Diagnostic challenges in von Willebrand disease. Report of two cases with emphasis on multimeric and molecular analysis

Identification of qualitative variants of von Willebrand disease (VWD) can be a diagnostic challenge because of discrepant results obtained in the multiple laboratory tests available for its appropriate classification. We report two cases of infrequent inherited variants of VWD with unclear preliminary results with the test panel available at the time of first consultation and that were finally diagnosed as a VWD type 2A/IID with a c.8318 G > C, p.Cys2773Ser mutation and a VWD type 2M with c.4225 T > G, p.Val1409Phe mutation, respectively. The description of these two cases highlights that despite the limited diagnostic panel for the evaluation of von Willebrand Factor (VWF) functionality, the multimeric analysis and genetic family studies were fundamental tools to achieve the final diagnosis.

Advanced cell-based modeling of the royal disease: characterization of the mutated F9 mRNA

Essentials The Royal disease (RD) is a form of hemophilia B predicted to be caused by a splicing mutation. We generated an iPSC-based model of the disease allowing mechanistic studies at the RNA level. F9 mRNA analysis in iPSC-derived hepatocyte-like cells showed the predicted abnormal splicing. Mutated F9 mRNA level was very low but we also found traces of wild type transcripts.

SUMMARY

Background The royal disease is a form of hemophilia B (HB) that affected many descendants of Queen Victoria in the 19th and 20th centuries. It was found to be caused by the mutation F9 c.278-3A>G. Objective To generate a physiological cell model of the disease and to study F9 expression at the RNA level. Methods Using fibroblasts from skin biopsies of a previously identified hemophilic patient bearing the F9 c.278-3A>G mutation and his mother, we generated induced pluripotent stem cells (iPSCs). Both the patient's and mother's iPSCs were differentiated into hepatocyte-like cells (HLCs) and their F9 mRNA was analyzed using next-generation sequencing (NGS). Results and Conclusion We demonstrated the previously predicted aberrant splicing of the F9 transcript as a result of an intronic nucleotide substitution leading to a frameshift and the generation of a premature termination codon (PTC). The F9 mRNA level in the patient's HLCs was significantly reduced compared with that of his mother, suggesting that mutated transcripts undergo nonsense-mediated decay (NMD), a cellular mechanism that degrades PTC-containing mRNAs. We also detected small proportions of correctly spliced transcripts in the patient's HLCs, which, combined with genetic variability in splicing and NMD machineries, could partially explain some clinical variability among affected members of the European royal families who had lifespans above the average. This work allowed the demonstration of the pathologic consequences of an intronic mutation in the F9 gene and represents the first bona fide cellular model of HB allowing the study of rare mutations at the RNA level.

Practical aspects of factor concentrate use in patients with von Willebrand disease undergoing invasive procedures: a European survey

INTRODUCTION

The bleeding propensity in von Willebrand disease (VWD) is usually moderate or mild and patients with VWD do not need continuous treatment, but do require extra increased haemostatic cover when undergoing dental or surgical procedures. Desmopressin can be effective in certain patient groups and this has been considered in a previous publication.

AIM

This paper now seeks to evaluate current knowledge and practice in the use of factor concentrate in the management of VWD patients undergoing invasive procedures.

METHODS

A literature search was performed on the use of factor concentrates to cover invasive procedures and a survey of current practice in a number of specialist haematology centres across Europe represented by the European Haemophilia Strategy Board was conducted.

RESULTS

Our review of the literature and the results of the survey showed considerable heterogeneity in treatment regimens, and a lack of consistency in reporting of the variables that determine factor concentrate dosing and monitoring.

CONCLUSION

By analysing the literature, examining guidelines and using consensus deliberation, this survey allowed the group to develop recommendations for management of VWD patients undergoing invasive procedures.

Practical aspects of DDAVP use in patients with von Willebrand Disease undergoing invasive procedures: a European survey

INTRODUCTION

Desamino D-arginine vasopressin (DDAVP or desmopressin) is a useful and effective haemostatic treatment for patients with von Willebrand Disease (VWD). However, there are still issues regarding in which subtypes of VWD DDAVP is appropriate and little consensus on its use in different surgical settings. We also lack information concerning the appropriate laboratory parameters that should be monitored.

AIM

The European Haemophilia Therapy Strategy Board (EHTSB) wished to investigate published information and clinical use of DDAVP in VWD patients.

