OBJECTIVE

The aim of the present study was to correlate the serological methods of coeliac disease diagnostic tests (IgA EmA and IgA anti-tTG) with the histological findings of the duodenal mucosa.

RESULTS

Forty-seven patients were studied and the data were analysed by the Pearson correlation. Seven patients (15%) with normal mucosa were negative for both assays. Forty untreated patients showed 89% agreement between the two serological methods, with all samples (40/40) positive to EmA and 80% (32/40) positive to anti-tTG. Eight positive samples to EmA, that were negative to anti-tTG, presented an increased number of intra-epithelial lymphocytes in the duodenal biopsy and clinical improvement with a gluten-free diet. Partial or total villous atrophy was detected with EmA titres equal to or higher than 1/10. The correlation coefficient between the two serological methods was R=0.797.

CONCLUSIONS

Both serological tests correlated very well with histological findings in negative patients and in those with high levels of antibodies. For patients with clinical evidence of CD but with low levels of antibodies, the combination of serological tests and intestinal biopsy is recommended.

BACKGROUND

Since spermatogonial stem cell transplantation (SSCT) and testicular tissue grafting (TTG) may have important clinical applications, the safety of these promising techniques has to be proved. This study was designed to characterize epigenetic modifications in prepubertal and adult mouse germ cells and to study these epigenetic mechanisms after SSCT and TTG.

METHODS

Testicular cell suspensions were transplanted to the testes of genetically sterile W/W(v) recipients. Intratesticular tissue grafting was performed between green fluorescent protein (GFP(+)) donors and GFP(-) acceptor mice. DNMT1 and DNMT3A expression, the general methylation status and the histone modifications H3K4me3, H3K9ac, H4K5ac, H4K8ac, H4K12ac and H4K16ac were studied in a stage-dependent manner by immunohistochemistry and compared with data from adult control mice.

RESULTS

The expression levels of DNMT1 and DNMT3A, the DNA methylation status and most of the stage-specific histone modifications after SSCT or TTG were not different from fertile adult controls. Although, in elongated spermatids, the acetylation pattern was as expected, the stage-dependent expression of H4K5ac and H4K8ac was altered after SSCT.

CONCLUSIONS

Intratesticular tissue grafting might be the better choice for fertility restoration. Disrupting the stem cell niche might influence epigenetic patterns. Since the function of H4K5ac and H4K8ac in spermatogonia and spermatocytes still has to be explored, in-depth epigenetical analyses are warranted.

Celiac disease (CD) is being increasingly reported from the wheat-eating population of north India. However, the exact prevalence of CD in children is not known as population screening studies are scarce. Our study aimed to determine the prevalence of CD in 400 children, 6 months to 12 years of age attending pediatrics department of a tertiary care hospital in north India. The study population was screened for antitissue transglutaminase (tTG) antibodies. Endoscopic duodenal biopsy was done in the anti--tTG positive subjects. Four patients were diagnosed with CD as per the modified ESPGHAN criteria. The prevalence of CD thus was 1 %, which was in concordance with screening studies using serological markers conducted in the West.

The nucleotide sequence of the virG gene for a transcriptional activator on the agropine-type hairy-root-inducing plasmid pRiA4 was determined. The sequence contained one possible open reading frame. The gene product with a molecular size of 26.5 kDa was identified by an Escherichia coli coupled-transcription-translation system using cloned virG plasmids as templates. However, neither an ATG nor a GTG start codon which could give rise to such a protein was identified in the nucleotide sequence. Instead, TTG was found as a candidate for the start codon. This TTG was preceded, like most other TTG start codons, by both a Shine-Dalgarno (SD) sequence and a T signal which are respectively complementary to the 3'-end region of 16S rRNA and the T psi loop of initiator tRNA. Further evidence for the start at TTG was obtained by gene fusion experiments. When the E. coli lacZ gene, whose expression entirely depends on the transcription and translation from upstream regions, was connected in-phase with virG either directly upstream or downstream of the TTG sequence, only the latter fused gene expressed the beta-galactosidase activity in Agrobacterium cells in response to a plant phenolic compound, acetosyringone. The TTG codon preceded by an SD sequence and a T signal is also conserved in the virG sequences from other three tumor-inducing plasmids previously reported.

