Kaija Laurila

Tissue transglutaminase autoantibody enzyme-linked immunosorbent assay in detecting celiac disease

BACKGROUND & AIMS Tissue transglutaminase has been reported to be the target for endomysial antibodies in celiac disease. We sought to establish whether immunoglobulin (Ig) A class tissue transglutaminase autoantibodies can be considered specific for celiac disease. METHODS Serum samples from 136 patients with untreated celiac disease (diagnosed according to the criteria of the European Society for Pediatric Gastroenterology, Hepatology and Nutrition) and 207 disease controls were studied. Enzyme-linked immunosorbent assay (ELISA) and Western blots were performed using calcium-treated and untreated tissue transglutaminase as antigen. Reticulin, endomysial, and mouse monoclonal tissue transglutaminase antibodies were studied by an indirect immunofluorescence method and gliadin antibodies with ELISA. RESULTS The calcium-activated tissue transglutaminase autoantibody ELISA was highly sensitive (129 of 136) and specific (194 of 207) in detecting celiac disease. The new autoantibody ELISA test correlated well with the endomysial antibody test. Tissue transglutaminase autoantibody ELISA showed a clearly better predictive potential than the IgA class gliadin antibody ELISA. Immunoblots and ELISA blocking studies showed that calcium is needed for the specific antigen-antibody reaction to occur. Double immunofluorescence staining in human umbilical cord with sera from patients with celiac disease and with monoclonal tissue transglutaminase antibodies showed complete overlap. CONCLUSIONS Calcium-activated tissue transglutaminase autoantibody ELISA is highly accurate in detecting untreated celiac disease. Tissue transglutaminase seems to be the target self-antigen for endomysial antibodies.

Increasing prevalence of coeliac disease over time.

Background  The number of coeliac disease diagnoses has increased in the recent past and according to screening studies, the total prevalence of the disorder is around 1%.

In vivo targeting of intestinal and extraintestinal transglutaminase 2 by coeliac autoantibodies.

Background: IgA class serum autoantibodies against type 2 (tissue) transglutaminase (TG2) bind to both intestinal and extraintestinal normal tissue sections in vitro, eliciting endomysial, reticulin, and jejunal antibody reactions. It is not known whether similar binding also occurs in coeliac patients in vivo, and may thereby contribute to disease manifestations. Aims: To investigate intestinal and extraintestinal coeliac tissues for the presence of in vivo bound TG2 specific IgA and its relation to small intestinal mucosal atrophy. Patients: We investigated jejunal samples with normal villous morphology from 10 patients with developing coeliac disease who subsequently progressed to a flat lesion, from 11 patients with dermatitis herpetiformis, and from 12 non-coeliac controls. Six extrajejunal biopsy samples (liver, lymph node, muscle, appendix), obtained based on independent clinical indications from patients with active coeliac disease, were also studied. Methods: Double colour immunofluorescent studies for in situ IgA, TG2, and laminin were performed. IgA was eluted from tissue sections and tested for TG2 specificity by enzyme linked immunosorbent assay and indirect immunofluorescence. Results: IgA (in one IgA deficient case IgG) deposition on extracellularly located TG2 was detected in jejunal and extrajejunal specimens of all coeliac patients, and also in seven of 11 dermatitis herpetiformis patients, of whom two had no circulating endomysial antibodies. IgA eluted from extraintestinal coeliac tissues was targeted against TG2. Conclusions: Coeliac IgA targets jejunal TG2 early in disease development even when endomysial antibodies are not present in the circulation. Extraintestinal target sites of coeliac IgA further indicate that humoral immunity may have a pathogenetic role.

Diagnosing Mild Enteropathy Celiac Disease: A Randomized, Controlled Clinical Study

