Detailed von Willebrand factor multimer analysis in patients with von Willebrand disease in the European study, molecular and clinical markers for the diagnosis and management of type 1 von Willebrand disease (MCMDM-1VWD).

BACKGROUND: Type 1 von Willebrand disease (VWD) is a congenital bleeding disorder characterized by a partial quantitative deficiency of plasma von Willebrand factor (VWF) in the absence of structural and/or functional VWF defects. Accurate assessment of the quantity and quality of plasma VWF is difficult but is a prerequisite for correct classification. OBJECTIVE: To evaluate the proportion of misclassification of patients historically diagnosed with type 1 VWD using detailed analysis of the VWF multimer structure. PATIENTS AND METHODS: Previously diagnosed type 1 VWD families and healthy controls were recruited by 12 expert centers in nine European countries. Phenotypic characterization comprised plasma VWF parameters and multimer analysis using low- and intermediate-resolution gels combined with an optimized visualization system. VWF genotyping was performed in all index cases (ICs). RESULTS: Abnormal multimers were present in 57 out of 150 ICs; however, only 29 out of these 57 (51%) had VWF ristocetin cofactor to antigen ratio below 0.7. In most cases multimer abnormalities were subtle, and only two cases had a significant loss of the largest multimers. CONCLUSIONS: Of the cases previously diagnosed as type 1 VWD, 38% showed abnormal multimers. Depending on the classification criteria used, 22 out of these 57 cases (15% of the total cohort) may be reclassified as type 2, emphasizing the requirement for multimer analysis compared with a mere ratio of VWF functional parameters and VWF:Ag. This is further supported by the finding that even slightly aberrant multimers are highly predictive for the presence of VWF mutations.

Impact of plasma von Willebrand factor levels in the diagnosis of type 1 von Willebrand disease: results from a multicenter European study (MCMDM-1VWD).

BACKGROUND: Presence of bleeding symptoms, inheritance and reduced von Willebrand factor (VWF) contribute to the diagnosis of type 1 von Willebrand disease (VWD). However, quantitative analysis of the importance of VWF antigen (VWF:Ag) and ristocetin cofactor activity (VWF:RCo) levels in the diagnosis is lacking. OBJECTIVES: To evaluate the relative contribution of VWF measurement to the diagnosis of VWD. PATIENTS AND METHODS: From the MCMDM-1VWD study cohort, 204 subjects (considered as affected by VWD based on the enrolling Center diagnoses and the presence of linkage with the VWF locus) were compared with 1155 normal individuals. Sensitivity, specificity and diagnostic positive likelihood ratios (LR) of VWF:Ag and VWF:RCo were computed. RESULTS: ABO blood group was the variable most influencing VWF levels, but adjustment of the lower reference limit for the ABO group did not improve sensitivity and specificity of VWF:Ag or VWF:RCo. The lower reference limit (2.5th percentile) was 47 IU dL(-1) for both VWF:Ag and VWF:RCo and showed similar diagnostic performance [receiver-operator curve area: 0.962 and 0.961 for VWF:Ag and VWF:RCo, respectively; P = 0.81]. The probability of VWD was markedly increased only for values below 40 IU dL(-1) (positive LR: 95.1 for VWF:Ag), whereas intermediate values (40 to 60 IU dL(-1)) of VWF only marginally indicated the probability of VWD. CONCLUSIONS: Although the conventional 2.5 lower percentile has good sensitivity and specificity, only VWF:Ag or VWF:RCo values below 40 IU dL(-1) appear to significantly indicate the likelihood of type 1 VWD. The LR profile of VWF level could be used in a diagnostic algorithm.

A quantitative analysis of bleeding symptoms in type 1 von Willebrand disease: results from a multicenter European study (MCMDM-1 VWD).

