887 resultados para Immunoglobulin A


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In modern society, blood donor motivation and recruitment is a fundamental part of health care delivery. Well defined and documented programmes exist throughout the world but new ideas are always welcome. The situation in the Sudan is different and much remains to be done by way of comparison with elsewhere. This thesis outlines the objectives of a study, how it was supported, sponsored and achieved. It describes briefly the geography of the Sudan, the source of Sudanese economy, climate, culture and historical backgrounds. The problems of existing services in the Sudan are reviewed and a brief account of the demographic characteristics of the Sudanese population is given. Two surveys done in West of Scotland and in the Sudan are described in detail. This work discloses and compares the positive motives that enhances giving of blood and the negative motives that hinders its donation. The comparison is between an Eastern Society with a voluntary motivation not fully activated because of lack of understanding and awareness of the need to give blood voluntarily for strangers and Western Society with a well established voluntary system of donation. An addition to this research was the investigation into the immunity to tetanus and hepatitis in the Sudanese population. An estimate of the percentage of individuals with detectable levels of hepatitis A and B antibodies and tetanus antibodies is included since there is a need to establish a plasmapheresis programme as part of a good Blood Transfusion Service for the procurement of specific immunoglobulin's. This work has revealed major differences between the West of Scotland and the Sudan and suggestions are made for their resolution. The main conclusion and comparison are summarised in Chapter 7. It is hoped that many of the suggestions in this thesis can be introduced in the Sudan at an early date.

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A 67-year-old woman developed severe edema of her right hand and forearm, for which she was treated with antibiotics, without benefit. The echography excluded a venous thrombosis. Subsequently, she referred a wasp sting before the development of the edema. Specific Hymenoptera venom immunoglobulin E (IgE) was found to be positive for paper wasp and yellow jacket. A large local reaction (LLR) was diagnosed due to the hymenoptera sting. Self-injectable epinephrine was prescribed for possible, though unlikely, systemic reactions following hymenoptera stings.

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Milk contains numerous bioactive substances including immunoglobulins, cytokines, growth factors and components that exert antibiotic and prebiotic activity (Field, 2005). Little is known about the biological effects of individual milk bioactives, despite the fact that natural milk improves intestinal development and immune system functions in neonates (Donovan et al., 1994; Field, 2005) relative to milk formula. Characterization of the biological effects of such components is important for optimal production of infant milk formulas to be used when mother’s milk is not available. Milk components with preliminary evidence of positive effects on the intestinal growth and mucosal immunity include osteopontin (OPN). Osteopontin is a phosphorylated acidic glycoprotein expressed by a number of different immune and non-immune cells and tissues (Sodek et al., 2000). It is also present in body fluids including blood, bile and milk (Sodek et al., 2000). Osteopontin is a multifunctional protein that is implicated in a wide number of biological processes including cell survival, bone remodeling, and immune modulatory functions (Sodek et al., 2000). Furthermore, Schack and colleagues (2009) demonstrated that the concentration of OPN in human milk is considerably higher than in bovine milk and infant formulas. Taken together, it is likely that OPN plays a role in the early development of gastrointestinal tract and mucosal immune responses in infants. Since the neonatal pig shares anatomical, physiological, immunological, and metabolic similarities with the human infants (Moughan, et al., 1992), they were selected as the animal model in our studies. Our first aim was to investigate the effects of OPN on piglet intestinal development. Newborn, colostrum-deprived piglets (n=27) were randomized to receive three treatments: formula with bovine OPN (OPN; 140 mg/L); formula alone (FF); or sow reared (SR) for 21 days. Body weight, intestinal weight and length, mucosal protein and DNA content, disaccharidase activity, villus morphology, and crypt cell proliferation were measured. Statistical significance was assigned at P<0.05. No significant effects of OPN were observed for body weight, intestinal weight and length. Mucosal protein content of SR piglets was lower than FF and OPN piglets in the duodenum, but higher than FF and OPN piglets in the ileum. No significant effects of diet in mucosal DNA content were detected for the three regions of the small intestine. Lactase and sucrase activities of SR piglets were higher than the two formula-fed groups in the duodenum, lower in the ileum. No significant effects of diet on lactase and sucrase activities were noted between two formula-fed groups in the duodenum and ileum. Jejunal lactase activity of FF piglets was higher than SR piglets, whereas no significant effect of diet was observed in jejunal sucrase activity among the three groups. Duodenal and ileal villus height and villus area of SR piglets were lower than two formula-fed groups, while OPN piglets did not differ from FF piglets. There was a significant effect of diet (P<0.0001) on jejunal crypt cell proliferation, with proliferation in OPN piglets being intermediate between that of FF and SR. In summary, supplemental OPN increased jejunal crypt cell proliferation, independent of evident morphological growth, and had a minor impact on disaccharidase activity in the small intestine of neonatal piglets. Rotavirus (RV) is the most common viral cause of severe gastroenteritis in infants and young children worldwide (Parashar et al., 2006). Maeno et al. (2009) reported that OPN knockout (OPN-KO) suckling mice were more susceptible to RV infection compared to wild-type (WT) suckling mice. To detect the role of OPN in intestinal immune responses of neonates, the goal of the second study was to evaluate whether supplemental OPN influenced the serum antibody responses to RV vaccination in neonatal piglets. Newborn, colostrum-deprived piglets were randomized into two dietary groups: formula with bovine OPN (OPN; 140 mg/L) and formula alone (FF) for 35 days. On d7, piglets in each dietary group were further randomized to receive rotavirus (RV) vaccination (Rotarix®) (FF+RV and OPN+RV) or remained non-vaccinated (FF+NV and OPN+NV). Booster vaccination was provided on d14. Blood samples were collected on d7, 14, 21, 28 and 35. RV-specific serum immunoglobulin (Ig) G, IgA, IgM and total serum IgG, IgA, IgM were measured by ELISA. Statistical significance was assigned at P<0.05, with trends reported as P<0.10. Body weight gain was unaffected by diet and/or vaccination. No significant effect of oral OPN supplementation was observed for RV-specific antibody responses and total Igs levels. After the combination of dietary groups, RV piglets had significantly higher RV-specific IgM concentrations compared to NV piglets. Although there were higher means of RV-specific IgG and RV-specific IgA concentrations in RV group than their counterparts in NV group, the difference did not reach statistical significance. RV-specific IgM reached a peak at d7 post booster vaccination (PBV), whereas the RV-specific IgG and IgA peaked later at PBV 14 or 21. Total Igs were unaffected by RV vaccination but were significantly increased over time, following similar pattern as RV-specific Igs. In summary, neonatal piglets generated weak antibody responses to RV vaccination. Supplemental OPN did not enhance RV-specific serum antibody responses and total serum Igs levels in neonatal piglets with or without RV vaccination. In conclusion, we observed normal developmental changes in the small intestine and serum Igs levels in neonatal piglets over time. Oral OPN supplementation showed minimal impacts on intestinal development and no effect on serum Igs levels. The role of supplemental OPN on the growth and development of infants is still inconclusive. Future studies should measure other physiological and immunological parameters by using different models of vaccination or infection.

