Staphylococcal enterotoxin A: a candidate for the amplification of physiological immunoregulatory responses in the gut

Staphylococcal enterotoxin A (SEA) is one of the bacterial products tested for modulation of unwanted immune responses. Of all the staphylococcal enterotoxins, SEA is the most potent stimulator of T cells. When administered orally, SEA acts as a superantigen (SA), producing unspecific stimulation of intra-epithelial lymphocytes (IELs) in the intestinal mucosa. This stimulation results in amplification of the normal local immunologic responses, which are mainly regulatory. This amplification is based on increased local production of IFN-γ by IELs, which acts on the nearby enterocytes. As a result, the enterocytes produce large amounts of tolerosomes, cellular corpuscles which detach themselves from the basal poles of the enterocytes and contain antigenic peptides that are conditioned to be interpreted as tolerogenic by the gut immune system. Tolerosomes are physiologically produced as a response to dietary peptides; it is already known that enterocytes posses the molecular mechanisms for processing peptides in a similar manner to lymphocytes. The fate of tolerosomes is not precisely known, but it seems that they merge with intestinal dendritic cells, conveying to them the information that orally administered peptides must be interpreted as tolerogens. SEA can stimulate this mechanism, thus favoring the development of tolerance to peptides/proteins administered subsequently via the oral route. This characteristic of SEA might be useful in therapy for regulating immune responses. The present paper reviews the current status of research regarding the impact of SEA on the enteric immune system and its potential use in the treatment of allergic and autoimmune diseases.     

Controversies in the laboratory diagnosis of celiac disease in children; new haplotypes discovered

The latest consensus on celiac disease in 2008, under the auspices of the International Societies of Pediatric Gastroenterology, Hepatology and Nutrition, shows that HLA DQ2/DQ8 typing indicates the highest negative predictive value for celiac disease, which would exclude the diagnosis of celiac disease. In Romania, there are no studies on the implication of HLA-DQ2/DQ8 in celiac disease in children. The aim of our study was to analyze the significance of genetic tests, with a focus on negative HLA-DQ2/DQ8 cases, as well as to determine the main haplotypes involved in celiac disease in children. We tested in 37 children with old celiac disease, confirmed based on the presence of intestinal villi changes on duodenal biopsy, the IgA anti-tissue transglutaminase antibodies (TgA-IgA) by ELISA and the IgA anti-endomysium antibodies (EmA-IgA) by indirect immunofluorescence, compared to HLA-DQ2/DQ8 typing by polymerase chain reaction (PCR). In 25 children, the determined HLA haplotypes predominantly belonged to DQ2, and in 3 children we report the presence of a new haplotype, DR3-DQ2/DR4-DQ8, formed by pattern 1, DR3-DQ2-the DQA1*0501 and DQB1*0201 alleles, and pattern 5, DR4-DQ8-the DQA1*0301 and DQB1*0302 alleles. In 9 children, genetic tests were negative for celiac disease. The identification of HLA-DQ2/DQ8 provides additional data in the diagnosis of celiac disease, but a rigid algorithm in the diagnosis of celiac disease has no practical applicability.     

Proinflammatory cytokines: an insight into pancreatic oncogenesis

Pancreatic cancer is a highly lethal disease, being one of the five leading death causes among oncologic patients. It is usually diagnosed late due to the paucity of clinical signs, and the current therapy means have limited success. One of the documented risk factors for developing pancreatic adenocarcinoma is chronic pancreatitis. It is postulated that a chronic inflammatory disease has a potential of evolving toward neoplasia, a fact that could account for a percentage of the pancreatic cancers. Starting from this assumption, we intended to analyze the serum reflection of some molecules with proinflammatory roles, and compare them in healthy individuals, in patients with chronic pancreatitis and with pancreatic adenocarcinoma. Additionally, we performed a biochemical and hematological assessment of the study groups, and compared the results with the immunological parameters analyzed in the same subjects. We found significantly higher levels of Tumor Necrosis Factor-alpha and Interleukin 6 in chronic pancreatitis and pancreatic adenocarcinoma sera (with higher levels in the pancreatitis group than in the cancer group), compared to healthy controls. Additionally, we found significantly higher levels of interleukin 8 and Macrophage Inflammatory Protein-3 alpha in pancreatic cancer, compared to chronic pancreatitis and controls. We also identified numerous correlations between the abovementioned cytokines/chemokines and biochemical parameters, not very much studied before. Our results plead for a pathogenic role of chronic inflammation in pancreatic carcinogenesis, thus offering a potential tool for earliy diagnose or targets for therapy.     