BACKGROUND: A quantitative description of bleeding symptoms in type 1 von Willebrand disease (VWD) has never been reported. OBJECTIVES: The aim was to quantitatively evaluate the severity of bleeding symptoms in type 1 VWD and its correlation with clinical and laboratory features. PATIENTS AND METHODS: Bleeding symptoms were retrospectively recorded in a European cohort of VWD type 1 families, and for each subject a quantitative bleeding score (BS) was obtained together with phenotypic tests. RESULTS: A total of 712 subjects belonging to 144 families and 195 controls were available for analysis. The BS was higher in index cases than in affected family members (BS 9 vs. 5, P < 0.0001) and in unaffected family members than in controls (BS 0 vs. -1, P < 0.0001). There was no effect of ABO blood group. BS showed a strong significant inverse relation with either von Willebrand ristocetin cofactor (VWF:RCo), von Willebrand antigen (VWF:Ag) or factor VIII procoagulant activity (FVIII:C) measured at time of enrollment, even after adjustment for age, sex and blood group (P < 0.001 for all the four upper quintiles of BS vs. the first quintile, for either VWF:RCo, VWF:Ag or FVIII:C). Higher BS was related with increasing likelihood of VWD, and a mucocutaneous BS (computed from spontaneous, mucocutaneous symptoms) was strongly associated with bleeding after surgery or tooth extraction. CONCLUSIONS: Quantitative analysis of bleeding symptoms is potentially useful for a more accurate diagnosis of type 1 VWD and to develop guidelines for its optimal treatment.

Linkage analysis in families diagnosed with type 1 von Willebrand disease in the European study, molecular and clinical markers for the diagnosis and management of type 1 VWD.

BACKGROUND: von Willebrand disease (VWD) type 1 is a congenital bleeding disorder caused by genetic defects in the von Willebrand factor (VWF) gene and characterized by a reduction of structurally normal VWF. The diagnosis of type 1 VWD is difficult because of clinical and laboratory variability. Furthermore, inconsistency of linkage between type 1 VWD and the VWF locus has been reported. OBJECTIVES: To estimate the proportion of type 1 VWD that is linked to the VWF gene. PATIENTS AND METHODS: Type 1 VWD families and healthy control individuals were recruited. An extensive questionnaire on bleeding symptoms was completed and phenotypic tests were performed. Linkage between VWF gene haplotypes and the diagnosis of type 1 VWD, the plasma levels of VWF and the severity of bleeding symptoms was analyzed. RESULTS: Segregation analysis in 143 families diagnosed with type 1 VWD fitted a model of autosomal dominant inheritance. Linkage analysis under heterogeneity resulted in a summed lod score of 23.2 with an estimated proportion of linkage of 0.70. After exclusion of families with abnormal multimer patterns the linkage proportion was 0.46. LOD scores and linkage proportions were higher in families with more severe phenotypes and with phenotypes suggestive of qualitative VWF defects. About 40% of the total variation of VWF antigen could be attributed to the VWF gene. CONCLUSIONS: We conclude that the diagnosis of type 1 VWD is linked to the VWF gene in about 70% of families, however after exclusion of qualitative defects this is about 50%.

Consensus perspectives on surgery in haemophilia patients with inhibitors: summary statement.

Summary. Participants in an international workshop on surgery in haemophilia patients with inhibitors developed a consensus summary of the findings and conclusions of the meeting. In the consensus, participants agreed upon revised definitions for minor and major surgery, including an intermediate degree of surgery. An evaluation system of intraoperative and postoperative bleeding was developed. Recommended doses of FEIBA((R)) and rFVIIa (both in bolus injections and in continuous infusion) for surgery were agreed. Participants also agreed on the main blood tests to be performed peri-operatively. They also suggested the need of a prospective evaluation in the future. Finally, the approximate number of surgical procedures and costs performed on haemophilia patients with inhibitors were analysed.

Laboratory tests for precise classification and genetic analysis of von Willebrand disease.

von Willebrand disease (vWD) is the most common inherited bleeding disorder, which is highly heterogeneous ranging from asymptomatic laboratory abnormality to a life threatening bleeding. The condition is caused by a quantitative or qualitative deficiency of von Willebrand factor (vWF). Since 1994 it has been classified into six subgroups based on evaluation of the vWF level and function. Correct classification of vWD is required for its optimal management. vWD is inherited as a dominant or recessive trait linked to the vWF gene. However, the inheritance of type 1 vWD is not always linked to the vWF gene and novel modifying genes are expected to play a significant role in the type 1 pathophysiology. Laboratory tests required for correct type classification and for genetic analysis have long been awaited in Czech Republic. The purpose of this report is to inform about discriminatory and genetic tests recently made available at the Institute of Haematology and Blood transfusion.

