Hemophagocytosis, hyper-inflammatory responses, and multiple organ damages in COVID-19-associated hyperferritinemia.

Hyperferritinemia comes to light frequently in general practice. However, the characteristics of COVID-19-associated hyperferritinemia and the relationship with the prognosis were not well described. The retrospective study included 268 documented COVID-19 patients. They were divided into the hyperferritinemia group (≥ 500 µg/L) and the non-hyperferritinemia group (< 500 µg/L). The prevalence of fever and thrombocytopenia and the proportion of patients with mechanical ventilator support and in-hospital death were much higher in the hyperferritinemia group (P < 0.001). The hyperferritinemia patients showed higher median IL-6, D-dimer, and hsCRP (P < 0.001) and lowered FIB level (P = 0.036). The hyperferritinemia group had a higher proportion of patients with AKI, ARDS, and CSAC (P < 0.001). According to the multivariate analysis, age, chronic pulmonary disease, and hyperferritinemia were found to be significant independent predictors for in-hospital mortality [HR 1.041 (95% CI 1.015-1.068), P = 0.002; HR 0.427 (95% CI 0.206-0.882), P = 0.022; HR 6.176 (95% CI 2.447-15.587), P < 0.001, respectively]. The AUROC curve was 0.88, with a cut-off value of ≥ 971 µg/L. COVID-19 patients with hyperferritinemia had a high proportion of organ dysfunction, were more likely to show hyper-inflammation, progressed to hemophagocytic lymphohistiocytosis, and indicated a higher proportion of death.

Divergent impacts of tocilizumab and colchicine in COVID-19-associated coagulopathy: the role of alpha-defensins.

Patients who are severely affected by coronavirus disease 2019 (COVID-19) may develop a delayed onset 'cytokine storm', which includes an increase in interleukin-6 (IL-6). This may be followed by a pro-thrombotic state and increased D-dimers. It was anticipated that tocilizumab (TCZ), an anti-IL-6 receptor monoclonal antibody, would mitigate inflammation and coagulation in patients with COVID-19. However, clinical trials with TCZ have recorded an increase in D-dimer levels. In contrast to TCZ, colchicine reduced D-dimer levels in patients with COVID-19. To understand how the two anti-inflammatory agents have diverse effects on D-dimer levels, we present data from two clinical trials that we performed. In the first trial, TCZ was administered (8 mg/kg) to patients who had a positive polymerase chain reaction test for COVID-19. In the second trial, colchicine was given (0·5 mg twice a day). We found that TCZ significantly increased IL-6, α-Defensin (α-Def), a pro-thrombotic peptide, and D-dimers. In contrast, treatment with colchicine reduced α-Def and Di-dimer levels. In vitro studies show that IL-6 stimulated the release of α-Def from human neutrophils but in contrast to colchicine, TCZ did not inhibit the stimulatory effect of IL-6; raising the possibility that the increase in IL-6 in patients with COVID-19 treated with TCZ triggers the release of α-Def, which promotes pro-thrombotic events reflected in an increase in D-dimer levels.

Targeting thrombogenicity and inflammation in chronic HIV infection.

Persons with HIV infection (PWH) have increased risk for cardiovascular disease (CVD), but the underlying mechanisms remain unclear. Coronary thrombosis is known to provoke myocardial infarctions, but whether PWH have elevated thrombotic propensity is unknown. We compared thrombogenicity of PWH on antiretroviral therapy versus matched controls using the Badimon chamber. Measures of inflammation, platelet reactivity, and innate immune activation were simultaneously performed. Enrolled PWH were then randomized to placebo, aspirin (81 mg), or clopidogrel (75 mg) for 24 weeks to assess treatment effects on study parameters. Thrombogenicity was significantly higher in PWH and correlated strongly with plasma levels of D-dimer, soluble TNF receptors 1 and 2, and circulating classical and nonclassical monocytes in PWH. Clopidogrel significantly reduced thrombogenicity and sCD14. Our data suggest that higher thrombogenicity, interacting with inflammatory and immune activation markers, contributes to the increased CVD risk observed in PWH. Clopidogrel exhibits an anti-inflammatory activity in addition to its antithrombotic effect in PWH.