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Hintergrund: Helicobacter pylori (H. pylori) zählt trotz abnehmender Inzidenz zu den häufigsten bakteriellen Infektionskrankheiten des Menschen. Die Infektion mit H. pylori ist ein Risikofaktor für Krankheiten wie gastroduodenale Geschwüre, Magenkarzinomen und MALT (Mucosa Associated Lymphoid Tissue)-Lymphomen. Zur Diagnostik von H. pylori stehen verschiedene invasive und nichtinvasive Verfahren zur Verfügung. Der 13C-Harnstoff-Atemtest wird zur Kontrolle einer Eradikationstherapie empfohlen, kommt in der Primärdiagnostik von H. pylori derzeit jedoch nicht standardmäßig in Deutschland zum Einsatz. Fragestellung: Welchen medizinischen und gesundheitsökonomischen Nutzen hat die Untersuchung auf H. pylori-Besiedlung mittels 13C-Harnstoff-Atemtest in der Primärdiagnostik im Vergleich zu invasiven und nichtinvasiven diagnostischen Verfahren? Methodik: Basierend auf einer systematischen Literaturrecherche in Verbindung mit einer Handsuche werden Studien zur Testgüte und Kosten-Effektivität des 13C-Harnstoff-Atemtests im Vergleich zu anderen diagnostischen Verfahren zum primären Nachweis von H. pylori identifiziert. Es werden nur medizinische Studien eingeschlossen, die den 13C-Harnstoff-Atemtest direkt mit anderen H. pylori-Testverfahren vergleichen. Goldstandard ist eines oder eine Kombination der biopsiebasierten Testverfahren. Für die gesundheitsökonomische Beurteilung werden nur vollständige gesundheitsökonomische Evaluationsstudien einbezogen, bei denen die Kosten-Effektivität des 13C Harnstoff-Atemtests direkt mit anderen H. pylori-Testverfahren verglichen wird. Ergebnisse: Es werden 30 medizinische Studien für den vorliegenden Bericht eingeschlossen. Im Vergleich zum Immunglobulin G (IgG)-Test ist die Sensitivität des 13C-Harnstoff-Atemtests zwölfmal höher, sechsmal niedriger und einmal gleich, und die Spezifität 13-mal höher, dreimal niedriger und zweimal gleich. Im Vergleich zum Stuhl-Antigen-Test ist die Sensitivität des 13C-Harnstoff-Atemtests neunmal höher, dreimal niedriger und einmal gleich, und die Spezifität neunmal höher, zweimal niedriger und zweimal gleich. Im Vergleich zum Urease-Schnelltest sind die Sensitivität des 13C-Harnstoff-Atemtests viermal höher, dreimal niedriger und viermal gleich und die Spezifität fünfmal höher, fünfmal niedriger und einmal gleich. Im Vergleich mit der Histologie ist die Sensitivität des 13C-Harnstoff-Atemtests einmal höher und zweimal niedriger und die Spezifität zweimal höher und einmal niedriger. In je einem Vergleich zeigt sich kein Unterschied zwischen 13C-Harnstoff-Atemtest und 14C-Harnstoff-Atemtest, sowie eine niedrigere Sensitivität und höhere Spezifität im Vergleich zur Polymerase-Kettenreaktion (PCR). Inwieweit die beschriebenen Unterschiede statistisch signifikant sind, wird in sechs der 30 Studien angegeben. Es werden neun gesundheitsökonomische Evaluationen in dem vorliegenden Bericht berücksichtigt. Die Test-and-Treat-Strategie mittels 13C-Harnstoff-Atemtest wird in sechs Studien mit einem Test-and-Treat-Verfahren auf Basis der Serologie sowie in drei Studien mit einem Test-and-Treat-Verfahren auf Basis des Stuhl-Antigen-Tests verglichen. Dabei ist das Atemtestverfahren dreimal kosteneffektiv gegenüber der serologischen Methode und wird von der Stuhl-Antigen-Test-Strategie einmal dominiert. Vier Studien beinhalten einen Vergleich der Test-and -Treat-Strategie auf Basis des 13C-Harnstoff-Atemtests mit einer empirischen antisekretorischen Therapie, wobei sich das Atemtesverfahren zweimal als kosteneffektive Prozedur erweist und zwei Studien einen Vergleich mit einer empirischen Eradikationstherapie. In fünf Studien wird das Test-and-Treat-Verfahren mittels 13C-Harnstoff-Atemtest einer endoskopiebasierten Strategie gegenübergestellt. Zweimal dominiert die Atemteststrategie die endoskopische Prozedur und einmal wird sie von dieser Strategie dominiert. Diskussion:Sowohl die medizinischen als auch die ökonomischen Studien weisen mehr oder minder gravierende Mängel auf und liefern heterogene Ergebnisse. So werden in der Mehrzahl der medizinischen Studien keine Angaben zur statistischen Signifikanz der berichteten Unterschiede zwischen den jeweiligen Testverfahren gemacht. Im direkten Vergleich weist der 13C-Harnstoff-Atemtest überwiegend eine höhere Testgüte als der IgG und der Stuhl-Antigen-Test auf. Aus den Vergleichen mit dem Urease-Schnelltest lassen sich keine Tendenzen bezüglich der Sensitivität ableiten, wohingegen die Spezifität des 13C-Harnstoff-Atemtests höher einzuschätzen ist. Für die Vergleiche des 13C-Harnstoff-Atemtest mit der Histologie, dem 14C-Harnstoff-Atemtest und der PCR liegen zu wenige Ergebnisse vor. In der eingeschlossenen ökonomischen Literatur deuten einige Studienergebnisse auf eine Kosten-Effektivität der Test-and-Treat-Strategie mittels 13C-Harnstoff-Atemtest gegenüber dem Test-and-Treat-Verfahren auf Basis der Serologie und der empirischen antiskretorischen Therapie hin. Um Tendenzen bezüglich der Kosten-Effektivität der Atemteststrategie gegenüber der Test-and-Treat-Strategie mittels Stuhl-Antigen-Test sowie der empirischen Eradikationstherapie abzuleiten, mangelt es an validen Ergebnissen bzw. ökonomischer Evidenz. Die Untersuchungsresultate hinsichtlich eines Vergleichs mit endoskopiebasierten Verfahren fallen diesbezüglich zu heterogen aus. Insgesamt kann keines der ökonomischen Modelle der Komplexität des Managements von Patienten mit dyspeptischen Beschwerden gänzlich gerecht werden. Schlussfolgerungen/Empfehlungen: Zusammenfassend ist festzuhalten, dass die Studienlage zur medizinischen und ökonomischen Beurteilung des 13C-Harnstoff-Atemtests im Vergleich zu anderen diagnostischen Methoden nicht ausreichend ist, um den Atemtest als primärdiagnostisches Standardverfahren im Rahmen einer Test-and-Treat-Strategie beim Management von Patienten mit dyspeptischen Beschwerden für die deutsche Versorgungslandschaft insbesondere vor dem Hintergrund der Leitlinien der Deutschen Gesellschaft für Verdauungs- und Stoffwechselkrankheiten (DGVS) anstelle einer endoskopiebasierten Methode zu empfehlen.