[Molecular study of type 2 von Willebrand disease]. / Molekulární studie von Willebrandovy choroby typu 2.

BACKGROUND: von Willebrand disease is an inherited bleeding disorders caused by mutations in the von Willebrand factor gene. We attempted to characterise the phenotype and the genotype in the first five families in Czech Republic affected by this heterogeneous disorder. METHODS AND RESULTS: The level of FVIII was measured by the one stage assay, the vWF:Ag by the immunoelectrophoresis, vWF:RiCo by aggregometry. For the vWF multimer analysis a western blot based technique was used. The vWF binding to FVIII was evaluated by the ELISA method. Two families were classified as the type 2A, one as the type 2B and two as the combined type 1/2N. Based on that knowledge, parts of the vWF gene were selected for genetic analysis. The previously described mutations Arg1374His and Gly1579Arg were identified in two families with the type 2A. In the family with type 2B a substitution Arg1308Cys was detected. In one family with the type 1/2N, two different previously described defects were found on the separate alleles of the vWF gene: a deletion of cytosine 2435 and a polymorphism Arg854Gln. Compound heterzygotes had the type 1/2N phenotype, while a carriers of the deletion had type 1 phenotype. In the second type 1/2N family, only the amino acid substitutions Thr791Me was found explaining the qualitative defect. A mutation underlying the quantitative deficiency needs to be searched for throughout the entire vWF gene. CONCLUSIONS: Based on the characterisation of the phenotype and genotype, five apparently unrelated families with the von Willebrand disease were diagnosed according to the revised classification. Our work represents laboratory basis for further studies into von Willebrand disease in Czech Republic.

Thirty-four novel mutations detected in factor VIII gene by multiplex CSGE: modeling of 13 novel amino acid substitutions.

Detection of causal mutations is required for genetic counseling. Molecular modeling combined with patients' phenotype provides significant insight into structure-function relationship of factor (F)VIII molecule. Our objective was to identify defects in the gene of FVIII by a sensitive and simple scanning technique with high throughput in order to study molecular mechanisms by which novel amino acid substitutions may lead to hemophilia A. A cohort of 81 families with mild, moderate and severe hemophilia A negative in intron 22 inversion was studied. For detection of mutations in the FVIII gene a conformation sensitive gel electrophoresis (CSGE) was modified by multiplexing. Thirteen novel amino acid substitutions were studied by molecular modeling and a correlation with the cross-reactive material (CRM) phenotype was performed. In 74 families, 59 different mutations were detected. Six different mutations were recurrent in 21 unrelated families. Thirty-four novel mutations included 19 point mutations, four small insertions, nine small deletions and two complex mutations. Thirteen novel amino acid substitutions occurred at residues conserved in FVIII orthologs. Five of them were associated with a discrepancy between FVIII activity and antigen; another five with CRM reduced phenotype and one with undetectable FVIII antigen. Multiplexing of the CSGE significantly increased its throughput without substantial loss of sensitivity. Molecular modeling suggested mechanisms by which substitutions at residues 382 and 569, located outside the proposed FIXa-binding region, may influence FVIII/FIXa interaction. His2155 was predicted to participate in FVIII/VFW binding.

[Molecular basis of hereditary antithrombin defects in 10 Czech families]. / Molekulární podstata vrozeného defektu antitrombinu u deseti ceských rodin.

BACKGROUND: Molecular basis of antithrombin deficiency has not yet been studied in Czech Republic. We looked for the causal mutations throughout the antithrombin gene in 26 patients from 10 unrelated families with antithrombin defect. METHODS AND RESULTS: We screened the gene by conformation sensitive gel electrophoresis and sequenced the mismatched regions using fluorescence technology to characterise mutations and polymorphisms. Mutations were detected in all ten families. Four novel mutations were identified in four families with type I antithrombin defect: Trp-6Arg, 5386-5387delCT, Glu163Stop, and 13246-13248del TGA causing deletion of Glu377 with change of Asn376 to Lys. In other three type I families we found following mutations: splicing site mutation G2777C, Arg197Stop and entire gene deletion. In the family carrying Trp-6Arg mutation antithrombin Vienna (Gln118Pro) was also detected. Leu99Phe recurrent in south-eastern Europe was identified in three families with type II defect. Only the homozygous carries of the mutation were symptomatic, although the heterozygous carries had decreased functional levels. CONCLUSIONS: Four novel mutations in families with type I antithrombin deficiency were characterised. In one family two different genetic defects were identified to be responsible for type I and II phenotypes. Altogether our data agree with the expected heterogeneity of the AT genetic defect.