Role of T-Cell Dysfunction, Inflammation, and Coagulation in Microvascular Disease in HIV.

BACKGROUND: Compared to uninfected adults, HIV-infected adults on antiretroviral therapy are at increased risk of cardiovascular disease. Given the increase in T-cell dysfunction, inflammation, and coagulation in HIV infection, microvascular dysfunction is thought to contribute to this excess cardiovascular risk. However, the relationships between these variables remain undefined. METHODS AND RESULTS: This was a cross-sectional study of 358 HIV-infected adults from the SCOPE cohort. Macrovascular endothelial function was assessed using flow-mediated dilation of the brachial artery and microvascular function by reactive hyperemia. T-cell phenotype was determined by flow cytometry. Plasma markers of inflammation (tumor necrosis factor-α, interleukin-6, high-sensitivity C-reactive protein, sCD14) and coagulation (fibrinogen, D-dimer) were also measured. In all HIV+ subjects, markers of inflammation (tumor necrosis factor-α, high-sensitivity C-reactive protein), coagulation (D-dimer) and T-cell activation (CD8+PD1+, CD4+interferon+cytomegalovirus-specific) were associated with worse reactive hyperemia after adjusting for traditional cardiovascular risk factors and co-infections. In treated and suppressed subjects, tumor necrosis factor-α and CD8+PD1+ cells remained associated with worse reactive hyperemia after adjustment. Compared to the untreated subjects, CD8+PD1+ cells were increased in the virally suppressed group. Reactive hyperemia was predictive of flow-mediated dilation. CONCLUSIONS: CD8+PD1+ cells and tumor necrosis factor-α were associated with microvascular dysfunction in all HIV+ subjects and the treated and suppressed group. Additionally, D-dimer, high-sensitivity C-reactive protein, sCD-14, and interleukin-6 were associated with microvascular dysfunction in all HIV+ subjects. Although T-cell dysfunction, inflammation, and microvascular dysfunction are thought to play a role in cardiovascular disease in HIV, this study is the first to look at which T-cell and inflammatory markers are associated with microvascular dysfunction in HIV-infected individuals.

Do Biomarkers of Inflammation, Monocyte Activation, and Altered Coagulation Explain Excess Mortality Between HIV Infected and Uninfected People?

BACKGROUND: HIV infection and biomarkers of inflammation [measured by interleukin-6 (IL-6)], monocyte activation [soluble CD14 (sCD14)], and coagulation (D-dimer) are associated with morbidity and mortality. We hypothesized that these immunologic processes mediate (explain) some of the excess risk of mortality among HIV infected (HIV+) versus uninfected people independently of comorbid diseases. METHODS: Among 2350 (1521 HIV+) participants from the Veterans Aging Cohort Study Biomarker Cohort (VACS BC), we investigated whether the association between HIV and mortality was altered by adjustment for IL-6, sCD14, and D-dimer, accounting for confounders. Participants were followed from date of blood draw for biomarker assays (baseline) until death or July 25, 2013. Analyses included ordered logistic regression and Cox Proportional Hazards regression. RESULTS: During 6.9 years (median), 414 deaths occurred. The proportional odds of being in a higher quartile of IL-6, sCD14, or D-dimer were 2-3 fold higher for viremic HIV+ versus uninfected people. Mortality rates were higher among HIV+ compared with uninfected people [incidence rate ratio (95% CI): 1.31 (1.06 to 1.62)]. Mortality risk increased with increasing quartiles of IL-6, sCD14, and D-dimer regardless of HIV status. Adjustment for IL-6, sCD14, and D-dimer partially attenuated mortality risk among HIV+ people with unsuppressed viremia (HIV-1 RNA ≥10,000 copies per milliliter) compared with uninfected people-hazard ratio (95% CI) decreased from 2.18 (1.60 to 2.99) to 2.00 (1.45 to 2.76). CONCLUSIONS: HIV infection is associated with elevated IL-6, sCD14, and D-dimer, which are in turn associated with mortality. Baseline measures of these biomarkers partially mediate excess mortality risk among HIV+ versus uninfected people.