OBJECTIVE

In 2012, European Society of Pediatric Gastroenterology, Hepatology, and Nutrition published novel guidelines on celiac disease (CD) diagnosis. Symptomatic children with serum anti-transglutaminase (anti-tTG) antibody levels ≥10 times upper limit of normal (ULN) could avoid duodenal biopsies after positive HLA test and serum anti-endomysial antibodies (EMAs). So far, both asymptomatic and symptomatic patients with anti-tTG titer <10 times ULN should undergo upper endoscopy with duodenal biopsies to confirm diagnosis. The aim of this study was to assess the accuracy of serological tests to diagnose CD in asymptomatic patients.

METHODS

We retrospectively reviewed data of 286 patients (age range: 10 months to 17 years) with CD diagnosis based on elevated titer of anti-tTG, EMA positivity, and histology. All patients were distinguished between symptomatic and asymptomatic; histological lesions were graded according to the Marsh-Oberhuber (MO) criteria. Fisher exact test was applied to analyze both groups in terms of diagnostic reliability of serological markers.

RESULTS

A total of 196 patients (68.53%) had anti-tTG titers ≥10 times ULN. Among them, a group of 156 patients (79.59%) also had symptoms suggestive of CD ("high-titer" symptomatic); of these, 142 patients (91.02%) showed severe lesion degree (3a, 3b, 3c MO). Conversely, 40 out of 196 patients (20.40%) were asymptomatic ("high-titer" asymptomatic) and 37 patients (92.5%) of them showed severe lesion degree (3a, 3b, 3c MO). No difference in histological damage was found between "high-titer" symptomatic and "high-titer" asymptomatic children (Fisher exact test, P=1.000).

CONCLUSIONS

If confirmed in large multicenter prospective studies, the "biopsy-sparing" protocol seems to be applicable to both symptomatic and asymptomatic patients with anti-tTG titer ≥10 times ULN, positive EMA, and HLA-DQ2/DQ8.

Poly-G sequences are found in different genomes including human and have the potential to form higher-order structures with various applications. Previously, long poly-G sequences were thought to lead to multiple possible ways of G-quadruplex folding, rendering their structural characterization challenging. Here we investigate the structure of G-quadruplexes formed by poly-G sequences d(TTG(n)T), where n = 12 to 19. Our data show the presence of multiple and/or higher-order G-quadruplex structures in most sequences. Strikingly, NMR spectra of the TTG₁₅T sequence containing a stretch of 15 continuous guanines are exceptionally well-resolved and indicate the formation of a well-defined G-quadruplex structure. The NMR solution structure of this sequence revealed a propeller-type parallel-stranded G-quadruplex containing three G-tetrad layers and three single-guanine propeller loops. The same structure can potentially form anywhere along a long G(n) stretch, making it unique for molecular recognition by other cellular molecules.

BACKGROUND

There is an association of celiac disease (CD) with several gastrointestinal illnesses. We aimed to determine the prevalence of CD in patients with inflammatory bowel disease (IBD) to evaluate the value of the routine serological tests for CD in these patients.

METHODS

patients with IBD underwent screening test for CD. The screening test was based on IgA anti-tTG antibody evaluated by ELISA method and IgA EMA (endomysial antibody) measured by the indirect immunofluorescence method. Fisher exact and chi-square and t tests were used for data analysis.

RESULTS

the study was conducted on 100 patients, with a mean age of 34.74 ± 12.03 (SD) years. The mean simplified Crohn's disease activity index was 90 ± 17 (SE) and the mean colitis activity index was 3.46± 0.96 (SE). Seventeen patients (17%) had IgA anti-tTG antibody levels above the cutoff point >> 20). Thirty-two patients were positive for IgA EMA. IgA EMA was positive in nine IgA anti-tTG positive patients (three patients with Crohn's Disease and six ones with ulcerative colitis). Then, the prevalence of serologic CD was 9% that was higher than that of general population. A significant correlation was found between the results of IgA EMA and those of IgA anti-tTG (P=0.001) whereas Fisher exact test revealed significant difference between frequency distribution of positive and negative results of IgA EMA and IgA anti-tTG in patients with ulcerative colitis and Crohn's disease (P=0).

