Haemostatic differences between SARS-CoV-2 PCR-positive and negative patients at the time of hospital admission

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is associated with thrombosis. We conducted a cohort study of consecutive patients, suspected of SARS-CoV-2 infection presented to the emergency department. We investigated haemostatic differences between SARS-CoV-2 PCR positive and negative patients, with dedicated coagulation analysis. The 519 included patients had a median age of 66 years, and 52.5% of the patients were male. Twenty-six percent of the patients were PCR-positive for SARS-CoV-2.PCR positive patients had increased levels of fibrinogen and (active) von Willebrand Factor (VWF) and decreased levels of protein C and α2-macroglobulin compared to the PCR negative patients. In addition, we found acquired activated protein C resistance in PCR positive patients. Furthermore, we found that elevated levels of factor VIII and VWF and decreased levels of ADAMTS-13 were associated with an increased incidence of thrombosis in PCR positive patients. In conclusion, we found that PCR positive patients had a pronounced prothrombotic phenotype, mainly due to an increase of endothelial activation upon admission to the hospital. These findings show that coagulation tests may be considered useful to discriminate severe cases of COVID-19 at risk for thrombosis.

Factor V Leiden, Antiphospholipid Antibodies and Thrombosis in Systemic Lupus Erythematosus

Thromboembolic complications are frequently observed in patients with systemic lupus erythematosus (SLE). Significant associations have been reported between these complications and the presence of antiphospholipid antibodies, notably the lupus anticoagulant and anti-cardiolipin antibodies. Factor V Leiden is a genetic disorder associated with an increased risk of venous thrombosis. We studied these factors in 173 patients with SLE in relation to both arterial and venous thrombosis. The frequency of factor V Leiden in SLE patients is comparable to that in the Dutch population (5%) and a risk factor for venous thrombosis (odds ratio 4.9; Cl 1.2-19.6), but not for arterial thrombosis. The lupus anticoagulant is a risk factor for both arterial thrombosis (odds ratio 7.1; Cl 2.9-17.4) and venous thrombosis (odds ratio 6.4; Cl 2.7-15.4). From multivariate analysis, both the lupus anticoagulant and factor V Leiden appeared independent risk factors for venous thrombosis.

The Origin of P-selectin as a Circulating Plasma Protein

P-selectin is a 140 kD protein found in the α-granules of platelets and the Weibel-Palade bodies of endothelial cells. On cell activation it is expressed on the cell surface and also secreted into plasma. Whether the circulating soluble P-selectin (sP-selectin) originates from platelets, endothelial cells, or both, is not known. We studied the level of sP-selectin in diseases with different platelet counts, with or without evidence of endothelial cell activation. Endothelial cell activation was confirmed by the detection of sE-selectin and EDl-fibronectin. A significant positive correlation between platelet count and sP-selectin concentration was observed in healthy controls, and in patients with thrombocytopenia due to bone marrow aplasia, or with thrombocytosis (r = 0.85; n = 47; p <0.001). In patients with idiopathic thrombocytopenic purpura (ITP) the sP-selectin concentration was 110 ± 39 ng/ml (n = 10), compared to 122 ± 38 ng/ml in healthy controls (n = 26). However, their mean platelet count was lower (58 X 109/1 versus 241 X 109/1 in the control group). Accordingly, the levels of sP-selectin expressed per platelet increased to significantly higher levels (2.0 ± 1.2 versus 0.6 ± 0.2 fg/platelet in the control group-; p <0.0001). This suggests increased platelet turnover in patients with ITP. High levels of sP-selectin were found in patients with sepsis (398 ± 203 ng/ml; n = 15) and with thrombotic thrombocytopenic purpura (TTP; 436 ± 162 ng/ml; n = 12). Compared with patients with ITP, the concentration of sP-selectin per platelet was higher in patients with sepsis (4.8 ± 4.3 fg/platelet; p <0.005) or TTP (17.1 ± 9.5 fg/platelet; p <0.001). Endothelial cells are very likely to be the source in these patients and the presence of endothelial cell activation was confirmed by increased levels of circulating E-selectin and ED 1 -fibronectin.

This study suggests that platelets are the major source of circulating sP-selectin in healthy individuals. Endothelial cell activation is associated with an increased sP-selectin concentration per platelet.

Soluble P-selectin as Parameter for Platelet Activation during Storage

Platelet concentrates stored at room temperature deteriorate. The so-called storage lesion is characterised by morphological changes and a loss of functionality. To find an assay for early platelet activation in platelet concentrates the morphological score, β-TG release and P-selectin expression were determined, and compared with the amount of soluble P-selectin. An ELISA was used to quantify soluble P-selectin in the storage medium. We found a significant correlation between the amount of soluble P-selectin and the percentage of P-selectin positive platelets (flow-cytometric analysis) (r = 0.7449; p <0.0001) or the amount of β-TG release (r = 0.6837; p<0.0001). The morphological score also correlated significantly (negative) with the amount of soluble P-selectin (r = -0.7669; p = 0.0002). From day 0 till day 8, the amount of soluble P-selectin increased constantly from 219 ± 49.2ng/ml to 556 ± 102.3 ng/ml. The detection of soluble P-selectin can be used to quantify activation of platelets during storage. The immuno-assay for soluble P-selectin is more sensitive than flow-cytometric analysis of the percentage of P-selectin-positive cells and allows earlier detection of platelet activation.

Depletion of Dense Granule Nucleotides during Storage of Human Platelets

The energy metabolism of human platelets was studied during storage of platelet concentrates. The platelets were prepared from buffy coats in PVC/DEHP bags and stored for 7 days at room temperature at a concentration of 1.0 × 109/ml with horizontal agitation. The total amount of ATP and ADP decreased with 40% during this storage. This decrease correlated with the disc-tosphere transformation associated with the loss of platelet viability. During storage, the ability to incorporate 3H-adenosine into metabolic ATP and ADP (45 min at 37° C) decreased with 50%. Via measurement of the specific activity of actin-bound ADP and the amount of incorporated radioactivity into total ATP and ADP, we calculated the content of the metabolic and storage pools of ATP and ADP. The results indicate that the decrease in adenine nucleotide levels during storage was mainly caused by a depletion of ATP and ADP from the storage pool, whereas the metabolic pool remained nearly intact. After 7 days, the ATP : ADP ratio of the storage pool had decreased from 1.0 to 0.3, indicating hydrolysis of ATP.

Diadenosine-triphosphate and diadenosine-tetraphosphate (present in the storage pool) decreased with only 30%, and the serotonin content remained nearly constant. Therefore, it is unlikely that the storage pool was completely secreted. Probably, the storage pool of nucleotides serves as an internal supply for maintaining the contents of the metabolic pool of ATP and ADP during storage of platelets.

Agonist-induced platelet reactivity correlates with bleeding in haemato-oncological patients

BACKGROUND AND OBJECTIVE

Prophylactic platelet transfusions are administered to prevent bleeding in haemato-oncological patients. However, bleeding still occurs, despite these transfusions. This practice is costly and not without risk. Better predictors of bleeding are needed, and flow cytometric evaluation of platelet function might aid the clinician in identifying patients at risk of bleeding. This evaluation can be performed within the hour and is not hampered by low platelet count. Our objective was to assess a possible correlation between bleeding and platelet function in thrombocytopenic haemato-oncological patients.

