Platelet-type von Willebrand Disease: Diagnostic Challenges. Flaws and Pitfalls Experienced in the THROMKID Quality Project.

BACKGROUND: Primary haemostasis defects comprise von Willebrand disease (VWD) and platelet disorders (PD). Although presenting with mild to moderate bleeding tendency in most cases, severe bleeding and blood loss may occur unexpectedly in trauma and surgery. Diagnosis of VWD and PD often remains difficult owing to the wide spectrum of clinical and laboratory manifestations. Platelet-type von Willebrand disease (PT-VWD) is frequently misdiagnosed as type 2B VWD. Discrimination between type 2B VWD and PT-VWD is crucial as treatment differs. METHODS AND RESULTS: A literature review revealed difficulties in diagnostic work-up and choice of optimal treatment of PT-VWD. Guidelines favour the therapeutic use of platelet concentrates. A telephone survey of diagnostic practice with regard to type 2B VWD/PT-VWD was conducted. The prevalence and incidence of type 2B and PT-VWD remained unclear, but PT-VWD may be underestimated. DISCUSSION: An international study estimated that PT-VWD constitutes up to 15% of the total number of patients diagnosed with type 2B VWD. Our survey confirmed difficulties with diagnosis and showed that some centres did not exclude PT-VWD in type 2B patients. Some authors emphasize that genetic testing is the gold standard for diagnosis, but functional testing allows immediate diagnosis. Due to the important therapeutic implications we suggest that type 2B VWD be confirmed by genetic testing and that in case of a negative result PT-VWD should be excluded. CONCLUSION: PT-VWD should be excluded in all suspected cases of type 2B. PT-VWD should be treated with platelet concentrates.

Comparison of manual and semi-automatic measuring techniques in MSCT scans of patients with lymphoma: a multicentre study.

OBJECTIVES: Multicentre evaluation of the precision of semi-automatic 2D/3D measurements in comparison to manual, linear measurements of lymph nodes regarding their inter-observer variability in multi-slice CT (MSCT) of patients with lymphoma. METHODS: MSCT data of 63 patients were interpreted before and after chemotherapy by one/two radiologists in five university hospitals. In 307 lymph nodes, short (SAD)/long (LAD) axis diameter and WHO area were determined manually and semi-automatically. Volume was solely calculated semi-automatically. To determine the precision of the individual parameters, a mean was calculated for every lymph node/parameter. Deviation of the measured parameters from this mean was evaluated separately. Statistical analysis entailed intraclass correlation coefficients (ICC) and Kruskal-Wallis tests. RESULTS: Median relative deviations of semi-automatic parameters were smaller than deviations of manually assessed parameters, e.g. semi-automatic SAD 5.3 vs. manual 6.5 %. Median variations among different study sites were smaller if the measurement was conducted semi-automatically, e. g. manual LAD 5.7/4.2 % vs. semi-automatic 3.4/3.4 %. Semi-automatic volumetry was superior to the other parameters (2.8 %). CONCLUSIONS: Semi-automatic determination of different lymph node parameters is (compared to manually assessed parameters) associated with a slightly greater precision and a marginally lower inter-observer variability. These results are with regard to the increasing mobility of patients among different medical centres and in relation to the quality management of multicentre trials of importance. KEY POINTS: • In a multicentre setting, semi-automatic measurements are more accurate than manual assessments. • Lymph node volumetry outperforms all other semi-automatically and manually performed measurements. • Use of semi-automatic lymph node analyses can reduce the inter-observer variability.

Induction therapy of AML with ara-C plus daunorubicin versus ara-C plus gemtuzumab ozogamicin: a randomized phase II trial in elderly patients.