METHODS

We conducted a literature survey on management of VWD during surgical interventions and undertook a survey of specialist haematologist centres across Europe to assess current management of VWD patients.

RESULTS

DDAVP is ineffective in type 3 VWD and its use in type 2B remains controversial due to the possibility of thrombocytopenia. It can, however, be used effectively to cover minor surgery and dental procedures in most other VWD patients. For major surgery there is wider use of factor concentrate in preference to DDAVP depending on the subtype of VWD. We give consensus recommendations on the use of DDAVP for surgical interventions in VWD including laboratory parameters that denote an adequate response and contraindications to its use.

CONCLUSIONS

DDAVP can be recommended to cover invasive procedure in selected patients with VWD, however, we need more information and systematic recording of adverse events associated with DDAVP use in VWD. A companion paper will be published covering the use of factor concentrates in VWD patients.

Adherence to prophylaxis and quality of life in children and adolescents with severe haemophilia A

Treatment adherence in adolescents with chronic diseases is around 50%, and failure is more common in preventive therapy. In haemophilia, contradictory results are reported by the published studies. The objective of this study was to evaluate adherence with factor VIII (FVIII) prophylaxis in Spanish patients with severe haemophilia A between age 6 and 20 years. Data were collected retrosp-ectively in the previous 2 years. The primary endpoint was the absolute adherence index (AAI), and the endpoints were related to clinical status, age, prophylaxis regimen, responsibility for factor administration and quality of life (QoL), assessed by the Haemo-QoL questionnaires. A total of 78 patients from 14 Spanish hospitals were recruited. Adherence ranged between -64.4 and 66.7 (mean -3.08). No differences were observed between children and adolescents (7.11 vs. 6.39; P = 0.809). A statistically significant association (P < 0.010) between infra adherent group and target joint was found, as was a statistically significant difference (P < 0.010) between the number of bleeding episodes experienced by the adherent group (mean 1.4) and by infra adherents (mean 4.5). There was no significant difference between AAI and prophylactic regimen (6.35 vs. 6.96, P = 0.848), neither between AAI and the person responsible for factor administration (5.57 vs. 8.79, P = 0.326). The Haemo-QoL scores (8-12 years) were related to adherence level (P < 0.05). Adherence was approximately ideal and patients perceived a high QoL. Because of the repercussions for compliance, it is essential to work during puberty on emotional and self-acceptance aspects of the disease, as well as coping, and the patient's family, school and health team relationships.

International cross-cultural validation study of the Canadian haemophilia outcomes: kids' life assessment tool

Health-related quality of life (HRQoL) assessment is recognized as an important outcome in the evaluation of different therapeutic regimens for persons with haemophilia. The Canadian Haemophilia Outcomes-Kids' Life Assessment Tool (CHO-KLAT) is a disease-specific measure of HRQoL for 4 to 18-year-old boys with haemophilia. The purpose of this study was to extend this disease-specific, child-centric, outcome measure for use in international clinical trials. We adapted the North American English CHO-KLAT version for use in five countries: France, Germany, the Netherlands, Spain and the United Kingdom (UK). The process included four stages: (i) translation; (ii) cognitive debriefing; (iii) validity assessment relative to the PedsQL (generic) and the Haemo-QoL (disease-specific) and (iv) assessment of inter and intra-rater reliability. Cognitive debriefing was performed in 57 boys (mean age 11.4 years), validation was performed in 144 boys (mean age 11.0 years) and reliability was assessed for a subgroup of 64 boys (mean age 12.0 years). Parents also participated. The mean scores reported by the boys were high: CHO-KLAT 77.0 (SD = 11.2); PedsQL 83.8 (SD = 11.9) and Haemo-QoL 79.6 (SD = 11.5). Correlations between the CHO-KLAT and PedsQL ranged from 0.63 in Germany to 0.39 in the Netherlands and Spain. Test-retest reliability (concordance) for child self-report was 0.67. Child-parent concordance was slightly lower at 0.57. The CHO-KLAT has been fully culturally adapted and validated for use in five different languages and cultures (in England, the Netherlands, France, Germany and Spain) where treatment is readily available either on demand or as prophylaxis.