MATERIALS AND METHODS

Inclusion was possible for admitted haemato-oncology patients aged 18 years and above. Furthermore, an expected need for platelet transfusions was necessary. Bleeding was graded according to the WHO bleeding scale. Platelet reactivity to stimulation by either adenosine diphosphate (ADP), cross-linked collagen-related peptide (CRP-xL), PAR1- or PAR4-activating peptide (AP) was measured using flow cytometry.

RESULTS

A total of 114 evaluations were available from 21 consecutive patients. Platelet reactivity in response to stimulation by all four studied agonists was inversely correlated with significant bleeding. Odds ratios (OR) for bleeding were 0·28 for every unit increase in median fluorescence intensity (MFI) [95% confidence interval (CI) 0·11-0·73] for ADP; 0·59 [0·40-0·87] for CRP-xL; 0·59 [0·37-0·94] for PAR1-AP; and 0·43 [0·23-0·79] for PAR4-AP. The platelet count was not correlated with bleeding (OR 0·99 [0·96-1·02]).

CONCLUSION

Agonist-induced platelet reactivity was significantly correlated to bleeding. Platelet function testing could provide a basis for a personalized transfusion regimen, in which platelet transfusions are limited to those at risk of bleeding.

Identification of N-linked glycosylation and putative O-fucosylation, C-mannosylation sites in plasma derived ADAMTS13

BACKGROUND

Acquired deficiency of ADAMTS13 causes a rare and life-threatening disorder called thrombotic thrombocytopenic purpura (TTP). Several studies have shown that aberrant glycosylation can play an important role in the pathogenesis of autoimmune diseases.N-linked glycosylation and putative O-fucosylation sites have been predicted or identified in recombinant ADAMTS13. However, it is not known which of these sites are glycosylated in plasma derived ADAMTS13.

OBJECTIVES

Here we investigated the presence of putative O-fucosylation, C-mannosylation and N-linked glycosylation sites on plasma derived ADAMTS13.

METHODS/RESULTS

Sites of N-linked glycosylation were determined by the use of peptide N-glycosidase-F (PNGase F), which removes the entire carbohydrate from the side chain of asparagines. Nine of the 10 predicted N-linked glycosylation sites were identified in or near the metalloproteinase,spacer, thrombospondin type 1 repeat (TSR1) and the CUB domain of plasma ADAMTS13. Moreover, six putative O-fucosylated sites were identified in the TSR domains of plasma ADAMTS13 by performing searches of the tandem mass spectrometry (MS/MS) data for loss of hexose (162 Da), deoxyhexose (146 Da), or hexose deoxyhexose(308 Da). The use of electron transfer dissociation (ETD) allowed for unambiguous identification of the modified sites. In addition to putative O-fucosylation and N-linked glycosylation, two putative C-mannosylation sites were identified within the TSR1 and TSR4 domains of ADAMTS13.

CONCLUSIONS

Our data identify several glycosylation sites on plasma derived ADAMTS13. We anticipate that our findings may be relevant for the initiation of autoimmune reactivity against ADAMTS13 in patients with acquired TTP.

Platelet function alterations in dengue are associated with plasma leakage

Severe dengue is characterised by thrombocytopenia, plasma leakage and bleeding. Platelets are important for preservation of endothelial integrity. We hypothesised that platelet activation with secondary platelet dysfunction contribute to plasma leakage. In adult Indonesian patients with acute dengue, we measured platelet activation status and the response to the platelet agonist TRAP using flow cytometer-based assays. Patients were monitored daily for plasma leakage by ultrasonography. Acute dengue was associated with platelet activation with an increased expression of the activated fibrinogen receptor (αIIbβ3), the lysosomal marker CD63 and the alpha-granule marker CD62P (P-selectin). Upon maximal platelet activation by TRAP, platelet function defects were observed with a significantly reduced maximal activated αIIbβ3 and CD63 expression and reduced platelet-monocyte and platelet-neutrophil complexes. Patients in the lowest tertile of activated αIIbβ3 and CD63 expression had an odds ratio for plasma leakage of 5.2 (95% confidence interval [CI] 1.3-22.7) and 3.9 (95% CI 1.1-13.7), respectively, compared to the highest tertile. Platelet-derived serotonin has previously been related to plasma leakage and we found increased intra-platelet serotonin concentrations in our patients. In conclusion, platelet activation with platelet function alterations can be found in patients with acute dengue and this may contribute to dengue-associated plasma leakage.

Systematic review and meta-analysis on the diagnostic performance of FDG-PET/CT in detecting bone marrow involvement in newly diagnosed Hodgkin lymphoma: is bone marrow biopsy still necessary?

BACKGROUND

This study aimed to systematically review and meta-analyze published data on the diagnostic performance of (18)F-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) in detecting bone marrow involvement in newly diagnosed Hodgkin lymphoma, and to determine whether FDG-PET/CT can replace blind bone marrow biopsy (BMB) in these patients.

PATIENTS AND METHODS

The PubMed/Medline and Embase databases were systematically searched for relevant studies. Methodological quality of each study was assessed. Sensitivities and specificities of FDG-PET/CT in individual studies were calculated and underwent meta-analysis with a random effects model. A summary receiver operating characteristic curve (sROC) was constructed with the Moses-Shapiro-Littenberg method. The weighted summary proportion of FDG-PET/CT-negative patients with a positive BMB among all cases was calculated under the fixed effects model.

RESULTS

Nine eligible studies, comprising a total of 955 patients with newly diagnosed Hodgkin lymphoma, were included. Overall, the studies were of moderate methodological quality. The sensitivity and specificity of FDG-PET/CT for the detection of bone marrow involvement ranged from 87.5% to 100% and from 86.7% to 100%, respectively, with pooled estimates of 96.9% [95% confidence interval (CI) 93.0% to 99.0%] and 99.7% (95% CI 98.9% to 100%), respectively. The area under the sROC curve was 0.9860. The weighted summary proportion of FDG-PET/CT-negative patients with a positive BMB among all cases was 1.1% (95% CI 0.6% to 2.0%).

CONCLUSION

Although the methodological quality of studies that were included in this systematic review and meta-analysis was moderate, the current evidence suggests that FDG-PET/CT may be an appropriate method to replace BMB in newly diagnosed Hodgkin lymphoma.

The observation of bleeding complications in haemato-oncological patients: stringent watching, relevant reporting

BACKGROUND

The reported percentage of haemato-oncological patients experiencing bleeding complications is highly variable, ranging from 5 to 70%, posing a major problem for comparison of clinical platelet transfusion trials using bleeding complications as a primary endpoint. In a pilot study we assessed the impact of the design of scoring of bleeding on the percentage of patients with WHO grade 2 or higher bleeding grades.

STUDY DESIGN AND METHODS

We performed a prospective, observational study using a rigorous bleeding observation system in thrombocytopenic patients with haemato-oncological disorders. Endpoints of the study were the percentage of patients and days with bleeding WHO grade ≥ 2 comparing designs in which skin bleeding represent a continuation of a previous bleed or a new bleed.

