PubMed Health⌕ Search

Biomedical subjects

P Eiras

Publications and source records attributed to P Eiras.

14 recordsLinked to original sources
PubMed2003

Beneficial effects of HLA class II incompatibility in living donor liver transplantation.

OBJECTIVE: To analyze the impact of HLA matching in both patient and graft evolution after LDLT. MATERIAL AND METHODS: Twenty recipients underwent LDLT with follow-up of 3 to 30 months. HLA typing was performed on all donor-recipient pairs; class I antigens were typed using serological methods and class II loci (DRB1 and DQB1) using low-resolution molecular typing. Recipient sera were cross-matched with donor lymphocytes. Antigen mismatches were analyzed for each locus individually, for each class as a whole and for HLA class I immunogenic triplets according to HLA Matchmaker software. RESULTS: Eighteen of 20 donor-recipient pairs were HLA haploidentical. All but one of the recipients had a negative cross-match before transplantation. While there was not a statistically significant correlation between HLA class I mismatches and the incidence of acute rejection episodes, HLA class II matching in DRB1 and DQB1 loci appeared to be associated with a higher incidence of acute rejection episodes after LDLT. Both host-versus-graft (HvG) and graft-versus-host (GvH) HLA class II compatibilities correlated with rejection episodes, especially for the GvH direction. CONCLUSIONS: HLA class II matching for DRB1 and DQB1 loci appears to be associated with a higher incidence of acute rejection episodes after LDLT. In this study, mismatches in class I HLA antigens are not related to an higher incidence of acute rejection episodes nor other complications after LDLT. Further studies are needed to unveil the role of HLA matching in LDLT.

Adolescent↗
PubMed2001

Anti-transglutaminase IgA ELISA: clinical potential and drawbacks in celiac disease diagnosis.

BACKGROUND: Since the identification of tissue transglutaminase (tTG) as the antigen for the anti-endomysial antibodies (EMA), several antigen-specific immunoassays have been reported for celiac disease (CD) screening. A first objective was to evaluate the suitability for CD screening of three different IgA tTG ELISAs, two of them based on guinea pig liver tTG (gp-tTG) (an in-house ELISA with a partially purified extract and a commercial ELISA with purified gp-tTG antigen) and a third recombinant human tTG (rh-tTG) ELISA. The results are compared with EMA and with the final clinical diagnosis. A second objective was to analyze antibody reactivities in those patients with anti-tTG and EMA discrepancies. METHODS: ELISA and EMA tests were used to measure IgA anti-tTG levels in sera from 259 patients (107 had CD and 72 had Type I diabetes mellitus). RESULTS: The purified gp-tTG ELISA was highly sensitive (97.7%) and specific (98.8%) in the detection of CD, almost equaling EMA. Rh-tTG ELISA did not improved the sensitivity of EMA, but its specificity was slightly superior. Immunoblot analysis with partially purified gp-tTG extract, the antigen most frequently used for anti-tTG detection, showed that the majority of false positives were due to IgA reactivities to contaminant proteins present in the liver antigenic extract. This low specificity was particularly problematic in diabetics. CONCLUSION: Purified tTG ELISAs, either with purified guinea pig liver or recombinant human antigens, can be used as quantitative and observer-independent alternatives to the traditional and time-consuming EMA in the screening of CD.

Blotting, Western↗
PubMed2000

Mechanistic aspects of the induction of apoptosis by lauryl gallate in the murine B-cell lymphoma line Wehi 231.

The effect of lauryl gallate (antioxidant E-312) has been studied on the mouse B-cell lymphoma line Wehi 231. This compound is able to inhibit protein tyrosine kinases (PTKs) in whole cells and in crude extracts with a better efficiency than other well-known PTK inhibitors such as herbimycin or genistein. Initial events triggered upon the incubation of cells with lauryl gallate in phosphate-buffered saline (up to 1 h) include the inhibition of tyrosine phosphorylation, discharge of the mitochondrial transmembrane potential, and induction of mRNA for Bcl-2. Long-term cultures in complete medium supplemented with fetal calf serum (up to 24 h) in the presence of this compound exhibit clear apoptotic features such as increase in phosphatidylserine in the cell surface, decrease in the functionality of mitochondria, cytochrome c release to the cytosol, activation of caspases, hypodiploidy, and oligonucleosomal breakdown of DNA. Comparison between Wehi cells overexpressing Bcl-2 (Wehi-bcl-2) with Wehi-neo cells shows a delay in the manifestations of the apoptotic signs, indicating that Bcl-2 has a partial protective effect on the apoptosis induced by lauryl gallate. The proapoptotic effect of lauryl gallate is not dependent on DNA or protein synthesis, is not blocked by the chelation of calcium, and is not reverted by N-acetylcysteine.

Acetylcysteine↗
PubMed2000

Intestinal intraepithelial lymphocytes contain a CD3- CD7+ subset expressing natural killer markers and a singular pattern of adhesion molecules.

Intestinal intraepithelial lymphocytes (i-IEL) represent one of the largest, non-organized lymphoid population in the body. They are located outside the epithelial basement membrane among the mucosal epithelial cells. We, and previously other groups, have reported the presence of a CD7+CD3-IEL subset in the epithelium of human small intestine. This subset is drastically reduced in coeliac disease (CD) patients. In the present work we accomplish a better phenotypic characterization of this CD3-IEL subset and demonstrate the expression of typical natural killer (NK) cell markers. Most, if not all, CD3-CD7+ cells express NKPR1 (CD161)[98% +/- 2] and CD122[92% +/- 6]. In addition, a variable percentage express CD2[55% +/- 16], CD94[24% +/- 18], CD56[44% +/- 21] and CD16[12% +/- 4], however, no CD57 expression was observed. Moreover, these cells contain perforin granules[75% +/- 5], supporting a potential cytolytic ability. Regarding adhesion molecules, CD18 and CD44 expression is absent, which is consistent with a limited capacity of migration. Altogether, these data suggest the presence of intraepithelial NK cells in human intestinal epithelium, a compartment where cytotoxic effectors have not been clearly defined.