BACKGROUND: Chemotherapy for elderly patients with acute myeloid leukemia (AML) results in a median overall survival (OS) of ≤ 1 year. Elderly patients often present with cardiac comorbidity. Gemtuzumab ozogamicin (GO) is active in elderly (≥ 60 years) patients with relapsed AML with low cardiac toxicity. PATIENTS AND METHODS: This randomized phase II study compared a standard combination of ara-C and daunorubicin (DNR; 7+3) versus ara-C plus gemtuzumab ozogamicin (7+GO) as the first course of induction therapy. Primary objectives were comparison of blast clearance on day 16, event-free survival (EFS), and remission duration. OS, complete remission (CR), and tolerability were secondary objectives. RESULTS: One hundred and nineteen patients with de novo AML, treatment-related AML, AML with a history of myelodysplastic syndrome (MDS), or high-risk MDS entered the study. Median age of 115 patients (intent-to-treat population) was 69 years. Protocol outlined a second course 7+3 for patients without blast clearance and two courses of high-dose ara-C consolidation upon CR. Both treatments were equally effective in blast clearance, CR, EFS, remission duration, or OS (median: 7+3, 9 months; 7+GO, 10 months). Induction death rate was higher in the GO group due to veno-occlusive disease. CONCLUSION: The study did not show significant superiority of 7+GO over standard 7+3.

Multiplate whole blood impedance point of care aggregometry: preliminary reference values in healthy infants, children and adolescents.

BACKGROUND: The aim of the present study was to evaluate paediatric reference values for platelet function using a point-of-care whole blood impedance aggregometry. METHODS, RESULTS & CONCLUSION: In 265 healthy infants and children aged

Prognostic relevance of angiogenesis in stage III NSCLC receiving multimodality treatment.

Compelling evidence indicates that microvessel density (MVD) is a prognostic marker in early nonsmall cell lung cancer (NSCLC). However, its role in lymph node metastases in stage III NSCLC receiving multimodality treatment is unknown. Lymph nodes of 142 patients with stage III NSCLC, treated in a trial of the German Lung Cancer Cooperative group, were evaluated for MVD. Median follow-up was 7.39 yrs. MVD was correlated with demographic and tumour-related variables and survival. MVD (median 33.9) did not correlate with survival. However, in multimodality-treated stage IIIA patients receiving tumour resection with negative margins (R0), those with a high MVD had significantly prolonged overall survival with a median of 4.96 yrs compared with 1.99 yrs for those with low MVD (p = 0.041). Cox regression analysis revealed that MVD was a prognostic factor in R0-resected stage IIIA (hazard ratio 0.417). Furthermore, a significant correlation of MVD to stage was observed, with significantly lower MVD in stage IIIA than IIIB (p = 0.0062), and a significant correlation of MVD to histological subtype was observed, with adenocarcinoma revealing the highest scores (p = 0.0001). Increased angiogenesis within lymph node metastases is a prognostic indicator for better survival in NSCLC patients. Thus, measurement of MVD might be useful in selecting patients for future neoadjuvant treatment decisions.

Use of palifermin for the prevention of high-dose methotrexate-induced oral mucositis.

BACKGROUND: Oral mucositis is a frequent problem after high-dose methotrexate (HD-MTX), impairing patient's quality of life, leading to higher rates of infections and delaying subsequent chemotherapy. This report describes the effect of palifermin in patients treated within the GMALL-B-ALL 2002 protocol containing HD-MTX who developed a severe mucositis in cycle A1/B1. PATIENTS AND METHODS: Ten patients, all with World Health Organization grades III-IV oral mucositis in cycles A1/B1, obtained palifermin with subsequent similar or identical cycles to reduce mucositis. Thus, patients serve as their own control for efficacy of palifermin. RESULTS: All 10 patients developed grades III-IV mucositis in cycles A1/B1 without palifermin, whereas only two of 10 developed grades III-IV mucositis in corresponding cycles A2/B2 with palifermin. Only four of 10 patients showed infections in the cycles with palifermin compared with 10 of 10 patients without palifermin. The duration of mucositits in patients who acquired a higher grade mucositis despite treatment with palifermin could be reduced from 12.9 days (median) without to 11 days with palifermin. The amount of i.v. opioid analgetics could be significantly reduced. CONCLUSION: Palifermin might reduce the incidence, severeness and duration of oral mucositis in HD-MTX-based chemotherapy and may influence clinical sequelae such as infection and quality of life.

