Miklós Udvardy

Shielding of the A1 domain by the D'D3 domains of von Willebrand factor modulates its interaction with platelet glycoprotein Ib-IX-V

Soluble von Willebrand factor (VWF) has a low affinity for platelet glycoprotein (GP) Ibα and needs immobilization and/or high shear stress to enable binding of its A1 domain to the receptor. The previously described anti-VWF monoclonal antibody 1C1E7 enhances VWF/GPIbα binding and recognizes an epitope in the amino acids 764–1035 region in the N-terminal D′D3 domains. In this study we demonstrated that the D′D3 region negatively modulates the VWF/GPIb-IX-V interaction; (i) deletion of the D′D3 region in VWF augmented binding to GPIbα, suggesting an inhibitory role for this region, (ii) the isolated D′D3 region inhibited the GPIbα interaction of a VWF deletion mutant lacking this region, indicating that intramolecular interactions limit the accessibility of the A1 domain, (iii) using a panel of anti-VWF monoclonal antibodies, we next showed that the D′D3 region is in close proximity with the A1 domain in soluble VWF but not when VWF was immobilized; (iv) destroying the epitope of 1C1E7 resulted in a mutant VWF with an increased affinity for GPIbα. Our results support a model of domain translocation in VWF that allows interaction with GPIbα. The suggested shielding interaction of the A1 domain by the D′D3 region then becomes disrupted by VWF immobilization.

Complement activation in thrombotic thrombocytopenic purpura

Summary.  Background:  Ultra‐large von Willebrand factor and deficiency of its cleaving protease are important factors in the events leading to thrombotic microangiopathy; however, the mechanisms involved are only partly understood. Whereas pathological activation of the alternative complement pathway is linked to atypical hemolytic uremic syndrome, the role of complement activation in thrombotic thrombocytopenic purpura (TTP) is unknown. The aim of this study was to investigate whether signs of complement activation are characteristic of TTP.

Seroreactivity to microbial components in Crohn's disease is associated with ileal involvement, noninflammatory disease behavior and NOD2/CARD15 genotype, but not with risk for surgery in a Hungarian cohort of IBD patients

Background: Antibodies directed against Saccharomyces cerevisiae (ASCA), perinuclear components of neutrophils (pANCA), and porin protein C of Escherichia coli (anti‐OmpC) are reported to be associated with disease phenotype and may be of diagnostic importance in inflammatory bowel disease (IBD). Since limited data are available from Eastern Europe, we assessed the above antibodies in Hungarian IBD patients. Methods: In all, 653 well‐characterized, unrelated consecutive IBD patients (Crohns disease [CD]: 558, m/f: 263/295, duration: 8.1 ± 10.7 years; ulcerative colitis [UC]: 95, m/f: 44/51, duration: 8.9 ± 9.8 years) and 100 healthy subjects were investigated. Sera were assayed for anti‐Omp and ASCA by enzyme‐linked immunosorbent assay (ELISA) and ANCA by indirect immunofluorescence assay (IIF). TLR4 and NOD2/CARD15 variants were tested by polymerase chain reaction/restriction fragment length polymorphism (PCR‐RFLP). Detailed clinical phenotypes were determined by reviewing the medical charts. Results: Anti‐Omp, ASCA, and atypical pANCA antibodies were present in 31.2%, 59.3%, and 13.8% of CD, 24.2%, 13.7%, and 48.5% of UC patients, and in 20%, 16%, and 5.6% of controls, respectively. ASCA and anti‐Omp positivity were associated with increased risk for CD (odds ratio [OR]ASCA = 7.65, 95% confidence interval [CI]: 4.37–13.4; OROmp = 1.81, 95% CI: 1.08–3.05). In a logistic regression analysis, anti‐Omp and ASCA were independently associated with ileal and noninflammatory disease, but not with a risk for surgery or response to steroids or infliximab. A serology dosage effect was also observed. ASCA and anti‐Omp antibodies were associated with NOD2/CARD15, in addition to a gene dosage effect. No associations were found in UC. Conclusions: Serological markers were useful in the differentiation between CD and UC in an Eastern European IBD cohort. Reactivity to microbial components was associated with disease phenotype and NOD2/CARD15 genotype, further supporting the role of altered microbial sensing in the pathogenesis of CD.

Acute phase proteins in the diagnosis and prediction of cirrhosis associated bacterial infections

Bacterial infections are common cause of morbidity and mortality in patients with cirrhosis. The early diagnosis of these infections is rather difficult.