The study of the effect of splicing mutations in von Willebrand factor using RNA isolated from patients' platelets and leukocytes

BACKGROUND

In von Willebrand factor (VWF) the effect of mutations potentially affecting mRNA processing or splicing is less predictable than that of other mutations (e.g. nonsense or missense substitutions). Bioinformatic tools can provide a valuable means to determine the consequences of potential splice site mutations (PSSM), but functional studies are mandatory to elucidate the true effect of the variation detected.

OBJECTIVES, PATIENTS AND METHODS

After identification of PSSM in VWD patients, we began a systematic study of their in vivo effect in RNA extracted from the patients' platelets and leukocytes.

RESULTS AND CONCLUSIONS

Thirteen pairs of primers were designed for full amplification of VWF mRNA by RT-PCR that, after sequencing of aberrant products, enabled elucidation of the PSSM consequences for mRNA processing. This procedure was used to study seven different PSSM identified in four patients demonstrating diverse molecular mechanisms such as exon skipping (c.533-2A>G and c.8155+3G>C) and the activation of a cryptic splice site (c.7730-1G>C). No visible effect was evident for c.1533+15G>A and c.5170+10C>T and the consequence of c.[546G>A;7082-2A>G] was hidden by nonsense-mediated mRNA decay (NMD). Results were compared with in silico predictions of four splice-site analysis tools. We demonstrate selective degradation of VWF mRNA bearing PSSM by NMD for several mutations, which suggests that NMD represents a general mechanism for truncating mutations in VWF. Furthermore, because NMD efficiency varies between cell types, use of RNA from both platelets and leukocytes for in vivo study of VWF PSSM offers complementary results, particularly in cases in which NMD occurs in the allele carrying the mutation.

Non-genetic risk factors and the development of inhibitors in haemophilia: a comprehensive review and consensus report

SUMMARY

The development of inhibitors to the infused factor in patients with haemophilia is a serious clinical problem. Recent evidence suggests that alongside the strong genetic contribution to inhibitor formation, there are a number of non-genetic factors--perceived by the immune system as danger signals--which promote formation of inhibitors. This study provides a comprehensive review of clinical studies relating to these factors and also presents a survey of opinion concerning their importance and clinical influence, conducted among the members of the European Haemophilia Treatment Standardisation Board (EHTSB). Taken together, this information highlights the lack of robust data concerning the influence of several non-genetic risk factors on inhibitor development, and an urgent need for prospective, well-conducted studies that adhere to recommendations made by the European Medicines Agency (EMEA) for studying inhibitors. Based on current literature, the EHTSB formulated consensus recommendations. It is desirable to minimize intensive treatment wherever possible, given the clinical situation. Prophylaxis should be offered to all children, although we still need to determine optimal dosing with respect to inhibitor development, and age for starting treatment. Vaccinations should be given subcutaneously and concomitant factor concentrate infusions avoided. According to the board, there is no evidence in the literature supporting suggestions that the type of concentrate influences inhibitor risk; but all patients should be monitored during their first exposures. Furthermore, there is no evidence to support an association between pregnancy-related issues, breast feeding and treatment-related factors (e.g. route of administration, or use of blood components) and inhibitor development.

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.

Prophylactic treatment of haemophilia patients with inhibitors: clinical experience with recombinant factor VIIa in European Haemophilia Centres

Many patients with haemophilia develop inhibitors to factor VIII and require bypassing agents to provide haemostatic cover for limb- or life-threatening bleeding episodes. Due to the reduced risk of blood-borne pathogen transmission with recombinant products, on-demand recombinant factor VIIa (rFVIIa; NovoSeven is the treatment of choice for children with inhibitors. In haemophiliac patients without inhibitors, primary prophylaxis has been clinical practice for several years. This paper summarises 13 case histories of rFVIIa secondary prophylaxis for haemophilia patients with inhibitors. This was a retrospective survey of adult and paediatric severe haemophilia patients with inhibitors treated with rFVIIa from ten European Haemophilia Centres. There was a wide variation in administered rFVIIa dose, from 200-250 microg kg(-1) per week to 220 microg kg(-1) daily. In many cases, this was lower than the recommended on-demand dose of rFVIIa. In 12/13 cases, prophylaxis with rFVIIa considerably reduced the number of bleeding episodes compared with previous treatment. Eight/nine patients were satisfied or very satisfied with rFVIIa treatment, and in cases reporting subjective quality of life (QoL), all were improved, much improved, or significantly improved. In haemophilia patients with inhibitors, prophylaxis with rFVIIa is highly effective in reducing the number of bleeding episodes and results in good patient compliance and improved QoL. Randomised controlled trials are needed to confirm these findings. Results of a recently completed clinical trial on secondary prophylaxis with rFVIIa in frequently bleeding haemophilia patients with inhibitors are expected in late 2006.

