Tests to measure serum endomysial antibodies (EMA) and antibodies to tissue transglutaminase (tTG) were developed to screen for celiac disease in patients consuming gluten. However, they are commonly used to monitor patients on a gluten-free diet (GFD). We conducted a meta-analysis to assess the sensitivity and specificity of tTG IgA and EMA IgA assays in identifying patients with celiac disease who have persistent villous atrophy despite a GFD.

We searched PUBMED, EMBASE, BIOSIS, SCOPUS, clinicaltrials.gov, Science Citation Index, and Cochrane Library databases through November 2016. Inclusion criteria were studies of subjects with biopsy-confirmed celiac disease, follow-up biopsies, and measurement of serum antibodies on a GFD, biopsy performed on subjects regardless of symptoms, or antibody test results. Our analysis excluded subjects with refractory celiac disease, undergoing gluten challenge, or consuming a prescribed oats-containing GFD. Tests were considered to have positive or negative findings based on manufacturer cut-off values. Villous atrophy was defined as a Marsh 3 lesion or villous height:crypt depth ratio below 3.0. We constructed forest plots to determine the sensitivity and specificity of detection for individual studies. For the meta-analysis, a bivariate random effects model was used to jointly model sensitivity and specificity.

Our search identified 5408 unique citations. Following review of abstracts, 442 articles were reviewed in detail. Only 26 studies (6 of tTG assays, 15 of EMA assays, and 5 of tTG and EMA assays) met our inclusion criteria. The most common reason studies were excluded from our analysis was inability to cross-tabulate histologic and serologic findings. The serum assays identified patients with persistent villous atrophy with high levels of specificity: 0.83 for the tTG IgA assay (95% CI, 0.79-0.87) and 0.91 for the EMA IgA assay (95% CI, 0.87-0.94). However, they detected villous atrophy with low levels of sensitivity: 0.50 for the tTG IgA assay (95% CI, 0.41-0.60) and 0.45 for the EMA IgA assay (95% CI, 0.34-0.57). The tests had similar levels of performance in pediatric and adult patients.

In a meta-analysis of patients with biopsy-confirmed celiac disease undergoing follow-up biopsy on a GFD, we found that tests for serum tTG IgA and EMA IgA levels had low sensitivity (below 50%) in detection of persistent villous atrophy. We need more-accurate non-invasive markers of mucosal damage in children and adults with celiac disease who are following a GFD.

Evaluation of: Lewis NR, Scott BB. Meta-analysis: deamidated gliadin peptide (DGP) antibody and tissue transglutaminase (tTG) antibody compared as screening test for celiac disease. Aliment. Pharmacol. Ther. 31(1), 73-81 (2010). In celiac disease (CD), deamidation of gliadin peptides, induced by tissue transglutaminase (tTG), generates novel antigenic epitopes evoking a specific immune response. Serological tests based on the detection of antibodies to deamidated gliadin peptides (DGP) have been developed with very promising results in terms of sensitivity and specificity for CD screening. In the present study, a meta-analysis of studies published from 1998 to 2008 was designed to compare the performance of DGP antibodies with that of tTG antibodies, the validated and routinely employed test for CD screening. The authors have limited their analysis to IgA class antibodies underlining that most of the considered studies had methodological imperfections, especially ascertainment bias. The results of this meta-analysis indicated that the pooled sensitivities for DGP and tTG antibodies were 87.8% (95% CI: 85.6-89.9) and 93% (95% CI: 91.2-94.5), respectively, and the pooled specificities were 94.1% (95%CI: 92.5-95.5) and 96.5% (95% CI: 95.2-97.5), respectively. In summary, although both tests represent a very good tool for identifying celiac patients, tTG antibodies display a higher predictive value than DGP antibodies, and must still be considered the best serological test for CD screening.

The nucleotide sequence of the gsh I gene for gamma-glutamylcysteine synthetase(GSH I) of Escherichia coli B has been determined. The gsh I structural gene contains 1557 bases in length and predicted a ploypeptide of 518 amino acids with a calculated molecular weight of 58,251. The value is in good agreement with that obtained from gel filtration and SDS/PAGE of GSH I. The initiation codon 5 bp downstream of putative Shine-Dalgarno sequence was an unusual TTG, which encoded methionine. For transcription, two sets of consensus promoter signals(-10 and -35 regions) overlapping each other were identified. The terminator signal shows the favored stem-loop structure with an adequate free energy delta G = -22.80 kcal/mol.

BACKGROUND

Tissue transglutaminase (TTG) antibodies and newly developed deamidated gliadin peptide (DGP) antibodies have better accuracy than native gliadin antibodies. Multiplex immunoassay (MIA) measures multiple antibodies simultaneously providing a complete antibody phenotype with reduced turnaround time and cost.

