Bleeding-related hospitalization in patients with von Willebrand disease and the impact of prophylaxis: Results from national registers in Sweden compared with normal controls and participants in the von Willebrand Disease Prophylaxis Network.

INTRODUCTION: Patients suffering from von Willebrand disease (VWD) have a variety of bleeding symptoms and require both outpatient care for treatment and, in more severe cases, hospitalization. AIM: To investigate the impact of having VWD on frequency of hospitalization compared to a control group and to evaluate whether regular replacement therapy (prophylaxis) is associated with reduction in the number of hospitalizations. METHODS: Linkage of national population-based registries was used in the Congenital Bleeding Disorders study in Sweden (CBDS). Data were from the von Willebrand Disease Prophylaxis Network (VWD PN). RESULTS: The national registries contained 2790 subjects with a diagnosis of VWD between 1987 and 2009. A total of 13 920 age- and gender-matched controls were identified. There were 2.0 times (range 1.5-2.5) as many inpatient hospitalizations among subjects with VWD compared to controls. The most common causes of hospitalization were gastrointestinal (GI) bleeding (n = 232 as primary diagnosis), menorrhagia (n = 198) and epistaxis (n = 192). Outpatient visits per year were also twice as common among those with VWD. From the VWD PN, 105 subjects were included (VWD type 3, 52.4%; type2A, 22.9%; type 1, 12.4% and other types, 3.9%). A total of 122 hospitalizations due to bleeding episodes, dominated by GI bleeds, were analysed. Significantly fewer hospitalizations occurred after initiation of prophylaxis (75 prior to and 45 after, P = .006). CONCLUSION: Our study indicates that subjects with VWD have a considerably higher consumption of healthcare resources compared to controls and that initiation of prophylaxis may reduce the number of hospitalizations due to bleeding.

Complications of haemophilia in babies (first two years of life): a report from the Centers for Disease Control and Prevention Universal Data Collection System.

AIM: To describe the prevalence and complications in babies ≤2 years with haemophilia. METHODS: We used a standardized collection tool to obtain consented data on eligible babies aged ≤2 years with haemophilia enrolled in the Centers for Disease Control and Prevention Universal Data Collection System surveillance project at US Hemophilia Treatment Centers (HTCs). RESULTS: Of 547 babies, 82% had haemophilia A, and 70% were diagnosed within one month of birth. Diagnosis was prompted by known maternal carrier status (40%), positive family history (23%), bleeding (35%) and unknown 2%; 81% bled during the first two years. The most common events were bleeding (circumcision, soft tissue, oral bleeding) and head injury. There were 46 episodes of intracranial haemorrhage (ICH) in 37 babies (7%): 18 spontaneous, 14 delivery related, 11 traumatic, 2 procedure related and 1 unknown cause. Of the 176 central venous access devices (CVADs) in 148 (27%) babies, there were 137 ports, 22 surgically inserted central catheters and 20 peripherally inserted central catheters. Ports had the lowest complication rates. Inhibitors occurred in 109 (20%) babies who experienced higher rates of ICH (14% vs. 5%; P = 0.002), CVAD placement (61% vs. 19%; P < 0.001) and CVAD complications (44% vs. 26%; P < 0.001). The most common replacement therapy was recombinant clotting factor concentrates. CONCLUSION: Bleeding events in haemophilic babies ≤2 years were common; no detectable difference in the rates of ICH by the mode of delivery was noted. Neonatal factor exposure did not affect the inhibitor rates. Minor head trauma, soft tissue and oropharyngeal bleeding were the leading indications for treatment.

Prophylaxis in severe forms of von Willebrand's disease: results from the von Willebrand Disease Prophylaxis Network (VWD PN).

The bleeding patterns of severe von Willebrand's disease (VWD) adversely affect quality of life, and may be life threatening. There is a presumed role for prophylaxis with VWF-containing concentrates, but data are scarce. The von Willebrand Disease Prophylaxis Network (VWD PN) was formed to investigate the role of prophylaxis in clinically severe VWD that is not responsive to other treatment(s).Using a retrospective design, the effect of prophylaxis was studied. Availability of records to document, or reliably assess, the type and frequency of bleeding episodes prior to, and after, the initiation of prophylaxis was required. Annualized bleeding rates were calculated for the period prior to prophylaxis, during prophylaxis and by primary bleeding indication defined as the site accounting for more than half of all bleeding symptoms. The Wilcoxon signed-rank test of differences in the medians was used. Sixty-one subjects from 20 centres in 10 countries were enrolled. Data for 59 were used in the analysis. The median age at onset of prophylaxis was 22.4 years. Type 3 VWD accounted for the largest number (N = 34, 57.6%). Differences in bleeding rates within individuals during compared with before prophylaxis were significant for the total group (P < 0.0001), and for those with primary bleeding indications of epistaxis (P = 0.0005), joint bleeding (P = 0.002) and GI bleeding (P = 0.001). The effect of prophylaxis was similar among those age < 18 years and those ≥ 18. One person developed an inhibitor during treatment. We conclude that prophylactic treatment of VWD is efficacious.

