L A Aarden

Sanquin Blood Supply Foundation, Amsterdamo, North Holland, Netherlands

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Publications (276)1386.31 Total impact

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    ABSTRACT: In a subset of patients, anti tumour necrosis factor (TNF) therapeutic antibodies are immunogenic, resulting in the formation of antidrug antibodies (ADAs). Neutralising ADAs compete with TNF for its binding site and reduces the effective serum concentration, causing clinical non-response. It is however unknown to which extent ADAs are neutralising.
    Annals of the Rheumatic Diseases 10/2014; DOI:10.1136/annrheumdis-2014-206237 · 9.27 Impact Factor
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    ABSTRACT: The production of antibodies to adalimumab in auto-immune patients treated with adalimumab is shown to diminish treatment efficacy. We previously showed that these antibodies are almost exclusively neutralizing, indicating a restricted response. Here we investigated the characteristics of a panel of patient-derived monoclonal antibodies for binding to adalimumab. Single B cells were isolated from two patients, cultured and screened for adalimumab specificity. Analysis of variable region sequences of sixteen clones suggests that the immune response against adalimumab is broad, involving multiple B-cell clones each using different combinations of V(D)J segments. A strong bias for replacement mutations in the complementarity determining regions (CDR) was found, indicating an antigen-driven response. We recombinantly expressed eleven different monoclonal antibodies and investigated their affinity and specificity. All clones except one are of high affinity (Kd between 0.6 and 233 pM) and compete with TNF as well as each other for binding to adalimumab. However, binding to a panel of single-point mutants of adalimumab indicates markedly different fine-specificities that also result in a differential tendency of each clone to form dimeric and multimeric immune complexes. We conclude that although all anti-adalimumab antibodies compete for binding to TNF, the response is clonally diverse and involves multiple epitopes on adalimumab. These results are important for understanding the relationship between self and non-self or idiotypic determinants on therapeutic antibodies and their potential immunogenicity.
    Journal of Biological Chemistry 10/2014; DOI:10.1074/jbc.M114.615500 · 4.60 Impact Factor
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    ABSTRACT: Clinical remission is today the treatment goal for Rheumatoid Arthritis (RA), which requires fast and assertive therapeutic decisions for a tight control of disease activity. Few objective parameters are available to guide clinical decisions, namely in switcher patients. We designed a preliminary algorithm introducing immunogenicity assessment in the current approach to RA patients receiving biotechnologic therapies. To evaluate the concordance between the new algorithm and current clinical practice, comparing the effectiveness of "immunogenicity-based" versus "empirical-based" switches in a cohort of patients with established RA receiving biologics. Methods: EULAR therapeutic response was evaluated in 105 RA patients (naive or switchers) over one year, through GEE analysis. Serum drug trough levels were assessed by ELISA and anti-drug antibodies (ADAb) by Bridging ELISA. Results During follow-up, 48.6% of patients (Group A) had concordant therapeutic decisions. One year after the therapeutic decision, patients from Group A had a higher probability of achieving response (OR = 7.91, p <0.001, 95% CI = 3.27-19.13) and low disease activity (OR = 9.77, p <0.001, 95% CI = 4.69-20.37). Non-responders to a TNFi in the presence of detectable serum drug trough levels and no detectable ADAb had higher probability of achieving response by switching to a drug with different MOA, rather than another TNFi, even after adjusting for potential confounders, such as DAS28 at the time of switch (OR = 6.76, p = 0.004, 95% CI = 1.82-25.04). Immunogenicity assessment might help to optimise therapeutic decisions, leading to a better control of disease activity with significant better clinical outcomes in RA patients receiving biotechnologic therapies.