Continuous infusion of B-domain deleted recombinant factor VIII (ReFacto) in patients with haemophilia A undergoing surgery: clinical experience

This retrospective, open-label, non-comparative study evaluated continuous infusion of recombinant factor VIII (ReFacto), B-domain deleted recombinant FVIII (BDDrFVIII), in patients with haemophilia A undergoing surgery and requiring >5 consecutive days of treatment. Sixteen patients from eight centres underwent a total of 20 procedures. Haemostatic outcome was assessed as 'excellent' or 'good' in 75% of procedures, and target FVIII:C levels were maintained throughout the continuous infusion period. The reported volume of blood loss during surgery was also within the normal range for non-haemophilic patients for the type of surgery performed. Red blood cell transfusions were required to balance excessive blood loss during BDDrFVIII continuous infusion in eight (40%) procedures (seven patients), five with bleeding or requiring volume replacement and three to treat anaemia secondary to blood loss. Non-serious adverse events considered by investigators as possibly or probably related to BDDrFVIII continuous infusion were infrequent (n = 5) considering the duration of treatment (n =239 cumulative days of continuous infusion), and all of these were mild-to-moderate in severity. No thromboembolic complications were reported except for one case of thrombophlebitis occurring at the infusion site. Only two patients (four events) experienced serious adverse bleeding; BDDrFVIII was otherwise well-tolerated. These data show that continuous infusion of BDDrFVIII provides reliable haemostasis and is an effective and well-tolerated regimen for patients with haemophilia A undergoing surgery.

Development of a new disease-specific quality-of-life questionnaire to adults living with haemophilia

A haemophilia-specific health-related quality-of-life questionnaire (named 'Hemofilia-QoL') was developed to assess quality-of-life in adults with haemophilia, and was psychometrically tested. Seventy-three interviews with haemophilia patients and health care professionals were used to generate the items included in the questionnaire, and expert ratings on the items formulated were used to screen them for potential omission. This was followed by psychometric testing in a sample of 35 patients. Preliminary psychometric testing of the revised questionnaire version, which contains 10 domains (physical health, physical role, joint damage, pain, treatment satisfaction, emotional role, mental health, social support), showed acceptable reliability (alpha = 0.94 for the Hemofilia-QoL total score) and validity, and this will be examined in a subsequent study with a larger patient sample.

Prevalence and genetic heterogeneity of the reverse transcriptase T69S-S-X insertion in pretreated HIV-infected patients

The emergence of resistance to antiretroviral drugs represents one of the main reasons for treatment failure in HIV-infected persons. Resistance to multiple nucleoside analogues may result from rearrangements in the HIV pol gene, in particular one insertion of two amino acids at position 69. Herein, we examined the prevalence of this resistant genotype and its genetic heterogeneity in a group of 475 healthy pretreated HIV-positive subjects in Spain. Only 4 (0.8%) carried the codon 69 insertion. It was always found coupled to the T69S mutation. The extra amino acids were S-S in 2 subjects and S-G in the other 2. The presence of the insert was seen only in subjects previously exposed to AZT monotherapy for at least 6 months.

Interferon and ribavirin combination therapy for chronic hepatitis C in human immunodeficiency virus-infected patients with congenital coagulation disorders

We have conducted an open, prospective trial to assess the safety and efficacy of interferon alfa-2b and ribavirin in combination for the treatment of chronic hepatitis C in human immunodeficiency virus (HIV)-infected hemophiliacs. Twenty hemophiliacs coinfected with HIV and hepatitis C virus (HCV), 18 of them under highly active antiretroviral therapy (HAART), with a mean CD4(+) cell count of 490 +/- 176 cells/mm(3) and undetectable (n = 9) or low-level HIV RNA (<10,000 copies/mL; n = 11), were treated with interferon-alfa2b (3 MU thrice weekly) and ribavirin (800 mg/d) for 6 or 12 months according to virologic response. Patients were monitored for tolerance and response at 4, 8, 12, 24, 36, and 48 weeks during treatment and every other month thereafter. All 20 patients enrolled completed at least 6 months of treatment with no major side effect requiring treatment withdrawal, dose reduction, or modification of HAART. Overall, 8 patients (40%) achieved a sustained virologic response at the end of the 6-month post-treatment follow-up. Sustained responders had lower baseline HCV-RNA levels (5.7 +/- 0.8 vs. 6.3 +/- 0.4 log10 IU/mL, P =.041) but were otherwise similar to nonresponders. All sustained responders had a decrease in HCV-RNA level of at least 1 log per month during the first 2 months and undetectable levels at 6 months. In conclusion, our results provide evidence that combination therapy with interferon and ribavirin is safe in HIV-infected hemophiliacs with stable CD4 cell count and undetectable or low-level HIV replication, and leads to eradication of HCV in 40% of these patients.