Pharmacokinetics and safety of OBI-1, a recombinant B domain-deleted porcine factor VIII, in subjects with haemophilia A.

OBI-1 is a recombinant B-domain deleted porcine factor VIII (FVIII). FVIII treatment in those with haemophilia A may be complicated by the development of anti-FVIII antibodies (inhibitors) leading to a failure to respond to treatment with human FVIII. To compare the pharmacokinetics and safety of a single dose of OBI-1 with Hyate:C in subjects with haemophilia A and inhibitors, subjects were randomized to receive either Hyate:C followed by placebo or placebo followed by OBI-1 in a double-blind fashion. FVIII levels were assayed using both a one-stage coagulation assay (OSCA) and chromogenic assay. Pharmacokinetic parameters for FVIII were calculated for 6/9 subjects randomized; in three subjects baseline anti-porcine FVIII inhibitors led to a lack of measurable FVIII activity. Mean C(max) appeared higher for OBI-1 (OSCA: 176.00 U dL(-1), standard deviation ± 88.00; chromogenic: 151.00 ± 31.51 U dL(-1)) than Hyate:C (OSCA: 82.3 ± 19.22 U dL(-1); chromogenic: 52.67 ± 13.8 U dL(-1)). Mean AUC also appeared higher for OBI-1 (OSCA: 2082.87 ± 1323.43 U h(-1) dL(-1) ; chromogenic: 1817.28 ± 625.14 U h(-1) dL(-1)) than Hyate:C (OSCA: 1177.8 ± 469.49 U h(-1) dL(-1); chromogenic: 707.61 ± 420.05 U h(-1) dL(-1)). Two infusion-related events occurred: one with Hyate:C, one with placebo. Four of five subjects without anti-porcine FVIII inhibitors at baseline remained porcine FVIII inhibitor negative 29 days after infusion. A single dose of OBI-1 appears to have higher bioavailability than Hyate:C in subjects with haemophilia A without measurable anti-porcine FVIII inhibitors, and is well tolerated. These results should be confirmed in a larger phase 2/3 study.

Abnormalities of prothrombin: a review of the pathophysiology, diagnosis, and treatment.

Prothrombin (factor II) deficiency is a rare autosomal recessive coagulation disorder that occurs in approximately 1 in 1-2 million people. Prothrombin is activated to thrombin, which in turn proteolytically cleaves fibrinogen to fibrin and contributes to forming a stable fibrin clot. The haemostatic level of prothrombin is thought to be between 20 and 40%, and the half-life is approximately 3 days. There are more than 40 known mutations in prothrombin. Both hypoprothrombinemia and dysprothrombinemia have been described. Low prothrombin activity typically prolongs both the activated partial thromboplastin time and prothrombin time. Clinical manifestations are predominantly mucosal or surgical- or trauma-associated bleeding, but joint bleeding and intracranial haemorrhages have been reported. No purified prothrombin products are available for replacement therapy. Both fresh frozen plasma and prothrombin complex concentrates contain prothrombin and may be used for treatment.

Incidence of inhibitors in a cohort of 838 males with hemophilia A previously treated with factor VIII concentrates.