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Mothers with good vitamin A nutritional status during gestation and lactation are better able to nourish and protect their infant with maternal milk. Our hypothesis is that women with more serum retinol have more retinol and secretory immunoglobulin A in colostrum. 190 healthy puerperal women from a Brazilian public maternity were recruited and divided according to the cutoff point for serum retinol (30 μg/dL). A number of the women was supplemented with 200000 UI (60 mg) of retinyl palmitate in the immediate postpartum. Serum and colostrum were collected on the 1st day postpartum and colostrum again on the following day. Retinol (serum and colostrum) was analyzed by HPLC and SIgA (colostrum) by turbidimetry. The mothers presented with adequate biochemical indicators of nutritional status, according to serum retinol (44.6 μg/dL). There were significant differences (p= 0.0017 and p= 0.043, respectively) in retinol and SIgA levels in the colostrum of mothers with serum retinol > 30 μg/dL and < 30 μg/dL. The concentration of SIgA in the colostrum of non-supplemented mothers on the 1st day postpartum was 822.6 mg/dL, decreasing after 24 hours to 343.7 mg/dL. Supplemented mothers showed levels of SIgA in colostrum of 498.9 mg/dL on the 2nd day postpartum (p= 0.00006). The colostrum of women with good vitamin A nutritional status had more retinol and SIgA. Additionally, maternal supplementation increases the levels of SIgA in colostrum. The higher levels of SIgA on the 1st day postpartum showed the importance of early breastfeeding, given that it provides considerable immunological benefits to newborn infants