The dysfunction of platelets in paroxysmal nocturnal hemoglobinuria.

INTRODUCTION: Thrombosis is a dangerous complication of paroxysmal nocturnal hemoglobinuria (PNH) and has a high mortality rate. However, the mechanism underlying the development of thrombosis in PNH remains unclear. To explore this, platelet function and serum complement activity were investigated in 14 patients with classical PNH, 11 with PNH aplastic anemia (AA) and 30 healthy controls. MATERIAL AND METHODS: Serum concentrations of the terminal complement complex (sC5b-9) were determined by enzyme-linked immunofluorescence assay (ELISA), and the levels of C5b-9, CD61 and CD62p on platelet membranes were determined by flow cytometry. Clinical parameters were assessed, including D-dimer and platelet aggregation induced by adenosine diphosphate (ADP) and arachidonic acid (ARA). RESULTS: Serum sC5b-9 concentrations were significantly lower in the PNH/PNH-AA than in the control group (P<0.01). C5b-9 deposition was significantly higher on CD59- platelets than on CD59+ platelets in PNH/PNH-AA patients and healthy controls (P<0.01 for each). D-dimer concentration was significantly higher in PNH/PNH-AA patients - especially those with lactate dehydrogenase (LDH) concentrations>1000U/L - than in controls (P<0.05). CD61 (P<0.05) expression was lower on CD59+ platelets in PNH than in controls and CD5- platelets in PNH. Expression of CD62p (P<0.01) was lower on CD59- and CD59+ platelets (P<0.01) in PNH cases than in controls. Platelet aggregation stimulated by the agonists ADP and ARA in the PNH/PNH-AA patients was significantly lower than that in controls (P<0.05). CONCLUSIONS: The adhesion and aggregation of platelets, especially of CD59+ platelets, were compensatively decreased in PNH/PNH-AA patients without active thrombosis.

Increase in myeloid-derived suppressor cells (MDSCs) associated with minimal residual disease (MRD) detection in adult acute myeloid leukemia.

Myeloid-derived suppressor cells (MDSCs) are thought to help provide a cellular microenvironments in many solid tumors, in which transformed cells proliferate, acquire new mutations, and evade host immunosurveillance. In the present study, we found that MDSCs (CD33 + CD11b + HLA-DR(low/neg)) in bone marrow were significantly increased in adult acute myeloid leukemia (AML) patients. MDSCs levels in newly diagnosed AML patients correlated well with extramedullary infiltration and plasma D-dimer levels. Remission rates in the MDSCs > 1500 group and MDSCs < 1500 group were 72.73 and 81.25 %, respectively. No significant differences were found between the two groups. MDSC levels in the complete remission group were significantly decreased after chemotherapy, while in the partial remission and non-remission groups, there were no significant differences. The level of MDSCs in the high minimal residual disease (MRD) group was significantly higher than that in the middle and low MRD groups. High levels of Wilms' Tumor-1 (WT-1) protein were strongly correlated with higher bone marrow MDSC levels. In conclusion, we report here a population of immunosuppressive monocytes in the bone marrow of patients with AML characterized by the CD33(high)CD11b + HLA-DR(low/neg) phenotype. These cells appear to impact the clinical course and prognosis of AML. This data may provide potentially important targets for novel therapies.

Pre-therapy inflammation and coagulation activation and long-term CD4 count responses to the initiation of antiretroviral therapy.