RESULTS

In four participating hospitals 64 patients suffering 870 evaluable thrombocytopenic days (platelet count < 80 × 10(9) L(-1)) were included. At least one episode of bleeding grade ≥ 2 occurred in 36 patients (56%). Most grade 2 bleeding complications occurred mucocutaneously. The percentage of days with bleeding of grade ≥ 2 was 16% but decreases to 8% when only newly developed skin bleeding was included.

CONCLUSION

Rigorous daily observation results in a bleeding incidence that is comparable to recent reportings applying the same method. The results of this study show that censoring for stable skin bleeding has a profound effect on bleeding incidence per day. The clinical relevance of rigorous or clinically judged bleeding scores as an endpoint remains to be defined.

New therapeutic options for immune thrombocytopenia

Understanding of the mechanisms and aetiology of immune thrombocytopenia (ITP) has progressed significantly in recent years. It is now recognised to be an autoimmune condition, involving not only platelet destruction, but also deficits in platelet production. This has led to widespread research exploring potential mechanisms for therapy, the result of which has been the development of romiplostim and eltrombopag. These new treatments target the thrombopoietin receptor (TPO-R), promoting formation of megakaryocytes and survival of platelets. Furthermore, the advances in the understanding of ITP have led to the production of guidelines to assist healthcare professionals in the diagnosis and treatment of ITP. This review examines the recommendations made in these guidelines, particularly the American Society of Haematology (ASH) 2011 evidence-based practice guidelines. In addition, searches were carried out to retrieve information on clinical trials of new molecules and off-label treatments for ITP. Corticosteroids, anti-Rho(D) immunoglobulins (anti-D), intravenous immunoglobulins (IVIg) and splenectomy are well-established treatments and continue to be recommended in the guidelines. The recently available romiplostim and eltrombopag, which are specific for treatment of IT P, are also included in the recommendations. The only off-label therapy to be recommended in the guidelines is the chimeric monoclonal antibody rituximab. However, investigations are ongoing into products approved for other indications, which may be beneficial to patients suffering from refractory ITP.

The active conformation of von Willebrand factor in patients with thrombotic thrombocytopenic purpura in remission

BACKGROUND

Functional deficiency of ADAMTS13 in thrombotic thrombocytopenic purpura (TTP) patients is associated with circulating ultralarge von Willebrand factor (VWF) molecules that display spontaneous platelet-binding capacities. Upon remission, however, ADAMTS13 activity does not always return to baseline.

OBJECTIVE

To study ADAMTS13 and VWF-related features in TTP patients in remission.

METHODS

ADAMTS13 activity, anti-ADAMTS13 antibodies, VWF antigen, ultralarge VWF and levels of VWF that circulate in a glycoprotein Ibalpha-binding conformation were determined in plasma samples of 22 acquired TTP patients in remission between 1 month and 6 years after achieving remission. The composition of active multimers was investigated with a novel immunoprecipitation assay based on monoclonal antibody AU/VWF-a12, which specifically recognizes the active conformation of VWF.

RESULTS

ADAMTS13 activity was undetectable in 23% of the patients, even years after they had achieved remission, and lack of ADAMTS13 activity was associated with increased active VWF levels and the presence of ultralarge VWF multimers. Active VWF levels and ultralarge VWF were also associated with blood groups. Results from immunoprecipitation experiments revealed the full range of multimers to be present.

CONCLUSION

ADAMTS13 deficiency and the concurrent presence of ultralarge VWF and increased active VWF levels can be detected in TTP patients for years after they have achieved remission. Immunoprecipitation results suggest that the active conformation of VWF may be present in the lower molecular weight multimers, but future studies are necessary to confirm our findings.

VH1-69 germline encoded antibodies directed towards ADAMTS13 in patients with acquired thrombotic thrombocytopenic purpura

BACKGROUND

Autoantibodies directed towards ADAMTS13 are present in the majority of patients with acquired thrombotic thrombocytopenic purpura (TTP). Analysis of a set of antibodies derived from two patients with acquired TTP revealed frequent use of the VH1-69 heavy chain gene segment for the assembly of anti-ADAMTS13 antibodies.

OBJECTIVE

We explored the ability of two VH1-69 germline gene-encoded antibodies to inhibit the von Willebrand factor (VWF)-processing activity of ADAMTS13 under different experimental conditions. Furthermore, the presence of VH1-69 encoded anti-ADAMTS13 antibodies in 40 patients with acquired TTP was monitored using monoclonal antibody G8, which specifically reacts with an idiotype expressed on VH1-69 encoded antibodies.

METHODS AND RESULTS

Binding of the two VH1-69 encoded monoclonal antibodies was dependent on the presence of the spacer domain. Both antibodies inhibited ADAMTS13 activity under static conditions, as measured by cleavage of FRETS-VWF73 substrate and cleavage of VWF multimers. The recombinant antibodies were also capable of inhibiting the processing of UL-VWF strings on the surface of endothelial cells. G8-reactive antibodies directed towards ADAMTS13 were present in plasma of all patients containing anti ADAMTS13 antibodies.

CONCLUSIONS

These results suggest that VH1-69 derived antibodies directed towards ADAMTS13 develop in the majority of patients with acquired TTP.

[Aggressive non-Hodgkin lymphoma in 3 patients with rheumatoid arthritis: discontinue the use of methotrexate]

3 female patients who were being treated with methotrexate developed a non-Hodgkin lymphoma. The first patient, 67 years old, presented with an enlarged thyroid gland. The cytological punction was inconclusive and an open biopsy revealed a B cell non-Hodgkin lymphoma, which was localised. A week before the biopsy the methotrexate was discontinued. The patient herself reported that the swelling of her thyroid gland was diminished after cessation of methotrexate. The lymphoma showed a complete remission without chemotherapy being given. The second patient, a 78-year-old woman, developed a non-Hodgkin lymphoma in one of her tonsils that showed a partial remission after withdrawal of the methotrexate therapy. The third patient, a 66-year-old woman, presented herself with a pulmonary non-Hodgkin lymphoma. In this patient withdrawal of the methotrexate resulted in a complete remission of the non-Hodgkin lymphoma as well. Although no epidemiological study has shown an increased risk of lymphoproliferative disorders during the use of methotrexate, these spontaneous remissions suggest an aetiological link. If a non-Hodgkin lymphoma develops in a patient being treated with methotrexate then the therapy should be discontinued and chemotherapy should not be given straightaway.

Lack of discriminating signs and symptoms in clinical diagnosis of influenza of patients admitted to the hospital

Objectives:

Rapid diagnosis of influenza in hospitalised patients is important to prevent the transmission of the infection in the hospital. This prospective observational cohort study was designed to determine the relationship between the clinical diagnosis of influenza made by the physician at admission and the presence of influenza virus in patients with respiratory tract infections.

Methods:

This prospective observational cohort study was conducted in a large Dutch teaching hospital in a period of four weeks during the influenza season 2004/2005. All patients of 18 years and older, admitted with respiratory tract infections were included in the study. Clinical and laboratory parameters, chest radiograph (CR), blood and sputum cultures and nasopharyngeal swab for polymerase chain reaction (PCR) were obtained for each patient. In addition, the physicians opinion at admission whether this patient had influenza was recorded.