    Annals of the rheumatic diseases 03/2014; 73 Suppl 1:A35. DOI:10.1136/annrheumdis-2013-205124.78 · 9.27 Impact Factor
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    ABSTRACT: Objectives: Removal of dead cells is essential in maintenance of tissue homeostasis and efficient removal prevents exposure of intracellular content to the immune system which could lead to autoimmunity. The plasma protease factor VII-activating protease (FSAP) can release nucleosomes from late apoptotic cells. FSAP circulates as an inactive single-chain protein, which is activated upon contact with either apoptotic or necrotic cells. In this study we investigated the role of FSAP in the release of nucleosomes from necrotic cells. Methods: Necrotic Jurkat cells were incubated with serum, purified tcFSAP and/or DNase I. Nucleosome release was analyzed by flow cytometry and agarose gel electrophoresis was performed to detect DNA breakdown. Results: We show that serum can release nucleosomes from necrotic cells. FSAP-deficient serum or serum in which FSAP is inhibited by an inhibiting antibody is unable to release nucleosomes from necrotic cells confirming that indeed FSAP is the essential serum factor in this process. Together with serum DNase I, FSAP induces release of DNA from the cells, the appearance of nucleosomes in the supernatant and fragmentation of the chromatin into eventually mononucleosomes. Conclusions: FSAP and DNase I are the essential serum factors cooperating in DNA degradation and nucleosome release in necrotic cells. We propose that this mechanism may be important in the removal of potential autoantigens. © 2013 American College of Rheumatology.
    Arthritis & Rheumatology 03/2014; 66(3). DOI:10.1002/art.38265 · 7.87 Impact Factor
  • Annals of the Rheumatic Diseases 01/2014; 71(Suppl 3):340-340. DOI:10.1136/annrheumdis-2012-eular.2549 · 9.27 Impact Factor
  • Annals of the Rheumatic Diseases 01/2014; 71(Suppl 3):360-360. DOI:10.1136/annrheumdis-2012-eular.2604 · 9.27 Impact Factor
  • Annals of the Rheumatic Diseases 01/2014; 72(Suppl 3):A436-A436. DOI:10.1136/annrheumdis-2013-eular.1315 · 9.27 Impact Factor
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    ABSTRACT: To determine a concentration-effect curve of adalimumab in rheumatoid arthritis (RA) patients taking into account the effect of methotrexate (MTX) on concentration and effect and to identify a therapeutic range for adalimumab concentrations. In a prospective observational cohort study, 221 consecutive patients with RA were treated with 40 mg adalimumab subcutaneously every other week. The relationship between adalimumab trough level and clinical efficacy after 28 weeks of follow-up was determined in a concentration-effect curve. A receiver-operator characteristics (ROC) curve established a therapeutic cut-off concentration. The effect of MTX on adalimumab trough levels was shown by dividing patients that are and are not concomitantly using MTX in the concentration-effect curve and a concentration table. Clinical efficacy improved with increasing adalimumab concentration and reached a maximum (mean disease activity score in 28 joints improvement of 2) with levels between 5-8 μg/mL. Levels exceeding 8 μg/mL were illustrated to have no additional beneficial effect on disease activity. The ROC curve showed an area under the curve of 0.695 (95% CI 0.626 to 0.764) for European League Against Rheumatism response and adalimumab levels: good responders versus non-responders and moderate responders. A cut-off of 5 μg/mL had a sensitivity of 91% and a specificity of 43%. Adalimumab levels are influenced by concomitant MTX use: patients on adalimumab monotherapy had a median adalimumab level of 4.1 μg/mL (IQR 1.3-7.7), whereas patients concomitantly taking MTX had a median level of 7.4 μg/mL (IQR 5.3-10.6, p<0.001). Adalimumab trough levels in a range of 5-8 μg/mL are sufficient to reach adequate clinical response. These levels are influenced substantially by concomitant MTX use.
    Annals of the rheumatic diseases 12/2013; 74(3). DOI:10.1136/annrheumdis-2013-204172 · 9.27 Impact Factor
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    ABSTRACT: Abstract Immunogenicity is a major issue of concern for monoclonal antibodies used in human diseases and is by default mainly determined in non-human primates (NHP), as target molecules are considered most similar in NHP compared to human. In this manuscript the predictive value of immunogenicity testing in minipigs for human safety is evaluated, as the immune system of the pig is functionally similar to that in other mammalian species. Adalimumab and infliximab (both monoclonal antibodies blocking TNFα) were used as model substances. Female Göttingen minipigs (4/group) were treated every other week with low (0.1 mg/kg), mid (1.0 mg/kg), or high dose (5 mg/kg) adalimumab or 5 mg/kg infliximab subcutaneous (SC) over a period of 8 weeks. After first and last dosing, pharmacokinetic analysis was performed. Anti-drug antibodies (ADAs) were measured on several time points. Furthermore, hematology, clinical chemistry, body weight, clinical signs, and histopathology of several organs were evaluated. No signs of toxicity of the treatments were observed in the limited organs and tissues collected. Eleven out of 12 minipigs treated with adalimumab elicited a detectable ADA response. Induction of ADA was correlated with decreased plasma levels of adalimumab. Infliximab clearance was comparable after first and last dose. Therefore, the presence of ADA directed to infliximab was considered highly unlikely. It was concluded that the minipig and NHP showed comparable suitability for immunogenicity prediction in humans. More studies with other biopharmaceutical products are needed to strengthen the status of the minipig as an alternative model for immunotoxicity testing including immunogenicity.