Pancreatic autoantibodies are associated with reactivity to microbial antibodies, penetrating disease behavior, perianal disease, and extraintestinal manifestations, but not with NOD2/CARD15 or TLR4 genotype in a hungarian IBD cohort†

Background: Pancreatic autoantibodies (PAB) and goblet cell autoantibodies (GAB) are specific for Crohns disease (CD) and ulcerative colitis (UC), but the sensitivity alone is low. Conventional antibodies and carbohydrates (glycans) are associated with disease phenotype and may be of diagnostic importance in inflammatory bowel disease (IBD). Our aim was to determine the accuracy of PAB and GAB autoantibodies as well as to study relevant phenotype–serotype associations. Methods: A Hungarian study cohort of 1092 subjects, including 689 well‐characterized, unrelated IBD patients (CD: 579, m/f ratio: 274/305, duration: 7.9 ± 11.2 years; UC: 110, m/f ratio: 53/57, duration: 8.9 ± 9.8 years), 139 celiac patients, 100 healthy, and 64 non‐IBD gastrointestinal controls were investigated. Sera were assayed for PAB‐GAB IgA/IgG, anti‐Omp, anti‐Saccharomyces cerevisiae antibodies (ASCA), and anti‐glycans. TLR4 and NOD2/CARD15 was tested by polymerase chain reaction / restriction fragment length polymorphism (PCR‐RFLP). Detailed clinical phenotypes were determined. Results: The prevalence of PAB was significantly more frequent in CD (41.1%) versus UC (22.7%), celiac (22.3%), and controls (8% and 4.6%, P < 0.01 for each), while GAB detection was poor in all groups except UC (15.4%). In CD the combination of PAB and/or anti‐glycans/ASCA increased the sensitivity to 72% and 59%, respectively, for isolated colonic disease. PAB was associated to gylcans (odds ratio [OR] 1.74,P = 0.002), ASCA IgG/IgA (OR 1.75, P = 0.002), Omp (OR 1.86, P = 0.001) as well as perforating, perianal disease, arthritis, ocular, and cutaneous manifestations (P = 0.002–0.032). In contrast, PAB and GAB antibodies were not associated with NOD2/CARD15 or TLR4, response to medical therapy, or need for surgery. No associations were found in UC. Conclusions: PAB autoantibodies in combination with ASCA or anti‐glycan antibodies increase the sensitivity for detecting CD, especially isolated colonic CD. Antibody response to PAB was associated with complicated disease phenotype and extraintestinal manifestations in this Eastern European IBD cohort.

THE ASSOCIATION OF REDUCED ENDOTHELIUM DERIVED RELAXING FACTOR-NO PRODUCTION WITH ENDOTHELIAL DAMAGE AND INCREASED IN VIVO PLATELET ACTIVATION IN PATIENTS WITH DIABETES MELLITUS

The role of reduced endothelial production of EDRF-NO in the pathogenesis of diabetic angiopathy has received much attention, however, most of the rather conflicting data were gained from animal experiments. Limited human experience seems to be available in insulin dependent diabetes, calling attention to decreased EDRF-NO production. Hereby the clinical, as well as laboratory investigation (urinary and serum nitrate/nitrite, lipid peroxidation, glucometabolic parameters, endothelial and in vivo platelet activation markers, etc.) of 35 non-insulin dependent (NIDDM) and 15 insulin dependent diabetics (IDDM) patients are given. Urinary and serum nitrate/nitrite concentrations were proven to be reduced in both patients groups. This change was independent of diabetes duration, presence of macroangiopathy, coronary heart disease and the glucometabolic parameters, however, correlation was registered with lipid peroxidation (total antioxidant status). An inverse correlation of nitrate/nitrite excretion with endothelial markers (von Willebrand factor, soluble thrombomodulin) was documented in NIDDM, this correlation was much stronger in IDDM. Moreover, in IDDM patients reduced nitrate/nitrite excretion was strongly associated with elevated plasmatic beta-thromboglobulin levels. The data presented here support to the hypothesis, that EDRF-NO production is reduced in diabetes and this reduction seems to correlate with endothelial damage. In IDDM the decreased nitrate/nitrite excretion may also lead to increased in vivo platelet activation, which suggests that the reduced amount of EDRF-NO might play a role in the pathogenesis of angiopathy in IDDM.

Clinical and Immunoserological Characteristics of Mixed Connective Tissue Disease Associated with Pulmonary Arterial Hypertension

We investigated the clinical characteristics and immunoserological alterations in patients with mixed connective tissue disease (MCTD) associated with pulmonary arterial hypertension (PAH). Anti‐U1RNP autoantibodies, anti‐endothelial cell antibodies (AECA) and serum thrombomodulin (TM) as well as von Willebrand factor antigen (vWFAg) concentrations were measured in 25 patients with MCTD associated with PAH and in 154 MCTD patients without PAH. The results showed that the probability of survival was lower in MCTD patients with PAH than in the 154 MCTD‐non‐PAH patients (5‐year survival rate in MCTD with PAH: 73%, versus 96% in MCTD‐non‐PAH; P < 0.01). AECA were more frequently present in the sera of MCTD patients with PAH than in MCTD‐non‐PAH (P < 0.001). Serum TM and vWFAg levels were higher in MCTD‐PAH patients than in MCTD‐non‐PAH patients (TM: P < 0.001; vWFAg: P < 0.001). Significant correlation was noticed between the quantity of AECA and TM level (r = 0.466) as well as the quantity of AECA and vWFAg level (r = 0.550). In conclusion, our results suggest that in MCTD the presence of AECA and endothelial cell activation may play a role in the development of PAH and in the maintenance of obliterative vascular processes.

