László Bene

Fontolizumab in moderate to severe Crohn's disease: a phase 2, randomized, double-blind, placebo-controlled, multiple-dose study.

Background: The safety and efficacy of fontolizumab, a humanized anti‐interferon gamma antibody, was investigated in patients with Crohns disease (CD). Elevated gut mucosal levels of interferon gamma, a key cytokine involved in the inflammatory process of CD, are associated with disease symptoms. Methods: A total of 201 patients with Crohns Disease Activity Index (CDAI) scores between 250 and 450 were randomized to receive an initial intravenous dose of 1.0 or 4.0 mg/kg fontolizumab or placebo, followed by up to 3 subcutaneous doses of 0.1 or 1.0 mg/kg fontolizumab or placebo every 4 weeks. Clinical response at day 29, the primary efficacy endpoint, was defined as a decrease in the CDAI of at least 100 points from baseline levels. Results: Of 201 patients, 135 (67%) completed the study. Day 29 response rates were similar in all treatment groups (31%–38%). At subsequent timepoints a significantly greater proportion of patients in the 1.0 mg/kg intravenous / 1.0 mg/kg subcutaneous fontolizumab group had clinical response and significantly greater improvement in the CDAI score compared with patients who received placebo. All fontolizumab groups had significant improvement in C‐reactive protein levels. The overall frequency of adverse events was similar in all groups (58%–75%); most events were related to exacerbation of CD. There was a low frequency (5.2%) of neutralizing antibodies to fontolizumab. Conclusions: Although a strong clinical response to fontolizumab was not observed, significant decreases in C‐reactive protein levels suggest a biological effect. Fontolizumab was well tolerated, and further studies to assess its efficacy are warranted. Inflamm Bowel Dis 2009

Efficacy and Safety of the Biosimilar Infliximab CT-P13 Treatment in Inflammatory Bowel Diseases: A Prospective, Multicentre, Nationwide Cohort

BACKGROUND AND AIMS Biosimilar infliximab CT-P13 is approved for all indications of the originator product in Europe. Prospective data on its efficacy, safety, and immunogenicity in inflammatory bowel diseases are lacking. METHODS A prospective, nationwide, multicentre, observational cohort was designed to examine the efficacy, safety, and immunogenicity of CT-P13 infliximab biosimilar in the induction treatment of Crohns disease [CD] and ulcerative colitis [UC]. Demographic data were collected and a harmonised monitoring strategy was applied. Early clinical remission, response, and early biochemical response were evaluated at Week 14, steroid-free clinical remission was evaluated at Week 30. Therapeutic drug level was monitored using a conventional enzyme-linked immunosorbent assay. RESULTS In all, 210 consecutive inflammatory bowel disease [126 CD and 84 UC] patients were included in the present cohort. At Week 14, 81.4% of CD and 77.6% of UC patients showed clinical response and 53.6% of CD and 58.6% of UC patients were in clinical remission. Clinical remission rates at Week 14 were significantly higher in CD and UC patients who were infliximab naïve, compared with those with previous exposure to the originator compound [p < 0.05]. Until Week 30, adverse events were experienced in 17.1% of all patients. Infusion reactions and infectious adverse events occurred in 6.6% and 5.7% of all patients, respectively. CONCLUSIONS This prospective multicentre cohort shows that CT-P13 is safe and effective in the induction of clinical remission and response in both CD and UC. Patients with previous infliximab exposure exhibited decreased response rates and were more likely to develop allergic reactions.

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.

