EXTRACELLULAR VESICLES AS MARKERS OF INFLAMMATION AND HYPERCOAGULABILITY DURING THE FIRST MONTH OF SARS-COV-2 INFECTION IN OUTPATIENTS AND HOSPITALIZED PATIENTS

Introduction

During SARS-CoV-2 infection, a severe hypercoagulability state is observed due to the stimulus of multiple mechanisms of hemostasis, such as coagulation, activation of platelets, endothelial cells, monocytes and neutrophils and impaired fibrinolysis. As a consequence, thrombotic complications are common in the course of COVID-19. Microvesicles (MVs) are intracellular transmitters that participate in pathological conditions, such as inflammatory and infectious processes, and are capable of triggering prothrombotic mechanisms. Since MVs release is potentially associated with COVID-19-induced coagulopathy, our aim was to identify during the course of the disease when the stimulus for MVs release occurs and whether this was associated with adverse outcomes.

Objective

We evaluated changes in the levels of MVs markers during the first month of SARS-CoV-2 infection in patients (pts) with severe disease (hospitalized in an Intensive Care Unit ‒ ICU) as compared to outpatients. We also evaluated the association between MVs markers with: inflammatory biomarkers (C-reactive protein, CRP), hypercoagulability (D-dimer) and death.

Methods

Blood samples were collected on three occasions: before the 10^th day of symptoms, in the 3^rd week of symptoms and in the 4^th week of symptoms for the quantification of the following MVs markers by flow cytometry: CD41A (platelet activation), CD162 (PSGL-1; leukocyte-platelet interaction), CD31 (endothelium-platelet interaction) and CD142 (tissue factor). Statistical tests of ANOVA with repeated measures, Mann-Whitney and regression methods were used.

Results

The population studied was 85 pts, being 25 from ICU. Mostly were men (51%), with a median age of 41 years. The concentration of MVs expressing CD31+, CD41+, CD162+ and CD142+ were persistently elevated in pts who required ICU compared to outpatients at the 3 moments studied, except for the levels of MVs-CD31+ and MVs-CD142+ that were similar between ICU and outpatients in the 4^th week of symptoms. However, despite the differences between the groups, there were no significant changes in the levels of MVs during the course of the disease within the groups. In subgroup analysis, we observed that increases in the levels of MVs-CD162+ and MVs-CD142+ in the 3^rd week of symptoms were associated with the risk of death (p=0.02 and p=0.06, respectively). We also observed that during the course of the disease an association between MVs, coagulability and inflammation was evident. In the 3rd week of symptoms, D-dimer levels were correlated with MV-CD31+ (r=0.52, p<0.0001), MV-CD162+ (r=0.35, p=0.001), MV-CD41A+ (r=0.44, p<0.0001) and MV-CD142+ (r=0.47, p<0.0001) and CRP values were correlated with MV-CD31+ (r=0.56, p=<0.0001), MV-CD162+ (r=0.48, p<0.0001), MV-CD41A+ (r= 0.41, p=0.0001), and MV-CD142+ (r=0.56, p<0.0001). By the 4^th week of symptoms, both D-dimers and CRP correlations with the above MVs remained unchanged.

Conclusion

To conclude, MVs that express antigens related to platelet activation, leukocyte-platelet interaction and endothelium-platelet interaction, as well as those related to tissue factor are released during the course of COVID-19 in pts with severe disease. After the 4^th week of symptoms, the release of these MVs was associated with signs of inflammation and hypercoagulability. Additionally, MVs that express tissue factor and leukocyte-platelet interaction antigens were particularly high among non-survivors, suggesting that these MVs may serve as markers of the risk of death. Finally, these findings suggest the participation of innate immunity and tissue factor pathways in the prognosis of COVID-19, and point towards a possible role of MVs as biomarkers of disease prognosis.

Carrier Detection in Severe (Type III) von Willebrand Disease Using Two Intragenic Restriction Fragment Length Polymorphisms

DNA from a family with a female member affected with severe (type III) vWD was analysed using three restriction enzymes and a partial vWF cDNA probe. Two restriction fragment length polymorphisms (RFLPs) detected with the enzymes Bgl II and Xba I proved to be informative in this family. A 36.0 Kb allele, demonstrated with the enzyme Xba I was rare in the general population but very important in this family for segregation analysis of the alleles and their association with the putative defective chromosome. The propositus was homozygous for the 36.0 Kb Xba I polymorphic band and heterozygous for the Bgl II polymorphism. She was the only member of the family showing this allelic pattern. The linkage of the alleles could be determined because her mother was homozygous for the 9.0 Kb Bgl II polymorphism but heterozygous for the Xba I polymorphism. The segregation of the alleles could be traced to the proband’s son and a niece. The genotypic analysis revealed that her niece could be considered as carrying a defective gene for severe vWD.

