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    P. Strengers

    Afdeling Klinische Chemie en Laboratoriumgeneeskunde (AKCL
    The public health implications of hepatitis E virus (HEV) in Europe have changed due to increasing numbers of hepatitis E cases and recent reports of chronic, persistent HEV infections associated with progression to cirrhosis in... more
    The public health implications of hepatitis E virus (HEV) in Europe have changed due to increasing numbers of hepatitis E cases and recent reports of chronic, persistent HEV infections associated with progression to cirrhosis in immunosuppressed patients. The main infectious risk for such immunosuppressed patients is exposure to undercooked infected pork products and blood transfusion. We summarised the epidemiology of HEV infections among blood donors and also outlined any strategies to prevent transfusion-transmitted HEV, in 11 European countries. In response to the threat posed by HEV and related public and political concerns, most of the observed countries determined seroprevalence of HEV in donors and presence of HEV RNA in blood donations. France, Germany, Spain and the United Kingdom (UK) reported cases of transfusion-transmitted HEV. Ireland and the UK have already implemented HEV RNA screening of blood donations; the Netherlands will start in 2017. Germany and France perfor...
    Of 52 patients fulfilling the criteria of chronic inflammatory demyelinating polyneuropathy, 20 (38%) did not improve after intravenous immunoglobulin treatment, two (4%) had a short-lasting improvement and subsequent infusions had no... more
    Of 52 patients fulfilling the criteria of chronic inflammatory demyelinating polyneuropathy, 20 (38%) did not improve after intravenous immunoglobulin treatment, two (4%) had a short-lasting improvement and subsequent infusions had no effect, nine (17%) reached a spontaneously or therapeutically induced complete remission, and 21 patients (40%) needed intermittent infusions to maintain improvement. All patients who improved initially had symptoms that significantly interfered with life-style. After treatment, 90% of these patients were independent in their daily activities. Significantly associated with improvement were disease duration of less than 1 year, progression of weakness until treatment, absence of discrepancy in weakness between arms and legs, areflexia of the arms, and slowed nerve conduction velocity of the motor median nerve. The probability of improvement if all these features are present in 93%.
    The development of antibodies to factor VIII (inhibitors) in response to clotting-factor concentrates administration in hemophilia is common during the first few years of treatment but rare in multitransfused patients. We have... more
    The development of antibodies to factor VIII (inhibitors) in response to clotting-factor concentrates administration in hemophilia is common during the first few years of treatment but rare in multitransfused patients. We have investigated the possible association of a recently introduced factor VIII concentrate (Factor VIII CPS-P) in The Netherlands with the occurrence of inhibitors. To this effect, we conducted two studies. First, we performed a national multicenter study in which clinical information and inhibitor test results were obtained for 447 hemophilia A patients over the period 1988 through 1991. Secondly, for a baseline comparison we estimated the frequency of inhibitor development in a closely followed cohort of 144 patients, from 1984 through 1989. Before the introduction of Factor VIII CPS-P, the incidence of new inhibitors was 4.4/1,000 patient-years in the national study from March 1988 through May 1990, and 3.9/1,000 patient-years in the cohort followed from 1984 t...
    Background and Objectives Plasma pools for the production of human plasma medicinal products are distinguished according to the collection method (recovered or apheresis plasma) and the donor remuneration status. National regulations and... more
    Background and Objectives Plasma pools for the production of human plasma medicinal products are distinguished according to the collection method (recovered or apheresis plasma) and the donor remuneration status. National regulations and the physical status of the donor determine the donation frequency and plasma volume per session. Relevant protein contents of different types of pools have not fully been compared. Materials and Methods We compared the levels of total protein, 15 main relevant plasma protein markers, and anti-B19 and anti-Streptococcus pneumoniae IgG in single-type pools of donations from different countries (Belgium, Finland, France, the Netherlands, Germany, United States). Both recovered plasma from non-remunerated donors and apheresis plasma from remunerated and non-remunerated donors were studied. Results Pools from paid US high-frequency, high-volume plasmapheresis donors showed significantly lower total protein ()9%), albumin ()15%), total IgG ()24%), IgM ()2...
    In the routine production of a factor VIII concentrate (produced by adsorption of contaminating proteins in cryoprecipitate to controlled-pore silica and concentration of the factor VIII effluent by ultrafiltration) the terminal dry-heat... more
    In the routine production of a factor VIII concentrate (produced by adsorption of contaminating proteins in cryoprecipitate to controlled-pore silica and concentration of the factor VIII effluent by ultrafiltration) the terminal dry-heat treatment has been replaced by pasteurization in the liquid state. High effectivity of this procedure with respect to virus inactivation was demonstrated using a variety of both lipid- and protein-enveloped model viruses, including HIV. Pair-wise quality control of dry-heated and pasteurized product revealed no significant differences, except in the composition of the formulation buffer. In a clinical study in which 17 patients with haemophilia A participated the pasteurized product was well tolerated and in vivo recovery and half-life of factor VIII were in the same (normal) range as found for the dry-heated counterpart.