BACKGROUND & AIMS The diagnostic criteria for celiac disease require small-bowel mucosal villous atrophy with crypt hyperplasia (Marsh III). However, mucosal damage develops gradually and patients may evince clinical symptoms before histologic changes appear. Endomysial antibodies are specific in predicting forthcoming villous atrophy. We hypothesized that patients with mild enteropathy but positive endomysial antibodies benefit from a gluten-free diet (GFD) similarly to patients with more severe enteropathy. METHODS Small-bowel endoscopy together with clinical evaluations was performed in all together 70 consecutive adults with positive endomysial antibodies. Of these, 23 had only mild enteropathy (Marsh I-II) and they were randomized either to continue on a gluten-containing diet or start a GFD. After 1 year, clinical, serologic, and histologic evaluations were repeated. A total of 47 participants had small-bowel mucosal lesions compatible with celiac disease (Marsh III), and these served as disease controls. RESULTS In the gluten-containing diet group (Marsh I-II) the small-bowel mucosal villous architecture deteriorated in all participants, and the symptoms and abnormal antibody titers persisted. In contrast, in the GFD group (Marsh I-II) the symptoms were alleviated, antibody titers decreased, and mucosal inflammation diminished equally to celiac controls (Marsh III). When the trial was completed, all participants chose to continue on a life-long GFD. CONCLUSIONS Patients with endomysial antibodies benefit from a GFD regardless of the degree of enteropathy. The diagnostic criteria for celiac disease need re-evaluation: endomysial antibody positivity without atrophy belongs to the spectrum of genetic gluten intolerance, and warrants dietary treatment.

Endomysial antibody-negative coeliac disease: clinical characteristics and intestinal autoantibody deposits

Background: Some patients with untreated coeliac disease are negative for serum endomysial autoantibodies (EmA) targeted against transglutaminase 2 (TG2). Aims: To evaluate the clinical and histological features of EmA-negative coeliac disease, and to examine whether EmA-equivalent autoantibodies against TG2 can be seen in the small-bowel mucosa when absent in serum. Patients: Serum EmA was studied in 177 biopsy-proved specimens from adult patients with coeliac disease. 20 patients with intestinal diseases served as non-coeliac controls; three had autoimmune enteropathy with villous atrophy. Methods: Clinical manifestations, small-bowel mucosal morphology, intraepithelial inflammation and TG2-specific extracellular immunoglobulin A (IgA) deposits were investigated in both serum EmA-negative and EmA-positive patients. Results: 22 patients with IgA-competent coeliac disease were negative for serum EmA. Three of these had small-bowel lymphoma. Patients with EmA-negative coeliac disease were older, had abdominal symptoms more often, and the density of γδ+ intraepithelial lymphocytes in their intestinal mucosa was lower than in EmA-positive patients; otherwise the histology was similar. All serum EmA-negative patients with coeliac disease, but none of the disease controls, had gluten-dependent mucosal IgA deposits alongside TG2 in the small-bowel mucosal specimens. In vivo deposited IgA was shown to be TG2-specific by its ability to bind recombinant TG2. Conclusions: Negative serum EmA might be associated with advanced coeliac disease. TG2-targeted autoantibodies were deposited in the small-bowel mucosa even when absent in serum. This finding can be used in the diagnosis of seronegative coeliac disease when the histology is equivocal. It may also be helpful in the differential diagnosis between autoimmune enteropathy and coeliac disease.

Elevation of IgG antibodies against tissue transglutaminase as a diagnostic tool for coeliac disease in selective IgA deficiency

Background: IgA serum autoantibodies against tissue transglutaminase (tTG) have an established diagnostic value in coeliac disease, and high efficacy tests are widely available for their detection. However, serological evaluation of IgA deficient subjects is still difficult. Aims: To evaluate the diagnostic potential of IgG class anti-tTG autoantibodies measured quantitatively using an enzyme linked immunosorbent assay (ELISA) compared with immunofluorescent detection of coeliac autoantibodies. Patients: We tested serum samples from 325 IgA deficient subjects, including 78 patients with coeliac disease, 73 disease controls, and 174 blood donors. Methods: IgG antibodies against human recombinant tTG were measured with an ELISA. IgG antiendomysium antibodies (EMA) were assayed by indirect immunofluorescence on human jejunum and appendix sections. Results: The IgG anti-tTG ELISA had a sensitivity of 98.7% and a specificity of 98.6%, and the correlation with IgG EMA titres was high (rs=0.91). One coeliac patient, initially negative in all autoantibody tests, displayed both IgG anti-tTG antibodies and IgG EMA during later gluten exposure. IgG anti-tTG antibodies and EMA titres showed significant decreases (p<0.001) in treated patients. The frequency of IgG anti-tTG autoantibody positivity was 9.8% among IgA deficient blood donors and 11 of the 12 positive subjects with known HLA-DQ haplotypes carried DQ2 or DQ8 alleles. Conclusions: IgG anti-tTG and IgG EMA autoantibody tests are highly efficient in detecting coeliac disease in IgA deficient patients. The high prevalence of coeliac antibodies among symptom free IgA deficient blood donors who also carry coeliac-type HLA-DQ genes indicates that all IgA deficient persons should be evaluated for coeliac disease.