Clinical Application of a Chromogenic Substrate Method for Determination of Factor VIII Activity

A chromogenic substrate kit for the determination of factor VIII activity (COATEST® Factor VIII) has been evaluated in five different laboratories, one of them using a semi-automated procedure. This chromogenic method was compared to one-stage clotting assays for factor VIII determination in plasmas from healthy subjects, carriers of hemophilia A, severe, mild and moderate hemophilia A as well as von Willebrand’s patients. In all these cases, a high correlation between these two methods was obtained (r = 0.96-0.99, n = 385) with a good agreement of the assigned potencies at all levels of factor VIII. A good correlation (r = 0.94) was also obtained for the levels of factor VIII after infusion of concentrates in six severe hemophiliacs or after administration of DDAVP to von Willebrand’s patients.

The chromogenic method is insensitive to preactivation of factor VIII by thrombin, thus yielding valid potency assignments also in these situations.

The precision was higher with the chromogenic method than with the one-stage clotting assays (C.V. = 2-5% vs 4-15%). Altogether, the new chromogenic substrate method has proven itself suitable for determination of factor VIII in plasma and concentrates.

An Enzyme Immunoassay (ELISA) for the Quantitation of Human Factor VII

A new solid phase enzyme-linked immunosorbent assay (ELISA) was developed for the quantitation of human Factor VII antigen (F VII Ag), using a monospecific rabbit anti-F VII antiserum. Anti-F VII F(ab′)2 fragments were adsorbed to polystyrene plates. The binding of serial dilutions of control or test plasma, containing F VII, was detected by incubation with peroxidase-labeled anti- FV II IgG followed by the addition of hydrogen peroxyde and O-phenylenediamine. This ELISA is specific, sensitive (detection limit: 0.05%) and accurate (coefficient of variation: 1.5-4% for within- and 1.6-9% for between-assays). F VII coagulant activity (F VII C) and F VII Ag were determined in large populations of controls and patients. In normal plasma (n = 38), F VII Ag ranged from 83 to 117% and the correlation coefficient between F VII Ag and F VII C was 0.94. In patients with severe (F VII C inf. 1%) congenital F VII deficiency (n = 5), F VII Ag was undetectable in two cases (inf. 0.05%) and markedly reduced (0.35 to 5.6%) in the three other cases. In patients with liver cirrhosis (n = 15), F VII Ag ranged from 21 to 59% and was in good correlation with F VII C (r = 0.84). In dicoumarol treated patients (n = 15), the levels of F VII Ag ranged from 51% to 79% and a poor correlation (r = 0.52) with F VIIC was observed. In “compensated” DIC (n = 5), levels of F VII Ag varied from 60 to 186%, with significantly higher F VII C levels (from 143 to 189%). In contrast, in “decompensated” DIC (n = 7), low F VII Ag and F VII C levels were observed (from 7 to 27%). In patients with deep-vein thrombosis (n = 25), high levels of F VII Ag (from 102 to 136%) and F VII C (from 110 to 150%) were demonstrated. In surgical patients, no significant difference was observed before and one day after intervention.

Multicenter Retrospective Study on the Utilization of FEIBA in France in Patients with Factor VIII and Factor IX Inhibitors

Factor VIII or factor IX replacement is frequently impossible in inhibitor-developing hemophiliacs, because of the level of the inhibitor titer. Activated prothrombin complex concentrates are one of the available options to treat the bleeding episodes in such patients. However, the efficacy of these products and the associated thrombogenic risk, particularly in prolonged administration such as employed during surgeries, are important concerns for hemophilia care providers. We performed a multicenter retrospective study to evaluate the use of FEIBA (Factor Eight Bypassing Activity) in France, and data is presented on 433 bleeding episodes, including surgical procedures, concerning 60 patients from 15 hemophilia centers.

The efficacy was judged as good or excellent in 352 episodes (81.3%), poor in 73 episodes (16.9%) and non-existent in 8 episodes (1.8%). Minor and major surgical procedures were successfully performed using FEIBA as a second-line therapy after human or porcine factor VIII, and in some occasions FEIBA was utilized as the only substitution product. The tolerance was assessed as good in 428 episodes (98.8%), but in 5 cases adverse effects were reported. Only 3 patients out of 52 regularly evaluated (5.8%) were HIV-seropositive, and for two of them the seroconversion occurred prior to the first use of FEIBA. In contrast, 80.4% of the patients were HCV-seropositive. An anamnestic response after the administration of FEIBA was noted in 31.5% of cases. This study points out the main features of the use of FEIBA in France, and particularly the low HIV seroprevalence in the patients treated. The good efficacy and the excellent tolerance still confer to this product a place to consider in the therapeutic options for the treatment of inhibitor-developing hemophiliacs or in acquired hemophilia.