BACKGROUND: Development of an inhibitory antibody to factor VIII is currently the most serious complication of hemophilia A treatment. The rate of inhibitor development in those that have been previously treated with factor concentrates is poorly defined. Understanding the baseline rate of inhibitor development in the population of previously treated patients (PTPs) is important when evaluating the effect of exposure to new factor replacement products on inhibitor formation. OBJECTIVES: To determine the rate of inhibitor development in PTPs with hemophilia A. METHODS: A cohort of males with hemophilia A who had data collected on four or more occasions prior to 30 March 2003, as part of the Center for Disease Control and Prevention's Universal Data Collection Project, were eligible for inclusion in the cohort. Patients were included in the cohort if they had at least two Bethesda assay measurements and did not have an inhibitor prior to or at the start of the study period. The overall incidence rate was estimated as the number of verified incident inhibitor cases divided by the total follow-up time in years multiplied by 1000 (cases per 1000 person-years). RESULTS: A total of 838 patients were included in the study. The overall incidence rate was calculated to be 2.14 cases per 1000 person years. All incident cases had more than 50 exposure days prior to inhibitor development. CONCLUSIONS: Given the low rate of inhibitor development in PTPs with hemophilia A, small, non-randomized studies are inadequate to determine the rate of inhibitor development after exposure to novel products. Ongoing, standardized, postmarketing surveillance is needed to determine if novel factor products pose an increased risk of inhibitor development.

Morphologic, immunologic and cytogenetic studies in children with acute lymphoblastic leukemia at diagnosis and relapse: a Pediatric Oncology Group study.

The morphologic, immunologic and cytogenetic features of leukemic cells obtained at the time of first bone marrow relapse were compared with those obtained at initial diagnosis in 287 children with acute lymphoblastic leukemia (ALL) who were entered consecutively in a laboratory classification study of the Pediatric Oncology Group (POG). L1 to L2 shifts in French-American-British morphologic subtype were more common than the reverse (81/178 versus 15/61, p less than 0.001). A small but marginally significant number of cases acquired cytoplasmic granules at relapse, and 50 cases underwent a shift in periodic acid-Schiff reactivity that slightly favoured positive to negative. Shifts in immunophenotype were relatively rare, although shifts in cases with a pre-B phenotype to early pre-B ALL or vice versa occurred in about a third of pre-B cases. Loss of HLA-DR or the common ALL antigen occurred in 20 and 11% of cases, respectively. Of the 116 cases with analyzable karyotypes at diagnosis and relapse, 36 (31%) showed a change in karyotypes at relapse, usually from normal to pseudodiploid or hyperdiploid. Cytogenetic evidence for the emergence of a new clone after initial diagnosis was found in only one case. Analysis of the correlation of clinical and lymphoblast biologic features with event-free survival after an initial marrow relapse failed to demonstrate any prognostic significance for the changes identified in this study. T-cell immunophenotype proved to be the only factor significantly related to the outcome of retrieval therapy.

Incidence and prognostic significance of MDM2 oncoprotein overexpression in relapsed childhood acute lymphoblastic leukemia.

MDM2 overexpression by pediatric ALL cells at initial diagnosis has been linked to poor response to therapy. In the present study, we evaluated the incidence of MDM2 overexpression by ALL cells from pediatric patients at first relapse and compared MDM2 protein levels with in vitro response to adriamycin and with duration of initial complete remission (CR1). Since an important role of MDM2 in enhancing cell proliferation and survival appears to be inhibition of p53 activity, we also evaluated the status of p53 in these patients' leukemic cells. MDM2 protein levels were determined by Western blot analysis of leukemic bone marrow cells obtained from 42 patients with B cell precursor (BCP) ALL who relapsed during or following therapy on standard POG ALL protocols. Twelve of 42 (29%) cases have MDM2 levels >/=10-fold higher than those detected in normal bone marrow mononuclear (NMMC) cells, which express relatively low levels of protein. Thirty cases (71%) expressed MDM2 at levels <10-fold those in NMMC, including 24 MDM2-negative cases (57%). P53 mutations were detected by single-strand conformation polymorphism analysis in two cases. Overexpression of MDM2 (>/=10-fold) was significantly correlated with adriamycin resistance and decreased duration of CR1. Eight of 12 (75%) overexpressers showed high levels of in vitro resistance to adriamycin, compared to four of 30 (13%) non-overexpressers (P < 0.005). The median CR1 for MDM2 overexpressers was 20.5 months (range: 3-75 months) compared to 41 months (range: 8-98 months) for non-overexpressers (P < 0.01). Four of 42 patients failed to achieve CR following re-induction: leukemic cells from three of these patients either overexpressed MDM2 or contained a mutant p53. These results indicate that overexpression of MDM2 plays a significant role in refractory pediatric ALL and is associated with early relapse, adriamycin resistance, and failure to respond to re-induction therapy. Leukemia (2000) 14, 61-67.

Sucrose formulated recombinant human antihemophilic factor VIII is safe and efficacious for treatment of hemophilia A in home therapy--International Kogenate-FS Study Group.