    OBJECTIVE To corroborate results obtained in The Netherlands with PPSB-SD, showing a safe acute reversal of anticoagulation within 15 minutes of administration. MATERIAL AND METHODS PPSB-SD is a concentrate prothrombin complex containing... more
    OBJECTIVE To corroborate results obtained in The Netherlands with PPSB-SD, showing a safe acute reversal of anticoagulation within 15 minutes of administration. MATERIAL AND METHODS PPSB-SD is a concentrate prothrombin complex containing a relatively constant high level of vitamin K-dependant coagulation factors II, VII, IX and X. PPSB-SD was administered to 14 patients treated with oral anticoagulants, according the patient's weight, the initial and the target INR (< 2.0 for moderate haemorrhage and abdominal surgery, or < 1.5 for severe haemorrhage and cardio-vascular interventions). INR values were measured with the Coagucheck Pro (Roche Diagnostics) upon admission and at 15 minutes, 1, 3 and 5 hours after treatment, and confirmed by the hospitals' laboratory. RESULTS Within 15 minutes 11 patients out of 12 reached their INR target (data were missing for 2 patients). INR decreased rapidly, then remained stable for the next 5 hours. All patients had a favourable outc...
    RATIONALE: From the early 70’s, C1 inhibitor concentrate manufactured from pooled human plasma has been available to patients with hereditary and acquired angioedema (HAE and AAE) and in 1997 a highly purified C1 inhibitor (Cetor®) was... more
    RATIONALE: From the early 70’s, C1 inhibitor concentrate manufactured from pooled human plasma has been available to patients with hereditary and acquired angioedema (HAE and AAE) and in 1997 a highly purified C1 inhibitor (Cetor®) was introduced. Many precautions have been taken to minimize the potential risk of viral transmission (e.g. rigorously controlled whole blood collection systems, extensive screening of each individual donation for a variety of blood-borne viruses, pasteurisation). To further minimize the potential risk of viral transmission, a 15 nm filtration was implemented in the manufacturing process giving rise to C1-inhibitor-N (anofiltered). DESIGN: A randomised, double-blind, controlled cross-over phase II study was conducted in which our primary objective was to compare the pharmacokinetics of the newly developed concentrate with conventional C1-inhibitor concentrate in HAE patients without signs of an attack of angioedema. Secondly, an open-label phase III study...
    AAFACT, a monoclonal purified, solvent/detergent treated human plasma-derived coagulation factor VIII concentrate obtained from plasma of voluntary, non-remunerated blood donors, is manufactured and marketed in the Netherlands by Sanquin... more
    AAFACT, a monoclonal purified, solvent/detergent treated human plasma-derived coagulation factor VIII concentrate obtained from plasma of voluntary, non-remunerated blood donors, is manufactured and marketed in the Netherlands by Sanquin Plasma Products since 1995. In a postmarketing surveillance study, 70 previously treated haemophilia A patients were included (73% severe, 14% moderate and 13% mild haemophilia A). Most of these patients were followed during 4 years for the appearance of adverse events, possible transmissions of blood-borne viruses and the occurrence of antibodies against FVIII. The efficacy of treatment was determined in each patient by the in vivo recovery of FVIII. During this study, only six adverse events, possibly related to the use of AAFACT, were reported. None of these were indicated as serious. Transmissions of HIV, HAV, HBV and HCV in the seronegative patients have not been observed. In none of the patients, inhibitors to FVIII were detected. The in vivo ...
    Research Interests:
    Improving transfusion practice for a donor means a safer donation process and maximal use of the donation. From the clinical perspective, it includes the production of the right type of blood component of adequate quality, administered at... more
    Improving transfusion practice for a donor means a safer donation process and maximal use of the donation. From the clinical perspective, it includes the production of the right type of blood component of adequate quality, administered at the right dose at the right moment to the right patient in order to obtain the expected or anticipated effect in absence of harm. Transfusion practice involves not only the complete blood chain, i.e. from the donation to clinical usage, but also the input from the competent authority that bears responsibility for the concepts of improving health care practice. In Europe, experience has shown that haemovigilance offers an effective tool in improving transfusion practice.
    To corroborate results obtained in The Netherlands with PPSB-SD, showing a safe acute reversal of anticoagulation within 15 minutes of administration. PPSB-SD is a concentrate prothrombin complex containing a relatively constant high... more
    To corroborate results obtained in The Netherlands with PPSB-SD, showing a safe acute reversal of anticoagulation within 15 minutes of administration. PPSB-SD is a concentrate prothrombin complex containing a relatively constant high level of vitamin K-dependant coagulation factors II, VII, IX and X. PPSB-SD was administered to 14 patients treated with oral anticoagulants, according the patient's weight, the initial and the target INR (< 2.0 for moderate haemorrhage and abdominal surgery, or < 1.5 for severe haemorrhage and cardio-vascular interventions). INR values were measured with the Coagucheck Pro (Roche Diagnostics) upon admission and at 15 minutes, 1, 3 and 5 hours after treatment, and confirmed by the hospitals' laboratory. Within 15 minutes 11 patients out of 12 reached their INR target (data were missing for 2 patients). INR decreased rapidly, then remained stable for the next 5 hours. All patients had a favourable outcome: bleeding was stopped and no haemor...