French Previously Untreated Patients with Severe Hemophilia A after Exposure to Recombinant Factor VIII : Incidence of Inhibitor and Evaluation of Immune Tolerance

Fifty French previously untreated patients with severe hemophilia A (factor VIII <1%), treated with only one brand of recombinant factor VIII (rFVIII), were evaluated for inhibitor development, assessment of risk factors and outcome of immune tolerance regimen. The median period on study was 32 months (range 9-74) since the first injection of rFVIII. Fourteen patients (28%) developed an inhibitor, four of whom (8%) with a high titer (≥10 BU). All inhibitor patients but one continued to receive rFVIII either for on-demand treatment or for immune tolerance regimen (ITR). Among these patients, inhibitor was transient in 2 (4%), became undetectable in 6 and was still present in 6. The prevalence of inhibitor was 12%. Presence of intron 22 inversion was found to be a risk factor for inhibitor development. Immune tolerance was difficult to achieve in our series despite a follow-up period of 16 to 30 months: immune tolerance was complete in only one out of the 3 patients undergoing low dose ITR and in one out of the 5 patients with high dose ITR.

Anti-A2 and anti-A1 domain antibodies are potential predictors of immune tolerance induction outcome in children with hemophilia A

BACKGROUND

Hemophilia A (HA) is a congenital bleeding disorder resulting from factor VIII deficiency. The most serious complication of HA management is the appearance of inhibitory antibodies (Abs) against injected FVIII concentrates. To eradicate inhibitors, immune tolerance induction (ITI) is usually attempted, but it fails in up to 30% of cases. Currently, no undisputed predictive marker of ITI outcome is available to facilitate the clinical decision.

OBJECTIVES

To identify predictive markers of ITI efficacy.

METHODS

The isotypic and epitopic repertoires of inhibitory Abs were analyzed in plasma samples collected before ITI initiation from 15 children with severe HA and high-titer inhibitors, and their levels were compared in the two outcome groups (ITI success [n = 7] and ITI failure [n = 8]). The predictive value of these candidate biomarkers and of the currently used indicators (inhibitor titer and age at ITI initiation, highest inhibitor titer before ITI, and interval between inhibitor diagnosis and ITI initiation) was then compared by statistical analysis (Wilcoxon test and receiver receiver operating characteristic [ROC] curve analysis).

RESULTS

Whereas current indicators seemed to fail in discriminating patients in the two outcome groups (ITI success or failure), anti-A1 and anti-A2 Ab levels before ITI initiation appeared to be good potential predictive markers of ITI outcome (P < 0.018). ROC analysis showed that anti-A1 and anti-A2 Abs were the best at discriminating between outcome groups (area under the ROC curve of > 0.875).

CONCLUSION

Anti-A1 and anti-A2 Abs could represent new promising tools for the development of ITI outcome prediction tests for children with severe HA.

Immune tolerance induction in haemophilia A patients with inhibitors by treatment with recombinant factor VIII: a retrospective non-interventional study

Immune tolerance induction (ITI) can overcome inhibitory factor VIII (FVIII) antibodies in haemophilia A patients receiving FVIII replacement therapy. The objective was to evaluate the use of sucrose-formulated, full-length recombinant FVIII (rFVIII-FS) for ITI therapy. Patients (<8 years at ITI start) with severe haemophilia A and a peak inhibitor titre >5 Bethesda units (BU) who underwent ITI with any rFVIII-FS dose for ≥ 9 months (or until success) were eligible for this retrospective study. Efficacy analyses included descriptions of ITI treatment regimens and outcomes; ITI success was determined solely at the discretion of the investigator. Safety analyses included assessment of adverse events. Of 51 enrolled patients, 32 [high dose (≥ 85 IU kg(-1) day(-1)), n = 21; low dose, n = 11] were eligible for analysis. ITI was successful in 69% (22/32) of patients (high dose, 66.7%; low dose, 72.7%) after a median of 1.4 years (range, 0.1-3.6 years). Influencing factors for ITI success were start of ITI <1 year after inhibitor detection and an inhibitor titre <10 BU at ITI start. All patients successfully tolerized with ITI continued to receive rFVIII-FS prophylaxis as maintenance therapy, with no inhibitor recurrence from the end of ITI until study enrolment. Use of rFVIII-FS for ITI was effective and well tolerated; success rates were similar to those in published studies.