Dose-escalated CHOEP for the treatment of young patients with aggressive non-Hodgkin's lymphoma: II. Results of the randomized high-CHOEP trial of the German High-Grade Non-Hodgkin's Lymphoma Study Group (DSHNHL).

BACKGROUND: The addition of etoposide to combination chemotherapy with cyclophosphamide, doxorubicin, vincristine and prednisone [etoposide to combination chemotherapy with cyclophosphamide, vincristine and prednisone (CHOEP)] improved outcome of young patients with good-prognosis aggressive lymphoma. To improve results further, the maximal dose-escalated version of CHOEP-21 tolerable without stem-cell support (high CHOEP: cyclophosphamide 1400 mg/m2, doxorubicin 65 mg/m2, vincristine 2 mg, etoposide 175 mg/m2 x3, prednisone 100 mg x5) was compared with CHOEP-21. PATIENTS AND METHODS: Intention-to-treat analysis of 389 young (18-60 years) patients with good-prognosis (age-adjusted International Prognostic Index = 0, 1) aggressive lymphoma randomized to CHOEP-21 (n = 194) or high CHOEP (n = 195). RESULTS: There was no difference in 3-year event-free (64% versus 67%; P = 0.734) or overall survival (83% versus 87%; P = 0.849). Neither low-risk nor low-intermediate risk patients benefited from high CHOEP. High CHOEP was more toxic than CHOEP-21 (grades 3 and 4 leukocytopenia 100% versus 87.2%, P < 0.001; thrombocytopenia 80.8% versus 9.6%, P < 0.001; infections 35% versus 11%, P < 0.001; therapy-associated deaths 3.1% versus 0%, P = 0.03). CONCLUSION: Dose-escalated CHOEP-21 does not provide clinical benefit for young patients with good-prognosis aggressive lymphomas. Since differences between chemotherapy regimens are compressed by the addition of rituximab, the results of this trial have bearing on strategies aiming to improve outcome of good-prognosis aggressive lymphomas in the rituximab era.

Amsacrine containing induction therapy in elderly AML patients: comparison to standard induction regimens in a matched-pair analysis.

Many elderly patients with newly diagnosed acute myeloid leukemia (AML) present with cardiac comorbidity precluding the use of anthracycline containing chemotherapy regimens. Amsacrine, a topoisomerase II inhibitor, has been proposed as possible alternative to anthracyclines. Here, we report about the combination of amsacrine (210 mg/m(2)), in replacement for daunorubicin (DNR), with standard dose cytarabine and thioguanine (TAA) to elderly patients (>or=60 years of age) with impaired cardiac function. The outcome of 16 patients with a median age of 66 years treated between 1997 and 2003 was compared with standard treatment regimens of the AMLCG study group in a matched-pair analysis. There were no statistically significant differences in response rate, relapse free survival or overall survival between TAA treated patients or standard therapy. In conclusion, replacing anthracyclines with amsacrine for induction therapy of AML patients with significant cardiac comorbidities represents a treatment option without compromising the potential curability of the disease.

Circulating angiopoietin-2 is a strong prognostic factor in acute myeloid leukemia.