Raft and Cytoskeleton Associations of an ABC Transporter: P-Glycoprotein

A novel flow cytometric assay has been described in an accompanying report (Gombos et al.,

Hypo-osmotic shock induces an osmolality-dependent permeabilization and structural changes in the membrane of carp sperm

We carried out spectrofluorimetric and flow cytometric measurements to investigate the effect of hypo-osmotic shock on cell membranes of common carp sperm. The time course of the permeability of the sperm cell membrane, as monitored by DNA-related propidium iodide (PI) fluorescence, was followed for 30 min after dilution of semen in hypo-osmotic environments of different ionic strengths. Spectrofluorimetric measurements indicated a continuous increase in the total PI emission intensity of a sperm suspension. Cell-by-cell flow cytometric measurements suggested that the permeability changes were of the all-or-none type. The permeabilized fraction of cells in the individual samples was time and osmolality dependent. The number and percentage of cells in which DNA was stained by PI increased gradually over time and reached a steady-state plateau value after 5-15 min. This equilibrium fraction of cells with a PI-permeable cytoplasmic membrane displayed an inverse relationship with the osmolality of the diluent, having a near 100% value for fresh water and distilled water. Dilution of sperm in hypo-osmotic medium brought about a fast decrease in the forward light-scattering signal on a short time scale compared to the pre-steady-state time of the permeabilization. With the addition of extracellular Ca2+ (1.8 mM), restoration of the light scattering signal was observed. Permeabilization of the membrane and restoration of light scattering were not coincident in time. We propose a two-dimensional reorganization of the lipid structure as the underlying mechanism of the latter process.

EGF‐induced redistribution of erbB2 on breast tumor cells: Flow and image cytometric energy transfer measurements

erbB2, a member of the epidermal growth factor (EGF) receptor-type tyrosine kinase receptor family, is overexpressed in breast carcinomas with poor prognosis. We examined the cell surface association of this receptor with itself and with other cell surface proteins by the Förster-type fluorescence resonance energy transfer using whole antibodies and Fab fragments. We found that erbB2 molecules homoassociate in unstimulated SK-BR-3, BT474 and BT474-M (a metastatic version of the parent BT474 line) breast tumor cells, and that the interaction was enhanced by EGF treatment in suspensions of SK-BR-3 and BT474-M cells. BT474 cells (with low EGF receptor expression) and attached SK-BR-3 cells do not respond to EGF. Image microscopic energy transfer measurements found considerable pixel-by-pixel heterogeneity in the homoassociation state of erbB2. In accordance with the EGF-induced redistribution of erbB2, EGF receptor was found to be in close proximity to erbB2 in FRET measurements. By labeling different epitopes on erbB2 and the lipid bilayer, we were able to prepare an epitope map of erbB2 molecule. Our data suggest the existence of dynamic cell surface patterns of erbB2 and point to functions fulfilled by these molecular complexes.

Clustering of Class I HLA Oligomers with CD8 and TCR: Three-Dimensional Models Based on Fluorescence Resonance Energy Transfer and Crystallographic Data

Fluorescence resonance energy transfer (FRET) data, in accordance with lateral mobility measurements, suggested the existence of class I HLA dimers and oligomers at the surface of live human cells, including the B lymphoblast cell line (JY) used in the present study. Intra- and intermolecular class I HLA epitope distances were measured on JY B cells by FRET using fluorophore-conjugated Ag-binding fragments of mAbs W6/32 and L368 directed against structurally well-characterized heavy and light chain epitopes, respectively. Out-of-plane location of these epitopes relative to the membrane-bound BODIPY-PC (2-(4,4-difluoro-5-(4-phenyl-1,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-1-hexadecanoyl-sn-glycero-3-phosphocholine) was also determined by FRET. Computer-simulated docking of crystallographic structures of class I HLA and epitope-specific Ag-binding fragments, with experimentally determined interepitope and epitope to cell surface distances as constraints, revealed several sterically allowed and FRET-compatible class I HLA dimeric and tetrameric arrangements. Extension of the tetrameric class I HLA model with interacting TCR and CD8 resulted in a model of a supramolecular cluster that may exist physiologically and serve as a functionally significant unit for a network of CD8-HLA-I complexes providing enhanced signaling efficiency even at low MHC-peptide concentrations at the interface of effector and APCs.

Association of adherence to therapy and complementary and alternative medicine use with demographic factors and disease phenotype in patients with inflammatory bowel disease.

