Validation of the first commercial ELISA for type 2N von Willebrand’s disease diagnosis

Summary. Type 2N von Willebrand’s disease (VWD) is characterized by a factor VIII (FVIII) deficiency and a low FVIII/VWF ratio related to a markedly decreased affinity of von Willebrand factor (VWF) to FVIII. Type 2N VWD is diagnosed using assays allowing the measurement of plasma VWF capacity to bind FVIII (VWF:FVIIIB). These assays, crucial in order to distinguish type 2N VWD patients from mild haemophiliacs A and haemophilia A carriers, remain exclusively homemade and limited to laboratories possessing a high level of expertise in VWD. We evaluated the first commercial ELISA (Asserachrom® VWF:FVIIIB; Stago) comparated to a reference method in a multicentric study involving 205 subjects: 60 healthy volunteers, 37 haemophiliacs A, 17 haemophilia A carriers, 37 patients with type 2N VWD, 9 heterozygous carriers for a 2N mutation and 45 patients with miscellaneous other types of VWD (all previously characterized). A diluted plasma sample adjusted to 10 IU dL^?1 of VWF:Ag was incubated with a rabbit antihuman VWF polyclonal antibody. After removing the endogenous FVIII, recombinant FVIII (rFVIII) was added and bound rFVIII was quantified using a peroxydase‐conjugated mouse antihuman FVIII monoclonal antibody. The intra‐assay and inter‐assay reproducibility was satisfactory. In all subgroups, both methods were well correlated. All type 2N VWD patients exhibited a markedly decreased VWF:FVIIIB (lower than 15%) and all heterozygous 2N carriers had a moderately decreased VWF:FVIIIB (between 30% and 65%). All controls (healthy subjects, haemophiliacs A and haemophilia A carriers) had a normal VWF:FVIIIB (higher than 80%) except one healthy volunteer and three haemophiliacs who exhibited a moderately decreased VWF:FVIIIB suggesting a heterozygous status for a 2N mutation. In conclusion, the Asserachrom® VWF:FVIIIB is easy to perform, standardized and accurate for type 2N VWD diagnosis with a 100% sensitivity and specificity.     

Use of autologous platelet‐rich clots for the prevention of local injury bleeding in patients with severe inherited mucocutaneous bleeding disorders

Summary. Stopping or preventing local bleeding in patients with inherited bleeding disorders linked to abnormal platelet function is traditionally treated by transfusion of blood cell products or recombinant factor VIIa. We now report the use in such patients of autologous platelet‐rich clots as an aid to preventing bleeding and to facilitating tissue regeneration at superficial sites. Two patients with von Willebrand’s disease (VWD) type 2B and one patient with type I Glanzmann thrombasthenia were treated after tooth extraction and dental surgery. A fourth patient with platelet‐type VWD underwent a skin biopsy. Whereas all four patients had a lifelong history of bleeding complications, the application of an autologous platelet‐rich clot immediately after surgery combined with tranexamic acid intake to slow fibrinolysis prevented blood loss and resulted in rapid and normal healing. This new procedure is simple, safe and inexpensive; it provides extra security for patients with a bleeding risk undergoing dentistry or superficial surgery.     

Clinical efficacy and safety of the factor VIII/von Willebrand factor concentrate BIOSTATE® in patients with von Willebrand’s disease: a prospective multi‐centre study

