is safe for long-term prophylaxis when given in the recommended dosage for an extended period of time. Efficacy to prevent arthropathy could not be seen as all patients had some degree of arthropathy at time of prophylaxis initiation. An additional study needs to be performed using FEIBA before arthropathy has developed.

Investigation of the mechanisms of therapy-related hypoglycaemia in children with acute lymphoblastic leukaemia.

AIM: To determine the mechanisms of fasting hypoglycaemia occurring during maintenance therapy (MT) for childhood acute lymphoblastic leukaemia (ALL). METHODS: Thirty-five children and adolescents with ALL, aged 2.4-17.4 y, were fasted for up to 16 h during MT. Nineteen of the children developed hypoglycaemia after 11 to 16 h of fasting. Blood samples for determination of metabolic changes were taken on completion of fasting. Nineteen patients underwent a glucagon stimulation test after 4 to 16 h of fasting during MT. Erythrocyte concentrations of the metabolites of methotrexate (E-MTX) and 6-mercaptopurine (E-TGN) were measured at the time of fasting. Fifteen out of 19 patients who became hypoglycaemic were re-studied 3 to 4 mo after cessation of therapy. RESULTS: In the hypoglycaemia group, plasma levels of gluconeogenic amino acids alanine and glutamine were lower (medians 117 vs 190 micromol L(-1), p = 0.009, and medians 396 vs 448 micromol L(-1), p = 0.031, respectively) than in the normoglycaemia group. Serum levels of free carnitine were lower (medians 20.3 vs 29.8 micromol L(-1), p = 0.027), free fatty acids higher (medians 3.09 vs 1.23 mmol L(-1), p < 0.001) and marked dicarboxylic aciduria was more common in the patients with hypoglycaemia (in 14/16 vs in 2/14, p < 0.001). Impaired responses to glucagon stimulation occurred in 36% (4/11) in the hypoglycaemia group and in 12.5% (1/8) in the normoglycaemia group (p = 0.243). No significant differences were detected in E-MTX and E-TGN between the groups. Most of the metabolic abnormalities returned to normal after cessation of chemotherapy. CONCLUSIONS: Low levels of gluconeogenic amino acids, especially of alanine, are associated with hypoglycaemia. Reduced hepatic glycogen stores may also be involved in the aetiology.

Deletion of the Ink4-locus (the p16ink4a, p14ARF and p15ink4b genes) predicts relapse in children with ALL treated according to the Nordic protocols NOPHO-86 and NOPHO-92.

Inactivation of the Ink4 gene locus locus on 9p comprising the tumour suppressor gene p16ink4a and its neighbours p14ARF and p15ink4b is common in childhood acute lymphoblastic leukaemia (ALL), but the prognostic significance is controversial. DNA from 230 patients was retrospectively analysed by Southern blotting, single strand conformation polymorphism (SSCP) and sequencing techniques. The results were correlated with clinical characteristics and outcome. One hundred and ninety-four fully analysed patients, similarly treated using the Nordic NOPHO-86 or the current NOPHO-92 protocols, were included in the outcome analysis. Deletions approached a minimally deleted region between the p16ink4a and p15ink4b genes, making the p14ARF gene the most commonly deleted coding sequence. Bi-allelic deletion was associated with high white blood cell count (WBC) (P < 0.001), T cell phenotype (P < 0.001) and mediastinal mass (P < 0.001). Patients with Ink4 locus bi-allelic deletions had an inferior pEFS (P < 0.01) and multivariate analysis indicated that bi-allelic deletion of the p16ink4a and the p14ARF genes was an independent prognostic risk factor (P < 0.05). Sub-group analysis revealed a pronounced impact of deletion status for high-risk patients, ie with high WBC. Deletion-status and clinical risk criteria (WBC) could thus be combined to further differentiate risk within the high-risk group. The analysis of the Ink4 locus adds independent prognostic information in childhood ALL treated by Nordic protocols and may help in selection of patients for alternative treatment.