OBJECTIVE

To evaluate the agreement between MIA and enzyme-linked immunosorbent assay (ELISA) test results for coeliac autibodies in biopsy-proven coeliac patients and controls and to model the diagnostic utility of combination testing.

METHODS

We compared the sensitivity, specificity and accuracy of MIA and ELISA methods for TTG and DGP antibodies in mainly adult untreated coeliac patients (n = 92) and controls (n = 124).

RESULTS

There was excellent agreement and a significant correlation between the results of MIA and ELISA methods (k>> 0.8, r>> 0.7) for all tests, except IgG. Diagnostic indices of individual and combination tests measured by the MIA method did not differ significantly from those measured by ELISA. The combination tests slightly increased sensitivity (if any test was positive) and specificity (if all tests were positive) compared to the individual tests.

CONCLUSIONS

Multiplex immunoassay testing for antibodies is as accurate as ELISA for coeliac disease diagnosis and has practical advantages over ELISA method. Rational combination testing can help identify patients who need intestinal biopsy and may reduce unnecessary biopsies.

The DNA sequence encoding the rbs repressor protein, RbsR, has been determined. Amino acid sequence analyses of the product of an rbsR-lacZ fusion and of affinity-purified RbsR demonstrate that translation begins at an unusual codon, TTG, and that the initial amino acid is removed during maturation of the protein. DNA-binding assays indicate that RbsR binds to a region of perfect dyad symmetry spanning the rbs operon transcriptional start site and that the affinity for the rbs operator is reduced by addition of ribose, consistent with ribose being the inducer of the operon. RbsR is a member of a family of homologous repressor proteins having very similar DNA-binding sites and binding to similar operator sequences.

During inflammation, T lymphocytes migrate out of the blood across the vascular endothelium in a multistep process. The receptors mediating T cell adhesion to endothelium are well characterized; however, the molecules involved in T cell transendothelial migration (TEM) subsequent to lymphocyte adhesion to the endothelium are less clear. To identify receptors mediating TEM, mAbs were produced against human blood T cells adhering to IFN-gamma-activated HUVEC in mice and tested for inhibition of lymphocyte TEM across cytokine-activated HUVEC. Most of the mAbs were against beta(1) and beta(2) integrins, but one mAb, 6B9, significantly inhibited T cell TEM across IFN-gamma, TNF-alpha, and IFN-gamma plus TNF-alpha-stimulated HUVEC, and did not react with an integrin. 6B9 mAb did not inhibit T cell adhesion to HUVEC, suggesting that 6B9 blocked a novel pathway in T cell TEM. The 6B9 Ag was 80 kDa on SDS-PAGE, and was expressed by both blood leukocytes and HUVEC. Immunoaffinity purification and mass spectrometry identified this Ag as tissue transglutaminase (tTG), a molecule not known to mediate T cell TEM. Treatment of HUVEC with 6B9 was more effective than treatment of T cells. 6B9 blockade selectively inhibited CD4(-), but not CD4(+), T cell TEM, suggesting a role for tTG in recruitment of CD8(+) T lymphocytes. Thus, 6B9 is a new blocking mAb to human tTG, which demonstrates that tTG may have a novel role in mediating CD8(+) T cell migration across cytokine-activated endothelium and infiltration of tissues during inflammation.

OBJECTIVE

In North America and Europe, the prevalence of celiac disease (CD) might be much greater than expected in previous estimates. Until recently, the prevalence of CD in Latin America remained largely unknown. So far, information regarding CD in Mexico is limited, and it is still considered a rare disease. Our aim was to determine the prevalence of tTGA in a large group of apparently healthy blood donors.

METHODS

Serum samples from 1009 consecutive blood donors, who attended a third level referral center in Mexico City, were collected between June 2004 and December 2004. Only Mexican Mestizo individuals were included. All sera were tested with a new generation human recombinant protein based tTGA-IgA ELISA commercial kit (Aeskulisa tTG-IgA, Wendelsheim, Germany). The cut-off value provided by the manufacturer was 15 U/mL.

RESULTS

The mean age of the blood donors was 34+/-10 years and 68% (n=683) were men. Six hundred fifty two subjects (65%) were born in Mexico City; and from the remaining 357 subjects, at least one was born in each of the 31 different states in our country. Twenty-seven (2.7%) blood donors were positive for tTGA-IgA; all of them with tTGA-IgA values above 30 U/mL (range 36 to 1639). Overall prevalence was 1:37 [27/1009, 95% confidence interval (CI)=1.6-3.7]. The prevalence among women was 1:33 (10/326, 95% CI=1.04-5.09) and for men 1:40 (17/683, 95% CI=1.24-3.73).