Results:

A total of 78 patients were hospitalized with respiratory tract infections. In 41 (53%) of them influenza virus was detected by PCR. Among the patients that were positive for influenza virus by PCR, a clinical diagnosis of influenza was made in 18 cases (44%). Conversely, clinical diagnosis of influenza was made in 16 out of 37 patients in whom influenza virus was not detected by PCR. Neither C-reactive protein, leucocytes count nor an infiltrate on CR were helpful in determining the cause of the respiratory tract infection.

Conclusions:

The present findings failed to demonstrate a significant relationship between the clinical diagnosis of influenza and PCR detection of the virus. Also, the virus was present at least twice more often than influenza was clinically diagnosed. As a consequence, the decision to take protective measures to control spread of the virus should not rely on the clinical diagnosis.

A sensitive and reliable semi-quantitative real-time PCR assay to detect JAK2 V617F in blood

Diagnosis of the myeloproliferative disorders, polycythemia vera (PV), essential thrombocythemia (ET) and idiopathic myelofibrosis (IMF) is difficult due to lack of diagnostic markers. Recently, the acquisition of a mutation in the Janus kinase 2 (JAK2) gene by hemopoietic cells has been described as a genetic defect underlying myeloproliferative disorders. The mutation leads to constitutive activation of JAK2, a tyrosine kinase involved in cytokine receptor signalling. Because of the clinical importance of this mutation (JAK2 V617F) in diagnosing myeloproliferative disorders and its relevance for disease progression, we developed a semi-quantitative real-time PCR test to detect JAK2 V617F. With this assay, quantities down to 0.8% JAK2 V617F amongst wild-type DNA could reliably be detected. For quantification purposes, low intra- and inter-assay variabilities ensure good reproducibility of the assay. Thus the JAK2 V617F qPCR assay described here is quick, robust, simple and more sensitive than direct sequencing, RFLP, ARMS assay and other methods published so far to detect JAK2 V617F. We therefore believe that the assay will contribute to early diagnosis of myeloproliferative disorders and to disease management, especially when JAK2-specific inhibitors have become available for therapeutic use.

Neurologic and hematologic response to fludarabine treatment in IgM MGUS polyneuropathy

We studied the efficacy of fludarabine in 16 patients with immunoglobulin M monoclonal gammopathy of unknown significance polyneuropathy in a prospective uncontrolled trial. The modified Rankin scale improved in 5/16 patients, all of whom had a demyelinating polyneuropathy. The motor conduction velocity improved by more than 10% in two or more nerves for four of five of these patients. Hematologic response in bone marrow occurred in three of five of these patients, whereas two of five already had small polyclonal B cell populations. There were no serious side effects.

Acute activation of the endothelium results in increased levels of active von Willebrand factor in hemolysis, elevated liver enzymes and low platelets (HELLP) syndrome

BACKGROUND

HELLP (hemolysis, elevated liver enzymes and low platelets) syndrome is a severe complication of pre-eclampsia in pregnancy, characterized by microvascular platelet thrombi. Activation of the endothelium is thought to play a key role in pre-eclampsia and HELLP syndrome. Activation of endothelial cells may lead to release of von Willebrand factor (VWF) multimers, which are highly reactive with platelets. Normally, newly released multimers are cleaved by ADAMTS13, resulting in less reactive derivatives.

OBJECTIVE

We hypothesized that HELLP syndrome is characterized by increased amounts of active VWF compared with healthy pregnancy and pre-eclampsia, due to acute activation of endothelial cells. This might contribute to thrombocytopenia and thrombotic microangiopathy.

METHODS

Active VWF and ADAMTS13 activity were measured in healthy pregnant volunteers (n = 9), patients with pre-eclampsia (n = 6) and patients with HELLP syndrome (n = 14) at similar gestational ages. To study the role of endothelial cell activation, the propeptide/mature VWF ratio was determined, and VWF released by cultured endothelial cells was analyzed.

RESULTS

Active VWF levels were increased 2.1-fold in HELLP syndrome compared with healthy pregnant volunteers (P < 0.001) and 1.6-fold compared with patients with pre-eclampsia (P = 0.001). ADAMTS13 activity was moderately decreased in patients with HELLP syndrome compared with healthy pregnant volunteers (P < 0.004), but not compared with patients with pre-eclampsia. The propeptide/mature VWF ratio was increased 1.7-fold compared with healthy pregnant volunteers (P < 0.001) and 1.5-fold compared with patients with pre-eclampsia (P < 0.05). A significant correlation was found between this ratio and the activation factor of VWF (r = 0.68, P < 0.001). The amount of active VWF was increased 1.4-fold in medium of stimulated endothelial cells when compared with non-stimulated cells (P < 0.05).

CONCLUSION

Acute endothelial cell activation in HELLP syndrome and decreased ADAMTS13 activity result in increased amounts of active VWF. This might explain the consumptive thrombocytopenia and thrombotic microangiopathy associated with HELLP syndrome. Inhibition of circulating active VWF could be a potential new approach in the treatment of patients with HELLP syndrome.

Multiple B-cell clones producing antibodies directed to the spacer and disintegrin/thrombospondin type-1 repeat 1 (TSP1) of ADAMTS13 in a patient with acquired thrombotic thrombocytopenic purpura

BACKGROUND

The cysteine-rich/spacer domains of ADAMTS13 contain a major binding site for antibodies in patients with acquired thrombotic thrombocytopenic purpura (TTP).

OBJECTIVE

To study the heterogeneity of the antibody response towards these domains an immunoglobulin V-gene phage-display library was constructed to isolate monoclonal anti-ADAMTS13 antibodies from the immunoglobulin repertoire of a patient with acquired TTP.

METHODS

Combined variable heavy chain (VH) and variable light chain (VL) segments, expressed as single-chain Fv fragments (scFv), were selected for binding to an ADAMTS13 fragment consisting of the disintegrin/thrombospondin type-1 repeat 1 (TSP1)/cysteine-rich/spacer domains.

RESULTS

Seven different scFv antibody clones were identified that were assigned to four groups based on their homology to VH germline gene segments. Epitope-mapping revealed that scFv I-9 (VH1-69), I-26 (VH1-02), and I-41 (VH3-09) bind to an overlapping binding site in the ADAMTS13 spacer domain, whereas scFv I-16 (VH3-07) binds to the disintegrin/TSP1 domains. The affinity of scFv for the disintegrin/TSP1/cysteine-rich/spacer domain was determined by surface plasmon resonance analysis and the dissociation constants ranged from 3 to 254 nM. The scFv partially inhibited ADAMTS13 activity. However, full-length IgG prepared from the variable domains of scFv I-9 inhibited ADAMTS13 activity more profoundly. Plasma of six patients with acquired TTP competed for binding of scFv I-9 to ADAMTS13.

CONCLUSION

Our data indicate that multiple B-cell clones producing antibodies directed against the spacer domain are present in the patient analyzed in this study. Our findings also suggest that antibodies with a similar epitope specificity as scFv I-9 are present in plasma of other patients with acquired TTP.