Neutrophil regeneration precedes healing of tissue destruction, as indicated by serum C-reactive protein, in children with cancer recovering from neutropenic fever.

AIM: To evaluate the relationship between absolute neutrophil count and C-reactive protein (CRP) in the recovery phase of neutropenic fever among paediatric patients with cancer. METHODS: A total of 102 paediatric oncology patients with 177 episodes of fever and neutropenia was studied prospectively in a two-centre setting. Antimicrobial therapy was discontinued 9 d (mean) post-initiation with a mean absolute neutrophil count of 1.8 x 10(9) l(-1) and CRP of 32 mg l(-1). RESULTS: The mean level of CRP below 20 mg l(-1) was reached on day 12. The level of CRP peaked on the day following the commencement of antimicrobial therapy. Throughout the episodes of fever and neutropenia higher levels of CRP were associated with a lower absolute neutrophil count. Following defervescence the pace of marrow recovery as evidenced by an increasing absolute neutrophil count to > 0.2 and > 0.5 x 10(9) l(-1) was more rapid than the normalization of serum CRP. There was a 2-3 d lag period between absolute neutrophil count exceeding the level of 200 x 10(6) l(-1) and the return of CRP to a baseline level. All episodes were treated successfully and there were no fatalities. CONCLUSION: Among patients recovering from neutropenia and fever the signs of marrow recovery remain the key criterion in evaluating the safety of discontinuing antimicrobial therapy, with serum CRP remaining more of an indicator of ongoing tissue repair.

Loss at 12p detected by comparative genomic hybridization (CGH): association with TEL-AML1 fusion and favorable prognostic features in childhood acute lymphoblastic leukemia (ALL). A multi-institutional study.

BACKGROUND: Genetic aberrations provide prognostic information in childhood ALL. The proportion of patients with detectable aberrations can be increased by combining G-banding with comparative genomic hybridization (CGH). PROCEDURE: We studied 79 children with ALL by CGH and G-banding, and explored the relationship of these findings to clinical features and outcome. RESULTS: CGH revealed DNA copy number changes in 57 patients (72%), 9 of whom had normal karyotype by G-banding. Gains were more frequent than losses, and changes of whole chromosomes more frequent than partial aberrations. Two frequent partial losses were found; at 9p and 12p. The 9 patients with loss at 12p were studied for the deletion of TEL (ETV6) gene and the fusion of TEL and AML1 genes by fluorescent in situ hybridization (FISH). Eight out of the 9 children with loss at 12p harbored the TEL-AML1 translocation and all 9 had the deletion of a nontranslocated TEL allele. All 9 had precursor-B phenotype and L1 morphology, and 8/9 had WBC below 50 x 10(9)/liter. All children were treated according to Nordic ALL protocols, had a good response to treatment based on day 15 bone marrow morphology, and 7 out of the 9 survived in continuous complete remission (median follow-up 74 months). CONCLUSIONS: CGH is a valuable tool in screening for genetic aberrations in childhood ALL. DNA copy number losses detected at 12p associate with TEL-AML1 fusion as well as with favorable prognostic features.

Helicobacter pylori and iron deficiency anaemia in children.

BACKGROUND: Both iron deficiency anaemia and Helicobacter pylori infection are rare in developed countries. A possible connection has been suggested between these two diseases and our aim was to define the clinical picture and to study the effect of bacterial eradication in H. pylori colonized children with severe anaemia. METHODS: Eight children with iron deficiency anaemia refractory to iron supplementation were examined with gastroscopy because of suspicion of H. pylori infection. Anaemia was treated with oral ferrous sulphate. Two patients needed blood transfusions. Eradication therapy was given either with combination of colloidal bismuth subcitrate and metronidazole or with omeprazole, clarithromycin and amoxycillin. Eradication was confirmed by urea breath test 4 weeks post-treatment. RESULTS: H. pylori infection was confirmed histologically and microbiologically in all children, who also presented with chronic, active gastritis. Bacteria were successfully eradicated in 7/8 patients. Correction of haemoglobin values was observed post-treatment, iron stores still being deficient at control in 4/8 children. CONCLUSIONS: Our results suggest that H. pylori might have a role in causing iron deficiency anaemia in school-age children. Screening for H. pylori should be extended to cover those patients with other clinical manifestations than symptoms from gastrointestinal tract.