To add an increased level of safety to antihemophilic factor replacement therapy, a full-length, recombinant Factor VIII (rFVIII) product has been developed without human-derived plasma proteins during purification and formulation and using an additional solvent/detergent viral inactivation step. This first clinical trial of a sucrose-formulated full-length rFVIII (rFVIII-FS) was conducted in previously treated patients (> or = 100 prior exposure days) with severe (<2% FVIII) hemophilia A in North America (NA) and Europe (EU). Pharmacokinetic profiles for rFVIII-FS were compared with those of currently licensed rFVIII product (Kogenate) in 35 patients. Safety and efficacy during home therapy were evaluated in 71 patients. The new formulation displayed a pharmacokinetic profile similar to that of rFVIII. Patients on home therapy received a cumulative total of 11,867 exposure days, 12,546 infusions, and 22,443,694 IU of rFVIII-FS. Of 2585 bleeds, 93.5% were treated with 1-2 infusions and 80.5% of responses were rated as excellent or good. No evidence of de novo inhibitor formation was observed. Only 0.27% of infusions were associated with any drug-related adverse event. Except for an episode of intermittent chest pain with palpitations which ceased after treatment with analgesics, associated adverse events were mild or moderate. Overall, rFVIII-FS provided excellent hemostatic control, was well-tolerated, and caused no significant adverse effects, thus demonstrating safety and efficacy for treatment of bleeds in patients with hemophilia A.

Dysfunctional protein C deficiency (type II). A report of 11 cases in 3 American families and review of the literature.

A cause of recurrent venous thrombosis is discernible in about 30% of symptomatic patients. Type I protein C (PC) deficiency (concomitant decrease of activity and antigen) is a well-described cause of venous thrombosis. Dysfunctional PC or type II PC deficiency (a disproportionate decrease in activity compared with antigen), however, is less well understood. Eleven subjects from three American families had dysfunctional PC. The patient base was moderately sized. These 11 subjects are compared with the 67 patients (39 symptomatic and 28 asymptomatic) that have been reported with dysfunctional PC at this time. Dysfunctional protein C deficiency is a more common cause of venous thrombosis than previously was recognized. Protein C activity should be determined in evaluating a patient with recurrent venous thromboses or thrombosis in early adult life. If the PC activity is low, repeat PC activity and a PC antigen levels should be determined so that patients with Type II PC deficiency will be identified. Further testing must include family studies to rule out an acquired deficiency and confirm the hereditary basis of the Type II PC deficiency.

The anemia of inflammation. A common cause of childhood anemia.

Pediatricians should understand that the anemia of inflammation is second only to iron deficiency in overall incidence. When evaluating a child for mild to moderate anemia, one should always consider hemolytic anemia, both immune and congenital, and blood loss. Careful scrutiny of the peripheral blood smear is always helpful and can assist in minimizing expensive and unnecessary evaluations. When the anemia of inflammation is suggested by history or physical examination and the CBC reveals a normocytic, or possibly microcytic, mild to moderate anemia with a normal peripheral blood smear, it is prudent to not embark on an extensive evaluation for the anemia but instead wait for the inflammation to resolve. This may take as many as 3 months, depending on the degree of inflammation. Because the anemia resolves with subsiding inflammation, it is best to avoid treatment with iron or RBC transfusions. More studies need to be performed concerning the pathogenesis of the anemia of acute inflammation in children and the best course of treatment, if needed. The role of erythropoietin in the treatment of this form of anemia, though promising in some adult models of inflammation, awaits exploration in pediatric patients.

In non-severe hemophilia A the risk of inhibitor after intensive factor treatment is greater in older patients: a case-control study.

BACKGROUND: Twenty-five percent of new anti-factor VIII (FVIII) antibodies (inhibitors) that complicate hemophilia A occur in those with mild and moderate disease. Although intensive FVIII treatment has long been considered a risk factor for inhibitor development in those with non-severe disease, its strength of association and the influence of other factors have remained undefined. OBJECTIVE: To evaluate risk factors for inhibitor development in patients with non-severe hemophilia A. METHODS: Information on clinical and demographic variables and FVIII genotype was collected on 36 subjects with mild or moderate hemophilia A and an inhibitor and 62 controls also with mild or moderate hemophilia A but without an inhibitor. RESULTS: Treatment with FVIII for six or more consecutive days during the prior year was more strongly associated with inhibitor development in those ≥30years of age compared with those <30years of age [adjusted odds ratio (OR) 12.62; 95% confidence interval (CI), 2.76-57.81 vs. OR 2.54; 95% CI, 0.61-10.68]. Having previously received <50days of FVIII was also not statistically associated with inhibitor development on univariate or multivariate analysis. CONCLUSIONS: These findings suggest that inhibitor development in mild and moderate hemophilia A varies with age, but does not vary significantly with lifetime FVIII exposure days: two features distinct from severe hemophilia A.