Angiogenesis plays an important role in solid tumors and hematologic malignancies. The angiopoietins act as essential regulators in this process. We investigated the impact of circulating angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and soluble Tie2 (sTie2) on overall survival in patients with acute myeloid leukemia (AML). Ang-1, Ang-2 and sTie2 were measured in plasma samples from 68 AML patients and 11 controls using enzyme-linked immunosorbent assay. Circulating levels of Ang-2 and sTie2 (median (range): 1098.0 (361.4-4147.6) pg/ml and 3.40 (1.21-10.00) ng/ml, respectively) were significantly elevated in AML patients as compared to controls (307.9 (199.7-1225.0) pg/ml and 2.88 (1.71-3.29) ng/ml; P<0.001 and P=0.014). In a univariate Cox proportional hazards model, higher levels of Ang-2 and sTie2 were predictive of poor survival. In multivariate analyses, Ang-2 and cytogenetics proved to be independent prognostic factors, with a relative risk of 4.07 (95% confidence interval (CI) 1.88-8.81) and 2.70 (95% CI 1.25-5.81), respectively. The 3-year survival rate for AML patients with Ang-2 levels>/=1495.6 pg/ml was only 14.7% compared to 64.7% for those with Ang-2 levels<1495.6 pg/ml. These data provide evidence that circulating Ang-2 represents an independent prognostic factor in AML and may be used as a prognostic tool in the risk-adapted management of AML.

An atlas of bloodstream-accessible bone marrow proteins for site-directed therapy of acute myeloid leukemia.

The concept of arming antibodies with bioactive payloads for a site-specific therapy of cancer has gained considerable interest in recent years. However, a successful antibody-based targeting approach critically relies on the availability of a tumor-associated target that is not only preferentially expressed in the tumor tissue but is also easily accessible for antibody therapeutics coming from the bloodstream. Here, we perfused the vasculature of healthy and acute myeloid leukemia (AML)-bearing rats with a reactive ester derivative of biotin and subsequently quantified the biotinylated proteins to identify AML-associated bone marrow (BM) antigens accessible from the bloodstream. In total, >1400 proteins were identified. Overall, 181 proteins were >100-fold overexpressed in AML as compared with normal BM. Eleven of the most differentially expressed proteins were further validated by immunohistochemistry and confocal microscopic analyses, including novel antigens highly expressed in AML cells (for example, adaptor-related protein complex 3 ß2) and in the leukemia-modified extracellular matrix (ECM) (for example, collagen-VI-α-1). The presented atlas of targetable AML-associated BM proteins provides a valuable basis for the development of monoclonal antibodies that could be used as carriers for a site-specific pharmacodelivery of cytotoxic drugs, cytokines or radionuclides to the BM in AML.

Chemotherapy in metastatic malignant triton tumor: report on two cases.

Malignant triton tumor (MTT) is a rare, highly malignant nerve sheath tumor with rhabdomyoblastic differentiation. Initial debulking surgery followed by adjuvant therapy is the current treatment of choice, but has very limited efficacy when optimal cytoreduction is not achieved by surgical procedure. Neoadjuvant therapy for MTT, to potentially facilitate subsequent surgery, eradicate micrometastatic lesions and, therefore, improve the therapeutical outcome, has never before been presented in literature. Here, we report on the multimodal management of two cases of advanced and metastatic MTT. Treatment modalities involved neoadjuvant and adjuvant chemotherapy, surgical resection, and radiation. In both cases, integrated Positron Emission Tomography/Computed Tomography (PET/CT) emerged as an important diagnostic tool for the reliable assessment of MTT response and metabolic remission.

Correlation of neuropilin-1 overexpression to survival in acute myeloid leukemia.

Neuropilin-1 (NRP-1), a vascular endothelial growth factors and semaphorin receptor functioning as mediator of angiogenesis and neuronal guidance, is expressed by various solid tumors. The importance of NRP-1 in hematological malignancies such as acute myeloid leukemia (AML) remains to be elucidated. Therefore, we determined NRP-1 expression by immunohistochemical analysis of bone marrow biopsies of patients with newly diagnosed, untreated AML. The expression of NRP-1 was significantly increased in AML patients (n = 76; median 12.9 arbitrary units (a.u.)) as compared with controls (n = 38; median 2.75 a.u.). Survival was significantly poorer in patients with high (> median) versus low (< or = median) NRP-1 expression levels with 5-year overall survival rates of 16.9 versus 49.6% (P = 0.050). In conclusion, our data provide evidence of increased NRP-1 expression in AML with significant correlation to survival. Thus, NRP-1 might constitute a promising target for antileukemic and antiangiogenic treatment strategies in AML.