Fasting hypoglycemia is common during maintenance therapy for childhood acute lymphoblastic leukemia.

Nineteen of 35 children (54%) with acute lymphoblastic leukemia receiving maintenance therapy consisting of daily oral 6-mercaptopurine and weekly oral methotrexate developed hypoglycemia (blood glucose level <2.7 mmol/L [50 mg/dL] or <2.9 mmol/L [54 mg/dL] with symptoms) during 16 hours of overnight fasting. In 15 of 15 re-studied children, fasting tolerance had improved, and in 67% (10/15), it had become normal a few months after cessation of therapy.

Initial P-glycoprotein expression in childhood acute lymphoblastic leukemia: no evidence of prognostic impact in follow-up.

Treatment results in childhood acute lymphoblastic leukemia (ALL) have improved remarkably during the past 20 years, but still 25% of children cannot be permanently cured. Drug resistance is a major cause of poor outcome. One of the most investigated resistance mechanisms is the P-glycoprotein (P-gp)-mediated multiple-drug resistance (MDR). The authors prospectively analyzed P-gp using flow cytometry with monoclonal antibody JSB1 in a population-based series of 103 children with ALL treated according to intensive Nordic ALL protocols. Increased P-gp expression was detected in 55 patients (53%). With a cutoff value of 1% P-gp-positive blasts in bone marrow, no difference was found in event-free survival (EFS) or overall survival between children with low vs. increased P-gp expression. The 4-year EFS in the whole series was 77%. Patients with T-ALL had higher P-gp levels than the others, 3.6% vs. 1.0% (p = .002). P-gp expression did not correlate with the white blood cell count, age, sex, or cytogenetics. The authors conclude that the level of P-gp expression cannot be used as a tool for treatment stratification in childhood ALL.

Granulocyte-macrophage colony-stimulating factor support in therapy of high-risk acute lymphoblastic leukemia in children.

BACKGROUND: Our purpose was to increase the dose intensity of chemotherapy and reduce the days with neutropenic fever in childhood high-risk (HR) acute lymphoblastic leukemia (ALL) by systematic use of granulocyte-macrophage colony-stimulating factor (GM-CSF). PROCEDURE: All children with HR-ALL in Finland during 1990-1996 were included. Two open-label study groups were formed: 1) 34 children diagnosed between January, 1992, and December, 1996, received seven or nine courses (depending on cranial RT or no cranial RT) of GM-CSF at 5 microg/kg s.c. daily until an absolute neutrophil count (ANC) of 1,000 x 10(6)/liter at scheduled places in the protocol and 2) 80 control children, those diagnosed between January, 1990, and December, 1991, plus all with significant coexpression of myeloid markers, did not receive GM-CSF. RESULTS: Dose intensity increased in patients who received regular GM-CSF support. The intensive phase of therapy, including induction, consolidation courses, and delayed intensification, was 33 days shorter (P < 0.001) in children with seven courses and 26 days shorter (P < 0.01) in those with nine courses of GM-CSF compared to controls. The number of infections during the whole ALL therapy was reduced by use of GM-CSF in children aged >5 years (P < 0.001), but not in those aged <5 years. The mean total duration of intravenous antibiotics per child was 39 days in the GM-CSF group and 48 days in the control group (P < 0. 001). Systematic use of GM-CSF was cost-effective. CONCLUSIONS: Systematic use of GM-CSF improved dose intensity by shortening the intensive treatment period by about 4 weeks. Use of GM-CSF reduced the days for inpatient antibiotics by about 1 week per child, which translates into reduced costs.