CONCLUSIONS

the prevalence of serologic CD in general population in Iran has been reported to be 0.6-0.96%. Then, its prevalence in our sample size was about ten times more than that in general population.

A diagnosis of celiac disease is made based on clinical, genetic, serologic, and duodenal morphology features. Recent pediatric guidelines, based largely on retrospective data, propose omitting biopsy analysis for patients with concentrations of IgA against tissue transglutaminase (IgA-TTG) >10-fold the upper limit of normal (ULN) and if further criteria are met. A retrospective study concluded that measurements of IgA-TTG and total IgA, or IgA-TTG and IgG against deamidated gliadin (IgG-DGL) could identify patients with and without celiac disease. Patients were assigned to categories of no celiac disease, celiac disease, or biopsy required, based entirely on antibody assays. We aimed to validate the positive and negative predictive values (PPV and NPV) of these diagnostic procedures.

We performed a prospective study of 898 children undergoing duodenal biopsy analysis to confirm or rule out celiac disease at 13 centers in Europe. We compared findings from serologic analysis with findings from biopsy analyses, follow-up data, and diagnoses made by the pediatric gastroenterologists (celiac disease, no celiac disease, or no final diagnosis). Assays to measure IgA-TTG, IgG-DGL, and endomysium antibodies were performed by blinded researchers, and tissue sections were analyzed by local and blinded reference pathologists. We validated 2 procedures for diagnosis: total-IgA and IgA-TTG (the TTG-IgA procedure), as well as IgG-DGL with IgA-TTG (TTG-DGL procedure). Patients were assigned to categories of no celiac disease if all assays found antibody concentrations <1-fold the ULN, or celiac disease if at least 1 assay measured antibody concentrations >10-fold the ULN. All other cases were considered to require biopsy analysis. ULN values were calculated using the cutoff levels suggested by the test kit manufacturers. HLA typing was performed for 449 participants. We used models that considered how specificity values change with prevalence to extrapolate the PPV and NPV to populations with lower prevalence of celiac disease.

Of the participants, 592 were found to have celiac disease, 345 were found not to have celiac disease, and 24 had no final diagnosis. The TTG-IgA procedure identified patients with celiac disease with a PPV of 0.988 and an NPV of 0.934; the TTG-DGL procedure identified patients with celiac disease with a PPV of 0.988 and an NPV of 0.958. Based on our extrapolation model, we estimated that the PPV and NPV would remain >0.95 even at a disease prevalence as low as 4%. Tests for endomysium antibodies and HLA type did not increase the PPV of samples with levels of IgA-TTG ≥10-fold the ULN. Notably, 4.2% of pathologists disagreed in their analyses of duodenal morphology-a rate comparable to the error rate for serologic assays.

In a prospective study, we validated the TTG-IgA procedure and the TTG-DGL procedure in identification of pediatric patients with or without celiac disease, without biopsy. German Clinical Trials Registry no.: DRKS00003854.

We conducted this mass screening study to determine the prevalence of celiac disease (CD) and characterize the celiac iceberg among Saudi pediatric population in Riyadh, the capital city of Saudi Arabia.

During the study period (January 2014-June 2016), we have conducted a cross-sectional, mass screening, immunoglobulin A-tissue transglutaminase (TTG-IgA)-based study on 7930 Saudi students from primary and intermediate schools in Riyadh. Students with positive TTG-IgA (>20 U/L) were called in the hospital to undergo a repeat of TTG-IgA; in those with borderline positive TTG-IgA (20-60 U/L), IgA-endomyseal antibody (EMA-IgA) test was performed. Children with TTG-IgA >60 U/L and children with borderline positive TTG-IgA and positive EMA-IgA were advised to undergo upper endoscopy and intestinal biopsies.