    Journal of Immunotoxicology 06/2013; DOI:10.3109/1547691X.2013.796023 · 1.91 Impact Factor
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    ABSTRACT: INTRODUCTION: Clinical remission is today the treatment goal for rheumatoid arthritis (RA), which requires fast and assertive therapeutic decisions for a tight control of disease activity. Few objective parameters are available to guide clinical decisions, particularly in switcher patients. We designed a preliminary algorithm introducing immunogenicity assessment in the current approach to patients with RA receiving tumour necrosis factor inhibitors (TNFi). OBJECTIVE: To evaluate the concordance between the new algorithm and current clinical practice, comparing the effectiveness of 'immunogenicity-based' versus 'empirical-based' switches in a cohort of patients with established RA receiving biologics. METHODS: EULAR therapeutic response was evaluated in 105 patients with RA (naive or switchers) over one year, through generalised estimation equation (GEE) analyses. Serum drug trough levels were assessed by ELISA and antidrug antibodies (ADAb) by Bridging ELISA. RESULTS: During follow-up, 48.6% of patients had therapeutic decisions concordant with the proposed algorithm (Group A), and 51.4% had discordant decisions (Group B). One year after the therapeutic decision, patients from Group A had a higher probability of achieving response (OR=7.91, p<0.001, 95% CI 3.27 to 19.13) and low disease activity (OR=9.77, p<0.001, 95% CI 4.69 to 20.37) than patients in Group B. CONCLUSIONS: Immunogenicity assessment might help to optimise therapeutic decisions, leading to a better control of disease activity with significantly better clinical outcomes in patients with RA receiving TNFi.
    Annals of the rheumatic diseases 05/2013; 73(6). DOI:10.1136/annrheumdis-2013-203296 · 9.27 Impact Factor
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    ABSTRACT: BACKGROUND AND OBJECTIVES: Therapeutic monoclonal antibodies are effective drugs for many different diseases. However, the formation of anti-drug antibodies (ADA) against a biological can result in reduced clinical response in some patients. Measurement of ADA in the presence of (high) drug levels is difficult due to drug interference in most assays, including the commonly used antigen binding test (ABT). METHODS: We recently published a novel method which enables the measurement of complexed antibodies against adalimumab (an anti-TNF antibody) in the presence of drug. Here we use this pH-shift-anti-idiotype ABT (PIA) to measure anti-adalimumab antibodies (AAA) in 99 rheumatoid arthritis (RA) patients treated for up to 3 years with adalimumab. RESULTS: 53 out of 99 RA patients produced AAA. In 50 of these PIA positive patients, AAA could be detected within the first 28 weeks of treatment. Patients in which AAA could be detected in the PIA after 28 weeks of treatment were more prone to declining adalimumab levels (<5 µg/ml) (p<0.01) and high AAA levels which could be detected in the ABT (p<0.05) at later time points. We observed transient AAA formation in 17/53 patients. CONCLUSIONS: Results show that AAA develop early in treatment. However, levels that completely neutralise the drug may be reached much later in treatment. Furthermore, the patients positive for PIA at 28 weeks have an increased chance to develop clinical non-response due to immunogenicity. In some of the patients, AAA formation is transient.