Outcome of allogeneic stem cell transplantation for AML and myelodysplastic syndrome in elderly patients (⩾60 years).

Allogeneic stem cell transplantation (SCT) remains the best curative option for patients with refractory AML or with high-risk myelodysplastic syndrome (MDS). For decades, age alone had been widely used as the primary criterion to assess eligibility for allogeneic SCT; however, prospective studies to evaluate allogeneic SCT in elderly patients are still limited. A total of 187 patients (median age of 64 years, range 60-77 years) with AML (87%) or MDS (13%) transplanted between 1999 and 2014 were included in this retrospective analysis. Relapse-free survival (RFS) and overall survival (OS) at 3 years were 32% (95% confidence interval (CI): 25-39%) and 35% (95%CI: 27-42%), respectively. Overall survival was 49% (95%CI: 35-64%) in AML patients who were transplanted in first complete remission (CR1), but even patients with active disease did benefit from transplantation, showing an OS at 3 years of 30% (95%CI: 20-40%). Multivariate analysis revealed disease- and patient-specific risk indices as independent prognostic factors for OS and non-relapse mortality (NRM). In conclusion, our monocenter results indicate that patients should not be generally withheld from allogeneic SCT because of age or disease status only. Specific risk models incorporating disease status and disease-specific risk factors at the time of transplantation as well as existing comorbidities are helpful tools to assess transplantation-associated risk factors of elderly patients.

Overexpression of vascular endothelial growth factor (VEGF) and its cellular receptor KDR (VEGFR-2) in the bone marrow of patients with acute myeloid leukemia.

Vascular endothelial growth factor (VEGF) and its cellular receptor VEGFR-2 have been implicated as the main endothelial pathway required for tumor neovascularization. However, the importance of the VEGF/VEGFR-2 system for angiogenesis in hematologic malignancies such as AML remains to be elucidated. In 32 patients with newly diagnosed untreated AML, we observed by immunohistochemical analysis of bone marrow biopsies significantly higher levels of VEGF and VEGFR-2 expression than in 10 control patients (P <0.001). In contrast, VEGFR-1 staining levels in AML patients were in the same range as in the controls. Expression of VEGF and VEGFR-2 was significantly higher in patients with a high degree of microvessel density compared to those with a low degree (VEGF: P =0.024; VEGFR-2: P =0.040) and correlated well with bone marrow microvessel density (r(s)=0.566 and 0.609, respectively; P <0.001). Furthermore, in patients who achieved a complete remission following induction chemotherapy VEGFR-2 staining levels decreased into the normal range. In conclusion, our results provide evidence for increased expression of VEGF/VEGFR-2 of leukemic blasts and correlation with angiogenesis in the bone marrow of AML patients. Thus, VEGF/VEGFR-2 might constitute promising targets for antiangiogenic and antileukemic treatment strategies in AML.

Comparative analysis of plasminogen activator inhibitor-1 expression in different types of atherosclerotic lesions in coronary arteries from human heart explants.