    A 6-year-old boy and a 3.5-year-old girl presented with unexplained episodes of angioedema without urticaria. Low serum C1 esterase inhibitor activity was found in both children. Family history revealed autosomal dominant inheritance in... more
    A 6-year-old boy and a 3.5-year-old girl presented with unexplained episodes of angioedema without urticaria. Low serum C1 esterase inhibitor activity was found in both children. Family history revealed autosomal dominant inheritance in the girl. The boy had a negative family history for angioedema. C1 esterase inhibitor deficiency is a rare but serious condition that may cause oedema of the upper respiratory tract and death by asphyxiation. Episodes of angioedema occur spontaneously, usually subsiding within 48-72 h. Between episodes, the patients are symptom free. Treatment consists of substitution of synthetic C1 esterase inhibitor during episodes of edema carrying a risk of upper airway obstruction. In patients who have more than one episode of severe angioedema per month, daily treatment with tranexamic acid should be considered. Both of these patients were not receiving daily treatment.
    In the treatment of reversal of oral anticoagulant therapy, a number of treatment modalities is available and depends on the severity of the clinical situation and the degree of the coagulopathy. FFP and PPSB (PCC) are commonly used in... more
    In the treatment of reversal of oral anticoagulant therapy, a number of treatment modalities is available and depends on the severity of the clinical situation and the degree of the coagulopathy. FFP and PPSB (PCC) are commonly used in the treatment and/or in combination with cessation of oral anticoagulant therapy and administration of Vitamin K. The double viral inactivated plasma product PPSB-SD is the first choice treatment in this indication because of the relatively constant, high concentrated level of the Vitamin K dependent coagulation factors II, VII, IX and X, compared to FFP.
    The development of antibodies to factor VIII (inhibitors) in response to clotting-factor concentrates administration in hemophilia is common during the first few years of treatment but rare in multitransfused patients. We have... more
    The development of antibodies to factor VIII (inhibitors) in response to clotting-factor concentrates administration in hemophilia is common during the first few years of treatment but rare in multitransfused patients. We have investigated the possible association of a recently introduced factor VIII concentrate (Factor VIII CPS-P) in The Netherlands with the occurrence of inhibitors. To this effect, we conducted two studies. First, we performed a national multicenter study in which clinical information and inhibitor test results were obtained for 447 hemophilia A patients over the period 1988 through 1991. Secondly, for a baseline comparison we estimated the frequency of inhibitor development in a closely followed cohort of 144 patients, from 1984 through 1989. Before the introduction of Factor VIII CPS-P, the incidence of new inhibitors was 4.4/1,000 patient-years in the national study from March 1988 through May 1990, and 3.9/1,000 patient-years in the cohort followed from 1984 t...
    EMOPHILIA A is a sex-linked hereditary bleeding dis- H order caused by a complete or partial deficiency of clotting factor VIII. In severe hemophilia (complete defi- ciency) bleeding occurs spontaneously, notably in joints and soft... more
    EMOPHILIA A is a sex-linked hereditary bleeding dis- H order caused by a complete or partial deficiency of clotting factor VIII. In severe hemophilia (complete defi- ciency) bleeding occurs spontaneously, notably in joints and soft tissue. In milder forms (partial deficiency) bleeding usu- ally only results from trauma or surgery. The disease pre- dominantly affects men (approximately 20/ 100,000 live
    Haemovigilance is a tool to improve the quality of the blood transfusion chain, primarily focusing on safety. In this review we discuss the history and present state of this relatively new branch of transfusion medicine as well as some... more
    Haemovigilance is a tool to improve the quality of the blood transfusion chain, primarily focusing on safety. In this review we discuss the history and present state of this relatively new branch of transfusion medicine as well as some developments that we foresee in the near future. The top 10 results and conclusions are: (1) Haemovigilance systems have shown that blood transfusion is relatively safe compared with the use of medicinal drugs and that at least in Europe blood components have reached a high safety standard. (2) The majority of the serious adverse reactions and events occur in the hospital. (3) The majority of preventable adverse reactions are due to clerical errors. (4) Some adverse reactions such as anaphylactic reactions often are not avoidable and therefore have to be considered as an inherent risk of blood transfusion. (5) Well-functioning haemovigilance systems have not only indicated how safety should be improved, but also documented the success of various measures. (6) The type of organisation of a haemovigilance system is of relative value, and different systems may have the same outcome. (7) International collaboration has been extremely useful. (8) Haemovigilance systems may be used for the vigilance and surveillance of alternatives for allogeneic blood transfusion such as cell savers. (9) Haemovigilance systems and officers may be used to improve the quality of aspects of blood transfusion other than safety, such as appropriate use. (10) Haemovigilance systems will be of benefit also for vigilance and surveillance of the treatment with other human products such as cells, tissues and organs.

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