Summary. von Willebrand’s disease (VWD) is an inherited bleeding disorder characterized by deficient levels of or dysfunctional von Willebrand factor (VWF). This phase II/III open‐label, multicentre study evaluated the efficacy and safety of BIOSTATE^®, a high purity plasma‐derived double‐virus inactivated FVIII/VWF concentrate, when used in non‐surgical bleeds, surgical procedures and prophylactic therapy in VWD patients for whom desmopressin treatment was deemed ineffective, inadequate or contraindicated. Twenty three patients (7 type 1, 9 type 2 and 7 type 3; 12 male, 11 female), who received FVIII/VWF concentrate as part of their VWD management, were recruited prospectively between December 2004 and May 2007 from eight centres in Australia and New Zealand. BIOSTATE dosing was based on pre‐treatment FVIII:C and/or VWF:RCo plasma levels and a predetermined dosing guide. Haemostatic efficacy of BIOSTATE was rated as excellent or good for all major and minor surgery events, long‐term prophylaxis, and for four of the six assessable non‐surgical bleeding events. Blood transfusions were required by two major surgery patients as well as one patient with a non‐surgical bleed. The median overall exposure to BIOSTATE across all groups was 8 days, greater in the prophylactic group (range 53–197) compared with major surgery (3–24), minor surgery (1–8) and non‐surgical bleeds (1–10). BIOSTATE was shown to be efficacious and well tolerated when treating patients with VWD. This study also provides important insights into dosing regimens with BIOSTATE and the role of monitoring therapy with FVIII:C and VWF:RCo.     

Screening women with menorrhagia for underlying bleeding disorders: the utility of the platelet function analyser and bleeding time

Menorrhagia is a very common clinical problem among women of reproductive age and recent studies have suggested that underlying bleeding disorders, particularly von Willebrand's deficiency and platelet function defects, are prevalent in women presenting with menorrhagia. The objective of this study was to determine the utility of the platelet function analyser (PFA-100) and bleeding time (BT) as initial screening tests for underlying bleeding disorders in women with menorrhagia. In this study, 81 women with a physician diagnosis of menorrhagia underwent PFA-100 testing, BT and comprehensive haemostatic testing. The effectiveness of the PFA-100 and BT as screening tools in women with menorrhagia was assessed using results of haemostatic testing for von Willebrand's disease (VWD) and platelet dysfunction. In women presenting with menorrhagia, the PFA-100 had a sensitivity 80%, specificity 89%, positive predictive value (PPV) 33%, negative predictive value (NPV) 98% and efficiency 88% for VWD. For platelet aggregation defects, the PFA-100 closure time had a sensitivity 23%, specificity 92%, PPV of 75%, NPV of 52% and efficiency 55%. The data suggest that the PFA-100 may be useful in stratifying women with menorrhagia for further von Willebrand testing; however, neither the PFA-100 nor the BT tests are effective for purposes of classifying women for standard platelet aggregometry testing in women presenting with menorrhagia.     

The impact of bleeding history,von Willebrand factor and PFA–100® on the diagnosis of type 1 von Willebrand disease: results from the European study MCMDM‐1VWD

The relationships between the Platelet Function Analyzer (PFA)‐100 and von Willebrand factor (VWF) levels and bleeding score (BS) were evaluated within a multicentre project on Molecular and Clinical Markers for the Diagnosis and Management of type 1 von Willebrand disease (MCMDM‐1VWD). PFA‐100 closure time, either with epinephrine (EPI) or adenosine diphosphate (ADP)‐cartridges, was measured in 107 index cases, 105 affected and 71 unaffected family members, and 79 healthy controls. By regression analysis VWF levels were strongly related to both closure times, with a non‐linear progression. In a multiple stepwise regression model, age‐ and sex‐adjusted PFA‐100 ADP and VWF ristocetin cofactor activity (VWF:RCo) were independently associated with BS. Most of the variation of BS was predicted by PFA‐100 ADP and VWF:RCo alone. In the subgroup of patients with subtle abnormalities of the multimeric pattern, VWF was invariably reduced and closure time prolonged in almost all of them. Neither PFA‐100 ADP nor EPI closure times appeared to significantly improve the diagnostic capability of VWF antigen (VWF:Ag) measurement. Thus, in an unselected population a normal PFA‐100 would be useful to exclude VWD, but whether it could replace the more specific VWF assay in patients with significant mucocutaneous bleeding symptoms remains to be investigated prospectively.     