CONCLUSIONS

On the basis of a well-recognized serologic screening method performed to blood donor samples, we demonstrated an unexpectedly high prevalence of tTGA positivity (2.6%) in the adult Mexican Mestizo population. Thus, the prevalence of CD in Mexico could be higher or similar to that observed in other countries. This observation contributes to increase the awareness for this under diagnosed disease in clinical practice and to consider CD as a global health problem.

We performed this study to clarify the independent effects of hyperandrogenaemia, hyperinsulinaemia, and obesity on lipid and lipoprotein levels in women with hyperandrogenaemia (HA) and anovulation which we designated as the polycystic ovary syndrome (PCO). We examined fasting lipid, lipoprotein, sex hormone and insulin levels in 38 women (21 obese (ob), 17 non-obese (nob] with HA and anovulation (PCO) and 38 normal ovulatory women (21 obese, 17 non-obese), matched for age and weight. The women with PCO had significantly increased androgen levels compared to the normal women. However, total oestradiol levels were similar in the PCO and normal women. Mean fasting insulin levels and 2-h glucose levels (both P less than 0.001) were significantly higher in ob PCO women. There were significant decreases (P less than or equal to 0.01) in high-density lipoprotein (HDL) levels in both the obese groups (ob PCO and ob normal) compared to the non-obese (nob PCO and nob normal) groups. Otherwise, mean lipid and lipoprotein levels did not differ in the ob or the nob PCO women compared to the control groups. The correlations between sex hormone, lipid and lipoprotein levels differed in the four groups of women. After statistical adjustment for potential hormonal interactions, nob PCO women had significant positive correlations between testosterone and LDL levels (R = 0.51, P less than 0.05) and insulin and TTG levels (R = 0.61, P less than 0.01). Ob normal women had a significant positive correlation between oestrone and TTG levels (R = 0.44, P less than or equal to 0.05). We conclude that (1) PCO women are in a low to risk for CVD primarily because of the increased prevalence of obesity rather than the reproductive hormone abnormalities associated with this disorder. However, by their lipid profiles, the PCO women were still in a low to intermediate risk group for CVD.

The expansion of a polyglutamine (polyQ) domain in neuronal proteins is the molecular genetic cause of at least eight neurodegenerative diseases. Proteins with a polyQ domain that is greater than 40 Q (Q40) residues form insoluble intranuclear and cytoplasmic inclusions. Expanded polyQ proteins self-associate by non-covalent interactions and become insoluble. They can also be covalently cross-linked by tissue transglutaminase (TTG), a calcium-dependent enzyme present in cells throughout the nervous system. However, it remains unclear whether TTG cross-linking directly contributes to the insolubility of the expanded polyQ proteins. Using an in vitro solubility assay, we found TTG cross-linked Q62 monomers into high molecular weight soluble complexes in a calcium-dependent reaction. Inhibition of TTG cross-linking by primary amine substrates including putrescine and biotinylated pentylamine antagonized TTG's ability to form soluble complexes. In contrast, primary amines (histamine and lysine) that were less effective inhibitors of TTG cross-linking did not inhibit Q62 from becoming insoluble. In summary, TTG can increase the solubility of expanded polyQ proteins by catalyzing intermolecular cross-links. This demonstrates directly that TTG will reduce the ability of expanded polyQ proteins from becoming insoluble. Furthermore, the effectiveness of a primary amine substrate at inhibiting formation of insoluble inclusions may be related to their ability to inhibit intermolecular cross-linking by TTG.

BACKGROUND

The screening and diagnosis of coeliac disease have been simplified by the advent of new serological tools.

OBJECTIVE

To assess the clinical utility of a newly developed kit for antibodies to human recombinant tissue transglutaminase (hu-anti-tTG) in a large population of patients undergoing intestinal biopsy for suspected intestinal disorders.

METHODS

We evaluated 426 serum samples from consecutive adult patients (250 from untreated coeliac disease patients and 176 from individuals in whom a diagnosis of coeliac disease had been excluded), obtained at the time of intestinal biopsy. Samples were tested for immunoglobulin A (IgA) hu-anti-tTG by enzyme-linked immunoabsorbent assay, IgA endomysial antibodies (EmA) by indirect immunofluorescence and IgA and IgG antigliadin antibodies by enzyme-linked immunoabsorbent assay. A sub-group of samples was also assessed for a guinea-pig-based anti-tissue transglutaminase.