We identified 221 students with positive TTG-IgA (2.8%). CD was diagnosed in 119 cases (1.5%, 1:67 Saudi children) (mean age 11.5 ± 2.62 years; girls 81 [68%]). Another 51 children had persistently borderline positive TTG-IgA but negative EMA (0.64%) and the remaining 51 had transiently positive TTG-IgA. We have identified 3 clinical patterns in the screening-identified cases with CD: a silent form (37%), a mild symptomatic form characterized by gastrointestinal symptoms in presence of normal growth or overweight/obesity (48%), and gastrointestinal symptoms associated with impaired growth in 15%.

Our study provided evidence of a high prevalence of CD among Saudi children (1.5%), a rate that is at least twice the average prevalence rate in Europe and North America.

The mayfly species Siphluriscus chinensis (Siphluriscidae) has valuable structures useful for phylogeny reconstruction, given its putative basal position within the Ephemeroptera. Here its nearly complete mitochondrial genome is sequenced. We built phylogenetic trees through multiple analytical strategies with some other insect mitogenomes. Structurally, the obtained mitochondrial genome of S. chinensis is 16,616 bp in length,(1) containing 37 genes and an extra trnK-like (trnK2 (AAA)) gene. The 12 PCGs start with typical ATN codons, except the nad1 gene which starts with an unnormalized TTG. Like other known mayfly mitogenomes, the strand bias has negative AT-skew and negative GC-skew. Phylogenetically, our topologies suggest that Odonata is the basally diverged clade in Pterygota; Ephemeroptera is the sister group of the Neoptera; and S. chinensis is indeed the most basal mayfly branch.

The Plecoptera (stoneflies) is a hemimetabolous order of insects, whose larvae are usually used as indicators for fresh water biomonitoring. Herein, we describe the complete mitochondrial (mt) genome of a stonefly species, namely Acroneuria hainana Wu belonging to the family Perlidae. This mt genome contains 13 PCGs, 22 tRNA-coding genes and 2 rRNA-coding genes that are conserved in most insect mt genomes, and it also has the identical gene order with the insect ancestral gene order. However, there are three special initiation codons of ND1, ND5 and COI in PCGs: TTG, GTG and CGA, coding for L, V and R, respectively. Additionally, the 899-bp control region, with 73.30% A+T content, has two long repeated sequences which are found at the 3'-end closing to the tRNA(Ile) gene. Both of them can be folded into a stem-loop structure, whose adjacent upstream and downstream sequences can be also folded into stem-loop structures. It is presumed that the four special structures in series could be associated with the D-loop replication. It might be able to adjust the replication speed of two replicate directions.

There is an urgent clinical need for a better laboratory celiac disease diagnosis with both less false positive results and minimal underdetection. The aim of the present study was to evaluate the performance and diagnostic accuracy of different assays in an outpatient population setting for the diagnosis for celiac disease (CD) in order to design an optimal algorithm. We used 15 different ELISA assays to assess 47 blood samples of newly diagnosed children (positive biopsy results) and 52 samples from age- and sex-matched children with negative biopsy results for CD. Scoring criteria were established for grading the assays performance and characteristics. The combined gliadin and tTG assays exhibited the best sensitivity (100%). The addition of other assays to the CeliCheck neo-epitopes assay improved specificity so that the final algorithm had 100% sensitivity, 96.2% specificity, and 98.1% accuracy. The clinical demand for both maximal sensitivity and maximal specificity cannot be achieved with a single test. Using a combination of a sensitive assay together with specific assays improved celiac disease detection rates, with an acceptable number of false positive results. This model, however, needs to be confirmed prospectively in both children and adults.

Skin biopsy samples from 145 relapse leprosy cases and from five different regions in Brazil were submitted for sequence analysis of part of the genes associated with Mycobacterium leprae drug resistance. Single nucleotide polymorphisms (SNPs) in these genes were observed in M. leprae from 4 out of 92 cases with positive amplification (4.3%) and included a case with a mutation in rpoB only, another sample with SNPs in both folP1 and rpoB, and two cases showing mutations in folP1, rpoB, and gyrA, suggesting the existence of multidrug resistance (MDR). The nature of the mutations was as reported in earlier studies, being CCC to CGC in codon 55 in folP (Pro to Arg), while in the case of rpoB, all mutations occurred at codon 531, with two being a transition of TCG to ATG (Ser to Met), one TCG to TTC (Ser to Phe), and one TCG to TTG (Ser to Leu). The two cases with mutations in gyrA changed from GCA to GTA (Ala to Val) in codon 91. The median time from cure to relapse diagnosis was 9.45 years but was significantly shorter in patients with mutations (3.26 years; P = 0.0038). More than 70% of the relapses were multibacillary, including three of the mutation-carrying cases; one MDR relapse patient was paucibacillary.