OBJECTIVES: Pre-antiretroviral therapy (ART) inflammation and coagulation activation predict clinical outcomes in HIV-positive individuals. We assessed whether pre-ART inflammatory marker levels predicted the CD4 count response to ART. METHODS: Analyses were based on data from the Strategic Management of Antiretroviral Therapy (SMART) trial, an international trial evaluating continuous vs. interrupted ART, and the Flexible Initial Retrovirus Suppressive Therapies (FIRST) trial, evaluating three first-line ART regimens with at least two drug classes. For this analysis, participants had to be ART-naïve or off ART at randomization and (re)starting ART and have C-reactive protein (CRP), interleukin-6 (IL-6) and D-dimer measured pre-ART. Using random effects linear models, we assessed the association between each of the biomarker levels, categorized as quartiles, and change in CD4 count from ART initiation to 24 months post-ART. Analyses adjusted for CD4 count at ART initiation (baseline), study arm, follow-up time and other known confounders. RESULTS: Overall, 1084 individuals [659 from SMART (26% ART naïve) and 425 from FIRST] met the eligibility criteria, providing 8264 CD4 count measurements. Seventy-five per cent of individuals were male with the mean age of 42 years. The median (interquartile range) baseline CD4 counts were 416 (350-530) and 100 (22-300) cells/µL in SMART and FIRST, respectively. All of the biomarkers were inversely associated with baseline CD4 count in FIRST but not in SMART. In adjusted models, there was no clear relationship between changing biomarker levels and mean change in CD4 count post-ART (P for trend: CRP, P = 0.97; IL-6, P = 0.25; and D-dimer, P = 0.29). CONCLUSIONS: Pre-ART inflammation and coagulation activation do not predict CD4 count response to ART and appear to influence the risk of clinical outcomes through other mechanisms than blunting long-term CD4 count gain.

A fibrin antibody binding to fibronectin induces potent inhibition of angiogenesis.

Antiserum from rabbits immunised with pure human fibrinogen was affinity purified on immobilised fibrin fragment E (FFE). This FFE antibody (Ab) induced significant growth inhibition of a human cancer xenograft in mice and suppression of tumour angiogenesis, leaving no formed vessels and only CD31-staining endothelial fragments in place. Tubule formation of HUVEC on MatrigelTM was also significantly inhibited by FFE Ab. Since MatrigelTM is fibrin-free, this effect implicated a different FFE Ab binding site than FFE. Flow cytometry of HUVEC showed that FFE Ab bound to HUVEC, but with a broad range of 55-98 %. Immunofluorescent staining of HUVEC explained this range, since FFE Ab was seen not to bind to human umbilical vein endothelial cells (HUVEC) directly but instead to a matrix protein variably adherent to HUVEC. This protein was identified as fibronectin (FN) by appearance, staining with FN Ab, and by a FN knockdown study. Neither HUVEC nor matrix reacted with fibrin D-dimer (DD) Ab. Immunofluorescent stains of HUVEC matrix with FFE and FN Ab's showed that these Ab's bound to the same epitopes on FN, as also seen on Western blots of purified FN. These findings indicate the presence of an antigenic determinant in fibrinogen/FFE that is homologous with an epitope(s) in FN recognised by FFE Ab, and critical for angiogenesis in this xenograft. The FN epitope(s) remains to be identified, but the present findings can be used for the selection of the appropriate clones from mice immunised with fibrinogen which can facilitate this identification, and which may also be of clinical use.

Electrochemical detection of D-dimer as deep vein thrombosis marker using single-chain D-dimer antibody immobilized on functionalized polypyrrole.

