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A new family with a bleeding diathesis and FVIII deficiency secondary to abnormal binding of von Willebrand factor (vWF) to factor VIII (FVIII) is described. Two propositi of this family, an 18-year-old male and a 33-year-old female, both with a history of epistaxis, bruising, bleeding from the gums, epistaxis, hemarthrosis, and hematoma, were analyzed. Also additional members of the same family with no bleeding history were also studied. The propositi showed normal vWF activities, low FVIII activity; one of them had been diagnosed as having hemophilia A and the other was a hemophilia A carrier. Both showed a very poor response to treatment with FVIII concentrates and desmopressin (DDAVP) but a good clinical response to cryoprecipitate. APTT was prolonged and no inhibitory activity was noticeable in their plasmas. Thirty-five units per kilogram body weight of Hemofil M was infused to both propositi and FVIII reached basal level within 60 minutes of the infusion. No FVIII response at all was observed in the female after intravenous DDAVP administration. However, the male who received the infusion of 35 U/kg body weight of Humate-P achieved a normal FVIII level that was maintained for 12 hours. Multimeric analysis of vWF was normal in all the members studied. Von Willebrand factor domain for FVIII binding was assayed in the two propositi and in six other members of the same family by using a non-isotopic and sensitive method, a modification of the one previously described, using the Hemofil M concentrate as exogenous FVIII. The data obtained showed that both propositi had similar binding to that observed by using plasma of a patient with severe von Willebrand disease. Furthermore, five siblings had a decreased binding of vWF to FVIII, when compared with plasma from normal individuals or patients with hemophilia A. We also observed that, for screening purpose, the ratio of bound FVIII/immobilized vWF (at saturation of the anti-vWF and offering of 1 U/ml of exogenous FVIII) distinguished two levels of abnormality (normal range 0.70-1.15, propositi 0.004-0.007, and remaining members affected 0.25-0.42). The most probable explanation is that the propositi are homozygous or double heterozygous, the other five siblings affected being heterozygous for a recessive vWF defect. This more accessible assay presented here may be of help in routine analysis for diagnosing this type of von Willebrand disease, which has important implications for therapy and genetic counseling.

A case of acquired von Willebrand disease (AvWD) associated with an IgA lambda multiple myeloma is reported. No form of inhibitor could be detected. SDS-agarose gel electrophoresis patterns of von Willebrand factor (vWF) both in plasma and platelet lysates were normal but a decrease in all-sized multimers with a type IA pattern was seen. After 1-deamino-8-D arginine vasopressin (DDAVP) infusion, vWF multimers larger than those seen in the resting state appeared in patient plasma, which were progressively cleared. Indirect immunofluorescence studies with a monoclonal antibody to vWF showed that vWF was selectively absorbed into myelomatous cells. This is the first case of AvWD associated with multiple myeloma resulting from the selective absorption of vWF into abnormal plasma cells. This feature established a new pathophysiological mechanism of AvWD in multiple myeloma and probably in other lymphoproliferative diseases.

The multimeric structure of von Willebrand factor (vWF) and its ristocetin-induced binding to platelets, using a simple and very sensitive radiomonoclonal antibody-labeled vWF method, was compared in normal plasma, single-donor cryoprecipitate (CP) and five different antihemophilic factor (AHF) concentrates. All the AHF showed a lack of larger vWF multimers, an abnormal 'triplet' pattern, and much lower vWF binding to platelets than that of plasma or CP, vWF being the lowest for those with a lesser proportion of larger vWF multimers. These results suggest that the combination of vWF multimeric analysis and the radiomonoclonal-labeled vWF method may be very useful in the assessment of AHF preparations.