OBJECTIVES: Clinical manifestations of coronary heart disease result primarily from the progressive development of atherosclerotic plaques and subsequent thrombus formation: processes which may be accelerated by an enhanced expression of plasminogen activator inhibitor (PAI-1) in the vessel wall. In the present study, content and expression of PAI-1 were comparatively analyzed in human coronary arteries in relation to the presence and severity of atherosclerotic lesions. METHODS: Segments of coronary arteries obtained from heart explants (n = 15) were classified by the presence and types of atherosclerotic lesions. Antigen and activity levels of PAI-1 were determined in protein extracts of intimal and medial layers. In situ hybridization and immunohistochemical analyses were performed on serial sections of representative tissue specimens. RESULTS: Total PAI-1 antigen consistently increased from macroscopically normal areas (MNAs) to early lesions (ELs) and to maximal levels in fibrous (FPs) and calcified (CPs) plaques. No PAI activity was detected, although PAI-1 in its free form was present in all vascular specimens. Both free PAI-1 and PAI-1 complexed with plasminogen activators were significantly increased in extracts of advanced lesions. However, there was a 2-3 fold molar excess of free versus complexed PAI-1 in FPs and CPs. These findings suggest the presence of relevant amounts of PAI-1 in its substrate rather than in its inhibitor conformation in areas of advanced lesions. Compared with MNAs, PAI-1 mRNA was strongly expressed within the thickened intima of ELs. The highest PAI-1 expression was observed in FPs and CPs, being mainly localized in areas surrounding the necrotic cores in co-localization with infiltrating macrophages. CONCLUSIONS: PAI-1 content is consistently increased in relation to the severity of the lesions in atherosclerotic coronary arteries. The concomitant elevation of PAI-1 mRNA suggests that the PAI-1 increase in regulated by local synthesis in the areas of atherosclerotic lesions.

Treatment strategies in patients with AML or high-risk myelodysplastic syndrome relapsed after Allo-SCT.

Non-relapse mortality after Allo-SCT has significantly decreased over the last years. Nevertheless, relapse remains a major cause for post SCT mortality in patients with AML and high-risk myelodysplastic syndrome (MDS). In this retrospective single-center analysis, we have analyzed the treatment outcomes of 108 patients with AML or MDS, who relapsed after Allo-SCT. Seventy of these patients (65%) were treated with salvage therapies containing chemotherapy alone, allogeneic cell-based treatment or the combination of both. Thirty-eight patients (35%) received palliative treatment. Median OS after diagnosis of relapse was 130 days. Compared with patients who received chemotherapy alone, response to salvage therapy was significantly improved in patients treated with a combination of chemo- and allogeneic cell-based therapy (CR rate 57% vs 13%, P=0.002). Among risk factors concerning pretreatment characteristics, disease status before first Allo-SCT, and details of transplantation, only the time interval from Allo-SCT to relapse was an independent predictor of response to salvage therapy and OS. These data confirmed that time to relapse after transplantation is an important prognostic factor. Up to now, only patients eligible for treatment regimens containing allogeneic cell-based interventions achieved relevant response rates.

Interactions and inhibition of blood coagulation factor Va involving residues 311-325 of activated protein C.

Activated protein C (APC) exerts its physiologic anticoagulant role by proteolytic inactivation of the blood coagulation cofactors Va and VIIIa. The synthetic peptide-(311-325) (KRNRTFVLNFIKIPV), derived from the heavy chain sequence of APC, potently inhibited APC anticoagulant activity in activated partial thromboplastin time (APTT) and Xa-1-stage coagulation assays in normal and in protein S-depleted plasma with 50% inhibition at 13 microM peptide. In a system using purified clotting factors, peptide-(311-325) inhibited APC-catalyzed inactivation of factor Va in the presence or absence of phospholipids with 50% inhibition at 6 microM peptide. However, peptide-(311-325) had no effect on APC amidolytic activity or on the reaction of APC with the serpin, recombinant [Arg358]alpha 1-antitrypsin. Peptide-(311-325) surprisingly inhibited factor Xa clotting activity in normal plasma, and in a purified system it inhibited prothrombinase activity in the presence but not in the absence of factor Va with 50% inhibition at 8 microM peptide. The peptide had no significant effect on factor Xa or thrombin amidolytic activity and no effect on the clotting of purified fibrinogen by thrombin, suggesting it does not directly inhibit these enzymes. Factor Va bound in a dose-dependent manner to immobilized peptide-(311-325). Peptide-(311-315) inhibited the binding of factor Va to immobilized APC or factor Xa.(ABSTRACT TRUNCATED AT 250 WORDS)

Overexpression of tissue-type plasminogen activator in atherosclerotic human coronary arteries.