Risk factors for cystoid macular oedema in patients with uveitis

PURPOSE

To determine ophthalmologic and systemic factors associated with the presence of cystoid macular oedema (CMO) in patients with uveitis.

METHODS

Retrospective cross-sectional study in which 97 consecutive patients with uveitis filled in an extensive questionnaire for the presence of cardiovascular diseases and its risk factors. An analysis of the ophthalmologic and questionnaire data was conducted.

RESULTS

CMO was present in 44% (43/97) of patients. Its presence was strongly associated with increasing age (P=0.001) and age at onset of uveitis (P<0.001). For patients older than 50 years, the risk of having CMO was 3.8-fold (95% confidence intervals 1.6-9.0) larger than for younger patients. The most frequent anatomic location of uveitis associated with CMO was panuveitis (49%). Papillary leakage on fluorescein angiography was associated with CMO (P<0.001), independently of other risk factors. After adjustment for age, multivariate logistic regression showed no association between cardiovascular disease and its risk factors and the presence of CMO.

CONCLUSIONS

Age, independent of duration of uveitis, was a major risk factor for the presence of CMO in uveitis. A positive correlation between CMO and papillary leakage on angiography was noted.

Pulmonary complications after T-cell-depleted allogeneic stem cell transplantation: low incidence and strong association with acute graft-versus-host disease

Lung injury limits the success of allogeneic stem cell transplantation (SCT). The overall incidence varies from 30 to 50% and non-infectious causes occur in one-third to one-half of these. We reviewed pulmonary complications in 369 consecutive patients who received a partially T-cell-depleted myeloablative allogeneic hematopoietic SCT at our institution between 1993 and 2003. All patients were treated uniformly with cyclophosphamide followed by total body irradiation. Control subjects were matched on sex, underlying diagnosis, age, type of transplantation and cytomegalovirus (CMV)-serostatus. Sixty-one patients (16.5%) developed pulmonary complications. Twenty-one patients (5.7%) developed infectious pneumonia. Forty patients developed non-infectious complications which were further subclassified as bronchiolitis obliterans (3.5%), bronchiolitis obliterans-organizing pneumonia (0.5%), diffuse alveolar hemorrhage (0.8%), idiopathic pneumonia syndrome (5.5%) or mixed etiology (0.5%). Acute graft-versus-host disease (GVHD) > or =grade II was significantly more common in pulmonary patients than in the controls (36/61 versus 22/61 patients, P=0.02). There was no significant difference in the incidence of chronic GVHD (P=0.09). CMV reactivation was significantly more frequent in patients with lung injury (P=0.02). Median survival was 41 weeks for the pulmonary patients and 350 weeks for the controls (P=0.001). Altogether, the incidence of pulmonary complications is low after T-cell-depleted SCT and is associated with acute GVHD and CMV reactivation.

Endothelial cell activation markers and delayed cerebral ischaemia in patients with subarachnoid haemorrhage

BACKGROUND

Endothelial cell activation may be connected with the pathogenesis of delayed cerebral ischaemia (DCI) after subarachnoid haemorrhage (SAH).

AIM

To assess the relationship between serial concentrations of circulating markers of endothelial cell activation (soluble intercellular adhesion molecule-1, soluble platelet selectin (sP-selectin), soluble endothelial selectin, ED1-fibronectin, Von Willebrand Factor (VWF) and VWF propeptide) and development of DCI.

METHODS

687 blood samples were collected from 106 consecutive patients admitted within 72 h after onset of SAH. Changes in levels were analysed in the last sample before and in the first sample after the onset of DCI (n = 30), and in subgroups with DCI occurring within 24 h after treatment of the aneurysm (n = 12) or unrelated to treatment of the aneurysm (n = 18). Patients without DCI (n = 56) served as controls.

RESULTS

Concentrations of sP-selectin, but not of the other markers, were found to increase considerably after DCI unrelated to treatment of the aneurysm (increase 25 ng/ml, 95% CI 8 to 43), whereas they tended to decrease in the control patients without DCI (decrease 13 ng/ml, 95% CI -28 to 2.4). Surgery was found to profoundly influence the levels of the markers irrespective of the occurrence of DCI.

CONCLUSION

The rise in sP-selectin level during DCI is suggested to be the result of platelet activation, as levels of the other markers of endothelial cell activation were not increased after DCI unrelated to treatment. Whether a causal role of platelet activation is implicated in the development of DCI should be determined in further studies in which the relationship between concentrations of markers and treatment is taken into account.

Early circulating levels of endothelial cell activation markers in aneurysmal subarachnoid haemorrhage: associations with cerebral ischaemic events and outcome

OBJECTIVE

To investigate the relation of endothelial cell activation with delayed cerebral ischaemia (DCI) and outcome after subarachnoid haemorrhage (SAH).

METHODS

Concentrations of soluble (s) intercellular adhesion molecule-1, sE-selectin, sP-selectin, ED1-fibronectin, von Willebrand Factor (vWf), and vWf propeptide were measured within three days of SAH onset. The associations with poor outcome were investigated at three months in 106 patients. In 90 patients in whom the occurrence of cerebral ischaemia could be dated accurately, two analyses were undertaken: one for all ischaemic events (n = 32), including those related to treatment, and another for spontaneous DCI (n = 11). Concentrations of markers were dichotomised at their medians. The associations of endothelial cell activation markers with outcome were expressed as odds ratios (OR) from logistic regression and those with ischaemic events as hazard ratios (HR) derived from Cox regression.

RESULTS

Early vWf concentrations were associated with poor outcome (crude OR = 4.6 (95% CI, 2.0 to 10.9; adjusted OR = 3.3 (1.1 to 9.8). Early levels of vWf were also positively related to occurrence of all ischaemic events (crude HR = 2.3 (1.1 to 4.9); adjusted HR = 1.8 (0.8 to 3.9) and with occurrence of spontaneous DCI (crude HR = 3.5 (0.9 to 13.1); adjusted HR = 2.2 (0.5 to 9.8). None of the other markers showed any associations.

CONCLUSIONS

Concentrations of sICAM-1, sP-selectin, sE-selectin, and ED1-fibronectin do not predict the occurrence of DCI or outcome. The positive associations of raised early vWf concentrations with ischaemic events and poor outcome after SAH may reflect a predisposition to further ischaemic injury through formation of microthrombi in the cerebral circulation.

Splenectomy for the treatment of thrombotic thrombocytopenic purpura

Plasma exchange is the treatment of choice for patients with thrombotic thrombocytopenic purpura (TTP) and results in remission in >80% of the cases. Treatment of patients who are refractory to plasma therapy or have relapsing disease is difficult. Splenectomy has been a therapeutic option in these conditions but its value remains controversial. We report on a series of 33 patients with TTP who were splenectomised because they were plasma refractory (n = 9) or for relapsed disease (n = 24). Splenectomy generated prompt and unmaintained remissions in all except five patients, in whom remission was delayed (n = 4) or who died with progressive disease (n = 1). Four postoperative complications occurred: one pulmonary embolism and three surgical complications. Median follow-up after splenectomy was 109 months (range 28-230 months). The overall postsplenectomy relapse rate was 0.09 relapses/patient-year and the 10-year relapse-free survival (RFS) was 70% (95% CI 50-83%). In the patients with relapsing TTP, relapse rate fell from 0.74 relapses/patient-year before splenectomy to 0.10 after splenectomy (P < 0.00001). Two patients died from first postsplenectomy relapse. Although these results are based on retrospective data and that the relapse rate may spontaneously decrease with time, we conclude that splenectomy, when performed during stable disease, has an acceptable safety profile and should be considered in cases of plasma refractoriness or relapsing TTP to reach durable remissions and to reduce or prevent future relapses.