We describe a rapid and sensitive method for detection and quantification of d-dimer which is a biomarker present at elevated concentrations in patients with deep vein thrombosis (DVT) disorders. The method uses an immunosensor based on a single-chain antibody (ScAb) immobilized on a transducer surface and with a densely packed receptor layer. Detection is based on the redox activity of a N-alpha bis(carboxymethyl)-L-lysine (ANTA)/Cu2+ complex attached to a polypyrrole backbone. The resulting hybrid material: polypyrrole ANTA/metal complex/His-tag ScAb was characterized by AFM, surface plasmon resonance (SPR) and differential pulse voltammetry (DPV) for the optimization of the biosensor formation. The biosensor offers a promising template for antibody immobilization and for immunodetection of a specific D-dimer. The biosensor shows a remarkable variation in redox activity of the ANTA/Cu2+ complex after the D-dimer association with a binding constant Kd of 1 ng mL(-1). Electrochemical impedance spectroscopy (EIS) allows monitoring D-dimer association with a linear response between 0.1 ng mL(-1) and 500 ng mL(-1) and a detection limit of 100 pg mL(-1) in PBS is obtained. The biolayer exhibits the same sensitivity for the detection of d-dimer in human patient plasma samples. This assay method is versatile, offers enhanced performance for the evaluation of proteins association and could easily be extended to the detection of other proteins, present in serum human sample.

Traditional risk factors and D-dimer predict incident cardiovascular disease events in chronic HIV infection.

OBJECTIVE: Cardiovascular disease (CVD) contributes significantly to HIV-related morbidity and mortality. Chronic immune activation and inflammation are thought to augment the progression of atherosclerotic disease. In this retrospective, case-control study of HIV-infected individuals, we investigated the association of traditional cardiac risk factors, HIV-related disease, and inflammation with CVD events. METHODS: HIV-infected individuals who experienced an incident CVD event while enrolled in National Institutes of Health clinical protocols from 1995 to 2009 were matched 2: 1 to HIV-infected individuals without known CVD. Markers of inflammation and cell activation were measured in serum or plasma using ELISA-based assays and peripheral mononuclear cells by four-color flow cytometry. RESULTS: Fifty-two patients experienced an incident CVD event. Events were related to smoking, dyslipidemia, hyperglycemia, and family history as well as elevated D-dimer, soluble vascular cell adhesion molecule-1, tissue inhibitor of metalloproteinase-1, and soluble tissue factor, but not high-sensitivity C-reactive protein. No significant differences in antiviral therapy, CD4 T-cell count, or CD38 and human leukocyte antigen-DR expression were identified between patients and controls. In multivariable analysis, smoking, family history, D-dimer, and glucose were independently related to CVD risk. CONCLUSION: In this cohort, CVD risk was related to traditional CVD risk factors and markers of thrombosis and endothelial damage, but not to high-sensitivity C-reactive protein or markers of T-cell activation such as CD38/human leukocyte antigen-DR coexpression. D-dimer may help identify HIV-infected patients at elevated CVD risk.

Increased tissue factor expression on circulating monocytes in chronic HIV infection: relationship to in vivo coagulation and immune activation.

HIV infection is associated with an increased risk of thrombosis; and as antiretroviral therapy has increased the lifespan of HIV-infected patients, their risk for cardiovascular events is expected to increase. A large clinical study found recently that all-cause mortality for HIV(+) patients was related to plasma levels of interleukin-6 and to D-dimer products of fibrinolysis. We provide evidence that this elevated risk for coagulation may be related to increased proportions of monocytes expressing cell surface tissue factor (TF, thromboplastin) in persons with HIV infection. Monocyte TF expression could be induced in vitro by lipopolysaccharide and flagellin, but not by interleukin-6. Monocyte expression of TF was correlated with HIV levels in plasma, with indices of immune activation, and with plasma levels of soluble CD14, a marker of in vivo lipopolysaccharide exposure. TF levels also correlated with plasma levels of D-dimers, reflective of in vivo clot formation and fibrinolysis. Thus, drivers of immune activation in HIV disease, such as HIV replication, and potentially, microbial translocation, may activate clotting cascades and contribute to thrombus formation and cardiovascular morbidities in HIV infection.

Acute kidney injury in non-severe pneumonia is associated with an increased immune response and lower survival.