In the present narrative review, we analyzed the relationship between seronegative celiac disease (SNCD) and immunoglobulin deficiencies. For this purpose, we conducted a literature search on the main medical databases. SNCD poses a diagnostic dilemma. Villous blunting, intraepithelial lymphocytes (IELs) count and gluten "challenge" are the most reliable markers. Immunohistochemistry/immunofluorescence tissue transglutaminase (tTG)-targeted mucosal immunoglobulin A (IgA) immune complexes in the intestinal mucosa of SNCD patients may be useful. In our experience, tTG-mRNA was similarly increased in seropositive celiac disease (CD) and suspected SNCD, and strongly correlated with the IELs count. This increase is found even in the IELs' range of 15-25/100 enterocytes, suggesting that there may be a "grey zone" of gluten-related disorders. An immune deregulation (severely lacking B-cell differentiation) underlies the association of SNCD with immunoglobulin deficiencies. Therefore, CD may be linked to autoimmune disorders and immune deficits (common variable immunodeficiency (CVID)/IgA selective deficiency). CVID is a heterogeneous group of antibodies dysfunction, whose association with CD is demonstrated only by the response to a gluten-free diet (GFD). We hypothesized a familial inheritance between CD and CVID. Selective IgA deficiency, commonly associated with CD, accounts for IgA-tTG seronegativity. Selective IgM deficiency (sIgMD) is rare (<300 cases) and associated to CD in 5% of cases. We diagnosed SNCD in a patient affected by sIgMD using the tTG-mRNA assay. One-year GFD induced IgM restoration. This evidence, supporting a link between SNCD and immunoglobulin deficiencies, suggests that we should take a closer look at this association.

BACKGROUND

Celiac disease (CD) is an immune-mediated enteropathy triggered by the ingestion of gluten in susceptible individuals, and its prevalence varies depending on the studied population. Given that information on CD in Latin America is scarce, we aimed to investigate the prevalence of CD in this region of the world through a systematic review and meta-analysis.

RESULTS

This was a two-phase study. First, a cross-sectional analysis from 981 individuals of the Colombian population was made. Second, a systematic review and meta-regression analysis were performed following the Preferred Reporting Items for Systematic Meta- Analyses (PRISMA) guidelines. Our results disclosed a lack of celiac autoimmunity in the studied Colombian population (i.e., anti-tissue transglutaminase (tTG) and IgA anti-endomysium (EMA)). In the systematic review, 72 studies were considered. The estimated prevalence of CD in Latin Americans ranged between 0.46% and 0.64%. The prevalence of CD in first-degree relatives of CD probands was 5.5%. The coexistence of CD and type 1 diabetes mellitus varied from 4.6% to 8.7%, depending on the diagnosis methods (i.e., autoantibodies and/or biopsies).

CONCLUSIONS

Although CD seems to be a rare condition in Colombians; the general prevalence of the disease in Latin Americans seemingly corresponds to a similar scenario observed in Europeans.

OBJECTIVE

Detection of faecal gluten immunogenic peptides (GIP) is a biomarker of recent gluten consumption. GIP levels can be used to monitor gluten intake and compliment clinical methods to evaluate compliance to gluten-free diet (GFD). In the present study, recent gluten intake was measured by GIP in children with coeliac disease (CD) and compared to routine clinical measures to evaluate GFD compliance.

METHODS

GIP was measured in 90 samples from 63 CD children (44 previously and 19 newly diagnosed with follow-up samples at 6 and 12 months on GFD). Compliance to GFD was evaluated based on clinical assessment, tissue transglutaminase (tTG) levels, and Biagi score.