Philadelphia chromosome-positive chronic myeloid leukemia and thoracic ganglioneuroma. Previously undescribed association.

A previously healthy 11 year-old-white boy presented with persistent mild leukocytosis and a posterior mediastinal mass. Surgical excision of the mass showed it to be a ganglioneuroma. Postoperatively, the patient had marked leukocytosis (white blood cell count 57,000/mm3) and a low leukocyte alkaline phosphatase score. Bone marrow aspirate for cytogenetics performed in the evaluation of the posterior mediastinal mass showed the presence of the Philadelphia chromosome (Ph) in 19 of 20 metaphase spreads. The diagnosis of Ph+ chronic myeloid leukemia (CML) was confirmed on repeat cytogenetics. Subsequent detailed skin examination showed six small cafe-au-lait spots but no other evidence of neurofibromatosis. This is the first report to describe an association between ganglioneuroma and Ph+ CML.

Anemia of acute inflammation in children.

We measured sequential changes in hemoglobin concentration and erythrocyte sedimentation rate in 27 previously healthy children hospitalized for a variety of moderately severe acute inflammatory processes. Among 18 retrospectively studied children, 61% had mild anemia for age on admission, and Hgb values dropped greater than 2 SD in 83% during active inflammation. During recovery, Hgb concentrations spontaneously rose greater than 1.3 gm/dl in 79% of the children. Mean Hgb drop was 1.8 gm/dl in 5.6 days, representing an average noniatrogenic blood loss of 107 ml, among nine prospectively studied children. Only one of these had laboratory evidence of hemolysis, and none had clinical evidence of bleeding or overhydration. Results of both studies combined showed that a mean 13% Hgb drop during active inflammation was followed by a mean 24% Hgb rise during resolution of acute inflammation. We conclude that most children with moderately severe acute inflammation experience a significant drop in Hgb within 1 week of illness onset, regardless of the specific cause of inflammation. In general, this mild to moderate anemia resolves without hematinic therapy.

Determination of heparin-induced thrombocytopenia: a rapid flow cytometric assay for direct demonstration of antibody-mediated platelet activation.

Heparin-induced thrombocytopenia (HIT) and thrombosis are serious complications of heparin therapy. Recently, we have reported a practical and rapid functional flow cytometric assay (FCA) for the diagnosis of HIT with high specificity and sensitivity compared with the radioactive serotonin-release assay (SRA). In the present study, we added an immune-neutralization assay to directly demonstrate the antibody-mediated process, and tested the immune compatibility of low-molecular-weight heparin (LMWH) Lovenox and the heparinoid Orgaran (danaproid) using plasma from 18 patients with HIT confirmed by both FCA and SRA. The clinical utility of this modified method is demonstrated by a pediatric patient with a complex clinical presentation who developed thrombocytopenia with multiple thromboses while on heparin therapy. ELISA and SRA (performed in three independent laboratories) for diagnosis of HIT were both negative. In contrast, the FCA for detecting activated platelets expressing anionic phospholipids, was highly and reproducibly positive with both unfractionated and LMWH. Another FCA also demonstrated the surface expression of the alpha-granule membrane p-selectin (CD62p). Compatibility testing with the heparinoid Orgaran was also positive (and with plasma from 4 of the 18 patients with HIT). Heparin was discontinued, along with full recovery of the platelet count. The capacity of the patient's plasma to activate platelets in the presence of heparin gradually decreased over 4 weeks consistent with antibody clearance. The responsible mechanism was clarified using an immune-neutralization assay, which showed a dose response neutralization of the plasma activity by antibodies against human Immunoglobulin G (IgG) and IgM. This assay was also reproducible in the 18 patients with HIT. We conclude that the functional FCA with its modification is practical, sensitive, and specific for reliable diagnosis of HIT. It can simultaneously assess the compatibility of alternative therapies and directly confirm the antibody-mediated process. Further, it is particularly useful to clarify mechanisms of thrombocytopenia and thrombosis and to direct therapy in patients with a complex presentation and confounding laboratory results who often need prompt diagnosis and treatment.