[Structural correlations in splenic tissue in idiopathic thrombocytopenic purpura in adults]. / Strukturální korelace slezinné tkáne pri idiopatické trombocytopenické purpure dospelých (ITP).

Immunologic activation of the splenic white pulp seemed to be an important feature of the structural changes in the 8 splenectomized patients with ITP. However, destruction of the platelets with CD 16+ monocytes was the most prominent change in the Billroth's cords of the splenic red pulp. Classical NK cells did not play an important role in platelets destruction.

[Clinical findings in individuals with the factor V Leiden mutation]. / Klinické nálezy u jedincu s Leidenskou mutací faktoru V.

Leiden mutation of the coagulation factor V is the most frequent known congenital risk factor of thrombophilia. The authors examined a group of 440 subjects with thrombosis in the case- or family-history. The mutation was found in 146. In 94 thrombotic manifestations were recorded in the case-history, five women were examined because of repeated abortions. 52.74% carriers of FVL had venous thrombosis of the lower extremities and pelvis in their case-history, 19.18% had pulmonary embolism in the case-history. In 27.40% during the initial manifestations of thrombosis no other risk factor of thrombosis was detected. In 10.27% the first thrombosis developed after an injury or operation. In 22.22% women the thrombosis was manifested during pregnancy or the puerperal period. Due to the high incidence of this defect screening of the resistance to activated protein C should be an integral part of examination of thrombophil conditions.

[Results of induction therapy in newly diagnosed acute myeloid leukemias in study 911 at the Institute of Hematology and Blood Transfusion]. / Výsledky indukcní lécby nove zjistených akutních myeloidních leukémií ve studii UHKT-911.

Thirty-seven patients with de novo acute myeloid leukemias were admitted to the Institute of Hematology and Blood Transfusion in Prague in February 1991-December 1993. Their age was 18-85 years with a median of 46 years. Two patients died on the day of admission, chemotherapy was initiated in 35 patients. Altogether 27 patients (77%) achieved complete remission (CR), i.e. 18 (81%) of 22 patients younger than 55 years and 9 (70%) of 13 patients older than 55 years. Only 7 (35%) of 20 patients achieved CR after a single therapy course 3/7 consisting of 3 doses of daunorubicin 45 mg/m2 on days 1, 3, 5 and cytosine arabinoside 150-200 mg/m2 every 12 hours for 7 days. However, 8 (61%) of 13 patients achieved CR after a single treatment course 4/7 with 4 doses of daunorubicin 45 mg/m2 on days 1, 3, 5, 7 and identical doses of cytosine arabinoside as in the 3/7 treatment. We used the course with 10 high-doses of cytosine arabinoside 2000 mg/m2 every 12 hours and daunorubicin 45 mg/m2 on days 4 and 5 (treatment HDAC/DNR) as the 1st, 2nd or 3rd induction therapy in 12 patients and 9 (75%) of them achieved CR. The treatment was associated with a high toxicity. An intensified therapy 3/7h similar to the 3/7 one but with the doubled dose of cytosine arabinoside 300-400 mg/m2 on days 5-7 was given to 5 patients as the 2nd induction but it did not improve the CR rate and it was associated with a high toxicity similar to the HDAC/DNR therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

[Late and slow diagnosis of acute promyelocytic leukemias--the main cause of early death]. / Pozdní a pomalá diagnostika akutních promyelocytárních leukémií--hlavní prícina casných úmrtí.