RESULTS

GIP was detectable in 16% of patients with previous CD diagnosis on GFD. Body mass index z score (P = 0.774), height z score (P = 0.723), haemoglobin concentration (P = 0.233), age (P = 0.448), sex (P = 0.734), or disease duration (P = 0.488) did not differ between those with detectable and nondetectable GIP. In newly diagnosed patients, on gluten-containing diet, GIP was detectable in 95% of them. Following GFD initiation, GIP decreased (P < 0.001); 17% and 27% had detectable levels at 6 and 12 months, respectively. Compared to GIP, the Biagi score, tTG, and clinical assessment presented sensitivity of 17%, 42%, and 17%, respectively. Likewise, GIP was detectable in 16%, 16%, and 14% of patients evaluated as GFD compliant according to the Biagi score, tTG, and clinical assessment, respectively. A combination of methods did not improve identification of patients who were noncompliant.

CONCLUSIONS

Inclusion of faecal GIP measurements is likely to improve identification of GFD recent noncompliance in CD management and could be incorporated into current follow-up strategies.

Tissue transglutaminase (TGM2; also known as TG2 or tTG) localizes to the syncytial microvillous membrane (MVM) of the human placenta, the primary interface between maternal and fetal tissue. To identify TGM2 substrates in the MVM, membrane vesicles were prepared and labeled with biotinylated acyl donor or acceptor probes. Biotinylated species were selected on an avidin affinity matrix and identified by mass spectrometry of tryptic peptides. The most abundant were cytoskeletal (actin, tubulin, and cytokeratin) and membrane-associated (annexins, integrins, and placental alkaline phosphatase) proteins. During pregnancy, apoptotic particulate material, the end product of the trophoblast life cycle, is shed from the MVM into maternal circulation. Shed material was isolated from primary trophoblast cultures in which syncytial-like masses develop by fusion. A substantial fraction of actin in the particles was in the form of covalent polymeric aggregates, in contrast to cellular actin, which dissociated completely into monomer in SDS-PAGE. When cells were cultured in the presence of transglutaminase inhibitors, actin in the shed particles remained exclusively in monomeric form, and a reduction in trophoblast intercellular fusion and differentiation was observed. These findings suggest that transglutaminase-mediated cross-linking stabilizes the particulate material shed from the placenta.

Celiac disease is associated with endomysial antibodies (EmA), which have recently been reported to be directed to tissue transglutaminase (tTG). To demonstrate binding of antibodies to recombinant tTG, human tTG was cloned, expressed by in vitro transcription/translation and used to develop novel radioligand assays for combined and single detection of immunoglobulin A (IgA) and G (IgG)-specific antibodies. IgA and IgG-tTGA were found in 43 (95.6%) of 45 patients with newly-diagnosed celiac disease verified by biopsy. In addition, all 30 sera from patients with gastrointestinal symptoms and positive EmA were positive for IgA-tTGA, and all but one serum (96.7%) had antibodies of the IgG class. Receiver-operating characteristic analysis including 574 sera from healthy controls revealed a specificity of 99.5%. By means of these new assays, we identified all patients with endomysial antibodies and achieved, at equal specificity, an even improved sensitivity (95.6%) as compared to EmA (91.1%) detected by the standard immunofluorescence test. Here, we have provided direct evidence that recombinant tTG is a major target of antibodies in celiac disease. Our data suggest that tTGA measured by radioligand assay have the power to overcome the limitations of the EmA-test. This new strategy may considerably facilitate large-scale screening for silent and latent celiac disease.

BACKGROUND

Low bone density and osteoporosis have been demonstrated in celiac disease populations in Europe, South America and the United States. Serological testing with tissue transglutaminase (TTG) and immunoglobulin A endomysial (EMA) antibodies is highly specific for celiac disease, while antigliadin antibody (AGA) testing is less specific.

OBJECTIVE

To evaluate the association of celiac serology with reduced bone density in adult women.