UNLABELLED: The plasminogen activator (PA)/plasmin system is involved in various pathological processes that are considered important features of atherogenesis and atherothrombosis. These include the proteolysis of fibrin deposits and extracellular matrix components as well as the induction of cell migration and mitogenesis. Tissue-type PA (TPA) is a key enzyme mediating plasminogen to plasmin conversion. TPA plasma concentrations are elevated in patients with advanced atherosclerosis and correlate with an increased risk for myocardial infarction and stroke. In this study, we have analysed the content and expression of TPA in human coronary arteries and their relation to the presence and severity of atherosclerotic lesions. METHODS: Segments of coronary arteries obtained from heart explants (n = 15) were classified by the presence and types of atherosclerotic lesions. TPA was quantitatively determined in protein extracts of intimal and medial layers. In situ hybridization and immunohistochemical analyses were performed on serial sections of representative tissue specimens. RESULTS: PA activity entirely attributable to the presence of active TPA was consistently detected in the protein extracts. Extractable TPA antigen and activity showed a significant graded increase in relation to the presence and severity of atherosclerotic lesions. The ratios of active over total TPA were increased several-fold in extracts of advanced lesions despite a concomitant threefold increase in TPA complexed to its inhibitor PA-1. In macroscopically normal arterial segments and in early lesions, TPA was expressed in the endothelium and in colocalization with vascular smooth muscle cells (VSMCs). In advanced plaques, TPA mRNA was mainly detected in the lateral regions of the fibrous caps in association with migrating VSMCs and in the vicinity of the core areas infiltrated by CD68-positive macrophages. CONCLUSIONS: TPA content and expression is consistently increased in relation to the severity of the lesions in atherosclerotic coronary arteries. This may contribute to plaque destabilization and disruption. Conversely, the increased intramural TPA activity may counteract mural fibrin deposition.

Increase of plasminogen activator inhibitor levels predicts outcome of leukocytopenic patients with sepsis.

Variables of the fibrinolytic system were prospectively studied in patients with haematologic malignancies in chemotherapy-induced leukocytopenia at onset and during the course of septicemia to evaluate their prognostic value. This group of patients was chosen because of their high risk of developing severe septic complications, thus allowing serial prospective testing of fibrinolytic variables prior to and during evolving sepsis or septic shock. 62 patients with febrile infectious events were accrued to the study. Of these, 13 patients progressed to severe sepsis and an additional 13 patients to septic shock as defined according to standard diagnostic criteria. At onset of fever, plasminogen activator inhibitor (PAI) activity and PAI-1 antigen levels increased from normal baseline levels and were significantly higher in the group of patients who developed septic shock compared to those with severe sepsis (medians: 10.6 versus 1.3 U/ml, p = 0.0001; 50.0 versus 5.0 ng/ml, p = 0.0002). The increase in PAI activity and antigen in septic shock was accompanied by an increase in tissue-type plasminogen activator antigen and total fibrin(ogen) degradation products and a decrease in alpha(2)-antiplasmin activity (p < 0.006). In contrast, in the group of patients that developed severe sepsis the variables of the fibrinolytic system remained unchanged at onset of fever. These differences between septic shock and severe sepsis were sustained throughout the septic episode for all variables (p < 0.0001). PAI activity of > 5 U/ml at onset of fever predicted a lethal outcome with a sensitivity of 92% and a specificity of 100%. Thus, septic shock in leukocytopenia is associated with significant activation of the fibrinolytic system presumably as a response of the vascular endothelium to inflammatory injury. Furthermore, PAI activity measurements are sensitive markers of an unfavourable prognosis.