While sepsis is a leading cause of acute kidney injury in critically ill patients, the relationship between immune response and acute kidney injury in less severely ill patients with infection is not known. Here we studied the epidemiology, 1-year mortality, and immune response associated with acute kidney injury in 1836 hospitalized patients with community-acquired severe and non-severe pneumonia. Acute kidney injury developed in 631 patients of whom 329 had severe and 302 had non-severe sepsis. Depending on the subgroup classification, 16-25% of the patients with non-severe pneumonia also developed acute kidney injury. In general, patients with acute kidney injury were older, had more comorbidity, and had higher biomarker concentrations (interleukin-6, tumor necrosis factor, D-dimer) even among patients without severe sepsis. The risk of death associated with acute kidney injury varied when assessed by Gray's survival model and after adjusting for differences in age, gender, ethnicity, and comorbidity. This risk was significantly higher immediately after hospitalization but gradually fell over time in the overall cohort and in those with non-severe pneumonia. A significantly higher risk of death (hazard ratio 1.29) was also present in those never admitted to an intensive care unit. Hence acute kidney injury is common even among patients with non-severe pneumonia and is associated with higher immune response and an increased risk of death.

[Soluble fibrin and D-dimer at normal pregnancy and pregnancy with risk of miscarriage].

ELISA for soluble fibrin (SF) quantification has been elaborated on the basis of our fibrin-specific monoclonal antibodies (mAb). Epitope for these mAb is localized in fibrin fragment Bbeta118-134. The method was used on the blood plasma of healthy pregnant women (control group) and pregnant women with the risk of fetal loss (RFL). The increased mean values of SF concentrations were observed at pregnancy with RFL as compared to the normal pregnancy at the terms from 4 to 24 weeks (17.87 +/- 3.15 mkg/ml and 9.03 +/- 1.58 mkg/ml accordingly, p < 0.05). A weak negative correlation between SF concentration and pregnancy term was found at RFL (r = -0.201, n=35), while there was no correlation between these variables in control group (r = 0.004, n=28). The mean values of SF concentration estimated by semiquantitative test (by phosphates salting out of SF) were also higher at the pregnancy with RFL as compared to the normal pregnancy. However, the absolute values of SF concentrations determined by salting out method were essentially higher than in the case of ELISA. Immunoblot analysis with mAb 2d-2a (epitope for which in fibrin molecule encompasses peptide bond Bbeta14-15), showed that the main molecular component of SF at normal pregnancy and RFL was oligomeric fibrin desAA with possible incorporation of fibrinogen and/or fibrin desA which was not stabilized by factor XIIIa. D-dimer concentrations determined in blood plasma samples of pregnant women by ELISA varied in the range of 1-224 ng/ml at the pregnancy period from 4 to 37 weeks. There was positive correlation between D-dimer concentration and pregnancy term both at normal pregnancy and pregnancy with RFL (r = 0.765, n=33 and r = 0.712, n=44 correspondingly). The mean values of D-dimer concentration at various terms of normal pregnancy and pregnancy with RFL did not vary considerably. Thus SF but not D-dimer quantification may give useful diagnostic information at the pregnancy with RFL.

[The location of components of fibrinolytic system in laryngeal cancer]. / Lokalizacja skladowych ukladu fibrynolizy w raku krtani.