Acute hypergranular promyelocytic leukemia (AML M3) belongs to malignant diseases leading very rapidly to death. Immediate treatment based on early diagnosis may cure one third of patients. The typical finding in peripheral blood of patients is pancytopenia with or without atypical promyelocytes. In published studies only 15-25% patients exhibit leukocyte counts above 10 x 10(9)/l. Five of our ten patients studied had leukocyte count above 10 x 10(9)/l. The difference might be in connection with late and slow diagnosis of AML M3. AML is not taken into consideration during medical examination even if the disease occurs in medical family. Thus we describe clinical signs of AML M3 that could be divided into three main groups: bleeding, infections and anemia. In patients with bleeding or anemia or with infections repeating within a short period or with an infection and concurrent signs of bleeding or anemia the complete blood cell count should be examined immediately. If blood cell count abnormalities are found the patient should be sent immediately to hematology unit for further examination and treatment. Early diagnosis enables to start "differentiation therapy" with all-trans retinoic acid that could be administered as monotherapy only in patients with leukocytes below 5 x 10(9)/l. Early diagnosis of AML M3 might ameliorate the fate of patients, since four of our five patients referred to us with elevated leukocyte counts expired in the first five days.

[Changes in humoral pressor and depressor factors in essential hypertension during lisinopril therapy]. / Zmeny presorických a depresorických humorálních faktoru u esenciální hypertenze pri lécbe lisinoprilem.

Arterial hypertension is nowadays no longer considered an isolated disorder of blood pressure regulation but a multifactorial disease with metabolic and cellular deviations. From the therapeutic aspect of thus conceived hypertension today inhibitors of the angiotensin converting enzyme seem most promising. With regard to their assumed comprehensive effect, the authors investigated simultaneously selected pressor and depressor humoral indicators and other indicators in 21 hypertensive patients with stage I and II of essential hypertension before and after three-month treatment with an angiotensin converting enzyme inhibitor lisinopril (Prinivil, Merck, Sharp and Dohme) and compared them with findings in 21 normotensive healthy subjects. Hypertensive subjects before treatment had, as compared with normotensives, significantly lower urinary kallikrein (7.8 +/- 1.2 < 18.0 +/- 4.2 EU/24hr, a significantly higher basal plasma adrenalin (1.27 +/- 0.20 > 0.54 +/- 0.20 pmol/ml) and adrenalin after a glucose load (1.26 +/- 0.22 > 0.51 +/- 0.12) and a higher relative plasma viscosity (1.74 +/- 0.02 > 1.67 +/- 0.01). The two groups did not differ significantly as to the plasma renin activity, plasma aldosterone and fibrinogen concentration and the level of urinary prostaglandins per 24 hr: 6-keto-prostaglandin F1a, thromboxane B2 and prostaglandins E and F2a. The 75 g glucose load produced an increased plasma renin, aldosterone and noradrenaline activity in normotensives as well as hypertensives before and after lisinopril treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Factor VIII gene mutations and RFLP analysis in hemophilia A.

Hemophilia A is an X-linked bleeding disorder caused by a quantitative or qualitative defect of coagulation factor VIII. Since factor VIII has been cloned and several intragenic and linked DNA polymorphisms discovered, DNA analysis is an accepted and commonly used method for carrier testing in hemophilia A. Both a direct method using detection of mutation and an indirect method based on linkage between the disease and DNA polymorphism are used for this purpose. In this study, DNA samples of 110 hemophilia A patients from 99 families were screened for factor VIII gene mutation using Southern blot analysis; in seven families, mutations were detected. In 13 females from six families with identified mutation, the direct diagnosis of carriers was performed. Four intragenic (BclI, XbaI, BglI and MspI in F8C locus) and two linked polymorphisms (TaqI in DXS52 locus and BglII in DXS15 locus) were studied in members of 47 hemophilia A families. BclI-XbaI-BglI haplotypes were analyzed in 90 unrelated X chromosomes. Eighteen out of 31 females (58%) were heterozygous for at least one intragenic polymorphism, and 29 out of 31 females (94%) were heterozygous for at least one intra- or extragenic polymorphism tested. Carrier diagnosis was made in 15 out of 25 possible carriers (60%) based on intragenic and in an additional 3 out of 25 (12%) only on linked polymorphism.