Spontaneous obturator internus muscle haematoma: a new unpublished cause of ilioipelvic pain in haemophilia

Obturator muscles haematoma are rarely reported. The most often reported cases are primary pyomyositis or posttraumatic haematomas occurring during pelvic fractures. We firstly report herein two cases of spontaneous obturator internus haematoma (OIH) in two haemophiliacs with inhibitor. Clinical data and imaging of two patients treated in our clinic are reported here according to previously defined criteria of OIH in posttraumatic situation. Both patients were children suffering from severe and moderate haemophilia A, respectively, with an inhibitor at the time of the event. The clinical feature was marked by an iliopelvic pain letting discussing hip haemarthrosis, appendicitis or iliopsoas haematoma. For both patients ultrasonography (US) failed to provide the diagnosis. Careful and repeated clinical examinations eventually lead to suspect obturator haematoma which was confirmed by abdominopelvic computed tomography (CT) and magnetic resonance imaging (MRI). Respectively, high dose of FVIII or rFVIIa regimen allowed a rapid control of the muscular bleeding in the low and high responder inhibitor patients. Spontaneous OIH may be added to the differential diagnosis of iliopelvic pain in severe forms of haemophilia. US still often performed at first in such case remains unhelpful; abdominopelvic CT or MRI should be performed to discriminate among different diagnoses, including OIH which stays probably undiagnosed.

Screening for von Willebrand disease: contribution of an automated assay for von Willebrand factor activity

Measuring von Willebrand factor (VWF) activity is essential to the diagnosis of von Willebrand disease (VWD). The VWF activity is usually assessed based on measurement of the ristocetin cofactor (VWF:RCo). However, that test is technically challenging and has high intra- and inter-assay variabilities. The HemosIL VWF activity (VWF:AC) is a fully automated assay, recently proposed as a good alternative to VWF:RCo for VWD diagnosis. This study was undertaken to assess this new method. First, the analytical performance of VWF:AC on an automated coagulo-meter (ACLTop) was determined, and then this new method was compared with VWF:RCo and the platelet function analyzer (PFA100) for 160 patients referred for VWD screening. The VWF:AC achieved acceptable precision with within-run and between-run coefficients of variation ranging from 2.3% to 14.1%, and linearity from 10% to 100%. Despite some marked differences between VWF:AC and VWF:RCo for 10 plasmas tested, their agreement for VWD diagnosis was good. The VWF:AC had sensitivity similar to that of PFA100 (close to 100%), but better specificity (97.7% vs. 66% or 60%, depending on the cartridge used). The good analytical performance, and the sensitivity and specificity of VWF:AC to detect VWF deficiency renders it a suitable method for VWD screening. Our findings support VWF:AC use for the diagnostic work-up of VWD, paying close attention to concomitant clinical signs and bleeding score, as recommended for VWD.

Surgical synovectomy of the knee in young haemophiliacs: long-term results of a monocentric series of 23 patients

BACKGROUND

In haemophiliacs, synovectomy is indicated for recurrent joint bleedings, despite medical treatment.

METHOD

We report a series of 23 surgical synovectomies of the knee with a median follow-up of 8.8 years. The median age of patients at surgery was 13.5 years. Clinical and radiological evaluations were made according to the Petrini and the Pettersson scores, at 1 and 5 years after surgery, and at the last follow-up. Wilcoxon and Spearman's tests were used for the statistical analysis.

RESULT

The Petrini score improved at 1 and 5 years (P < 0.001). Nine patients have 20 years of follow-up and a stable result. In more than half of the knees, no episode of recurrent bleeding occurred. The effect of surgery on the range of motion (ROM) was moderate and mobilisation under anaesthesia did not improve it significantly. There was a progressive worsening of the radiological score, but no correlation between clinical and radiological score was noticed (ρ = 0.08, P = 0.77).

CONCLUSION

Complete synovectomy gives good long-term results in term of bleeding recurrence and overall function.

[French guidelines. Long-term prophylaxis for severe haemophilia A and B children to prevent haemophiliac arthropathy]

During the last decades, long-term prophylaxis has become the gold standard for the treatment of children with severe haemophilia A or B. Prophylactic replacement regimens modify the natural history of the disease by aiming at the prevention of haemarthrosis, target joints and arthropathy. This treatment represents a constraint and an enhanced exposure to anti-haemophilic concentrates, which means potential increase of related risks and significant additional cost. The context of crisis of confidence due to the blood borne infections in the 1980s, may have delayed prophylaxis as an universal gold standard.In the early 2000s, the French group CoMETH proposed recommendations based on the review of the international experience. At first, specific guidelines of long-term prophylaxis were dedicated to children with severe haemophilia A or B, aged 3 years or less, with no history of target joint or arthropathy. The main concerns of this regimen consist in the early start and the escalating intensification of the treatment. In the French haemophilia care centres, the diffusion of these guidelines has apparently induced a significant turning point in therapeutic practices for haemophilia children. In 2006, more comprehensive recommendations were diffused to take into account all the children with severe haemophilia, whatever the bleeding history and joint status. The analysis of their impact, jointly with the National cohort "France Coag Network", will first assess the widespread implementation of the recommendations and the observance of the prophylactic regimen and identify factors associated to the compliance.