[A woman suffering from systemic lupus erythematosus and acquired thrombotic thrombocytopenic purpura]

A 41-year-old woman with known systemic lupus erythematosus (SLE) was diagnosed with thrombotic thrombocytopaenic purpura (TTP). At the time of admission she was suffering from petechia, purpura and had neurological symptoms. At first a relapse of the SLE was suspected. Additional laboratory findings demonstrated haemolytic anaemia, thrombocytopaenia and high levels of fragmentocytes. After multiple plasmapheresis treatments and immunosuppressive therapy she recovered. TTP can be differentiated from other thrombotic microangiopathic syndromes by its normal levels of prothrombin time, partially activated thromboplastin time (APTT), fibrinogen and direct Coombs-test. Further investigation is needed to confirm the diagnosis by determination of the activity of Von Willebrand factor cleaving protease ADAMTS-13. In this patient, the ADAMTS-13 activity returned after plasmapheresis. This case demonstrates the importance of fast and appropriate laboratory testing in order to diagnose TTP quickly.

[Activity loss of Von Willebrand factor cleaving protein (ADAMTS-13) is diagnostic for primary and pregnancy-related thrombotic thrombocytopenic purpura]

OBJECTIVE

To determine whether the measurement of the Von Willebrand factor cleaving protease ADAMTS-13, such as is carried out at the University Medical Centre of Utrecht, The Netherlands, contributes towards the diagnosis and treatment of patients with thrombotic thrombocytopenic purpura (TTP).

DESIGN

Descriptive.

METHOD

In a group of 98 patients from 21 hospitals, with a Coombs-negative haemolytic anaemia and thrombocytopenia, the ADAMTS-13 activity was measured. Treatment was given irrespective of ADAMTS-13 activity.

RESULTS

ADAMTS-13 activity was absent in 27 of 29 patients diagnosed with primary TTP and in all 5 pregnancy-TTP patients. In patients suffering from TTP after bone marrow transplantation (post-BMT) and in all other patients included in this study, ADAMTS-13 activity was normal. Of the 32 patients with absent ADAMTS-13 activity, 28 underwent plasmapheresis. This treatment proved effective as all 28 patients responded well. 17 patients with normal ADAMTS-13 activity also underwent plasmapheresis; 5 (30%) responded well to treatment. In 2 cases a final diagnosis of primary TTP was made, in a further 2, haemolytic uraemic syndrome and in 1 case sepsis was diagnosed.

CONCLUSION

In this study, the absence of ADAMTS-13 activity predicted primary TTP and TTP of pregnancy with a sensitivity of 93% and a specificity of 100%. Absence of ADAMTS-13 activity is a strong indication for plasma exchange.

Spinal Dural Arteriovenous Fistulas Are Not Associated With Prothrombotic Factors

Background and Purpose— The cause of spinal dural arteriovenous fistulas (SDAVF) is unknown. In intracranial dural arteriovenous fistulas, an association with factor V Leiden mutation has been found. Therefore, we studied the association between prothrombotic factors and SDAVF.

Methods— Factor V Leiden mutation, factor II mutation, protein S, protein C, factor VIII, von Willebrand factor, antithrombin III, and lupus anticoagulant were determined by means of standard laboratory tests in 40 patients and 119 control subjects matched for sex and age.

Results— Factor V Leiden mutation was not found in the patient group and was found twice in the control group. Factor II mutation was found in 1 patient and in none of the control subjects. There was no decreased activity of protein S, protein C, factor VIII, von Willebrand factor, or antithrombin III in patients in comparison with controls. Lupus anticoagulant was not found in the patient group and once in the control subjects.

Conclusions— We conclude that it is unlikely that prothrombotic factors are involved in the pathogenesis of spinal dural arteriovenous fistulas, but subtle associations are not ruled out.

Endothelial markers in chronic heart failure: training normalizes exercise-induced vWF release

BACKGROUND

Chronic heart failure (CHF) is characterized by endothelial dysfunction. Vascular endothelium is important for control of haemostasis and vasoregulation. The aim of the present study was to investigate plasma levels of several endothelial markers and the exercise-induced changes on these plasma levels in CHF patients. Subsequently, the effect of a 6-month training programme on these markers is described.

MATERIALS AND METHODS

Twenty-nine male CHF patients (NYHA II/III, age 60 +/- 8 year, body mass index 26.7 +/- 2.3 kg m(-2), left ventricular ejection fraction 26.3-7.2%; mean +/- SD) participated. Patients were randomly assigned to a training or control group. Training (26 weeks; combined strength and endurance exercises) was four sessions/week: two sessions supervised and two sessions at home. Before and after intervention, anthropometry, endothelial markers (haemostasis and vasoregulation), maximal workload and peak oxygen uptake were assessed.

RESULTS

Physical training positively affected maximal workload. Plasma levels of endothelial markers were not affected by physical training and not related to exercise tolerance. After training, stimulated (maximal exercise) plasma von Willebrand Factor (vWF) release was present, whereas at baseline this release was absent.

CONCLUSION

Physical training led to normalization of the stimulated plasma vWF release. Plasma levels of other endothelial markers were not affected by physical training either at rest or under stimulated (maximal exercise) conditions.

Intraocular and plasma levels of cellular fibronectin in patients with uveitis and diabetes mellitus

AIMS

To determine intraocular and plasma levels of cellular fibronectin (cFN) in patients with uveitis or diabetes mellitus (DM) and to assess the association with disease activity, macular oedema, and vascular leakage on fluorescein angiography. In addition, to examine whether cFN is locally produced in the eye.

METHODS

Intraocular and plasma levels of cFN were determined by ELISA in 39 patients with uveitis (23 active, 16 non-active), in 11 patients with DM (eight with and three without diabetic retinopathy) and in 17 control patients. The influence of diabetic retinopathy, inflammatory activity, vascular leakage, and macular oedema (MO) on intraocular and plasma cFN levels was studied. Local production of cFN was determined by calculating absolute and relative intraocular to plasma ratios. Aqueous and vitreous levels of cFN were compared.

RESULTS

No differences in plasma cFN levels were found between patients with uveitis, DM, or controls. Intraocular cFN levels were significantly raised in patients with uveitis and DM, specifically in those with active disease (active uveitis and active diabetic retinopathy versus controls: p = 0.001 and 0.002 respectively). Further, intraocular cFN levels were significantly elevated in patients with macular oedema or vascular leakage, irrespectively of whether associated with uveitis or DM (p = 0.001 and 0.002). Intraocular cFN levels were consistently higher in the vitreous than the aqueous. Intraocular production of cFN was documented by elevated absolute and relative intraocular to plasma ratios in nine out of 11 patients tested.