BACKGROUND AND AIMS Previous studies have suggested an increasing use of complementary and alternative medicine (CAM) in patients with inflammatory bowel disease (IBD). Furthermore, a significant number of IBD patients fail to comply with treatment. The aim of our study was to evaluate the prevalence of non-adherence and the use of CAM in Hungarian patients with IBD. METHODS A total of 655 consecutive IBD patients (CD: 344, age: 38.2 [SD 12.9]years; UC: 311, age: 44.9 [15.3]years) were interviewed during the specialist visit by self-administered questionnaire including demographic and disease-related data as well as items analyzing the extent of non-adherence and CAM use. Patients taking more than 80% of each prescribed medication were classified as adherent. RESULTS The overall rate of self-reported non-adherence (CD: 20.9%, UC: 20.6%) and CAM (CD: 31.7%, UC: 30.9%) use did not differ between Crohns disease (CD) and ulcerative colitis (UC). The most common causes of non-adherence were: forgetfulness (47.8%), too many/unnecessary pills (39.7%), being afraid of side effects (27.9%) and too frequent dosing. Most common forms of CAM were herbal tea (47.3%), homeopathy (14.6%), special diet (12.2%), and acupuncture (5.8%). In CD, disease duration, date of last follow-up visit, educational level and previous surgeries were predicting factors for non-adherence. Alternative medicine use was associated in both diseases with younger age, higher educational level, and immunosuppressant use. In addition, CAM use in UC was more common in females and in patients with supportive psychiatric/psychological therapy. CONCLUSIONS Non-adherence and CAM use is common in patients with IBD. Special attention should be paid to explore the identified predictive factors during follow-up visits to improve adherence to therapy and improving patient-doctor relationship.

Novel calibration method for flow cytometric fluorescence resonance energy transfer measurements between visible fluorescent proteins

The combination of fluorescence resonance energy transfer (FRET) and flow cytometry offers a statistically firm approach to study protein associations. Fusing green fluorescent protein (GFP) to a studied protein usually does not disturb the normal function of a protein, but quantitation of FRET efficiency calculated between GFP derivatives poses a problem in flow cytometry.

Modification of membrane cholesterol level affects expression and clustering of class I HLA molecules at the surface of JY human lymphoblasts

Recently we have found that class I HLA molecules, key elements of the antigen presentation system for CD8 + effector cells, show a clustered lateral distribution (homoassociation) at the surface of activated human T- and B-lymphocytes as well as virus-transformed T- and B-lymphoblasts, in contrast to a disperse distribution on resting human PBLs (Matk6 et al. (1994) J. Immunol. 152, 3353; Bene et al. (1994) Eur. J. Immunol. 24, 2115). Expression of beta2m-free HLA heavy chains and exogenous beta2m have been shown as potential regulation factors of HLA-I clustering, which in turn may affect cytotoxic activity of CD8+ effector cells. Here we report a study on the effect of plasma membrane-modification (by exogenous cholesterol and phosphatidylcholine) on the expression of free HLA heavy chains and beta2m-bound HLA-I molecules on JY human B-lymphoblasts. The modulating effect of these two treatments on the lipid fluidity of cells was demonstrated by fluorescence anisotropy of DPH lipid probe. The lateral clustering (association) of HLA-I molecules was detected by flow cytometric fluorescence resonance energy transfer (FCET) and digital imaging microscopic photobleaching energy transfer (pbFRET) methods, using flourescein-isothiocyanate (FITC) (donor)- and tetramethyl-rhodamine-isothiocyanate (TRITC) (acceptor)-labeled W6/32 or KE2 antibodies directed against intact HLA-I molecules. Cholesterol enrichment of the plasma membrane increased membrane fluidity and reduced the expression of heavy- and light-chain determinants of HLA-I molecules and free heavy chains (FHCs). This was accompanied with a higher degree of HLA-I clustering as shown by the enhanced intermolecular energy transfer efficiency. In contrast, cholesterol depletion resulted in membrane fluidization and increased expression of HLA-I epitopes. Our results suggest that both cholesterol level and lipid structure/fluidity of the plasma membrane in lymphoblastoid cells may also potentially regulate lateral organization and consequently the presentation efficiency of HLA-I molecules.