Pharmacokinetics and pharmacodynamics of a new highly secured fibrinogen concentrate

BACKGROUND

Inherited afibrinogenemia is a rare autosomal recessive disorder characterized by the absence or trace amounts of plasma fibrinogen inducing varying bleeding tendencies. Little is known about the pharmacokinetics of plasma-derived fibrinogen concentrates used in the treatment of afibrinogenemic patients.

OBJECTIVE

This open, prospective, multicenter study assessed the pharmacokinetic and pharmacodynamic profiles of FIBRINOGENE T1 (FGT1; LFB, Les Ulis, France), a human fibrinogen concentrate treated with three specific biological safety steps.

PATIENTS/METHODS

Five adult patients with congenital afibrinogenemia received a single infusion of 0.06 g kg(-1) of FGT1. Plasma samples drawn up to day 14 were assayed for fibrinogen antigen and activity and for coagulation parameters in a central laboratory.

RESULTS

Fibrinogen antigen and activity were similar and highly correlated, with very low between-patient variability for pharmacokinetic parameters. Fibrinogen levels increased rapidly and significantly, with a mean plasma concentration of 1.39 g L(-1) being achieved 1 h after the end of the infusion, leading to almost complete in vivo recovery (94%). The mean half-life was 3.4 days, with slow linear elimination, and the distribution was mainly restricted to the vascular compartment. Coagulation parameters were normalized after the infusion and during the following 6-10 days. FGT1 was well tolerated overall.

CONCLUSIONS

FGT1 behaves like natural functional fibrinogen, and its pharmacokinetic properties are in line with those expected from a fibrinogen concentrate. Our findings suggest that FGT1 can restore efficient hemostasis in afibrinogenemic patients, and predict good clinical efficacy.

Should prophylaxis be used in adolescent and adult patients with severe haemophilia? An European survey of practice and outcome data

A survey of 21 haemophilia doctors, throughout Europe, who care for a total of approximately 5000 patients with bleeding disorders addressing practice and opinions regarding prophylaxis in patients aged 16-24 years and adults aged over 50 years, is presented. The outcome of adolescent patients who reduced or stopped prophylaxis was recorded. Eighteen of 19 respondents would consider modification of established prophylaxis in the adolescent age group, principal considerations being avoidance of risks of further concentrate exposure, predicted poor compliance and treatment costs. The preferred age for modification was 16-20 years, but there was very little consensus on the particular prophylactic regime recommended. Approximately, half of a cohort of 218 patients with severe haemophilia successfully reduced or stopped prophylaxis when they reached adolescence. Only 26 of 92 (28%) of the patient cohort who stopped prophylaxis, required reintroduction of a prophylactic regime and 12 of 59 (20%) of those who reduced the intensity of prophylaxis had to reintroduce a more intensive regime. A majority of respondents would consider starting prophylaxis in those over 50 years. There was no consensus as to indications for this practice or the nature of the prophylaxis protocol. We conclude that there is an absence of consensus on the management of patients with severe haemophilia, as they pass through adolescence and young adulthood, and reach the age of 50. Aggregate outcome data suggest a significant proportion of patients in the 18-22 years age range may be able to reduce or stop prophylaxis. A substantial number of older patients are on prophylaxis.

ReFacto and Advate: a single-dose, randomized, two-period crossover pharmacokinetics study in subjects with haemophilia A

ReFacto is a recombinant B-domain-deleted, monoclonal antibody-purified, solvent-detergent-treated factor VIII (BDDrFVIII) with no albumin added to the final formulation. Although ReFacto has been shown to be bioequivalent to a plasma-derived FVIII product (Hemophil-M) in a randomized, crossover pharmacokinetic (PK) study, the comparability of ReFacto with the full-length (complete sequence) recombinant FVIII (FLrFVIII, Advate) product has not been previously examined in this manner. The primary objective of this study was to compare the PKs of ReFacto with those of Advate in patients with severe haemophilia A. This was a third-party unblinded, randomized, multicentre, two-period crossover PKs study of ReFacto and Advate in subjects with severe haemophilia A (FVIII:C < or =1%). Blood samples were collected over a 48-h period after i.v. administration of each of the FVIII products. FVIII:C was determined using the chromogenic substrate assay (CSA) in a central laboratory. The plasma FVIII:C PK parameters of ReFacto and Advate were determined using non-compartmental analysis. Bioequivalence was assessed on maximum plasma concentration (C(max)) and the area under the plasma concentration vs. time curves (AUCs) using an anova. The two products were judged to be equivalent if the 90% confidence limits of the ratio of the geometric mean values of C(max) and AUCs fell within the interval of 80-125%. Results from this PKs comparison of two different rFVIII products, using chromogenic substrate assay to measure FVIII:C, showed that ReFacto and Advate are bioequivalent to each other.