RESULTS

According to the cut-off for hu-anti-tTG, the sensitivity, specificity and positive and negative predictive values were 91%, 96%, 97% and 87%, respectively. Simultaneous determination of EmA showed values of 86%, 100%, 100% and 83% for the same parameters. Although 19 coeliac disease patients (7.6%) were negative for EmA and hu-anti-tTG, both tests rendered superior statistical values to antigliadin antibody tests. At diagnosis, IgA deficiency was detected in 11 patients, but both assays were able to detect samples with mild to moderate deficiency. The comparison of hu-anti-tTG with EmA showed excellent concordance between the tests (kappa statistic, 0.85). Discordance was observed in 20 samples from coeliac disease patients (8%) and in nine samples from controls (5%). Fifteen samples had an EmA-negative but hu-anti-tTG-positive serology, and five showed the converse pattern. Comparison of human recombinant and guinea-pig tests showed concordant results in 96% of cases.

CONCLUSIONS

The quantitative determination of hu-anti-tTG type IgA using a commercial enzyme-linked immunoabsorbent assay kit was highly sensitive and specific for the detection of coeliac disease. Our results in a large population of patients with a clinical condition suggestive of the disorder demonstrated that the test can be used to detect a substantial number of patients otherwise unrecognized by IgA EmA.

Genetic defects of the CD95 (Fas/Apo-1) receptor/ligand system, has recently been involved in the development of human and murine autoimmunity. We investigated whether a deregulation of the ;tissue' transglutaminase (tTG), a multifunctional enzyme which is part of the molecular program of apoptosis, may act as a cofactor in the development of autoimmunity. We found that MRLlpr/lpr, which are characterized by a defect in the CD95 receptor and suffer of a severe systemic lupus erythematosus-like disease, produce large amounts of circulating tTG autoantibodies. This phenomenon is paralleled by an abnormal accumulation of an inactive enzyme protein in the accessory cells of lymphoid organs. To investigate the molecular mechanisms by which tTG inhibition may contribute to the development of autoimmunity we generated a cell culture model system consisting of L929 cells stably transfected with a full length tTG cDNA. When L929 cells were killed by Tumor Necrosis Factor alpha (TNFalpha) a pronounced release of DNA and Lactate Dehydrogenase (LDH) was observed. Overexpression of tTG in these cells largely prevented the leakage of macromolecules determined by TNFalpha treatment, an effect which is abolished by inactivating the enzyme cross-linking activity by a synthetic inhibitor. These in vitro observations provided the basis to explain the increased levels of plasmatic LDH we detected in MRLlpr/lpr mice. These data suggest that lack of an active tTG may represent a cofactor in the development of autoimmunity.

OBJECTIVE

The association between maternal celiac disease (CD) and both reduced fertility and increased risk of adverse pregnancy-related events has been long documented. However, no evidences are available regarding the pathogenic mechanisms of this link. The aim of this study was to determine whether anti-tissue transglutaminase (anti-tTG) antibodies are involved in the damage of trophoblastic cells in vitro.

METHODS

Human primary trophoblastic cells, isolated from term placenta, were exposed to anti-tTG immunoglobulin G (IgG) antibodies, both commercially available and separated from sera of three untreated celiac women. The ability of anti-tTG antibodies to bind to trophoblastic cells, invasiveness of placental cells through a layer of extracellular matrix, and the activity of cellular matrix metalloprotease (MMP) and cellular apoptosis were evaluated, as indicators of trophoblast damage, by TdT-mediated dUTP digoxigenin nick end labeling (TUNEL) and annexin V expression.

RESULTS

Anti-tTG IgG showed a specific dose- and time-dependent binding to human trophoblast. In addition, trophoblastic cells, after being exposed to anti-tTG IgG antibodies, both commercially available and separated from sera of celiac women, showed an impaired invasiveness, a decreased activity of cellular MMP, and a greater percentage of TUNEL positivity and annexin V positivity.

CONCLUSIONS

We showed that the binding of anti-tTG antibodies to trophoblast might represent a key mechanism by which the embryo implantation and pregnancy outcome are impaired in untreated celiac pregnant women. Because healthy trophoblast development is essential for placental and fetal development, these data provide a novel mechanism for CD-induced infertility, early pregnancy loss, and intrauterine growth retardation.

The first polyhydroxyalkanoic acid (PHA) synthase gene (phbCRr) of a Gram-positive bacterium was cloned from a genomic library of Rhodococcus ruber in the broad-host-range plasmid vector pRK404. The hybrid plasmid harboring phbCRr allowed the expression of polyhydroxybutyric acid (PHB) synthase activity and restored the ability of PHB synthesis in a PHB-negative mutant of Alcaligenes eutrophus. Nucleotide sequence analysis of phbCRr revealed an open reading frame of 1686 bp starting with the rare codon TTG and encoding a protein of relative molecular mass 61,371. The deduced amino acid sequence of phbCRr exhibited homologies to the primary structures of the PHA synthases of A. eutrophus and Pseudomonas oleovorans. Preparation of PHA granules by discontinuous density gradient centrifugation of crude cellular extracts revealed four major bands in an SDS polyacrylamide gel. A Mr 61,000 protein was identified as the PHA synthase of R. ruber by N-terminal amino acid sequence determination.