Laryngeal cancer is the most common neoplasm of the head and neck region. Laryngeal cancer patients experience thromboembolic complications more often than the general population. Our previous studies revealed in loco activation of blood coagulation in laryngeal cancer. The purpose of the present study was to examine the interactions among the laryngeal cancer cells and fibrinolytic system components in loco. Twenty-two cases of squamous carcinoma of the larynx were examined. AMeX method-preserved cancer tissues were examined using immunohistochemical ABC method. Fibrin and D-D fibrin dimers were demonstrated in the matrix, predominantly on the tumor-host front. Plasminogen, tissue-type plasminogen activator (t-PA) and plasmin were detected in cancer cells, but the intensity of their expression revealed a negative correlation with the degree of malignancy. A weak expression of high molecular weight urokinase (HMW-UK) was observed in cancer cells in the centers of the cancer foci, and a product of its degradation--low molecular weight urokinase (LMW-UK) was observed in cancer cells on the invasion front. The presence of plasminogen activator inhibitors (PAI-1, PAI-2, PAI-3) was also documented in the cancer cells. The expression of urokinase receptor (u-PAR) was very weak. Based on the results of the study, we suggest that in laryngeal cancer a suboptimal activation of fibrinolysis occurs that contributes to fibrin deposition in the tumour.

[Clinical evaluation of a test for plasma fibrin/fibrinogen degradation products (FDP) based on monoclonal anti-FDP antibody technology: an application for the scoring system of the disseminated intravascular coagulation (DIC) diagnostic criteria].

Fibrin/fibrinogen degradation products(FDP) have been measured using serum samples which were specially prepared for the FDP test because of the usage of anti-human fibrinogen antibody for the assay. Since diagnostic criteria for DIC were established by the study group on thrombosis and hemostasis which is supported by the Japanese Ministry of Health and Welfare(JMHW), serum FDP assay have been used as standard methods to diagnose DIC in Japan. Recently, a reagent using an anti-human FDP monoclonal antibody was developed and this has enabled the use of plasma samples for FDP measurement. The comparability, especially of the DIC score, of a new assay, Latex test BL-2 P-FDP, using plasma samples with a conventional assay for serum was investigated. Two sets of DIC scores based on data from the two tests were compared and the correlation was high with 97.5% of the patients being diagnosed with the same DIC status. In four disease groups--DIC, thrombosis, leukemia and solid cancer--high comparability between the two tests was also shown and no significant difference was observed in the correlation coefficient and the slope coefficient between serum and plasma samples. To conclude, it is suggested that "Latex test BL-2 P-FDP" is applicable to the diagnostic criteria for DIC from JMHW without any difficulty.

[Role of D-dimer in diagnosis of venous thrombosis and embolism]. / Rol' D-dimera v diagnostike venoznykh trombozov i émbolii u terapevticheskikh bol'nykh.

AIM: To analyze efficiency of semi-quantitative fast D-dimer test in diagnosis of deep vein thrombosis (DVT) and thromboembolism of pulmonary artery (TPA). MATERIAL AND METHODS: The study enrolled 42 patients (26 males and 16 females) aged 25 to 86 years. 30 and 12 of them were suspected to have DVT and TPA, respectively. DVT was verified at ultrasound dopplerography and radionuclide phlebography in 16 of 30 suspects. TPA was verified by x-ray, perfusion scintigraphy of the lungs and at autopsy (one case) in 7 of 12 suspects. D-dimer levels in the blood were measured by latex parts agglutination reaction. The parts were covered with monoclonal antibodies to D-dimer. The reagents were provided by the kit Roche/Diagnostica Stago. RESULTS: The D-dimer test was positive in 20 of 23 DVT patients and negative in 3 cases (13%). Of 19 patients with rejected diagnosis of DVT/TPA the test was negative in 17(89.4%) and positive in 2 patients (10.6%). Thus, sensitivity and specificity of the D-dimer test was 87% and 89.4%, respectively. CONCLUSION: High sensitivity of the test allows to use it in screening for DVT/TPA. Negative D-dimer test rejects DVT, while positive test needs verification by other methods.

Elastase mediated fibrinolysis in acute promyelocytic leukemia.