IgG-F-actin antibodies in celiac disease and dermatitis herpetiformis

Anti-actin antibodies are found in 52-85% of patients with autoimmune hepatitis or chronic active hepatitis and in 22% of patients with primary biliary cirrhosis. In patients with celiac disease, anti-actin antibodies correlate with the degree of villous atrophy. Studies on their involvement in celiac disease and dermatitis herpetiformis in Romania have not been done. The purpose of this study was to evaluate of the quality of IgG anti-F-actin antibodies (IgG-AAA) tests compared with IgA tissue transglutaminase antibodies (IgA-TgA) having IgA endomysial antibody (IgA-EmA) as gold standard in celiac disease and dermatitis herpetiformis and to see if there is any relationship between them. The study included 70 pediatric patients with celiac disease under gluten-free diets and 10 adult patients with dermatitis herpetiformis, during 2010. The IgG-AAA antibodies levels were determined by ELISA. Assessing the qualities of IgG-AAA compared to IgA-TgA, we obtained the following values sensitivity (Se) 27.8%, specificity (Sp) 79.4%, respectively Se 88.9%, Sp 79.4% in celiac disease and Se 33.3%, Sp 100%, respectively Se 100%, Sp 100% in dermatitis herpetiformis. Also, there was a prevalence of 24.3% and 30% of IgG-AAA in the two groups of patients, but no statistically significant associations were found. Therefore, we concluded that IgG-AAA can not replace IgA-TgA in children patients with celiac disease under gluten-free diets and in adult patients with dermatitis herpetiformis. AAA-IgG serum activity in both diseases exist, but without a relationship of association with them.     

Trait-Associated SNPs Are More Likely to Be eQTLs: Annotation to Enhance Discovery from GWAS

Although genome-wide association studies (GWAS) of complex traits have yielded more reproducible associations than had been discovered using any other approach, the loci characterized to date do not account for much of the heritability to such traits and, in general, have not led to improved understanding of the biology underlying complex phenotypes. Using a web site we developed to serve results of expression quantitative trait locus (eQTL) studies in lymphoblastoid cell lines from HapMap samples (http://www.scandb.org), we show that single nucleotide polymorphisms (SNPs) associated with complex traits (from http://www.genome.gov/gwastudies/) are significantly more likely to be eQTLs than minor-allele-frequency–matched SNPs chosen from high-throughput GWAS platforms. These findings are robust across a range of thresholds for establishing eQTLs (p-values from 10⁻⁴–10⁻⁸), and a broad spectrum of human complex traits. Analyses of GWAS data from the Wellcome Trust studies confirm that annotating SNPs with a score reflecting the strength of the evidence that the SNP is an eQTL can improve the ability to discover true associations and clarify the nature of the mechanism driving the associations. Our results showing that trait-associated SNPs are more likely to be eQTLs and that application of this information can enhance discovery of trait-associated SNPs for complex phenotypes raise the possibility that we can utilize this information both to increase the heritability explained by identifiable genetic factors and to gain a better understanding of the biology underlying complex traits.     

Occurrence of fungi with mycotoxic potential in grain of transylvania and potential hazardous effects in broiler chicken

Investigations on the mycological quality of feeds from Transylvanian farms are presented. The investigations had two objectives:

A newly discovered founder population: the Roma/Gypsies

The Gypsies (a misnomer, derived from an early legend about Egyptian origins) defy the conventional definition of a population: they have no nation-state, speak different languages, belong to many religions and comprise a mosaic of socially and culturally divergent groups separated by strict rules of endogamy. Referred to as "the invisible minority", the Gypsies have for centuries been ignored by Western medicine, and their genetic heritage has only recently attracted attention. Common origins from a small group of ancestors characterise the 8-10 million European Gypsies as an unusual trans-national founder population, whose exodus from India played the role of a profound demographic bottleneck. Social and economic pressures within Europe led to gradual fragmentation, generating multiple genetically differentiated subisolates. The string of population bottlenecks and founder effects have shaped a unique genetic profile, whose potential for genetic research can be met only by study designs that acknowledge cultural tradition and self-identity.     