CONCLUSIONS

Elevated intraocular cFN levels were found in uveitis and DM, especially in those with active processes, intraocular vascular damage, and MO. These results suggest that locally produced cFN levels reflect intraocular vascular damage.

[Acquired von Willebrand syndrome]

Two patients, a man aged 69 and a woman aged 64, were diagnosed with Von-Willebrand syndrome caused by monoclonal gammopathy. The man, who was admitted for hip surgery, had a history of long episodes of epistaxis. The patient was treated with immunoglobulin and the hip operation was carried out with no complications. The woman suffered from haemorrhagic diathesis. She was advised that should she undergo an invasive procedure then treatment with a prophylactic with intravenous immunoglobulin or Von-Willebrand factor (VWF)/factor-VIII-concentrates must be administered. Acquired Von-Willebrand syndrome is a rare condition with an estimated prevalence of 0.04-0.13%. It is linked to a large number of underlying diseases such as paraproteinaemia, multiple myeloma (Kahler's disease), myeloproliferative disease, lymphoproliferative disease, auto-immune disease, solid tumours and hypothyroidism. Recognition depends on a careful case-history and identification of the underlying disease. For its diagnosis VWF antigen. VWF propeptide, activated partial thromboplastin time and factor VIII are of importance. Technically, it is difficult to show the presence of VWF antibodies as it concerns a heterogeneous group of antibodies. There are two pillars of treatment: symptomatic treatment of the bleeding tendencies using desmopressin, VWF-concentrate or intravenous gammaglobulin, and treatment of the underlying disease. The latter form of treatment can lead to acquired Von-Willebrand-syndrome disappearing altogether.

Differential diagnosis of skin lesions after allogeneic haematopoietic stem cell transplantation

Allogeneic haematopoietic stem cell transplantation (i.e. bone marrow or peripheral blood stem cell transplantation) is a common procedure in the treatment of various haematological disorders such as aplastic anaemia, (pre)leukaemias, some malignant lymphomas, multiple myeloma and immunodeficiency states. Many of these patients develop erythematous skin lesions following transplantation. Although graft- versus-host disease is the major differential diagnosis in these situations, many other causes of erythema are encountered. The large number of transplant patients means that more and more pathologists are confronted with the challenging problem of making a correct diagnosis in these situations. In this review article we therefore describe the different causes of erythema and their differential diagnoses. In most cases the clinical presentation is related to the microscopical features. Besides acute and chronic graft-versus-host disease, we discuss the (common) drug reactions and non-specific features such as Sweet's syndrome, erythema nodosum and eosinophilic folliculitis. In addition, we deal with the recurrence of original diseases and infections. With this knowledge every pathologist should feel comfortable when looking at skin biopsies of patients after haematological stem cell transplantation.

Extremely high levels of von Willebrand factor antigen and of procoagulant factor VIII found in multiple myeloma patients are associated with activity status but not with thalidomide treatment

Venous thromboembolism (VTE) is a major complication in patients with multiple myeloma (MM) during treatment with thalidomide combined with chemotherapy and/or dexamethasone. The pathophysiology is not clear. We performed a cross-sectional study in 20 MM patients who were treated with thalidomide for refractory/relapsed disease. Seven patients (35%) experienced an episode of VTE. Plasma samples were analyzed for known risk factors for VTE and compared with those from 30 MM patients without thalidomide treatment. The patients groups differed in their baseline characteristics in activity status only. Extremely high levels of factor VIII-coagulant activity (FVIII:C, mean 352%) and von Willebrand factor antigen (VWF-Ag, 374%) were found in all patients using thalidomide. All other prothrombotic risk factors were normal. In patients with VTE, VWF-Ag but not FVIII:C, levels were significantly higher as compared with patients without VTE. Patients without thalidomide treatment had significantly lower levels of both coagulation factors but the difference was only due to difference in activity status. High FVIII:C/VWF-Ag levels are found in patients with active MM and this is probably a reflection of increased bone marrow angiogenesis in MM. These prothrombogenic circumstances could contribute to the high incidence of VTE during treatment with thalidomide in combination with dexamethasone/chemotherapy.

[Withdrawing the use of acetylsalicyclic acid prior to an operation usually not necessary]

Acetylsalicylic acid (aspirin) induces an irreversible inactivation of cyclo-oxygenase in blood platelets which lasts for the entire period that the platelets remain in the circulatory system, 7 to 10 days. In order to prevent excessive bleeding, patients presenting for surgery are asked to stop using aspirin 10 days before the procedure. Some studies have found that aspirin causes increased peri-operative blood loss, whilst other studies have found that it does not. All effect studies found in Medline (January 1966-May 2002) on surgery and bleeding complications due to aspirin were analysed. The studies available were assessed for methodological quality and the results were summarised in an evidence table. No clinically relevant bleeding complications were reported for cardiovascular, vascular and orthopaedic surgery and epidural anaesthesia. Most studies reported an increase in clinically non-relevant bleeding induced by aspirin. The literature contains too little information on cataract surgery, dermatological surgery, gynaecological and abdominal surgery, ENT and dental surgery, urological surgery, lung biopsy and endoscopic biopsy. In those types of surgery in which even a minor bleeding leads to severe complications, e.g. neurosurgery, aspirin should be withdrawn 5-10 days in advance. Also in patients with coagulation disorders, aspirin should be withdrawn prior to the operation. There is no scientific evidence for the withdrawal of aspirin in all patients, 5-10 days prior to surgery. Indeed for heart patients in particular, the continued use of aspirin is recommended.

Endothelial cell activation is associated with cerebral white matter lesions in patients with cerebrovascular disease

Cerebral MRI scanning frequently shows white matter lesions in elderly people. They are related to cognitive impairment and may result in dementia. Although vascular risk factors are associated with the presence of white matter lesions, the exact pathogenesis remains unclear. Animal studies have indicated involvement of endothelial cells in the pathogenesis of white matter lesions and possibly dementia. We investigated the relation between endothelial cell activation and white matter lesions in individuals with cerebrovascular disease. In 29 patients with an acute stroke (n = 11) or TIAs associated with a symptomatic internal carotid artery stenosis (n = 18), markers of endothelial cell activation such as intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), sE-selectin, and sP-selectin were measured by means of ELISA. All individuals underwent 1.5-T MRI scanning. White matter lesions were rated for the periventricular and the subcortical region separately. Individuals with severe periventricular white matter lesions had higher levels of sP-selectin (245.5 ng/mL vs. 172.7 ng/mL, p = 0.01) and sVCAM-1 (547.8 ng/mL vs. 454.0 ng/mL, p = 0.04) than those without. This association was only found in individuals with a symptomatic carotid artery stenosis. No such association was found for subcortical white matter lesions. We did not detect any relation between sICAM-1 and sE-selectin and white matter lesions. Endothelial cell activation may play a role in the pathogenesis of white matter lesions, especially in periventricular white matter. Possibly, this activation represents the influence of vascular factors on the cerebral endothelium as a prelude to increasingly severe small vessel disease.