METHODS

A clinical database containing all bone density testing data in the province of Manitoba was linked to a database containing all celiac serology data for the province. The study cohort consisted of 376 women older than 20 years of age with bone density measurements preceding initial celiac serology by six months or less. Bone density was assessed in relation to TTG/EMA and AGA seropositivity, and compared with seronegative controls in age-, height- and weight-adjusted models.

RESULTS

There was significantly lower bone density in TTG/EMA seropositive women than with seronegative controls for all sites tested (lumbar spine, total hip, trochanter, femoral neck; all P<0.05). TTG/ EMA seropositive women also had a significantly higher prevalence of osteoporosis (67.7% versus 44.8%; P<0.05). There was lower bone density at the three hip sites (all P<0.05) in AGA seropositive women, but after excluding TTG/EMA seropositive women, isolated AGA seropositivity showed no significant association with any bone density measurements.

CONCLUSIONS

TTG/EMA seropositivity was associated with lower bone density and a higher prevalence of osteoporosis compared with seronegative controls.

BACKGROUND

Celiac disease is common in both children and adults. Small intestinal biopsy is mandatory for establishing a diagnosis. Anti-endomysial antibodies, detected by immunofluorescence, have a sensitivity and specificity close to 100% in the diagnosis of CD. Recently, tissue transglutaminase has been identified as the target autoantigen of antibodies against endomysium, and TTG antibodies are comparable to EMA-IMF in the diagnosis of CD.

OBJECTIVE

To evaluate a new enzyme-linked immunosorbent assay kit for EMA, compared to EMA-IMF and TTG antibodies in the diagnosis of CD.

METHODS

Our study population included all subjects with positive EMA-IMF who underwent intestinal biopsy (n = 21). From the same sera, TTG antibodies and EMA-ELISA were determined, and all antibody results were compared to the biopsy findings.

RESULTS

EMA-IMF was able to predict biopsy findings of CD in 19 of 21 cases (90.5%). When patients with biopsy findings compatible with CD and positive EMA-IMF (n = 19) were tested for EMA-ELISA and TTG antibodies, 18 of the 19 were positive for both EMA-ELISA and TTG antibodies. A significant correlation was found between EMA-ELISA and TTG antibody titers (r = 0.74, P < 0.001).

CONCLUSIONS

Our study demonstrates that EMA-ELISA is comparable to TTG antibodies in the diagnosis of CD, and supports the use of EMA-ELISA as a serologic marker for this disease.

OBJECTIVE

The purpose of this study was to investigate the activation patterns of the primary auditory cortex in response to varying intensities of pure tone stimuli.

METHODS

A 1,000-Hz pure tone stimulus was delivered monaurally to the right ear of 12 normal-hearing right-handed volunteers in 20-second on-off cycles. Stimuli were applied at 20 and 50 dB hearing level (HL) above threshold in 12 subjects and at 0, 20, 40, and 50 dB HL above threshold in 6 subjects. Functional magnetic resonance imaging (fMRI) data were obtained using a 1.5-T scanner and echoplanar imaging. Activated pixels were identified in the transverse temporal gyrus (TTG) of both hemispheres in response to pure tone stimuli at each intensity level using cross-correlation analysis (0.6; P < 0.0001).

RESULTS

Of the 24 right and left TTGs imaged (n = 12), activation to pure tone stimuli at 20 and 50 dB HL above threshold was seen in 46% and 79% of TTGs, respectively, with bilateral hemispheric activation in 27% and 64% of subjects, respectively. The mean numbers of activated voxels were 4.0 and 13.0, respectively. Of the 12 right and left TTGs imaged at 0, 20, 40, and 50 dB HL above threshold, activation was seen in 33%, 42%, 58%, and 75% of TTGs, respectively. The mean numbers of activated voxels were 5.8, 3.2, 9.8, and 15.3, respectively. There was a nonsignificant trend toward contralateral (left) dominant TTG activation with increased tone intensity.

CONCLUSIONS

Our results show an increased likelihood of TTG activation, increased TTG activation volume, and increased bilateral hemisphere TTG activation with increasing pure tone intensity. Our results suggest that the primary auditory cortex reflects or is directly involved in the central processing of sound intensity and that varying the intensity of even simple stimuli can alter the patterns of fMRI activation in auditory cortex.