Recombinant factor VIIa (Novoseven) restores deficient coagulation: experience from an ex vivo model

The action of recombinant factor VIIa (rFVIIa) in coagulation deficiencies with increased risk of bleeding was investigated using in vitro perfusion. Blood samples were drawn from healthy donors, a patient with hemophilia A and inhibitors, and six patients undergoing oral anticoagulant treatment. Fragmin 10 U/mL was used as anticoagulant. rFVIIa (10 microg/mL in plasma) was added to blood samples, incubated for 1 minute at 37 degrees C, and perfusion studies performed for 10 minutes at 600 x s(-1) through annular chambers containing damaged vascular segments. Subendothelial fibrin and platelets were expressed as a percentage of subendothelial surface screened. Under different conditions, rFVIIa consistently restored or improved fibrin formation on the damaged vascular subendothelium exposed to circulating blood. It restored fibrin deposition in blood from the hemophilia A patient; in patients undergoing acenocoumarol treatment, it reduced the international normalized ratio (INR) from 2.47 to 1.25 with a significant increase in fibrin deposition. Platelet deposition varied slightly between clinical conditions but was less evident in the hemophilia A patient. These data support the concept that rFVIIa facilitates fibrin formation in these clinical situations, promoting procoagulant activity at sites of vascular damage where tissue factor is exposed. This could improve hemostasis in patients with hemophilia A and inhibitors, and in patients treated with oral anticoagulants.

Influence of von Willebrand factor on the reactivity of human factor VIII inhibitors with factor VIII

In order to determine the difference in reactivity of factor (F) VIII inhibitors against the FVIII/von Willebrand factor (vWF) complex and against vWF-deficient FVIII, we investigated a panel of 10 antibodies to FVIII from multitransfused individuals with severe haemophilia A and other pathologies. Immunoblotting of purified FVIII and purified thrombin-cleaved FVIII revealed that in all cases inhibitor epitopes could be localized in the heavy chain (A2 subunit) while in four cases they were also present in the light chain. One of the FVIII inhibitors remained unclassified. The effect on FVIII:C of purified IgG from inhibitor plasmas was tested against a high purity FVIII/vWF concentrate and a monoclonally purified FVIII concentrate with only trace contents of vWF, by two different functional assays. Our results suggest that for those inhibitors showing A2 plus light chain (LC) reactivity, the IgG concentration required to inhibit 50% of FVIII activity in vitro is higher for the FVIII/vWF complex than for the vWF-deficient FVIII. We conclude that there might be a protective role of vWF (at least in vitro) against FVIII inhibitors with A2 and LC subunit specificity.

Incidence of factor VIII inhibitors in severe haemophilia: the importance of patient age

The potential effect of age at the start of replacement therapy on the development of factor VIII (FVIII) inhibitors was assessed in 62 severe (FVIII < 2 IU/dl) haemophilia A patients who started FVIII therapy at one of two haemophilia centres. Inhibitors were tested on an annual basis. Persistent or high-titre inhibitors were detected in 15 patients (24%). Kaplan-Meier cumulative incidence at 3 years from first FVIII exposure was 41% (95% CI 22-67%) in patients starting therapy before the age of 6 months, 29% (95% CI 13-57%) in patients starting therapy between 6 and 12 months of age, and 12% (95% CI 4-34%) in those starting therapy beyond 1 year of age (P = 0.03). By multivariate analysis, the influence of age was shown to be independent of other variables, including calendar year at the onset of therapy and baseline FVIII plasma levels. In conclusion, patient age at initial treatment appears to influence inhibitor formation. If confirmed, this finding would have a major impact on the management of haemophilia.