The bleeding syndrome of acute promyelocytic leukemia (APL) is complex and consists of disseminated intravascular coagulation (DIC) and hyperfibrinolysis. Elastase, derived from malignant promyelocytes, is believed to mediate the fibrinogeno- and fibrinolysis by aspecific proteolysis. In this study we measured the role of elastase in fifteen patients with APL by using an assay for elastase degraded fibrin(ogen) and the results were compared with those obtained in patients with sepsis induced DIC. High levels of elastase were observed in sepsis and APL. The levels of fibrinogen and fibrin degradation products were significantly higher in APL patients compared to patients with sepsis induced DIC. Nevertheless, the level of elastase degraded fibrin(ogen) was higher in the sepsis group (635.3 ng/ml, compared to 144.3 ng/ml in APL; p <0.0001). So, the enormous increase in fibrin and fibrinogen degradation products in APL cannot be explained by elastase activity. This study suggests a minor role for elastase mediated proteolysis in the hemorrhagic diathesis in APL patients.

A monoclonal antibody specific to the granulocyte-derived elastase-fragment D species of human fibrinogen and fibrin: its application to the measurement of granulocyte-derived elastase digests in plasma.

When granulocytes are stimulated under certain clinical conditions, elastase is released therefrom and digests fibrin(ogen) independently of the plasmin system, which may also be mobilized simultaneously. Thus, discrimination of these 2 systems becomes urgent for the diagnosis and treatment of the underlying diseases. Using as immunogen a 97-kd granulocyte-elastase digest of human fibrinogen, we raised an antibody IF-123 that specifically recognizes elastase digests of human fibrin(ogen). The 97-kd elastase fragment resembles plasmic fragment D(1), and the epitope of this antibody is located on the Aalpha (196-204) residue segment. This segment appears to be masked in fibrin(ogen) but exposed when the Aalpha Leu 204-Ile 205 peptide bond is cleaved by elastase. Cathepsin G concomitantly released from granulocytes failed to expose the epitope. By an enzyme immunoassay using IF-123 as the capture antibody, the elastase digests of fibrin(ogen) can be measured in plasma samples without interference by abundantly coexisting fibrinogen. Indeed, we found that the elastase digests were mostly elevated in patients with inflammation or malignant tumors, but remained in a normal range in patients with a benign gastrointestinal tract disease such as duodenal ulcer and polyps in the gallbladder or the colon. Like the plasmic D-dimer, the elastase digests predominantly consisted of the DD/E complex and DD/E-containing high-molecular weight derivatives apparently corresponding to the phase-3 plasmic digests of cross-linked fibrin. (Blood. 2000;95:1721-1728)

Tissue factor pathway inhibitor expression in human crescentic glomerulonephritis.

BACKGROUND: Tissue factor (TF) pathway inhibitor (TFPI), the major endogenous inhibitor of extrinsic coagulation pathway activation, protects renal function in experimental crescentic glomerulonephritis (GN). Its glomerular expression and relationship to TF expression and fibrin deposition in human crescentic GN have not been reported. METHODS: Glomerular TFPI, TF, and fibrin-related antigen (FRA) expression were correlated in renal biopsies from 11 patients with crescentic GN. Biopsies from 11 patients with thin basement membrane disease and two normal kidneys were used as controls. RESULTS: TFPI was undetectable in control glomeruli but was detectable in interstitial microvessels. In crescentic biopsies, TFPI was detected in cellular crescents and was more prominent in fibrous/fibrocellular crescents, indicating a correlation with the chronicity of crescentic lesions. TFPI appeared to be associated with macrophages but not endothelial or epithelial cells. TFPI was generally undetectable in regions of the glomerular tuft with minimal damage. In contrast, TF and FRA were strongly expressed in regions of minimal injury, as well as in more advanced proliferative and necrotizing lesions. Despite prominent TF expression, FRA was less prominent in fibrous/fibrocellular crescents in which TFPI expression was maximal. CONCLUSIONS: These data suggest that TFPI is strongly expressed in the later stages of crescent formation and is inversely correlated with the presence of FRA in human crescentic GN. This late induction of TFPI may inhibit TF activity and favor reduced fibrin deposition in the chronic stages of crescent formation.