Weekly polyethylene glycol conjugated L-asparaginase compared with biweekly dosing produces superior induction remission rates in childhood relapsed acute lymphoblastic leukemia: a Pediatric Oncology Group Study.

The relapse rate in childhood acute lymphoblastic leukemia (ALL) is approximately 30% but few reinduction regimens have investigated the intensive use of polyethylene glycol Escherichia coli asparaginase (PEG-Asp). Therefore, we assessed the pharmocokinetics and efficacy of PEG-Asp in this setting. Children with B-precursor ALL, in first marrow and/or extramedullary relapse were eligible. Reinduction included doxorubicin on day 1, prednisone for 28 days, vincristine weekly for 4 weeks, and PEG-Asp either weekly or biweekly by randomization. Asparaginase levels and antibody to both E coli asparaginase and PEG-asp were measured weekly just before each PEG-asp dose. Overall, 129 of 144 patients (pts) (90%) achieved a complete remission (CR). There was a highly significant difference in CR rates between weekly (69 of 71; 97%) and biweekly (60 of 73; 82%) PEG-Asp dosing (P =.003). Grade 3 or 4 infectious toxicity was common (50%), but only 4 pts died of sepsis during induction. Other toxicities were infrequent and hypersensitivity was rare (6 of 144; 4%). Low asparaginase levels were associated with high antibody titers to either native (P =.024) or PEG asp (P =.0013). The CR rate was significantly associated with higher levels of asparaginase (P =. 012). Patients with ALL in first relapse receiving weekly PEG-Asp had a higher rate of second remission compared with biweekly dosing. Low levels of asparaginase were associated with high antibody titers. Increased asparaginase levels may correlate with an improved CR rate. The use of intensive PEG-Asp should be explored further in the treatment of ALL. (Blood. 2000;96:1709-1715)

Severe neonatal protein C deficiency: prevalence and thrombotic risk.

Severe deficiencies of protein C, a pivotal coagulation-regulatory protein, have been reported in neonates as an apparently transient condition. In this prospective study, cord blood was collected at 193 deliveries and assays of protein C were correlated with clinical status, other coagulation results, and outcome. Protein C levels of less than 0.1 unit/ml were found most frequently in preterm infants with respiratory distress, infants of diabetic mothers, and infants of twin gestations. Levels of protein C correlated with levels of factor VIII activity but did not correlate with markers of consumptive coagulopathy. A protein C level less than 0.1 unit/ml was significantly correlated with the subsequent onset of thrombosis, even when the effects of gestational age and birth weight were excluded. Low cord blood levels of protein C may reflect delayed maturation or increased turnover in certain infants and appear to convey an independent risk of thrombosis, but the critical concentration of protein C necessary to maintain neonatal hemostasis is not known.

The prolonged thrombin time of nephrotic syndrome.

PURPOSE: Little information is available that documents the incidence and possible etiology of a prolonged thrombin time (TT) found in children with nephrotic syndrome. We speculated that this prolonged TT might best be explained by an altered fibrinogen similar to that found in the newborn. PATIENTS AND METHODS: We describe 20 children with nephrosis, an unexplained prolonged TT and reptilase time (RT), and an elevated fibrinogen level. Thrombin and/or plasmin effect on plasma fibrinogen was studied by analyzing for soluble monomer, D-dimer, fibrin degradation products, B beta 1-42 peptide, and by polyacrylamide gel electrophoresis (PAGE) and agarose electrophoresis. Structural changes in the fibrinogen molecule were investigated using two-dimensional gel (2D gel) electrophoresis. Fibrinogen was purified via glycine precipitation, and the sialic acid (SA) content was determined. RESULTS: No evidence for in vivo thrombin and/or plasmin effect on fibrinogen could be detected in 13 of 20 children tested. Additionally, no fibrin/fibrinogen degradation products or soluble fibrin complexes were detected using PAGE or agarose electrophoresis in this group of patients. The B beta isoforms of nephrosis fibrinogen were similar in isoelectric point on 2D gel electrophoresis to those of fetal fibrinogen and demonstrated a greater electronegative shift when compared with normal adult fibrinogen. Also, the SA content of nephrosis and fetal fibrinogen were greater than that measured in adult fibrinogen. Both nephrosis and fetal fibrinogen were more resistant to neuraminidase treatment than was normal adult fibrinogen. CONCLUSIONS: These data support the notion that an altered fibrinogen exists in some children with nephrotic syndrome characterized by an increased TT and RT, elevated fibrinogen, and both an increased negative charge and SA content.