BACKGROUND

Celiac disease is reported to be common among North Africans, particularly Tunisians. Nevertheless, the prevalence of coeliac disease in the general population has not been previously investigated.

OBJECTIVE

This study aimed to determine the prevalence of celiac disease among children in Tunisia and to describe the clinical profile of the screened patients.

METHODS

A mass screening study based on drawing lots was carried out on schoolchildren in Ariana, a Tunisian district. A participation agreement was obtained from 6286 children (3175 boys, age: 9.7+/-3 years). Two children of known celiac disease were present in this population. All participants were tested for IgA antitissue transglutaminase antibodies (IgA-tTG) by a commercial enzyme-linked immunosorbent assay (ELISA) and total IgA levels. Sera, found positive by the initial screening, were assessed by immunofluorescence for the presence of IgA antiendomysium antibodies (IgA-AE). Positive participants were also called in for serological control, intestinal biopsy, biological exploration (hemoglobin rate, calcemia and albuminemia) and bone mineral densitometry.

RESULTS

Among the 6284 participants, 139 (1/45) were positive for IgA-tTG. Forty-two of these had low-level IgA-tTG and no one had IgA deficiency. IgA-AE was detected in 40 participants. One hundred and seven children were called in, 28 had both positive tests (IgA-tTG +/IgA-AE+) and 79 were only positive for IgA-tTG (IgA-tTG +/IgA-AE-). Intestinal biopsy was performed in the 28 participants of the first group (IgA-tTG +/IgA-AE+) and confirmed celiac disease in 26 cases. In the second group (IgA-tTG +/IgA-AE-), intestinal biopsy was performed in 26 children and histological examination was normal in all cases. Among the 26 biopsy-proven celiac disease children, six (23%) had typical clinical symptoms of celiac disease, whereas the others had atypical forms with 11 (42%) asymptomatic. In 23 biopsy-proven celiac disease children, bone mineral density was significantly lower than that of a group of 109 normal children (0.850+/-0.06 g/cm2 versus 0.912+/-0.06 g/cm2, P<0.05). Seven participants (30.4%) among the celiac disease children and six (7.5%) among the controls had a total-body Z score for bone mineral density of <-2 (P<0.001).

CONCLUSIONS

The prevalence of celiac disease in Tunisian schoolchildren, estimated to be about 1/157, is close to the European prevalence. Most of the screened children showed an atypical and asymptomatic form, but even the typical forms were underdiagnosed. Ostopenia was frequently observed in celiac disease patients.

Tissue transglutaminase (tTG) seems to be the target self-antigen for endomysial antibodies in coeliac disease (CD) and to catalyse the critical deamidation of gliadin which strengthens its recognition by HLA-restricted gut-derived T cells. To date, it has not been demonstrated whether gliadin is cross-linked to tTG within the gut wall, a phenomenon known to occur in vitro. We therefore investigated the putative presence of tTG and gliadin complexes directly in duodenal mucosa. The immunoprecipitation and Western blotting experiments were performed on mucosal biopsies obtained from untreated, treated CD patients and biopsied controls, by using either anti-tTG or anti-gliadin antibodies, in both denaturating/reducing or nondenaturating/nonreducing conditions. A subset of experiments was performed by using anti-tTG antibodies purified by affinity chromatography from sera of untreated coeliac patients. The localization of tTG and gliadin was studied by immunofluorescence at confocal laser microscopy on seriate sections of diseased and normal duodenal mucosa by using the same antibodies of the coimmunoprecipitation section. The amounts of tTG and gliadin coimmunoprecipitated with anti-tTG monoclonal antibody in untreated CD mucosa were significantly increased compared to those of the other two groups. When performing the experiments in nondenaturating/nonreducing conditions, a high molecular weight band formed by both molecules, was evidenciated. Also the anti-tTG antibodies purified from patients' sera turned out to be able to coimmunoprecipitate the two molecules. The analysis by confocal microscopy showed that tTG colocalizes with gliadin at the epithelial and subepithelial levels in active CD, and only in the lamina propria of the villi in normal mucosa. Our findings firstly demonstrated that gliadin was directly bound to tTG in duodenal mucosa of coeliacs and controls, and the ability of circulating tTG-autoantibodies to recognize and immunoprecipitate the tTG-gliadin complexes.