Rapid hemophilia A molecular diagnosis by a simple DNA sequencing procedure: identification of 14 novel mutations

We here describe a simple, efficient DNA sequencing procedure for hemophilia A molecular diagnosis. In severe patients we first test for the presence of factor VIII gene intron 22 inversion using a recently described single-tube PCR method. In moderate, mild, or inversion-negative severe patients we systematically sequence the promoter, all exons and splice junctions of factor VIII gene. Specially designed primers allow amplification of 23 PCR products under the same salt conditions and thermocycling parameters. The whole sequencing procedure, from blood extraction to mutation identification, can be readily done within 42 h when using regular instruments or in just 14 h when using a high-throughput sequencer. Thus, this is a versatile and cost-effective strategy with little hands-on time requirements. Since its implementation we have identified mutations in 45/46 hemophilia A patients, 14 of which are novel. Once the genetic defect has been identified, accurate genetic counseling is then easily performed.

Factor IX gene sequencing by a simple and sensitive 15-hour procedure for haemophilia B diagnosis: identification of two novel mutations

We have developed a simple, sensitive and cost-effective direct DNA sequencing procedure for the molecular diagnosis of haemophilia B. All factor IX gene essential regions were amplified under identical thermocycling parameters allowing mutation identification in less than 15 h from blood sample collection. Identical results in terms of accuracy and speed were obtained when using a single hair as the source of DNA. Using this approach, we have found mutations in 10 out of 10 haemophilia B patients, two of which are novel (P287T and S123C). Very suitable for individual studies, this procedure can be easily scaled up for higher throughput.

Treatment with interferon plus ribavirin in anti-HIV negative patients with congenital coagulation disorders and chronic hepatitis C

BACKGROUND

Hepatitis C virus (HCV) infected hemophiliacs respond at low rate to interferon (IFN) monotherapy.

AIMS

To assess efficacy of IFN and RBV in HIV negative hemophiliacs with chronic hepatitis C and identify early predictive factors of response.

METHODS

Twenty naive patients were treated with interferon and RBV for twelve months. Response was assessed by both serial ALT and HCV RNA levels.

RESULTS

Normalization of ALT with clearance of HCV RNA occurred in seven (35%) patients. Age and age at infection were the only features associated with a higher likelihood of response. In all responders the viral load had decreased by at least one log within two months of starting treatment.

CONCLUSIONS

Combination of interferon and ribavirin is well tolerated by hemophiliacs who achieve similar sustained response rates to non-hemophiliacs. Quantitative assessment of viral load at two months of treatment is a useful method to identify non-responders at an early stage.

Evaluation of the putative role of C-C chemokines as protective factors of HIV-1 infection in seronegative hemophiliacs exposed to contaminated hemoderivatives

BACKGROUND

Overproduction of beta-chemokines and genetic variations in chemokine receptors have been correlated with protection against infection by HIV-1 or slow progression to AIDS in infected individuals.

STUDY DESIGN AND METHODS

The protective role of chemokines and their receptors was evaluated in a group of seven uninfected (seronegative) hemophiliacs transfused with hemoderivatives presumably contaminated with HIV-1. This group was compared to a group of seven infected (seropositive) hemophiliacs and a group of healthy donors (controls). The CD4+ cell count, intracellular cytokine levels, beta-chemokine levels in plasma, beta-chemokine production by PBMNCs, and expression of chemokine receptors CCR5 and CXCR4 in CD4+ cells were evaluated. The occurrence of protective genotypes in CCR5, CCR2b, and SDF-1 (stromal cell-derived factor 1) genes and susceptibility to infection by HIV-1 were also studied.

RESULTS

Significant differences in the production and plasma levels of beta-chemokines among the three groups were not detected. Lower IL-2 and IFN-gamma production was observed in the uninfected exposed hemophiliacs than in the controls. Genetic analysis of CCR5, CCR2b, and SDF-1 showed several polymorphisms associated with resistance in some HIV-exposed uninfected hemophiliacs. However, these genetic features cannot explain the protection of all exposed hemophiliacs. In fact, only one patient, carrying two copies of CCR5 from which 32 bp was deleted, showed low CCR5 expression and low susceptibility to infection by a CCR5-using HIV-1 strain. In contrast, PBMNCs from all other individuals supported infection in vitro by both CCR5- and CXCR4-using HIV-1 strains.