    Annals of the rheumatic diseases 01/2013; 72(10). DOI:10.1136/annrheumdis-2012-202407 · 9.27 Impact Factor
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    ABSTRACT: OBJECTIVES: Millions of patients worldwide are treated with therapeutic monoclonal antibodies. These biological therapeutics can be immunogenic, resulting in anti-drug antibody formation which leads to loss of response. Fully human biological agents, such as the anti-tumour necrosis factor α (anti-TNFα) antibody adalimumab, are considered to be weakly immunogenic, but anti-adalimumab antibodies (AAA) were recently detected in more than half of treated patients with rheumatoid arthritis (RA) within 28 weeks of treatment. A study was undertaken to determine the mechanism by which AAA lead to loss of response. METHODS: The specificity of the repertoire of AAA was investigated in a cohort of 50 AAA-positive RA patients. Inhibition experiments using TNFα and patient-derived anti-adalimumab monoclonal antibodies were performed. RESULTS: The antibody response against adalimumab is highly restricted: Fab fragments of a single monoclonal antibody specific for the idiotype of adalimumab inhibited 98.65% (25th-75th percentiles: 98.25-99.90) of the total anti-adalimumab reactivity in serum from 50 AAA-positive patients. The anti-adalimumab response was confined to the TNFα binding region of adalimumab, thereby neutralising its therapeutic efficacy. In line with this restricted specificity, small immune complexes were found in the circulation of AAA-forming patients. CONCLUSIONS: The humoral immune response against adalimumab is highly restricted and limited to the idiotype of the therapeutic antibody. All antibodies result in functional neutralisation of the drug, thereby providing a mechanism by which AAA formation leads to clinical non-response.
    Annals of the rheumatic diseases 07/2012; 72(1). DOI:10.1136/annrheumdis-2012-201445 · 9.27 Impact Factor
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    ABSTRACT: A substantial part of rheumatoid arthritis (RA) patients is chronically treated with adalimumab. Some of these patients produce antibodies against adalimumab, which correlate with lower serum drug levels and reduced clinical response. Long term exposure to antigens may result in antigen specific IgG4 production as was demonstrated in studies on prolonged exposure to antigens such as different allergens, Factor VIII and IFN-β. Here, we investigate whether long term treatment of RA patients with the therapeutic monoclonal antibody adalimumab leads to the production of specific IgG4 antibodies. We developed radio immunoassays to detect total IgG or IgG4 against adalimumab and applied these in a cohort of 271 consecutive RA patients during 3 years of adalimumab treatment. In 32 % of the 271 patients antibodies against adalimumab were detectable. IgG4 antibodies were detected in 29 % of the patients. The proportion IgG4 of total IgG against adalimumab varies widely between patients, and IgG4 was found to contribute significantly to the anti drug antibody (ADA) response in some patients. In the immune response against adalimumab in adalimumab-treated RA patients a considerable part of the ADA is IgG4. Although IgG4 is often considered to be harmless due to its lack of effector function, neutralization of adalimumab by IgG4 antibodies will lead to a reduced clinical response.
    Journal of Clinical Immunology 05/2012; 32(5):1000-6. DOI:10.1007/s10875-012-9705-0 · 2.65 Impact Factor
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    ABSTRACT: Factor VII-activating protease (FSAP) is a serine protease that circulates in plasma in its inactive single-chain form and can be activated upon contact with dead cells. When activated by apoptotic cells, FSAP leads to the release of nucleosomes. The serpins C1-inhibitor and α(2) -antiplasmin are reported to be the major inhibitors of FSAP. However, regulation of FSAP activity by Kunitz-type inhibitors is not well studied. To compare the inhibition of FSAP activity and FSAP-induced nucleosome release from apoptotic cells by tissue factor pathway inhibitor (TFPI) with that of C1-inhibitor and α(2) -antiplasmin. Apoptotic cells were incubated with plasma or FSAP in presence of the inhibitor, and nucleosome release was analyzed with flow cytometry. Monoclonal antibodies against TFPI and altered forms of TFPI were used to investigate which domains of TFPI contribute to FSAP inhibition. We show that TFPI abrogates FSAP activity and nucleosome release from apoptotic cells. TFPI is a much more efficient inhibitor than C1-inhibitor or α(2) -antiplasmin. The active site of K2 is required for inhibition of FSAP. A direct binding interaction between FSAP and the C-terminal domain of TFPI is also required for efficient inhibition. Inhibition of FSAP-induced nucleosome release by recombinant TFPI might, in part, explain the anti-inflammatory effects of recombinant TFPI infusion observed in animal and human sepsis.