Biomaterials that mimic the extracellular matrix in both modularity and crosslinking chemistry have the potential to recapitulate the instructive signals that ultimately control cell fate. Toward this goal, modular protein polymer-based hydrogels were created through genetic engineering and enzymatic crosslinking. Animal derived tissue transglutaminase (tTG) and recombinant human transglutaminase (hTG) enzymes were used for coupling two classes of protein polymers containing either lysine or glutamine, which have the recognition substrates for enzymatic crosslinking evenly spaced along the protein backbone. Utilizing tTG under physiological conditions, complete crosslinking occurred within 2 min, as determined by particle tracking microrheology. Hydrogel composition impacted the elastic storage modulus of the gel over 4-fold and also influenced microstructure and degree of swelling, but did not appreciably effect degradation by plasmin. Mouse 3T3 and primary human fibroblasts were cultured in both 2- and 3-dimensions without a decrease in cell viability and displayed spreading in 2D. The properties, which are controlled through the specific nature of the protein polymer precursors, render these gels valuable for in situ therapies. Furthermore, the modular hydrogel composition allows tailoring of mechanical and physical properties for specific tissue engineering applications.

OBJECTIVE

The study was undertaken to evaluate the frequency of inherited medullary thyroid carcinoma (MTC) among patients with apparent sporadic disease. A stepwise algorithm was used depending on clinical indices and the age of patient at MTC diagnosis.

METHODS

One hundred sixteen patients with MTC verified by postoperative pathologic examination were subjected to genetic analysis of RET exons 10, 11, 13, 14, and 16 by means of polymerase chain reaction, restriction endonuclease digestion, and DNA sequencing.

RESULTS

Among 116 apparent sporadic MTC patients, we identified eleven (9.5%) RET germline mutation carriers. Seven of these (6.0%) were found by routine analysis (exons 10 and 11). The frequency of inherited disease among patients younger than 45 years at diagnosis was 10.2% by analysis of typical mutations in exons 10 and 11. Extended genetic analysis (sequencing of exons 11, 13, 14, and 16) yielded 6.1% additional diagnoses, giving a risk of 16.3% in this age group. One previously unreported mutation in exon 11 affected codon 649 (TCG>TTG, Ser>Leu). In the true sporadic MTC patients younger than 30 years at diagnosis, frequencies of 36% and 4.5% in polymorphic variants L769L and S836S, respectively, were observed. The frequency for L769L was higher than in older patients (P <.05).

CONCLUSIONS

The frequency of inherited disease among apparent sporadic medullary thyroid carcinoma patients is close to 10% in the Polish population of MTC patients. The extended analysis of all known RET proto-oncogene mutation sites is obligatory in patients younger than 45 years at diagnosis, but we also see the need to analyze the impact of rarer mutations in older patients.

Root hairs of Arabidopsis roots develop on trichoblasts located over the anticlinal (radial) walls of underlying cortical cells. Non-hair cells, on the other hand, develop on atrichoblasts overlying the periclinal (tangential) walls of cortical cells. Dark-grown wild-type seedlings, which produce little ethylene, are largely root hairless. Exogenous treatment of dark-grown plants with either ethylene or 1-aminocyclopropane-1-carboxylic acid (ACC) restores the development of root hairs in cells overlying the anticlinal cortical cell walls, indicating that cells in this position are more sensitive to ethylene than atrichoblasts. We used mutations in genes that overproduce ethylene (eto1, eto2, eto3 and eto4) to illustrate the positive regulatory role of ethylene. The preferential development of root hairs on epidermal cells overlying the cortical anticlinal cell walls in these mutants also illustrates that trichoblasts are more sensitive to ethylene than atrichoblasts. CTR1 is a negative regulator of the ethylene response and might, therefore, be a candidate regulator of differential sensitivity. CTR1 mRNA is expressed in all cell types in the root, suggesting that its transcriptional pattern alone cannot account for the differential sensitivity of epidermal cells to ethylene. Cellular mapping of wild-type and mutant roots supports previous findings indicating that ethylene acts after, and perhaps independently, of TTG during the establishment of cell fate in the root epidermis.

BACKGROUND

This study was conducted to evaluate whether tissue transglutaminase (tTG) may be involved in airway inflammation of toluene diisocyanate-induced occupational asthma (TDI-OA).

METHODS

We enrolled 93 patients with TDI-OA, 177 asymptomatic exposed subjects, 43 patients with allergic asthma, and 70 unexposed normal controls. The prevalence of serum immunoglobulin G (IgG) to tTG in the TDI-OA group (20.2%) was significantly higher than that in the three other groups (P < 0.001).