A 60-yr-old woman had had a bleeding disorder for the last 13 yr, with laboratory features of monoclonal gammopathy and von Willebrand's disease (vWD). There was no evidence of family vWD. She had a prolonged bleeding time, low levels of factor VIII/von Willebrand factor activities and decreased ristocetin-induced platelet agglutination. Platelet von Willebrand factor (vWF) was normal. Plasma vWF showed a unique multimeric pattern with absence of larger and intermediate multimers and a disproportionate increase of the fastest moving multimer with normal satellite bands, thus differing from previously described types of vWF. No evidence for inhibitor, non neutralizing antibody or proteolytic activity against vWF was found in her plasma or IgG fraction. DDAVP response was very poor. We suggest that this patient had a unique, probably acquired, vWD. Nevertheless the possibility of its being a new subtype of congenital vWD associated with an unrelated monoclonal gammopathy cannot be ruled out.

Circulating inhibitors against von Willebrand factor (vWF) that show the properties of heterologous IgG antibodies have been described in a few patients with severe von Willebrand disease (vWD). The present study provides further characterization of inhibitors from two patients with severe vWD. Inhibitors in both, like polyclonal rabbit antibody, detected all sizes of multimers and the complex structure of each multimer from platelets and plasma of normal individuals as well as from plasma of patients with IIA, IIB, and IIC vWD. Both inhibitors and the rabbit antibody reacted mainly with the intact 225-Kd vWF subunit and the 189-H and 140-Kd fragments in contrast to monoclonal antibodies specific for vWF fragments that detected a higher relative proportion of 176-Kd fragment. Furthermore, all these antibodies recognized fragment III, although one inhibitor and rabbit polyclonal antibody reacted poorly and the other inhibitor did not react at all with reduced fragment II of vWF digested with Staphylococcus aureus V-8 protease. These data suggest that although human inhibitors from severe vWD patients may behave, to some extent, as polyclonal heterologous antibodies against native vWF, the former show striking differences in their target specificity as well as a much broader specificity than that described for human factor VIII inhibitors.

Total hemolytic complement (CH50) and eight antigenic fractions of the complement system were determined in 30 patients with hematological neoplasias, distributed into the following groups: six cases of non-Hodgkin's lymphomas (NHL), seven cases of chronic lymphocytic leukemia (CLL), five cases of Hodgkin's disease (HD), seven cases of acute leukemia (AL), three cases of chronic myeloid leukemia (CML) and two cases of multiple myeloma (MM). CH50 was titred accordingly to a modification of the Kabat and Mayer method, C1q, C1s, C3, C4, C5, INHC1, C3A and properdin were determined with specific antisera by Manani and Laurell's techniques. The results obtained showed significant increase in CH50 above normal values in patients with HD, AL, and CML, especially the former, even in early stages. C1s was found to be increased in CML and AL, as well as C3 in CML. C4 is increased in CML and HD. C5 follows a course similar to C4, being also increased CLL and MM. C9 is increased in all groups, except NHL. A significant increase in C3A was found in NHL, HD and AL. There were no significant variations in C1s, INHC1 and properdin in any of the former groups. No correlation was found between clinical course and complement increase. The role of complement in neoplastic disease is discussed.

Factor VIII and von Willebrand factor proteins were evaluated in 115 patients having the chronic phase of the Toxic Epidemic Syndrome (TES), a new multisystemic disease probably caused by the ingestion of denatured rapeseed oil, and in 50 control volunteers. Higher circulating levels of factor VIII procoagulant activity (VIII:C) (158 +/- 58.4 U/dl), von Willebrand factor antigen (vWF:Ag) (166.1 +/- 55.5 U/dl) and von Willebrand factor ristocetin cofactor activity (vWF:RCo) (178.7 +/- 55.2 U/dl) were seen in TES patients (p less than 0.001, TES patients versus control subjects, for each parameter). The increased levels of vWF:Ag and vWF:RCo observed in TES patients correlated with the scleroderma like lesion of the skin, with the sicca syndrome and with Raynaud's phenomenon (p less than 0.01), but not with other clinical manifestations. The multimeric analysis of vWF in 92% of the TES patients was similar to that found in normal plasma, but in the remaining 8% a very slight increase of larger vWF multimers in plasma were observed. The raised levels of vWF found in TES patients in the chronic phase may reflect an "in vivo" vascular injury.