Increased plasma von Willebrand factor antigen levels but normal von Willebrand factor cleaving protease (ADAMTS13) activity in preeclampsia

The activity of ADAMTS13, the von Willebrand factor (VWF) cleaving protease is low in several conditions, including HELLP (haemolysis, elevated liver enzymes, and low platelet count) syndrome. As HELLP syndrome develops in most cases on the basis of preeclampsia, our aim was to determine whether plasma ADAMTS13 activity is decreased in preeclampsia. Sixty-seven preeclamptic patients, 70 healthy pregnant women and 59 healthy non-pregnant women were involved in this case-control study. Plasma ADAMTS13 activity was determined with the FRETS-VWF73 assay, while VWF antigen (VWF:Ag) levels with an enzyme-linked immunosorbent assay. The multimeric pattern of VWF was analyzed by SDS-agarose gel electrophoresis. There was no significant difference in plasma ADAMTS13 activity between the preeclamptic and the healthy pregnant and non-pregnant groups (median [25-75 percentile]: 98.8 [76.5-112.8] %, 96.3 [85.6-116.2] % and 91.6 [78.5-104.4] %, respectively; p > 0.05). However, plasma VWF:Ag levels were significantly higher in preeclamptic patients than in healthy pregnant and non-pregnant women (187.1 [145.6-243.1] % versus 129.3 [105.1-182.8] % and 70.0 [60.2-87.3] %, respectively; p < 0.001). The multimeric pattern of VWF was normal in each group. Primiparas had lower plasma ADAMTS13 activity than multi-paras (92.6 [75.8-110.6] % versus 104.2 [92.1-120.8] %; p = 0.011). No other relationship was found between clinical characteristics, laboratory parameters and plasma ADAMTS13 activity in either study group. In conclusion, plasma ADAMTS13 activity is normal in preeclampsia despite the increased VWF:Ag levels. However, further studies are needed to determine whether a decrease in plasma ADAMTS13 activity could predispose preeclamptic patients to develop HELLP syndrome.

Changes in the expression and distribution of the inducible and endothelial nitric oxide synthase in mucosal biopsy specimens of inflammatory bowel disease

Objective The role of nitric oxide (NO) in the pathophysiology of inflammatory bowel disease (IBD) is controversial. The aim of this study was to investigate the expression and localization of nitric oxide synthase isoforms (iNOS, eNOS) in IBD colonic mucosa. Material and methods Forty-four patients with IBD (24 ulcerative colitis (UC), 20 Crohns disease (CD) and 16 controls) were investigated by colonoscopy. iNOS and eNOS in tissue sections was demonstrated by histochemistry (NADPH-diaphorase reaction) and immunohistochemistry. Cell type analysis and quantitative assessment of the iNOS immunoreactive (IR) cells and densitometry of iNOS in immunoblots were also performed. Results iNOS-IR cells were significantly numerous in inflamed mucosa of UC (64±4 cells/mm2) than in CD (4±2 cells/mm2). iNOS-IR/CD15-IR cells showed significant elevation in inflamed (i) versus uninflamed (u) UC mucosa (UCu 8±3%, UCi 85±10%) In CD, the percentage of iNOS-IR/CD68-IR cells was lower in inflamed sites (CDu 23±8%, CDi 4±3%). Immunoblot of biopsies revealed significant elevation of iNOS in active UC compared with uninflamed sites, whereas in CD no significant changes were detected. Differences were observed in eNOS and endothelial marker CD31 immunoreactivity. In patients with UC and in controls the ratios of eNOS/CD31-IR vessels were 82.3% and 92.0% respectively, whereas in CD the ratio was 8.3% with a concomitantly significant increase of CD31-IR vessels. The distribution and morphological characteristics of the NOS-IR inflammatory cells and endothelia were similar to those showing NADPH-diaphorase reactivity. Conclusions Differences observed in the expression and distribution of NOS isoforms in immune and endothelial cells may contribute to better understanding of the structural and physiological changes in UC and CD.

European Perspective on Multiple Myeloma Treatment Strategies: Update Following Recent Congresses

The management of multiple myeloma has undergone profound changes over the recent past as a result of advances in our understanding of the disease biology as well as improvements in treatment and supportive care strategies. Notably, recent years have seen a surge in studies incorporating the novel agents thalidomide, bortezomib, and lenalidomide into treatment for different disease stages and across different patient groups. This article presents an update to a previous review of European treatment practices and is based on discussions during an expert meeting that was convened to review novel agent data published or presented at medical meetings until the end of 2011 and to assess their impact on treatment strategies.