No effect of acenocoumarol therapy on levels of endothelial activation markers in sickle cell disease

Sickle cell patients are characterized by a chronic inflammatory and hypercoagulable state, depicted by elevated levels of pro-inflammatory cytokines, endothelial adhesion molecules, and elevated markers of thrombin generation. We set out to determine whether anticoagulation with a coumadin derivative reduces inflammation in sickle cell disease. Therefore, serum levels of NFkappaB-regulated endothelial adhesion molecule soluble vascular cell adhesion molecule-1 and serum levels of non-NFkappaB-dependent markers of endothelial activation (soluble cellular fibronectin and von Willebrand factor antigen) were compared during treatment with acenocoumarol (INR 1.6-2.0) and placebo. No effect on circulating levels of the measured parameters was observed during treatment with acenocoumarol as compared to placebo. In the targeted INR range, anticoagulation of sickle cell patients with acenocoumarol does not seem to reduce endothelial activation.

Relationship between graft-versus-host disease and graft-versus-leukaemia in partial T cell-depleted bone marrow transplantation

The success of allogeneic bone marrow transplantation (BMT) is limited by the major complications, graft-versus-host disease (GVHD) and relapse. The very beneficial effect of maximal T-cell depletion of the graft for prevention of GVHD has been counterbalanced by an increase in graft failure and relapse of disease. Therefore, we started an approach of partial T-cell depletion of the graft. GVHD and graft-versus-leukaemia (GVL) are strongly correlated after non-T cell-depleted BMT. Here, we report whether the correlation between GVHD and GVL also exists in partial T cell-depleted BMT from sibling donors. We retrospectively studied 117 adult patients with early haematological malignancies. Our method of partial T-cell depletion gave a relapse rate in patients with acute leukaemias similar to that observed in non-T cell-depleted BMT. However, patients with chronic myeloid leukaemia had a relapse rate that was similar to that observed in maximal T cell-depleted BMT. We found a significant correlation between the presence of chronic GVHD and an improved disease-free survival. Nevertheless, overall survival was lower in patients with chronic GVHD. There was no correlation between the occurrence of acute GVHD and disease-free or overall survival.

Lupus anticoagulant and history of thrombosis are not associated with persistent endothelial cell activation in systemic lupus erythematosus

Antiphospholipid antibodies (aPL), especially lupus anticoagulant (LAC), characterize systemic lupus erythematosus (SLE) patients at increased risk for arterial and venous thromboembolic complications. It has been reported that purified human anti-phospholipid antibodies cause endothelial cell activation in in vitro experiments. In order to investigate whether increased endothelial cell activation is associated with thromboembolic events in SLE patients with LAC, we measured plasma levels of thrombomodulin (TM), von Willebrand factor (vWf), sP-selectin, vascular cell adhesion molecule-1 (sVCAM-1) and ED1-fibronectin in a study of 76 patients with SLE. Patients were subdivided on the basis of: no history of thrombosis and LAC-negative (n = 22) or LAC-positive (n = 17); positive history of thrombosis and LAC-negative (n = 16) or LAC-positive (n = 21). The median SLE disease activity index (SLEDAI) was 4. Although concentrations of sTM, vWf, sP-selectin and sVCAM-1 were significantly elevated in SLE compared with values in healthy controls, they did not differ between the four groups, between patients with or without history of thrombosis, and between patients with or without LAC. Presence of anticardiolipin antibodies could not explain these negative findings. Adjustment of the concentrations for significantly associated variables, such as age, hypertension, smoking, immunosuppressive treatment and concentrations of creatinine, cholesterol and homocysteine, did not change the main results of the study. Only sTM was significantly lower in patients with both LAC and thrombosis than in patients without both these features after adjustment for serum creatinine concentrations. In conclusion, we did not find an association between endothelial cell activation and presence of LAC or history of thrombosis in SLE.

Cyclosporine is associated with endothelial dysfunction but not with platelet activation in renal transplantation

BACKGROUND

Cyclosporine (CsA) is associated with thrombotic micro-angiopathy and endothelial dysfunction. Markers of endothelial dysfunction may serve to identify patients at risk for development of vascular injury. In this study we measured von Willebrand Factor (vWF) and sP-selectin as possible markers for endothelial dysfunction in renal transplant recipients at different concentrations of CsA. Because sP-selectin can also be derived from platelets an additional in vitro study was performed to study the potential effect of CsA on the expression of P-selectin on platelet surface, while the effects of CsA on the interaction of platelets with Endothelial Cell Matrix (ECM) were studied under flow conditions in a perfusion chamber model.

METHODS

CsA was stepwisely replaced by mycophenolate mofetil (MMF) in 15 renal transplant recipients (more than 6 months after transplantation). VWF and sP-selectin were measured at normal CsA (median trough level 130 microg/l), low CsA (trough level 45 microg/l) and after stopping CsA. MMF 2 g daily was added while lowering and stopping CsA. Platelet activation was investigated by measurement of P-selectin on platelet surface by flow-cytometry (FACS), after incubation with CsA (0, 2, 20 and 200 mg/l) in vitro and after perfusion of whole blood over ECM with CsA (0 or 2 mg/l, peak levels).

RESULTS

Stepwise withdrawal of CsA gave a dose-related decrease of both vWF and sP-selectin, suggesting reversible endothelial dysfunction. FACS showed no expression of P-selectin on platelets by CsA. Also perfusion studies over ECM demonstrated no platelet activation by CsA but even inhibition of platelet adhesion and aggregation.

CONCLUSIONS

The use of CsA is not accompanied by platelet activation. However endothelial dysfunction induced by CsA does occur as reflected by increased vWF and sP-selectin. (See Editorial p. 1).

Persistent increase in plasma thrombomodulin in patients with a history of lupus nephritis: endothelial cell activation markers

OBJECTIVE

To investigate the presence of continuing endothelial cell activation in patients with systemic lupus erythematosus (SLE) and its relationship with lupus nephritis.

METHODS

We measured plasma concentrations of soluble thrombomodulin (sTM), vascular cellular adhesion molecule-1 (sVCAM-1), von Willebrand factor (vWf), sP-selectin, and ED1-fibronectin in 75 SLE patients with a median SLE disease activity index (SLEDAI) of 4. Forty patients with a history of lupus nephritis, confirmed by renal biopsy in 33, were compared with 35 patients without lupus nephritis and 25 controls. For subgroup analysis in patients with clinically stable remission we excluded patients with a SLEDAI > 6 or with evidence of renal disease activity.

RESULTS

In the total SLE patient group sTM, sVCAM-1, vWf, and sP-selectin were significantly elevated compared with controls. In patients with a history of lupus nephritis plasma levels of sTM and vWf were significantly increased compared with SLE patients without nephritis. After adjustment for significantly associated variables, especially creatinine clearance and age, in a multivariate linear regression analysis, sTM remained significantly elevated in patients with a history of lupus nephritis (difference 28.9 ng/ml, 95% CI 11.5-46.4). In the subgroup analysis of 57 patients, the results remained unchanged.

CONCLUSION

The increase of sVCAM-1, sP-selectin, sTM, and vWf reflects a state of persistent endothelial cell activation. Multivariate regression analysis shows that the elevated sTM levels are strongly associated with a history of lupus nephritis, independent of creatinine clearance or disease activity, suggesting endothelial cell activation specifically localized in the kidneys.