Effects of crowding by mono-, di-, and tetrasaccharides on cytochrome c-cytochrome c peroxidase binding: comparing experiment to theory

In cells, protein-protein interactions occur in an environment that is crowded with other molecules, but in vitro studies are almost exclusively performed in dilute solution. To gain information about the effects of crowding on protein complex formation, we used isothermal titration calorimetry to measure the stoichiometry, the free energy change, and the enthalpy change for the binding of yeast iso-1-ferricytochrome c to yeast ferricytochrome c peroxidase in dilute solution and in solutions crowded with the sugars glucose, sucrose, and stachyose. The stoichiometry is 1:1 under all conditions. The sugars stabilize the complex, but by only 0.1-0.5 kcal.mol(-)(1), and the increased stability is not correlated with the change in enthalpy of complex formation. We then compared the measured stability changes to values obtained from several analyses that are currently used to predict crowding-induced changes in biomolecular equilibria. None of the analyses are completely successful by themselves, and the results suggest that a complete analysis must account for both excluded-volume and chemical interactions.     

Iron deficiency interrupts energy transfer from a disconnected part of the antenna to the rest of Photosystem II

Iron deficiency changed markedly the shape of the leaf chlorophyll fluorescence induction kinetics during a dark-light transition, the so-called Kautsky effect. Changes in chlorophyll fluorescence lifetime and yield were observed, increasing largely the minimal and the intermediate chlorophyll fluorescence levels, with a marked dip between the intermediate and the maximum levels and loss of the secondary peak after the maximum. During the slow changes, the lifetime-yield relationship was found to be linear and curvilinear (towards positive lifetime values) in control and Fe-deficient leaves, respectively. These results suggested that part of the Photosystem II antenna in Fe-deficient leaves emits fluorescence with a long lifetime. In dark-adapted Fe-deficient leaves, measurements in the picosecond-nanosecond time domain confirmed the presence of a 3.3-ns component, contributing to 15% of the total fluorescence. Computer simulations revealed that upon illumination such contribution is also present and remains constant, indicating that energy transfer is partially interrupted in Fe-deficient leaves. Photosystem II-enriched membrane fractions containing different pigment-protein complexes were isolated from control and Fe-deficient leaves and characterized spectrophotometrically. The photosynthetic pigment composition of the fractions was also determined. Data revealed the presence of a novel pigment-protein complex induced by Fe deficiency and an enrichment of internal relative to peripheral antenna complexes. The data suggest a partial disconnection between internal Photosystem II antenna complexes and the reaction center, which could lead to an underestimation of the Photosystem II efficiency in dark-adapted, low chlorophyll Fe-deficient leaves, using chlorophyll fluorescence. This revised version was published online in August 2006 with corrections to the Cover Date.     

Is interleukin-17 a proatherogenic biomarker?

The importance of chronic inflammation in atherogenesis and cytokine involvement in all stages of atherosclerotic plaque development is now obvious. Our approach of the significant cytokines involved in atherogenesis or cardiovascular diseases is based on a correlation between clinical research and experiments on animal models. The contribution of IL-17 in atherogenesis remains controversial. In this study we investigated the role of IL-17 in cardiovascular diseases and in atherosclerosis associated with pathological aging. We performed a case-control study, enrolling subjects aged over 65 years in both groups. We included 40 patients with cardiovascular disorders and 10 healthy volunteers. IL-17 levels were measured in the serum of patients and healthy controls, along with serum total cholesterol and triglycerides. Significantly higher levels of IL-17 were obtained in patients compared to healthy controls (p<0.001). The level of this biomarker correlated significantly with two biochemical parameters - serum total cholesterol and triglycerides (the Pearson coefficient showed statistical significance, p=0.033, respectively p=0.043). We did not find any correlation between IL-17 and these two parameters in the control group. Our study is useful in understanding the physiopathological implications of IL-17 in the atherogenesis process. This could represent a starting point for future studies, including research regarding the therapeutic potential of IL-17 in pathological aging.