A Systematic Review: The use of desmopressin for treatment and prophylaxis of bleeding disorders in pregnancy

Summary. Desmopressin (DDAVP) is commonly used for treatment and prevention of bleeding complications in patients with bleeding disorders including haemophilia A, von Willebrand’s disease (VWD) and other less common disorders. This article reviews the current evidence for the use of DDAVP in pregnancy to clarify its efficacy and safety with regard to maternal and foetal outcome. A search of the literature found 30 studies that reported DDAVP use in pregnancy for prophylaxis or treatment of bleeding complications with 216 pregnancies reported in total. The most common indication was prophylaxis for prevention of bleeding during pregnancy and postpartum haemorrhage. DDAVP was used successfully in the first and early second trimester for bleeding prophylaxis in 50 pregnancies. No postpartum bleeding complications were reported in 167 out of 172 pregnancies when DDAVP was used for peripartum haemostatic cover. Twenty‐nine studies reported no significant adverse events as a result of treatment with DDAVP. One case of water intoxication seizure and one case of premature labour following the use of DDAVP was reported in a single study. Other maternal side effects included facial flushing and headache and were reported by one study. These side effects were generally well tolerated by patients. There were no other significant adverse events reported in any of the studies as a result of DDAVP use. Foetal outcome was recorded in ten studies with no adverse foetal outcomes. In conclusion, this review shows that DDAVP in selected cases is effective in reducing bleeding complications associated with pregnancy and childbirth with a good safety record. Further research is needed to confirm these findings as they are based on the currently available evidence from small studies and case series only.     

Response of cutaneous Crohn’s disease to infliximab and methotrexate

Cutaneous or metastatic Crohn's disease is a rare complication of Crohn's disease and is frequently refractory to medical treatment. A case of metastatic Crohn's disease affecting first the abdominal wall and subsequently both submammary folds is reported. These extraintestinal manifestations occurred many years after proctocolectomy. The activity of cutaneous disease was associated with a chronic active fistulizing disease. Skin manifestations were resistant to treatment with steroids, antibiotics and azathioprine. Repetitive treatment with infliximab led to significant improvement of both cutaneous and fistulous disease. However, disease relapsed and even progressed after a period of 6 weeks following each infliximab treatment. Only the introduction of methotrexate, together with repetitive administration of infliximab, allowed maintenance of the patient in remission.     

Variability in platelet‐ and collagen‐binding defects in type 2M von Willebrand disease

Type 2M von Willebrand disease (VWD) includes qualitative defects in von Willebrand factor (VWF) function, with normal multimer distribution but a defect in VWF activity with respect to platelet or collagen binding. We characterized novel VWF gene mutations found in type 2M VWD subjects enrolled in the Zimmerman Program for the Molecular and Clinical Biology of VWD. Subjects were enrolled based on a pre‐existing diagnosis of type 2M VWD. Testing included full‐length gene sequencing, VWF antigen (VWF:Ag), VWF ristocetin cofactor activity (VWF:RCo), VWF collagen binding and multimer distribution. Recombinant VWF variants were synthesized using site‐directed mutagenesis and expressed in HEK293T cells. Platelet binding was measured by flow cytometry with fixed platelets and ELISA with recombinant glycoprotein Ibα (GPIbα). Four novel VWF A1 domain mutations were found in individuals with type 2M VWD: S1358N, S1387I, S1394F and Q1402P. All subjects had a history of bleeding, VWF:RCo < 40 IU dL^?1, VWF:RCo/VWF:Ag ratios <0.6 and normal multimer distribution. No defect in expression, secretion, or multimerization was found for any of the mutations. All showed decreased binding to intact platelets, and decreased or absent binding to a mutant GPIbα construct with spontaneous VWF binding. 1387I had decreased binding to all collagen types tested. 1402P had reduced binding exclusively to type VI collagen. Type 2M VWD is a heterogeneous category comprised of both collagen‐ and platelet‐binding defects. Understanding the precise defect for each mutation may ultimately lead to better diagnosis and treatment.     