    Journal of Thrombosis and Haemostasis 03/2012; 10(6):1165-71. DOI:10.1111/j.1538-7836.2012.04712.x · 5.55 Impact Factor
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    ABSTRACT: Rheumatoid factors are antibodies directed against IgG that may confound immunogenicity testing for therapeutic monoclonal antibodies. We developed antigen-binding assays to monitor anti-drug-antibody (ADA) responses against infliximab and adalimumab using F(ab')2 fragments of the drug. This avoids possible detection of rheumatoid factor activity. During development of these assays, a number of sera from patients before treatment as well as several healthy control sera were tested positive. None of these sera contained antibodies specific for the therapeutic mAb. Instead, they were found to contain anti-hinge antibodies. We demonstrate that this aspecific antibody binding can be inhibited by adding F(ab')2 of intravenous immunoglobulin (IVIG), which consists of pooled polyclonal IgG derived from plasma. Using this protocol, anti-infliximab antibodies can be measured specifically without interference by anti-hinge antibodies.
    Journal of immunological methods 01/2012; 375(1-2):93-9. DOI:10.1016/j.jim.2011.09.011 · 2.01 Impact Factor
  • F Stephan, L A Aarden, S Zeerleder
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    ABSTRACT: Factor VII-activating protease (FSAP) is a serine protease in plasma that has a role in coagulation and fibrinolysis. FVII could be activated by purified FSAP in a tissue factor independent manner and pro-urokinase has been demonstrated to be a substrate for purified FSAP in-vitro. However, the physiological role of FSAP in haemostasis remains unclear. More recently FSAP is suggested to be involved in inflammation. It modulates vascular permeability directly and indirectly by the generation of bradykinin. Furthermore, FSAP is activated by dead cells induced by the inflammatory response and subsequently removes nucleosomes from apoptotic cells. FSAP activation can be detected in sepsis patients as well. However, whether FSAP activation upon inflammation is beneficial or detrimental remains an open question. In this review the structure, activation mechanisms and the possible role of FSAP in inflammation are discussed.
    Hamostaseologie 01/2012; 32(1):51-5. DOI:10.5482/ha-1187 · 1.59 Impact Factor
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    ABSTRACT: To investigate the relationship between serum etanercept levels and clinical response. In 292 etanercept-treated patients with rheumatoid arthritis clinical and pharmacological data were determined at baseline and after 1, 4 and 6 months of etanercept treatment. Differences in etanercept levels between good, moderate and European League Against Rheumatism (EULAR) non-responders were assessed after 6 months of therapy. After 6 months of therapy etanercept levels were significantly higher in good responders (median (IQR) 3.78 (2.53-5.17)) compared with both moderate 3.10 (2.12-4.47) and EULAR non-responders 2.80 (1.27-3.93) (all p<0.05). There was a significant association between clinical response and serum etanercept levels (regression coefficient 0.54, 95% CI 0.21 to 0.86, p=0.001). When patients were categorised into quartiles according to the height of etanercept levels, the lowest quartile (etanercept level <2.1 mg/l) comprised 40% of all non-responders. The highest quartile (etanercept level >4.7 mg/l) comprised 35% of all good EULAR responders. Anti-etanercept antibodies were detected in none of the sera. The authors demonstrated that lower etanercept levels were associated with non-response. Therapeutic drug monitoring and the possibility of the adjusted dosing regimes in the selected groups of patients should be investigated further as a possible tool to optimise treatment with etanercept.
    Annals of the rheumatic diseases 09/2011; 71(1):88-91. DOI:10.1136/annrheumdis-2011-200184 · 9.27 Impact Factor
  • Molecular Immunology 08/2011; 48(14):1687-1687. DOI:10.1016/j.molimm.2011.06.285 · 3.00 Impact Factor
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    ABSTRACT: The presence of anti-drug antibodies (ADA) in adalimumab-treated patients is associated with reduced serum adalimumab levels and a lower clinical response. Currently, there is no standard for measurement of anti-drug antibodies and many factors influence the results. Consequently, the incidence of ADA as reported in different studies varies considerably. Here we investigated the differential effect of drug interference in two common types of assays used to measure anti-adalimumab: an antigen binding test (ABT) and a more often-used bridging elisa. We measured ADA to adalimumab in a cohort of 216 rheumatoid arthritis patients treated with adalimumab for 28 weeks. Only 15 samples (7%) were positive in the bridging elisa, compared to 29 (13%) in the ABT, despite the fact that the bridging elisa was the most sensitive assay. Furthermore, in an ABT specific for IgG4, 48 samples (22%) were found positive. The bridging elisa was found to detect only the bivalent form of (drug-specific) IgG4, resulting in an underestimation of ADA levels. However, the predominant reason for the different outcomes of these assays was a differential susceptibility to drug interference. In particular, the bridging elisa only detected ADA in the absence of detectable amounts of circulating adalimumab and is therefore not suited for measurement of ADA in complex with the drug. In summary, we showed that a bridging elisa is susceptible to drug interference and typically measures ADA only in absence of detectable drug levels.