Factor VIII/von Willebrand factor was analyzed before and after the infusion of 500 ml of Dextran 70 to normal volunteers. Factor VIII procoagulant activity, factor VIII related antigen and ristocetin cofactor activity showed a significant decrease, reaching after six hours the minimum level, which did not correlate with the hemodilution effect caused by dextran. Ristocetin-induced platelet agglutination (RIPA) in volunteers' platelet-rich plasma (PRP) did not show any significant change between preinfusion time and six hours after the infusion. Multimeric analysis of von Willebrand factor (vWF) showed a progressive decrease of all the multimers which was more pronounced in the largest multimers. No change was seen in the "triplet" structure of vWF. No effect was noticed when dextran was incubated "in vitro" either with PRP or platelet-poor plasma. The modification induced by dextran is close to the pattern seen in subtype Ib von Willebrand's disease.

A familial bleeding disorder characterized by an association of Type IIB von Willebrand's disease (vWD) with a complex thrombocytopenic thrombocytopathy is described in two patients from the same generation. Findings typical of type IIB vWD included enhanced ristocetin-induced binding of patient von Willebrand factor (vWF) to platelets of patients and normal individuals in association with the absence of larger multimers from plasma. Abnormalities in platelet function included deficient platelet aggregation to ADP, collagen, epinephrine, and arachidonic acid; and defective release of 14C-serotonin, vWF, and platelet factor 4 (PF4) in response to thrombin, collagen, or ADP. Platelet factor 4 and platelet vWF were decreased when measured per mg of total platelet protein. In addition, the binding of normal vWF to patient platelets stimulated with thrombin was decreased. Platelet size was increased with a very heterogeneous distribution width. Electron microscopic evaluation showed giant platelets with dense and alpha bodies present. The platelet count was borderline or slightly decreased in the resting state and declined to frankly thrombocytopenic levels at the time of acute bleeding episodes; this state was associated with the presence of platelet aggregates in blood smears.

von Willebrand factor (vWF) from platelet lysate and plasma, collected in the presence of protease inhibitors, was studied in two patients with type IIC von Willebrand disease (vWD). Platelet and plasma vWF showed the smallest multimer increased, but the latter had a repeating single band whereas the former had a repeating "doublet." This platelet-plasma discrepancy observed for the first time in these patients suggests that the repeating "doublet" or single band described in other type IIC patients represent minor subgroups of type IIC vWD.

The multimeric and subunit patterns of plasma von Willebrand factor (vWF) were analyzed in eight patients with myeloproliferative syndrome (MS) in order to investigate the possible existence of heterogeneity in the "in vivo" proteolytic cleavage of the protein, previously observed in this entity. Six patients lacked large vWF multimers, five of them having normal bleeding times (BT) and clinically documented episodes of thrombotic origin, whereas one patient had long BT and bleeding symptoms. Seven patients showed a relative increase in the 176 kDa subunit fragment while the 189 kDa polypeptide was increased in only one. In addition, another patient (and prior to any therapy) showed the presence of a new fragment of approximately 95 kDa which disappeared after Busulfan therapy. The collection of blood from these patients with proteinase inhibitors did not correct the abnormalities. The infusion of DDAVP to two patients with abnormal vWF was accompanied by: the appearance of larger vWF multimers which disappeared rapidly from plasma; an increase in the relative proportion of the satellite bands of each multimer and a further increase of the 176 kDa fragment. These data point to some heterogeneity in the vWF abnormality present in MS which may be related in part to a variable degree of proteolysis of vWF occurring "in vivo" rather than "in vitro", and which may be associated to either a thrombotic or a bleeding diathesis. They also suggest that despite the presence of abnormal, already proteolyzed vWF, DDAVP-enhanced proteolysis occurs in MS to a similar extent to what is described in normal individuals.