Treatment of severe von Willebrand disease with a high-purity von Willebrand factor concentrate (Wilfactin): a prospective study of 50 patients

BACKGROUND AND OBJECTIVES

A plasma-derived von Willebrand factor (VWF) concentrate with low factor VIII (FVIII) content was specifically developed to treat von Willebrand disease (VWD). Efficacy and safety were investigated by merging the results of two comparable protocols conducted prospectively in 5 European and 12 French centers.

METHODS AND RESULTS

Fifty patients with clinically severe VWD (72% had VWF ristocetin cofactor activity less than 10 IU dL(-1) and 46% had FVIII < 20 IU dL(-1)) were treated with the concentrate as the only therapy, except for clinical situations requiring a priming dose of FVIII to rapidly correct an intrinsic coagulation defect. A total of 139 spontaneous bleeding episodes were treated; only 53 (38%) needed a concomitant FVIII dose. Outcome was excellent or good in 89% of the episodes. Forty-four patients underwent 108 surgical or invasive procedures. Outcome was excellent or good in 95 scheduled procedures (only VWF was infused) and 13 emergency procedures (a priming FVIII dose was co-administered with the first VWF infusion). There were no thrombotic complications and none of the 18 patients with type 3 VWD developed anti-VWF or anti-FVIII antibodies.

CONCLUSIONS

This concentrate safely and effectively provides hemostasis in patients with clinically severe VWD.

Impact of Choice of Treatment for Bleeding Episodes on Inhibitor Outcome in Patients With Mild/Moderate Hemophilia A and Inhibitors

Patients with mild/moderate hemophilia A (MHA) may develop inhibitors to factor VIII (FVIII). In this condition, FVIII clotting activity (FVIII:C) baseline levels may remain stable for some patients, but may be reduced to less than 0.01 U/mL for others. Several risk factors for the development of inhibitors in MHA have been proposed. Genetic factors, such as mutations in the FVIII gene, may play a central role; however, other influences, such as intensive treatment with FVIII products, may also be important. Optimal treatment regimens have yet to be determined, not only for the eradication of inhibitors, but also for the management or surgical prophylaxis of hemorrhages associated with this condition. Several treatment options for the control of bleeding in patients with MHA and inhibitors (MHAI) are currently available, and the choice of therapeutic strategy should be given careful consideration; some treatments may produce an anamnestic response, thus delaying the return to FVIII:C baseline levels and adversely affecting the duration of the severe bleeding phenotype. To increase our knowledge of MHAI, a retrospective collection of data is currently being performed among hemophilia centers in France and Belgium. Based on five examples of patients with MHAI collated from preliminary study data, we illustrate the impact on inhibitor outcome of the therapeutic choices used to treat bleeding episodes in these patients.

Recommendations for postmarketing surveillance studies in haemophilia and other bleeding disorders

Prospective surveillance studies to monitor drug safety in the postapproval period are rarely employed systematically, although they are of greatest value for caregivers, drug users and regulatory authorities. Safety issues have affected not only conventional pharmaceuticals, but also especially coagulation factors in haemophilia treatment. The reputation of postmarketing surveillance (PMS) studies has been questionable, mainly due to their misuse to solicit prescriptions. Other weaknesses include inappropriate design, lack of standardized observation, limited follow-up periods, absence of rigour in identifying potential adverse drug effects, and infrequent publication. Although well-designed clinical trials represent the gold standard for generating sound clinical evidence, a number of aspects would make PMS studies valuable, if properly conducted. One of their main advantages is broader inclusion, and absence of an 'experimental' design. Lack of proper guidelines, and standardization may constitute a reason for the generally low quality of PMS studies. This paper proposes guidelines for haemophilia-specific PMS studies, in order to improve the acceptance of a basically valuable tool. In the absence of consistent regulatory guidance it will be especially important that the design and supervision of PMS studies involves physicians from the beginning. This will not only make such studies more scientifically relevant, but also help to implement them into daily clinical practice. Specifically in haemophilia, PMS studies may provide valuable data on clinical outcomes, or Quality of Life, which is of great importance when considering adequate standards of care in haemophilia patients.