    Journal of immunological methods 07/2011; 372(1-2):196-203. DOI:10.1016/j.jim.2011.07.019 · 2.01 Impact Factor
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    ABSTRACT: Adjuvant therapy with interferon-α (IFN) only benefits a small subgroup of melanoma patients and a predictive marker selecting responders does not exist. IFN induces increased ferritin and decreased C-reactive protein (CRP) levels; however, an association with treatment effect was not studied. Serum was collected from patients participating in the European Organization for Research and Treatment of Cancer 18 952 trial comparing adjuvant treatment with IFN to observation. Serial ferritin and CRP levels were determined using enzyme-linked immunosorbent assays, before treatment and up to 24 months. Ferritin levels are influenced by sex and age; therefore ratios of serial ferritin and CRP values with corresponding pretreatment values were calculated. Cox regression model and landmark method at end of induction and 6 months were used to evaluate the association between ferritin, CRP and distant metastasis-free survival (DMFS). Baseline ferritin levels were comparable in the two treatment groups (P=0.92). However, ferritin ratios were significantly higher in IFN-treated patients (N=96) compared with untreated patients (N=21) at end of induction (mean: 2.88 vs. 0.75; P=0.0003) and at 6 months (mean: 3.18 vs. 1.02; P=0.009). In the IFN arm, higher ferritin ratios at end of induction and at 6 months were not associated with improved outcome (respectively, P=0.66 and 0.86). Concerning CRP ratios, no differences between the treatment groups, neither an association with DMFS, were observed. Administration of IFN in melanoma patients induced increase in ferritin levels but not in CRP levels. Ferritin and CRP ratios have no prognostic value regarding DMFS.
    Melanoma research 05/2011; 21(4):344-51. DOI:10.1097/CMR.0b013e328346c17f · 2.10 Impact Factor

Publication Stats

14k Citations
1,386.31 Total Impact Points

Institutions

  • 2005–2014
    • Sanquin Blood Supply Foundation
      • Department of Immunopathology
      Amsterdamo, North Holland, Netherlands
    • VU University Medical Center
      Amsterdamo, North Holland, Netherlands
  • 1975–2014
    • University of Amsterdam
      • • Faculty of Medicine AMC
      • • Department of Surgery
      • • Laboratory for Experimental and Clinical Immunology
      • • Central Laboratory of the Netherlands Red Cross Blood Transfusion Service
      • • Laboratory of Cell Biology and Histology
      • • Department of Internal Medicine
      Amsterdamo, North Holland, Netherlands
  • 2013
    • Hospital Garcia de Orta
      Almada, Setúbal, Portugal
  • 1993–2006
    • Academisch Medisch Centrum Universiteit van Amsterdam
      • • Department of Hematology
      • • Department of Surgery
      Amsterdamo, North Holland, Netherlands
  • 2004
    • VU University Amsterdam
      • Department of Adult Intensive Care
      Amsterdam, North Holland, Netherlands
  • 1999
    • Leiden University
      Leyden, South Holland, Netherlands
  • 1976–1999
    • Hong Kong Red Cross Blood Transfusion Service
      Hong Kong, Hong Kong
  • 1988–1998
    • Academic Medical Center (AMC)
      Amsterdamo, North Holland, Netherlands
  • 1987–1997
    • Red Cross
      Washington, Washington, D.C., United States
  • 1996
    • Oklahoma Medical Research Foundation
      Oklahoma City, Oklahoma, United States
  • 1992
    • University Medical Center Utrecht
      • Department of Immunology
      Utrecht, Provincie Utrecht, Netherlands
  • 1983
    • University at Buffalo, The State University of New York
      • Department of Microbiology and Immunology
      Buffalo, New York, United States