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Monoclonal antibodies and novel antibody formats are currently one of the principal therapeutic in the biopharmaceutical industry worldwide and are widely used in the treatment of autoimmune diseases and cancer. It is for this reason that the productivity and quality of antibody production requires improvement; specifically investigations into the engineering of antibodies and any issues that may arise from the production of these therapeutics. The work presented in this thesis describes an investigation into the folding and assembly of seven antibodies plus the novel antibody format FabFv. IgG is comprised of two identical HCs and two identical LCs. The folding process of immunoglobulin is controlled by the CH1 domain within the HC. The CH1 domain remains in a disordered state and is sequestered by BiP in the endoplasmic reticulum. Upon the addition of a folded CL domain, BiP is displaced, the CH1 domain is able to fold and the complete IgG protein can then be secreted from the cell. The results presented in this thesis however, have outlined an additional mechanism for the folding of the CH1 domain. We have shown that the CH1 domain is able to fold in the absence of LC resulting in the secretion of HC dimers in a VH dependent manner. The proposed mechanism for the secretion of HC dimers suggests that some VH domains can interact with each other in order to bring the CH1 domains in close proximity to enable folding to occur. As HC dimer secretion is a hindrance in antibody production, this result has highlighted an engineering target to improve antibody yield. Examination of the folding of IgG4 with the variable region A33 has revealed the inability to secrete LC dimers, cleavage of the HC during expression and secretion of HC dimers in the Fab, FabFv and full length forms. The attributes described have also been shown to be variable region dependent. This has introduced a new concept that the variable domain is important in determining the expression and secretion of antibodies and their individual chains. Pulse chase and 2D gel electrophoresis analysis of the novel antibody format FabFv has revealed that the folding and expression of the LC and HC causes multimeric species of FabFv to be secreted, as opposed to the monomeric form which is the desired therapeutic. Our hypothesis is that this process occurs via a LC dependent mechanism. The proposed hypothesis suggests that further engineering to the LC could diminish the formation and secretion of FabFv multimers. The results from these investigations can be applied to increase the productivity of therapeutics and increase the biological understanding of the domain interactions of IgG during folding, assembly and secretion.

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International audience

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Dissertação (mestrado)—Universidade de Brasília, Instituto de Ciências Biológicas, Departamento de Biologia Celular, Pós-Graduação em Biologia Molecular, 2015.