RESULTS

TDI-OA patients with serum IgG to tTG had significantly lower methacholine PC(20) values (P < 0.02) and significantly higher prevalence of specific immunoglobulin E to vapor type TDI-human serum albumin conjugate (P < 0.01; r(2) = 0.411, P < 0.05). TDI exposure could increase tTG activity via reactive oxygen species (ROS) production, which was found to cross-link with cytokeratin 19 on immunoblot analysis.

CONCLUSIONS

Therefore, TDI exposure may activate tTG via ROS-mediated mechanism in the airway epithelium leading to persistent airway inflammation in TDI-OA patients.

BACKGROUND

The detection of auto antibodies directed against tissue transglutaminase (anti-tTG antibodies) has a well-established role in the diagnosis of coeliac disease, but the value of these antibodies in long-term follow-up is controversial.

OBJECTIVE

To determine if serial anti-tTG antibody measurements could confirm adherence to a gluten-free diet (GFD) and identify patients at risk of disease complications.

METHODS

In a 54-month cohort follow-up study, 182 adult patients were assessed. Data recorded included self-assessment of GFD adherence; anti-tTG antibody concentration and serum ferritin, vitamin B12 and folate. Where available, bone mineral density (BMD) and duodenal histology data were retrieved.

RESULTS

Persistently elevated anti-tTG antibody levels were significantly associated with abnormal duodenal histology (P < 0.001), low ferritin (P < 0.01) and poor adherence to the GFD (P < 0.001). The specificity was >85% while the sensitivity was 39-60%. Anti-tTG antibody concentrations fell rapidly following successful initiation of a GFD, and maintenance of normalization identified those who continued to be adherent to the diet.

CONCLUSIONS

This study supports a strategy of using anti-tTG antibody concentrations to monitor newly diagnosed and established patients with coeliac disease, and to target dietetic intervention to reduce the risk of complication.

The role of immunoglobulin A (IgA) anti-tissue transglutaminase antibodies (IgA-tTG) as predictors of untreated celiac disease (CoD) is well documented, and the presence and levels of these antibodies are most accurately monitored with native or recombinant human antigens. However, IgA-deficient CoD patients are not identified by IgA serology, and conflicting results concerning the diagnostic validity of IgG antibodies against gliadin (IgG-AGA), endomysium (IgG-EmA), and tTG (IgG-tTG) have been reported. The aim of the present study was to evaluate the utility of IgG-tTG for the detection of CoD in IgA-deficient patients. Samples from 115 IgA-deficient and 200 IgA-sufficient subjects were collected and tested for the presence of IgA and IgG antibodies against tTG, EmA, and AGA. Antibodies against tTG were measured by an enzyme-linked immunosorbent assay based on recombinant human tTG, and antibodies against EmA were determined by immunofluorescence. The values for IgG-tTG showed a higher correlation (correlation coefficient [r] = 0.91) with those for IgG-EmA for the IgA-deficient subjects than for the IgA-sufficient subjects (r = 0.88). The overall concordance of the positive and negative results between IgG-tTG and IgG-EmA was 97%, and the IgG-tTG assay discriminated between IgG-EmA-positive and -negative subjects with IgA deficiency at a rate of 100%. Elevated levels of IgG-tTG and IgG-EmA were measured in 70% of the IgA-sufficient subjects. IgG-tTG detection with recombinant human tTG is a good alternative to IgG-EmA detection, and the addition of IgG-tTG assessment to present screening methods may improve the ability to identify IgA-deficient subjects with CoD.

OBJECTIVE

To provide an estimate of the prevalence of celiac disease by race/ethnic origin in large sample of US population.

METHODS

Data from the 2009-2010 and 2011-2012 NHANES were combined and analyzed. The NHANES is a nationally representative survey with oversampling of certain minorities. Sample-based frequencies were reported and weighted frequencies were used to estimate prevalence.

RESULTS

A total of 14,701 participants were checked for tissue transglutaminase (tTG) and endomysial (EMA) IgA antibodies. Seventy-four participants had positive tTG and/or EMA corresponding to prevalence of 0.79 % (95 % CI 0.54-1.04 %). Non-Hispanic white were more likely to be positive for both compared with other races (72.0 vs 31.7 %; p = 0.010) and less likely to be weakly positive for tTG but positive for EMA (3.6 vs 26.4 %; p = 0.03). The prevalence of positive serology according to race was as follows: 1.08 % (95 % CI 0.70-1.45 %) in non-Hispanic white, 0.23 % (95 % CI 0.03-0.43 %) in Mexican, 0.22 % (95 % CI 0.01-0.44 %) in non-Hispanic black, 0.38 % (95 % CI 0.00-0.89 %) in "other Hispanic," and 0.15 % (95 % CI 0.00-0.34 %) in other races including multiracial and undeterminable in non-Hispanic Asian due to the presence of only one positive EMA test. 0.9 % of the NHANES sample participants followed gluten-free diet. Of this group of participants, 85 % were never diagnosed with celiac disease and 99 % of them had negative celiac disease serology.