Antigens, CD7↗
PubMed2000

Intraepithelial lymphocytes and coeliac disease: permanent changes in CD3-/CD7+ and T cell receptor gammadelta subsets studied by flow cytometry.

UNLABELLED: Permanent changes in intestinal intraepithelial lymphocytes have been observed in coeliac patients. The aim of this investigation was to study small intestinal intraepithelial lymphocytes by using flow cytometry and to evaluate its diagnostic value in coeliac disease. Three-colour flow cytometry analyses were performed on isolated epithelial cells of 117 intestinal biopsies obtained from 113 children (54 coeliac disease, 4 other enteropathies, 18 Helicobacter pylori associated gastritis and 37 normal controls). A multiple logistic regression model was developed to select the best intraepithelial lymphocytes subset predictor of coeliac disease. Coeliac patients had significant higher levels of T cell receptor gammadelta intraepithelial lymphocytes than control patients (p < 0.01), H. pylori patients (p < 0.01) and other enteropathies (p < 0.05). The density of CD3-/CD7+ intraepithelial lymphocytes, a intraepithelial lymphocyte subset poorly characterized by immunohistochemical methods, was significantly lower in coeliac patients than in the control group (p < 0.01). H. pylori group (p < 0.01) and other enteropathies (p < 0.01). Both changes remained altered independent of the coeliac patient's diet. The data were used on a logistic regression analysis in order to calculate sensitivity [94.4%; 95% confidence interval (CI) 83.7-98.6%], specificity (94.9%; 95% CI 84.9-98.7%) and likelihood ratio for a positive test 18.5 (95% CI 6.1-55.8) in the diagnosis of coeliac disease. CONCLUSION: Changes in T cell receptor gammadelta and CD3-/CD7+ intraepithelial lymphocytes subsets are permanently observed in paediatric coeliac disease. Their assessment, by three-colour flow cytometry on routine diagnostic biopsies, permits a better characterization of coeliac enteropathy and represents a valuable procedure to identify coeliac patients with different clinical presentations.

Adolescent↗
PubMed1998

Flow cytometry description of a novel CD3-/CD7+ intraepithelial lymphocyte subset in human duodenal biopsies: potential diagnostic value in coeliac disease.

Intraepithelial lymphocytes (IEL) represent a heterogeneous cellular compartment of unknown functions and controversial ontogeny. Previous observations in humans indicate that the majority of IEL subsets express the CD3 complex associated with either the alphabeta or the gammadelta T-cell receptor components, and describe the characteristic increase of CD3+TCRgammadelta+ IEL in coeliac disease. In the present work, we analyze the surface antigen expression of intraepithelial lymphocytes isolated from duodenal biopsies of control subjects and coeliac disease patients. We describe a CD3-CD7 + IEL subset frequently found in control subjects (41.41+/-21.8), with the following features: 1) most of these cells are CD45R0+ CD103+ and CD44- CD28- CD5-; 2) a significant percentage express CD56 (44.7%+/-21.3), CD2 (55.1%+/-16.2), and CD94 (16.2%+/-7.3). Furthermore, they are CD122+ and CD25-; 3) this CD3- IEL subset exhibit an activated phenotype expressing higher levels of CD69, CD103, and CD38 than the CD3+ subset. Interestingly, this CD3- subset is drastically reduced in CD patients (2.2+/-2.9 in active disease, 6.3+/-4.6 in treated patients versus 41.4+/-21.8 in control subjects). The imbalanced ratio "increased TCRgammadelta versus decreased CD3- CD7+" is a permanent finding in CD patients following clinical and histological remission. This parameter might provide helpful diagnostic information (easily obtained by 3-color FCM from diagnostic biopsies), and suggest a potential implication in the pathogenesis of coeliac disease.

Antigens, CD7↗
PubMed1998

Inhalant allergy to egg yolk and egg white proteins.

BACKGROUND: Several egg white and egg yolk and avian proteins have been described as a cause of inhalant allergy. Sometimes inhalational type I hypersensitivity to these proteins is associated with food allergy to egg. OBJECTIVE: We studied two patients who experienced respiratory and food allergic symptoms upon exposure to egg or avian antigens through the inhalative or digestive routes. Clinical and immunological studies were carried out in order to identify individual allergens from these sources that could be responsible for crossreactivity reactions. RESULTS: Patient 1 showed IgE sensitization to egg yolk livetins, feathers, and chicken serum. Specific bronchial challenge with chicken albumin and livetin extracts elicited a positive early asthmatic response and an increase in serum eosinophil cationic protein. Immunoblot and CAP-inhibition studies in this patient supported that chicken albumin (alpha-livetin) was the crossreactive antigen present in egg yolk and chicken serum and feathers. Patient 2 showed sensitization to egg white, ovomucoid and lysozyme. However, SDS-PAGE and immunoblot studies demonstrated contaminating lysozyme in the ovomucoid extract and identified lysozyme as the main allergen causing egg sensitization in this patient. Conjunctival challenge test confirmed allergy to lysozyme. CONCLUSION: Egg yolk and egg white proteins may act not only as ingested allergens but also as aeroallergens. Immunological studies using highly purified preparations of egg proteins are useful for the accurate diagnosis of allergic reactions to egg proteins and to identify individual allergens that may be responsible for crossreactivity reactions.

Adult↗