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Introduction: Involvement of penis is a rare presentation in henoch-schonlein purpura (HSP). The presentations are mainly due to the deposition of immunoglobulin A (IgA) into the vessel walls. In this report, we present the clinical history of nine HSP cases that presented with penile skin involvement. Case Presentation: All patients were referred in the acute phase of HSP. Penile skin involvement was evident as erythema, edema, ecchymosis, or induration of prepuce and/or penile shaft, that appeared simultaneously with skin rash in seven patients. Gastrointestinal involvement was positive in six patients. Patients were treated with steroids and follow up visits were normal except for one patient that developed crescentic glomerulonephritis. Conclusions: We present nine cases of HSP with penile involvement in order to indicate another rare aspect of HSP and its possible complications as well as its appropriate treatment.

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Background: CD166, an adhesion molecule of the immunoglobulin superfamily, is one of the crucial effectors that traffic lymphocytes into tissues. Till now, the expression and role of CD166 in the chronic kidney disease remains unknown. Objectives: In the present study, we are to examine the expression of CD166 in the chronic kidney disease, and to explore its function with CD4+ T cells. Materials and Methods: CD166 expression was tested by Flow Cytometry (FACS) in the primary macrophages stimulated with LPS. In vivo, the expression of CD166 and CD4 were examined in the kidney tissues of adriamycin-induced nephropathy (AN) mice by immnohistochemistry. Macrophages and lymphocytes were co-cultured, the interaction between CD166 and CD4 was tested by immunofluorescent staining. Furthermore, the effects of CD166 on the activation and proliferation of T cells were explored. Results: In this study, CD166 expression was found to be upregulated on activated macrophages and glomerular endothelia in the adriamycin-induced nephropathy (AN) mice and CD4+ T cells were increased with CD166 expression in the AN mice. The interaction between macrophages and CD4+ T cells indicated that CD166 played a key role in the recruitment of lymphocytes in the chronic kidney disease, and neither proliferation nor activation of T cells was affected by CD166. Conclusions: CD166 expressed on macrophages and endothelia in AN kidney, and the function was related to the recruitment of CD4+ T cells into inflamed kidney, indicating that CD166 may be a potential target for reducing the inflammatory infiltrates in the chronic kidney disease.

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Background: Celiac disease is an immune-mediated inflammation of the small intestine caused by sensitivity to dietary gluten in genetically sensitive individuals. Objectives: In this study, we aimed to evaluate the predictive value of tissue transglutaminase (tTG) antibodies for the diagnosis of celiac disease in a pediatric population in order to determine if duodenal biopsy can be avoided. Patients and Methods: The subjects were selected among individuals with probable celiac disease, referring to a gastrointestinal clinic. After physical examinations and performing tissue transglutaminase-immunoglobulin A (tTG-IgA) tests, upper endoscopy was performed if serological titer was higher than 18 IU/mL. Therapy started according to pathologic results. Results: The sample size was calculated to be 121 subjects (69 female and 52 male subjects); the average age of subjects was 8.4 years. A significant association was found between serological titer and pathologic results; in other words, subjects with high serological titer had more positive pathologic results for celiac disease, compared to others (P < 0.001). Maximum sensitivity (65%) and specificity (65.4%) were achieved at a serological titer of 81.95 IU/ml; the calculated accuracy was lower in comparison with other studies. As the results indicated, lower antibody titer was observed in patients with failure to gain weight and higher antibody titer was reported in diabetic patients. Conclusions: As the results indicated, a single serological test (tTg-IgA test) was not sufficient for avoiding intestinal biopsy.

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Hypersensitivity to the chicken egg is a widespread disorder mainly affecting 1-2% of children worldwide. It is the second most common food allergy in children, next to cow's milk allergy. Egg allergy is mainly caused by hypersensitivity to four allergens found in the egg white; ovomucoid, ovalbumin, ovotransferrin and lysozyme. However, some research suggests the involvement of allergens exclusively found in the egg yolk such as chicken serum albumin and YGP42, which may play a crucial role in the overall reaction. In egg allergic individuals, these allergens cause conditions such as itching, atopic dermatitis, bronchial asthma, vomiting, rhinitis, conjunctivitis, laryngeal oedema and chronic urticaria, and anaphylaxis. Currently there is no permanent cure for egg allergy. Upon positive diagnosis for egg allergy, strict dietary avoidance of eggs and products containing traces of eggs is the most effective way of avoiding future hypersensitivity reactions. However, it is difficult to fully avoid eggs since they are found in a range of processed food products. An understanding of the mechanisms of allergic reactions, egg allergens and their prevalence, egg allergy diagnosis and current treatment strategies are important for future studies. This review addresses these topics and discusses both egg white and egg yolk allergy as a whole.