CONCLUSION

It is not possible to assign to beta-chemo-kines and polymorphisms in chemokine receptors a central role in preventing HIV-1 infection. Natural protection against HIV-1 infection is likely to be due to a multiplicity of factors.

Dynamics of dominance of a dipeptide insertion in reverse transcriptase of HIV-1 from patients subjected to prolonged therapy

A small proportion (0.8%) of individuals of a cohort of HIV-1 infected patients subjected to prolonged therapy with nucleoside analogues included a recently recognised dipeptide insertion in their RT (Ser-Ser or Ser-Gly between RT codons 69 and 70). To study the dynamics of dominance of genomes with this genetic change, sequential HIV-1 isolates from two patients were analyzed with regard to consensus sequences and complexity of mutant spectra. The two patients displayed completely different, complex evolutionary patterns leading to temporary dominance of dipeptide insertions. In one patient, a virus very closely related to an ancestor virus from the same patient overtook the population at late times, displacing genomes encoding a Ser-Ser insertion. In another patient the sequential dominance of genomes with Ser-Ser insertion-->no insertion-->Ser-Gly insertion was observed. These three types of genomes coexisted in the mutant spectrum of one HIV-1 isolate. Complexity was also reflected in the shape of phylogenetic trees derived with genomes from the mutant spectrum at each time point. The results suggest that HIV-1 genomes encoding a dipeptide insertion between RT codons 69 and 70 do not show a clear selective advantage over other genomes lacking the insertion. Such an absence of a clear selective advantage will favor that such genomes encoding this RT insertion become dominant only in a transient fashion, and following disparate kinetics in different patients.

Hepatitis G virus infection markers (RNA and anti-E2 antibodies) in a multicenter cohort of hemophiliacs

BACKGROUND AND OBJECTIVE

To investigate the prevalence and evolution of hepatitis G virus (HGV) infection in hemophiliacs and to correlate evolution of HGV infection markers with immunologic parameters in those patients co-infected with HIV.

DESIGN AND METHODS

HGV RNA and anti-E2 antibodies were studied in 124 patients. Serial samples were drawn every 4 months from 1992 to 1996. Lymphocyte subsets including T-helper lymphocytes, T-suppressor lymphocytes, T-cytotoxic lymphocytes, activated T-lymphocytes and natural killer cells were analyzed.

RESULTS

Prevalences were 22.6% for HGV RNA and 18.5% for anti-E2. Four patients had both HGV RNA and anti E2, so the overall prevalence of HGV infection in hemophiliacs was 37.9% (11.5% in 200 controls, p<0.0001). After a median follow-up of 36.6 months 20 patients remained HGV RNA positive, whereas HGV RNA had cleared in 8, with an actuarial probability of clearance at 36 months of 34.6%. Only 2 patients developed anti-E2 antibodies. Four patients cleared anti-E2, with an actuarial probability at 36 months of 24.8%. In patients with HIV infection, both lower CD4+ lymphocyte count (p=0.01) or higher CD8+ lymphocyte count (p=0.03) showed predictive value for probability of clearing HGV-RNA. CD4+/CD8+ ratio (p=0.002) was the only variable included in the best model for HGV-RNA disappearance.

INTERPRETATION AND CONCLUSIONS

A more accurate estimation of the prevalence of HGV infection can be achieved with the determination of both HGV RNA and anti-E2. Anti-E2 response can be undetectable or transitory after disappearance of HGV-RNA, giving therefore rise to the possibility of underestimating HGV prevalence with currently diagnostic methods. In HIV-positive patients, cellular immune function seems to be involved in the resolution of HGV infection, following the significant correlation found between clearance of HGV-RNA and CD4+/CD8+ lymphocyte populations.

Recombinant factor VIIa in continuous infusion during central line insertion in a child with factor VIII high-titre inhibitor