Emergency and out of hours care of patients with inherited bleeding disorders

Recently, the United Kingdom Haemophilia Centre Doctors Organisation published recommendations for the standard of care for assessment and treatment of patients with bleeding disorders in the emergency department (A&E). An audit was undertaken to compare the level of care to the acceptable standards in a tertiary hospital A&E, attached to a haemophilia comprehensive care centre. A&E attendances were found by cross referencing all patients with known bleeding disorders against the EDMS attendance system. Visits from the past 3 years were identified to produce sufficient data and electronic notes from these visits were then accessed, and marked against the proforma. Data were available from 45 of a total of 54 patients, who had a total of 75 emergency visits documented. In all aspects of care, the standards were not adequately met including the average length of time between booking and clinical assessment, early initiation of specific haemostatic treatment, seeking haematology advice and arrangement of follow-up. Also no specialist clotting investigations were done with only 9/11 patients admitted having their haematological diagnosis recorded. In addition, only very few patients had the severity of bleeding disorder noted and less than half their first line treatment documented. There were significant differences in the standard of care for haemophilia patients provided by the A&E department when compared with acceptable standards. Measures have been put in place and policies have been drafted to improve this situation and provide the best possible care to persons with haemophilia.     

Infliximab-induced lupus in Crohn’s disease: a case report

An 18-year-old male patient was under treatment with infliximab at a dose of 5 mg/kg at Weeks 0, 2 and 6 for refractory Crohn's disease. In June 2002, the patient was admitted to the Outpatient Clinic of the Rheumatology Unit for arthralgia affecting the small joints, non-pruritic crops of purple skin lesions and malar rash in the face. Serum antinuclear antibodies were positive (1:640 speckled pattern), and anti-double-stranded DNA was positive (1:80); moreover, positivity of anti-extractable nuclear antigen was observed. Antihistone antibodies, lupus anticoagulant and anticardiolipin antibodies were negative. A diagnosis of infliximab-induced lupus was made and the drug treatment was withdrawn. However, 3 months after withdrawal of treatment, the patient still showed clinical and laboratory symptoms of systemic lupus erythematosus. After 6 months of treatment, systemic lupus erythematosus-related symptoms disappeared and anti-double-stranded DNA returned to normal. The patient is currently under treatment with prednisone 20 mg/day for systemic lupus erythematosus and with oral mesalazine 2.4 mg/day for Crohn's disease. Treatment with infliximab is known to produce an increase of autoantibodies (antinuclear antibodies, anti-double-stranded DNA), but not clinical disease. This is the first case, to our knowledge, of onset of prolonged infliximab-induced lupus.     

Continuing low incidence of Crohn’s disease in Northwest Greece

AIM OF STUDY: The largest population-based study for inflammatory bowel disease in Northwest Greece. MATERIALS AND METHODS: A retrospective survey for the years 1982-1997. RESULTS: Of 400 patients, 334 had ulcerative colitis, 43 Crohn's disease and 23 indeterminate colitis. CONCLUSIONS: Crohn's disease still remains rare in Northwest Greece.     

The role of platelet von Willebrand factor in platelet adhesion and thrombus formation: a study of 34 patients with various subtypes of type I von Willebrand disease

Summary In order to investigate the respective role of plasma and platelet von Willebrand factor (vWF) in mediating platelet adhesion and thrombus formation, we performed ex vivo perfusion studies with native blood from patients with various subtypes of type I von Willebrand disease (vWD). We studied 34 patients with type I vWD (19 'platelet normal', five 'platelet low', two 'platelet discordant', eight 'Vicenza'). Parallel studies were carried out on nine patients with severe vWD (type III). At high shear rate (2600 s^-1) we found that the defect in platelet-vessel wall interactions in patients having a normal platelet vWF content ('platelet normal' and 'Vicenza') involved thrombus formation, whereas platelet adhesion was normal. At this high shear rate, platelet adhesion and thrombus volume were significantly decreased in patients with subtypes 'platelet low' and 'platelet discordant', i.e. when platelet vWF is either low or dysfunctional. These results indicate that platelet vWF may substitute for plasma vWF to promote platelet adhesion. emphasizing the important role of platelet vWF. They also confirm the role of vWF in thrombus formation at high shear rate because an abnormal thrombus volume was observed in all patients. even when platelet adhesion was normal.     