Rubber contact urticaria. Allergenic properties of 19 brands of latex gloves

To compare the immediate skin test reactivity of various latex (natural rubber) surgical and cleaning gloves. prick tests were performed on 40 latex‐allergic persons, 26 of whom were sensitized by surgical and 14 by cleaning latex gloves. 6/17 surgical gloves tested and 1/2 cleaning gloves caused positive reactions in almost all (over 87%) of the allergic subjects. In contrast. the frequencies of positive reactions to 4 other surgical latex gloves were us low as 8–21%, suggesting that not all surgical gloves arc equally allergenic. Control prick tests with I synthetic rubber and 1 polyvinyl chloride (PVC) glove were negative in all subjects. 2 surgical latex gloves causing either a high or low number of positive prick tests in allergic subjects were analyzed with high‐pressure liquid chromatography (HPLC). Similar allergenic protein fractions were detected, which showed protein peaks at MW 2000 5000 and 3000 daltons. Corresponding proteins were detected in I latex cleaning glove analyzed and in natural rubber. This result confirms that allergnic proteins persist in various surgical and cleaning latex gloves after manufacture from natural rubber and may cause contact, urticaria symptoms toms in sensitized people.

Immunoglobulin A autoantibodies against transglutaminase 2 in the small intestinal mucosa predict forthcoming coeliac disease

Reliable markers of early developing coeliac diseases are needed. Coeliac autoantibodies in the serum or Marsh I inflammation may be indicators of subsequent coeliac disease.

Intraepithelial Lymphocytes in Celiac Disease

OBJECTIVE:The aim of this study was to investigate the value of immunohistochemical characterization of different intraepithelial lymphocytes (IELs) in the diagnostic workup of celiac disease (CD).METHODS:The study involved 928 consecutive adult patients undergoing endoscopy undertaken on suspicion of CD or to ascertain the dietary compliance; the control group consisted of 59 adults who underwent endoscopy because of indigestion. Small bowel mucosal morphology, CD3+, αβ+, and γδ+ IELs were determined.RESULTS:CD was detected in 138 and excluded in 545 adults. CD3+ and γδ+ IELs both showed a sensitivity of 93% for CD; specificity was 73% and 88%, respectively. For αβ+ cells, the sensitivity was 83% and specificity, 66%. The mucosal morphology recovered on a gluten-free diet and the densities of different IELs, even γδ+ cells, decreased. Only the density of γδ+ cells remained elevated compared with controls.CONCLUSIONS:Counting of IELs is recommended in borderline cases where the histology is difficult to interpret. An increase especially in γδ+ cells strengthens the probability of CD. However, IELs are not invariably increased in CD.

Resurrection of gliadin antibodies in coeliac disease. Deamidated gliadin peptide antibody test provides additional diagnostic benefit.

Objective. Circulating antibodies against naïve, whole gliadin have been replaced by more accurate endomysial and tissue transglutaminase antibody tests in the diagnosis of coeliac disease. The purpose of this study was to compare these serological tests with a new test recognizing antibodies against deamidated and defined gliadin peptides. Material and methods. The study population comprised selected coeliac disease patients in a tertiary clinic: newly detected patients before and after a gluten-free diet, patients with persistent small-bowel mucosal villous atrophy despite a strict gluten-free diet and non-coeliac controls reporting abdominal symptoms after ingestion of cereals. Comparisons were made between serum IgA-class gliadin peptide, endomysial, tissue transglutaminase and conventional gliadin antibodies. Results. The deamidated gliadin peptide antibody test showed a sensitivity of 91% and a specificity of 98% in coeliac disease. The tissue transglutaminase antibody test performed equally well. The specificity of endomysial antibody was just as high, but its sensitivity was lower, 80%. The conventional gliadin antibody test showed poor sensitivity and specificity. Combination of the deamidated gliadin peptide and tissue transglutaminase tests offered the best sensitivity without loss of specificity in the diagnosis of coeliac disease. All antibody levels declined in line with mucosal recovery. The deamidated gliadin peptide antibody test showed six of the nine cases with small-bowel mucosal damage persisting on a gluten-free diet, whereas tissue transglutaminase detected only two cases and endomysial antibody none. Conclusions. The new gliadin peptide antibody test proved highly accurate in the diagnostic work-up and follow-up of coeliac disease and can be endorsed in combination with the tissue transglutaminase test.