The TTG-2 gene has been identified at the site of chromosomal translocations in acute T-cell leukemia's (T-ALL). These breakpoints map to a region between 2 and 30 kb upstream of TTG-2 in chromosome 11p13. To establish the role of these translocation breakpoints in the deregulation of TTG-2 in T-ALL we have determined the complete structure of this gene. Isolation of new TTG-2 cDNA clones from fetal liver identified an alternative transcript (TTG-2a) containing two new noncoding 5' exons. Analysis of exon/intron boundaries, identified 6 exons spread over 35 kb in 11p13. The gene encodes two alternative transcripts initiating from two promoters. TTG-2a, from promoter 1 (P1) and TTG-2b, from promoter 2 (P2) differ in the length of the 5' untranslated region, but encode the same protein. A high level of TTG-2a was present in fetal liver and spleen, whereas in adult kidney a low level of TTG-2a and a high level of TTG-2b was found. The transcription start site for TTG-2a was identified by RNase protection experiments and it displayed sequence homology to an initiator element (inr). P1 lacks a TATA box, but binding sites for SP1 and GATA-1 are present. This new genomic organisation revealed that all known chromosomal translocations map upstream of P2, removing P1 and putative upstream regulatory sequences leaving P2 intact. These results show that chromosomal translocations disrupt the TTG-2 gene itself, further confirming its role in the development of T-ALL.

OBJECTIVE

Serum immunoglobulin A-class tissue transglutaminase (tTG-ab) and endomysial antibody (EMA) tests play a key role in the diagnostic evaluation of celiac disease. Recently, a novel whole blood rapid test based on self-tissue transglutaminase (tTG) was developed for celiac disease case finding. Based on the same principle, a whole blood self-tTG enzyme-linked immunosorbent assay (ELISA), especially applicable to large-scale screening of celiac disease, has been produced. We assessed the value of this new test in celiac disease antibody detection.

METHODS

The new test uses endogenous tTG found in red blood cells of whole blood in IgA-class tTG-ab measurement by detecting tTG-tTG-ab complexes formed after hemolysis of the whole blood sample. Stored whole blood samples from 150 untreated celiac disease patients and 107 control individuals without celiac disease were evaluated, and the test results were compared with those of the whole blood rapid test, 2 conventional serum-based tTG-ab ELISA tests, and 2 EMA tests.

RESULTS

A total of 15 whole blood samples were found to be clotted or dried after storage and were excluded from further evaluation. The whole blood ELISA test had a specificity (98%) comparable to that of the conventional serological tests, the sensitivity (91%) being slightly lower. The test was concordant with the whole blood rapid test in 92% of cases, with 2 serological ELISA tests in 91% and 94% of cases and with EMA tests in 94% and 93% of cases.

CONCLUSIONS

Whole blood self-tTG-based testing is accurate in celiac antibody detection, also when an ELISA method is applied. The testing requires no serum separation or external tTG.

The hepatitis C virus (HCV) core protein is a structural protein that packages the viral genomic RNA. In this study, we demonstrate that a stable core protein dimer could be produced in liver cells. The production of this protein could be enhanced by calphostin C and serum deprivation. This protein was determined to be the core protein dimer because of its reactivity with the anti-core antibody, its similar electrophoretic mobility compared with that of the core protein dimer generated by cross-linking with glutaraldehyde, and its increase in size by a hemagglutinin tag fused to the core protein sequence. This core protein dimer was highly stable and resistant to SDS and beta-mercaptoethanol. The enzyme that mediated the formation of this stable core protein dimer was determined to be the tissue transglutaminase (tTG) because, first, tTG could be activated by calphostin C and serum deprivation; second, the formation of this dimer was suppressed by monodansylcadaverine, a tTG inhibitor; and third, the core protein could be cross-linked by tTG in vitro. Thus, the HCV core protein represents the first known viral structural protein substrate of tTG. The post-translational modification by tTG reduced the RNA binding activity of the core protein, raising the possibility that tTG may regulate the biological functions of the HCV core protein.