Thermodynamic resolution of periosteal reaction and taphonomic change

New bone formation (e.g., periosteal reaction) is one component of bone and joint disease diagnosis. Its application in the archeologic record has been compromised by lack of standardization. An objective technique for validating observations seems especially valuable when visual examination of a single data set results in widely disparate perspectives. Such discrepancies as to presence or absence of periosteal reaction are amenable to objective analysis. Bone, as any other form of matter, has a variety of properties. Some are characterized by weight or volume and are referred to as colligative. Some are related to its intrinsic nature, independent of mass. The latter are referred to as non-colligative. Non-colligative properties of matter provide an opportunity to assess structure, independent of quantity. Study of one such property, entropy, revealed that taphonomic changes can confidently be distinguished from bone surface reaction. Contrasted with the homogeneous entropy of normal bone, the loss of surface bone inherent in taphonomy results in reduced entropy. Contrasted with the homogenous patterns of normal bone, specific non-homogenous patterns allow periosteal reaction to be recognized, independent of variety of periosteal reaction or its origin. Thermographic approach allows observational techniques to be independently validated. Such validation allows for greater facility in interobserver archeologic site sample comparisons.

A blinded in vitro study with Refacto mock plasma samples: similar FVIII results between the chromogenic assay and a one-stage assay when using a higher cephalin dilution

Assay of factor VIII (FVIII) in patient samples is routinely carried out using the one-stage assay rather than the chromogenic substrate assay. The introduction of new FVIII preparations for the treatment of haemophilia A, including immunopurified FVIII and particularly, recombinant FVIII (rFVIII) concentrates, has led to discrepancies between the results obtained with the two assays. In patients treated with rFVIII concentrates, FVIII levels measured with the one-stage assay can be 20-50% lower than those measured with the chromogenic assay. In this study, the one-stage assay was performed with cephalin dilutions higher than those recommended by the manufacturer. B-domain-deleted recombinant FVIII, Refacto, was diluted to eight different concentrations, ranging from 1-100 IU dL(-1), in FVIII-deficient plasma and the FVIII activity of the eight solutions was determined by the chromogenic method in a central laboratory. Aliquots were then assayed by the one-stage method in the four participating laboratories, using different dilutions of CK-Prest. When CK-Prest was reconstituted according to the manufacturer's recommendations (dilution 1 : 1), the difference between the one-stage and chromogenic methods was close to 30%. CK-Prest cephalin dilutions of 1 : 5 and 1 : 8 gave very similar results with the two methods, without increasing the interlaboratory coefficient of variation. These findings confirm the influence of phospholipids on the one-stage assay, particularly the importance of using a phospholipid concentration close to the physiological value in platelets. This modified one-stage method may therefore offer an alternative to the use of a concentrate-specific standard.

Skeletal clues apparently distinguishing Waldenstrom's macroglobulinemia from multiple myeloma and leukemia

This study was conducted to characterize macroscopically and by conventional radiography the bony lesions in a case of Waldenstrom's macroglobulinemia and to compare and contrast it with those of the other major hematologic lymphoproliferative disorders, multiple myeloma and leukemia. Two varieties of lytic skeletal lesions were found in Waldenstrom's macroglobulinemia. One was sharply defined, spheroid lesions with smooth borders and effaced/erased trabeculae. The second was in the form of coalescing pits (holes) with smooth, minimally remodeled edges. The appearance combined features of multiple myeloma and leukemia, but were mutually exclusive in those diseases. Spheroid lesions with effaced edges were absent in leukemia, while pits were absent in multiple myeloma. Fronts of resorption were not noted in Waldenstrom's macroglobulinemia. The combination of some of the features of leukemia and myeloma appear to allow recognition of Waldenstrom's macroglobulinemia.

[Clues to recognition of kidney disease in archaeologic record: characteristics and occurrence of leontiasis ossium]

The possible osseous effect of kidney dysfunction was evaluated in a modern skeletal population for future use in assessment of archaeologic samples. Frequency and distribution on the bones of cysts, articular surface alterations, subperiosteal resorption, porosity, osteochondritis, digital tuft alteration and periosteal reaction were recorded in 94 individuals with known kidney failure in the Hamann-Todd collection. Independent radiologic analysis was also pursued. The results were compared with a control sample. The pattern of joint surface alteration and periosteal reaction may facilitate recognition of chronic renal disease in the osseous record. Subtle manifestations of leontiasis ossium are present in the form of cranial thickening and increased cranial size and weight, but teeth spacing are rare. Pseudo osteomatous lesions are common. This study perhaps explains the apparent rarity of actual leontiasis ossium.