CONCLUSIONS

Potentially 0.79 % of the general US population demonstrate serologic evidence of celiac disease autoimmunity. The prevalence is 4-8 times higher among non-Hispanic white compared with other races. Close to 1 % of the population is electively following gluten-free diet despite having little evidence of the disease.

In this study, we identified lysine residues in the fibrinogen Aalpha chain that serve as substrates during transglutaminase (TG)-mediated cross-linking of plasminogen activator inhibitor 2 (PAI-2). Comparisons were made with alpha(2)-antiplasmin (alpha(2)-AP), which is known to cross-link to lysine 303 of the Aalpha chain. A 30-residue peptide containing Lys-303 specifically competed with fibrinogen for cross-linking to alpha(2)-AP but not for cross-linking to PAI-2. Further evidence that PAI-2 did not cross-link via Lys-303 was the cross-linking of PAI-2 to I-9 and des-alphaC fibrinogens, which lack 100 and 390 amino acids from the C terminus of the Aalpha chain, respectively. PAI-2 or alpha(2)-AP was cross-linked to fibrinogen and digested with trypsin or endopeptidase Glu-C, and the resulting peptides analyzed by mass spectrometry. Peptides detected were consistent with tissue TG (tTG)-mediated cross-linking of PAI-2 to lysines 148, 176, 183, 457 and factor XIIIa-mediated cross-linking of PAI-2 to lysines 148, 230, and 413 in the Aalpha chain. alpha(2)-AP was cross-linked only to lysine 303. Cross-linking of PAI-2 to fibrinogen did not compete with alpha(2)-AP, and the two proteins utilized different lysines in the Aalpha chain. Therefore, PAI-2 and alpha(2)-AP can cross-link simultaneously to the alpha polymers of a fibrin clot and promote resistance to lysis.

BACKGROUND

Aedes albopictus is distributed widely in China, as a primary vector of Dengue fever and Chikungunya fever in south of China. Chemical insecticide control is one of the integrated programmes to prevent mosquito-borne diseases. Long-term applications of pyrethroids have resulted in the development of resistance in Ae. albopictus populations in China. However, the susceptibility of Ae. albopictus to pyrethroids in Hainan Island was unclear. Knockdown resistance (kdr), caused by point mutations in the VGSC gene, is one of the mechanisms that confer resistance to DDT and pyrethroids. This study was to investigate the resistance level of Ae. albopictus populations in Haikou City to three pyrethroid insecticides, and elucidate the relationship between the resistant phenotype and kdr mutations.

METHODS

The Aedes albopictus samples were collected in Xinbu Island (XI), Longtang Town (LT), Shishan Town (ST), Baishamen Park (BP), and Flower Market (FM) from Haikou City, Hainan Island, China. The larval susceptibility to deltamethrin, permethrin and beta-cypermethrin was tested by larval bioassays, and adult susceptibility to deltamethrin and DDT was determined by adult bioassays. The degree of resistance was determined by resistance ratio value (RR50>> 3) for larvae and by mortality for adult. The kdr alleles at codon 1534 of the VGSC gene were genotyped. The relationship between kdr genotypes and resistant phenotypes was analyzed by Chi-square test.

RESULTS

Out of five populations, assessed by larval bioassays, XI was susceptible to deltamethrin and permethrin; LT was susceptible to permethrin and beta-cypermethrin; and ST was susceptible to permithrin. FM and BP both were resistant to all of the three pyrethroids, and FM showed the highest degree of resistance, with RR50 values from 65.17 to 436.36. A total of 493 individuals from the larval bioassays were genotyped for kdr alleles. Five alleles were detected, including two wildtype alleles, TTC(F) (67.04 %) and TTT(F) (0.41 %), and three mutant alleles, TGC(C) (0.30 %), TCC(S) (31.54 %) and TTG(L) (0.71 %). There was a clear correlation between mutant alleles (or F1534S) and resistant phenotypes (P < 0.01).

CONCLUSIONS

Two novel kdr mutant alleles F1534S and F1534L were detected in the pyrethroid resistant populations of Ae. albopictus in Haikou Hainan, China. For the first time, the mutant F1534S was associated with pyrethroid resistance in Ae. albopictus.