Evaluation of the von Willebrand factor antigen (vWF‐Ag) assay using an immuno‐turbidimetric method (STA Liatest® vWF) automated on the MDA®180 coagulometer

The standard enzyme‐linked immunosorbent assay (ELISA) test for von Willebrand factor antigen (vWF‐Ag), though sensitive and specific, does not deliver the flexibility to handle single sample assessments economically or provide rapid, emergency testing capability. The present study examined the performance characteristics of an immuno‐turbidimetric assay kit (STA Liatest^®) modified for automation on the MDA^®180 coagulation analyser using a supplied protocol. One hundred and sixteen patient samples were assessed by both the standard and the modified method. The correlation coefficient was 0.98 across the range of values 1–487 IU/dl. Above 200 IU/dl, where specimen dilution was indicated, there was greater diversity (r = 0.86) between the techniques. Plotting the difference between methods against the mean of both showed excellent agreement between methods below 100 IU/dl vWF. The intra‐assay and interassay coefficients of variation were less than 3% at both low and normal range levels. The MDA^®180 automated vWF assay merits consideration as an alternative to ELISA testing that provides random access and result availability within 30 min.     

A rare case of Paget’s disease of the bone in the Philippines

A 40‐year‐old Filipina presented with a 2‐year history of progressive bilateral inguinal and hip pain with limited range of motion. She had a bad fall which led to widespread body pains for 6 months partially relieved on multiple analgesic and anti‐inflammatory agents. There was progressive weight loss and anemia. Focused musculoskeletal examination revealed moderate degree of generalized muscle atrophy, pain‐limited range of motion of bilateral hip and shoulder joints, with equivocal muscle strength of both proximal and distal muscle groups of all extremities. Metastatic bone disease was ruled out when skeletal survey disclosed mixture of osteolytic and osteoblastic lesions, predominantly osteoblastic, on multiple sites. Bone turnover markers were elevated. Bone biopsy revealed histopathologic results compatible with Paget’s disease of the bone. Management included oral calcium and vitamin D supplement followed by parenteral zoledronic acid, and a rehabilitation program. Four months after bisphosphonate therapy, the patient reported significant relief of symptoms with complete resolution of the previously noted generalized body pains, although she ambulates with use of an assistive device. Due to the rarity of the condition among Filipinos, this case was a diagnostic dilemma in itself, as it is most likely the first published case in the Philippine literature.     

Effect of fibrinolysis on bleeding phenotype in moderate and severe von Willebrand disease

Patients with von Willebrand disease (VWD), the most common inherited bleeding disorder, display large variation in bleeding tendency, which is not completely related to VWF levels. The cause of variability in clinical expression is largely unknown. The effect of plasma fibrinolytic capacity on bleeding tendency in VWD patients has not been investigated. We hypothesized that enhanced fibrinolysis may result in a more severe bleeding phenotype. Therefore, we measured the fibrinolytic potential in patients with moderate or severe VWD to investigate the contribution of fibrinolysis to the bleeding tendency. Fibrinolytic potential was measured as plasma clot lysis time (CLT) with and without addition of potato carboxypeptidase inhibitor (PCI) in 638 patients with moderate or severe VWD who participated in a nationwide multicentre cross-sectional study. Bleeding severity was measured using the Bleeding Score (BS).The CLTs were significantly longer, indicative of hypofibrinolysis, in men compared to women with VWD [106.2 (IQR 95.7-118.1) vs. 101.9 (IQR 92.8-114.0) min]. The CLTs prolonged with increasing age. No association was found between VWF or FVIII levels and CLT, or between VWF or FVIII levels and CLT(+PCI) . No association was observed for BS in a model with 10log-transformed CLT, adjusted for age, gender, VWF:Act and FVIII [b = 6.5 (95%CI -0.3 to 13.4)]. Our study showed that the plasma fibrinolytic potential does not influence bleeding tendency in VWD patients and therefore does not explain the variability in bleeding phenotype in VWD.