European data of a clinical trial with a sucrose formulated recombinant factor VIII in previously treated haemophilia A patients

To increase the safety of antihaemophilic treatment, the production process of full-length recombinant factor VIII (FVIII) KOGENATE Bayer (Kogenate FS) has been modified. Human albumin is no longer added as stabilizer during purification and in final formulation. Instead, the new KOGENATE Bayer production process uses sucrose as a stabilizer in the formulation and adds solvent/detergent virus inactivation step. An European clinical trial was carried out in Germany and France in previously treated patients with severe haemophilia A who had more than 100 exposure days to exogenous FVIII. Pharmacokinetic data was analysed according to one-stage and chromogenic assays. Efficacy and safety during home therapy and in surgical procedures were evaluated; inhibitor formation was carefully monitored. Safety and efficacy were evaluated in 33 European patients for 24 months. Patients received more than 13 million IU KOGENATE Bayer. Over 75% of patients accrued more than 100 exposure days with the new product. Of 875 bleeding episodes, 90.7% were treated with 1 or 2 infusions and 75.8% of responses to treatment were rated as 'excellent' or 'good'. Prophylactic treatment was the most common mode of therapy (60.7% of infusions). The product was well-tolerated and FVIII recovery studies were consistent throughout the study period. Only 0.26% of adverse events were reported to be drug related. No evidence of de novo inhibitor formation was observed. Overall, KOGENATE Bayer was efficacious, safe and well-tolerated for the treatment of haemophilia A in multitransfused patients.

Comparison of radiological and gross examination for detection of cancer in de-fleshed skeletons

The reliability of visual examination of de-fleshed bones was assessed for detection of postcranial metastatic disease in individuals known to have had cancer. This was compared with standard clinical radiological techniques. The skeletons of 128 diagnosed cancer patients from an early 20th century autopsied skeletal collection (Hamann-Todd Collection) were examined. Radiological examination detected evidence of metastatic disease in 33 individuals, compared to 11 by visual examination of the postcranial skeletons. Four of these cases were detected by both techniques. Blastic lesions were most commonly overlooked on visual examination, because they were localized to trabecular (internal bone) structures. The ilium was the most commonly affected bone, with lytic or blastic lesions detected in 30 out of 33 individuals. While the proximal femur was affected in only nine individuals, X-ray of the proximal femur and ilium detected all individuals with postcranial evidence of metastatic disease. Skeletal distribution of metastases provides no clue to the location of origin or histological subtype of the cancer. A survey of archeological human remains for metastatic cancer requires radiological examination. Such skeletal surveys should X-ray at least the ilia and femora.

Origins of spondyloarthropathy in Perissodactyla

OBJECTIVE

Spondyloarthropathy has clearly been documented as not limited in occurrence to humans. Transmammalian in nature, it is of interest to understand the antiquity, and perhaps the origins, of this disorder in animal groups sufficiently represented in the skeletal record.

METHODS

Fossil and recent skeletons of perissodactylae from North America were systematically examined to determine the occurrence and population frequency of spondyloarthropathy.

RESULTS

Spondyloarthropathy was the most common form of arthritis recognized in the extant and fossil records. Common in extinct families such as Brontotheriidae and Chalicotheriidae, a progressive increase in the frequency of spondyloarthropathy was observed through geologic time in Equidae and Rhinocerotidae.

CONCLUSION

Erosive arthritis of the spondyloarthropathy variety is now documented as not only persisting in Perissodactyla, but as actually increasing significantly in frequency (3-6 fold). Given the unusual evolutionary penetrance of this "disease," the possibility must be considered that its persistence provides evidence for some unknown benefit to the affected host.

Skeletal Manifestations of Leprosy: Analysis of 137 Patients from Different Clinical Settings in the Pre- and Postmodern Treatment Eras

This study was conducted to further characterize the nature of leprosy-related bone alterations, to develop a hypothesis of their pathophysiology, and to define the impact of treatment on bone damage. Radiographs of 60 patients under care at the Carville, Louisiana leprosy hospital were compared with 50 from the early (before availability of effective treatment) part of this century and with 27 from the Toronto (Ontario, Canada) leprosy clinic. Two-thirds of lesions were so severe that distal digital tufts had been lost to whittling, resorption, or fragmentation. Fifty percent were felt to be pathognomonic for the changes of leprosy. Resorption, fragmentation, and malaligned fractures are highly suggestive of leprosy, while diaphyseal whittling appears specific when medullary sclerosis or wavy diaphyseal borders are present. Medicinal intervention appeared to be of limited benefit for bone damage; perhaps greater attention to joint/bone protection (as recommended in diabetes management) will prove helpful. Environmental adjustment to minimize injury risk and daily limb examination for injury are recommended.