Recombinant factor VIIa (rFVIIa) is a recently added new tool for the treatment of haemophilia patients with inhibitors. A major drawback in the use of rFVIIa is its short half-life, which necessitates frequent bolus injections. Thus the use of rFVIIa in continuous infusion appears to be a good alternative. We describe the use of rFVIIa, administered by continuous infusion with a minipump during the insertion of a central venous catheter in a child with a high-titre factor VIII inhibitor. rFVIIa was administered as an intravenous bolus (90 micrograms kg-1 [4.5 kIU kg-1]), 1 h prior to central line insertion, after which the continuous infusion was immediately started for 5 days. The infusion rate was based on the clearance obtained from a previous pharmacokinetic study. Effective haemostasis and normal healing of surgical incisions were achieved after central line insertion. No local thrombophlebitis nor evidence of generalized activation of the coagulation cascade was observed. Single-dose pharmacokinetic parameter values were clearance (Cl) 34.6 mL h-1 kg-1, volume of distribution (Vd) 40.6 mL kg-1 and mean residence time (MRT) 1.17 h. The recovery was 2.27% U-1 kg-1. rFVIIa showed a monophasic decay. Cl during continuous infusion was 23.4 +/- 6.9 mL h-1 kg-1. The administration of rFVIIa by continuous infusion is effective, safe and more convenient when compared to other clotting factors. Moreover, continuous infusion provides significant economic savings (77% decrease in rFVIIa requirements).

Factor VIII gene inversions in severe hemophilia A: results of an international consortium study

Twenty-two molecular diagnostic laboratories from 14 countries participated in a consortium study to estimate the impact of Factor VIII gene inversions in severe hemophilia A. A total of 2,093 patients with severe hemophilia A were studied; of those, 740 (35%) had a type 1 (distal) factor VIII inversion, and 140 (7%) showed a type 2 (proximal) inversion. In 25 cases, the molecular analysis showed additional abnormal or polymorphic patterns. Ninety-eight percent of 532 mothers of patients with inversions were carriers of the abnormal factor VIII gene; when only mothers of nonfamilial cases were studied, 9 de novo inversions in maternal germ cells were observed among 225 cases (approximately 1 de novo maternal origin of the inversion in 25 mothers of sporadic cases). When the maternal grandparental origin was examined, the inversions occurred de novo in male germ cells in 69 cases and female germ cells in 1 case. The presence of factor VIII inversions is not a major predisposing factor for the development of factor VIII inhibitors; however, slightly more patients with severe hemophilia A and factor VIII inversions develop inhibitors (130 of 642 [20%]) than patients with severe hemophilia A without inversions (131 of 821 [16%]).

An association between clotting factor concentrates use and mortality in human immunodeficiency virus-infected hemophilic patients

There is much evidence that clotting factor concentrates (CFC), especially the so-called intermediate-purity preparations, exert an immunomodulating effect in vitro. The impact of this effect on the outcome of human immunodeficiency virus (HIV) infection in hemophiliacs is still controversial. In this retrospective cohort study, the effects of treatment with CFC on mortality and progression to acquired immunodeficiency syndrome (AIDS) were estimated while controlling for individual risk factors. Logistic regression and survival analysis, including the Cox proportional-hazards regression model, were performed with data from a 11-year follow-up of 225 hemophilic patients seropositive for HIV type 1 (HIV-1) of two hemophilia centers. Mortality and progression to AIDS rates were strongly associated with lower administration of CFC. After adjusting for age, a statistically significant and robust association was observed. The use of CFC was negatively associated with progression to AIDS (P = .0252) and mortality (P = .0033). The adjusted relative hazards of mortality and progression to AIDS rate between the most treated patients (> 700 IU/kg/yr) versus the least treated (< or = 700 IU/kg/yr) were 0.53 (confidence limits, 0.33 to 0.86) and 0.57 (0.39 to 0.84), respectively. Although the effects of other unmeasured risk factors cannot be excluded with certainty, these results suggest that there is a negative association between treatment with CFC and progression to AIDS and mortality.

Hemophilic pseudotumor: multicenter experience over a 25-year period

Pseudotumor is an infrequent manifestation of bleeding diathesis seen in hemophiliacs, the management of which is still controversial. To ascertain the effectiveness of the main therapies of choice, we have reviewed 1,831 patients affected by hemophilias A (1,108) and B (172), von Willebrand's disease (329), and other miscellaneous coagulopathies (222) diagnosed between 1965 and 1990 in a multicentric, retrospective study. Pseudotumor was proven in 21 patients. Replacement therapy was given in 15 cases as the first therapeutic approach, with complete success attained in only two, whereas surgery, which was carried out in 14 patients, completely resolved the process in eight (P = 0.017). Patients over 40 years of age demonstrated worse prognosis than younger patients (P = 0.02), but no other clinical parameters were shown to have influenced the patients' evolution. Surgical management was the most effective treatment for pseudotumor, although more conservative therapies cannot be overlooked in selected cases.