Anti-Transglutaminase Antibodies and Age

Screening tests using serum tissue transglutaminase IgA may facilitate the identification of undiagnosed celiac disease among Japanese population

The prevalence of celiac disease (CD) among Japanese population has been unknown, whereas it has been increasingly recognized in the US and in the European countries. The aim of the present study is to identify possible cases with CD among Japanese population and clarify the relevance of screening for the disease. We conducted a serologic screening for the disease among 710 Japanese patients and 239 healthy volunteers at a local tertiary teaching hospital, using an anti-tissue transglutaminase IgA (TTG-IgA) test, and histological examination of the small intestines from the TTG-IgA positive subjects. There were no TTG-IgA positive sera among the healthy volunteers. Twenty of the patients (2.8%), including eight with malignant lymphoma, were tested positive for TTG-IgA. The histological examination of the eleven patients among those with positive TTG-IgA, seven showed villous atrophy and partial lymphocytes infiltration in the mucosa, which could be compatible to mucosal changes observed in CD. Five of them had non-Hodgkin lymphoma in the gastrointestinal tracts. Serologic tests using TTG-IgA might be relevant to screen for those with undiagnosed CD among Japanese population.

Transglutaminse 2 and EGGL, the protein cross-link formed by transglutaminse 2, as therapeutic targets for disabilities of old age

Aging of the extracellular matrix (ECM), the protein matrix that surrounds and penetrates the tissues and binds the body together, contributes significantly to functional aging of tissues. ECM proteins become increasingly cross-linked with age, and this cross-linking is probably important in the decline of the ECM's function. This article reviews the role of ε-(γ-glutamyl)-lysine (EGGL), a cross-link formed by transglutaminase enzymes, and particularly the widely expressed isozyme transglutaminase 2 (TG2), in the aging ECM. There is little direct data on EGGL accumulation with age, and no direct evidence of a role of EGGL in the aging of the ECM with pathology. However, several lines of circumstantial evidence suggest that EGGL accumulates with age, and its association with pathology suggests that this might reflect degradation of ECM function. TG activity increases with age in many circumstances. ECM protein turnover is such that some EGGL made by TG is likely to remain in place for years, if not decades, in healthy tissue, and both EGGL and TG levels are enhanced by age-related diseases. If further research shows EGGL does accumulate with age, removing it could be of therapeutic benefit. Also reviewed is the blockade of TG and active removal of EGGL as therapeutic strategies, with the conclusion that both have promise. EGGL removal may have benefit for acute fibrotic diseases, such as tendinopathy, and for treating generalized decline in ECM function with old age. Extracellular TG2 and EGGL are therefore therapeutic targets both for specific and more generalized diseases of aging.

Elevated serum autoantibody against high mobility group box 1 as a potent surrogate biomarker for amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is a complicate and progressive onset devastating neurodegenerative disease. Its pathogenic mechanisms remain unclear and there is no specific test for diagnosis. For years, researchers have been vigorously searching for biomarkers associated with ALS to assist clinical diagnosis and monitor disease progression. Some specific inflammatory processes in the central nervous system have been reported to participate in the pathogenesis of ALS. As high mobility group box 1 (HMGB1) is elevated in spinal cord tissues of patients with ALS, we hypothesized, therefore, that serum autoantibody against HMGB1 (HMGB1 autoAb) might represent an effective biomarker for ALS. Patients with ALS, Alzheimer's disease, Parkinson's disease, and healthy age-matched control subjects were recruited for this study. ALS group consisted of 61 subjects, the other groups each consisted of forty subjects. We generated a polyclonal antibody against HMGB1 and developed an ELISA-based methodology for screening serum samples of these subjects. All samples were coded for masked comparison. For statistic analyses, two-tailed Student's t-test, ANOVA, Bonferroni multiple comparison test, Spearman correlation, and receiver operating characteristic curve were applied. We discovered that the level of HMGB1 autoAb significantly increased in patients with ALS as compared with that of patients with Alzheimer's disease, Parkinson's disease, and healthy control subjects. The differences between all groups were robust even at the early stages of ALS progression. More importantly, higher HMGB1 autoAb level was found in more severe disease status with significant correlation. Our study demonstrates that serum HMGB1 autoAb may serve as a biomarker for the diagnosis of ALS and can be used to monitor disease progression.

Anti-transglutaminase antibodies in non-coeliac children suffering from infectious diseases

Anti-transglutaminase antibodies are the diagnostic markers of coeliac disease. A role is suggested for infectious agents in the production of anti-transglutaminase antibodies. The aim was to measure positive anti-transglutaminase antibody levels in children with infectious diseases and to compare immunological and biological characteristics of the anti-transglutaminase antibodies derived from these children with that from coeliac patients. Two hundred and twenty-two children suffering from infectious diseases were enrolled prospectively along with seven biopsy-proven coeliacs. Serum samples were tested for anti-transglutaminase antibodies and anti-endomysium antibodies; positive samples were tested for coeliac-related human leucocyte antigen (HLA)-DQ2/8 and anti-viral antibodies. Purified anti-transglutaminase antibodies from the two study groups were tested for urea-dependent avidity, and their ability to induce cytoskeletal rearrangement and to modulate cell-cycle in Caco-2 cells, using phalloidin staining and bromodeoxyuridine incorporation assays, respectively. Nine of 222 children (4%) tested positive to anti-transglutaminase, one of whom also tested positive for anti-endomysium antibodies. This patient was positive for HLA-DQ2 and was diagnosed as coeliac following intestinal biopsy. Of the eight remaining children, two were positive for HLA-DQ8. Levels of anti-transglutaminase returned to normal in all subjects, despite a gluten-containing diet. Purified anti-transglutaminase of the two study groups induced actin rearrangements and cell-cycle progression. During an infectious disease, anti-transglutaminase antibodies can be produced temporarily and independently of gluten. The infection-triggered anti-transglutaminase antibodies have the same biological properties as that of the coeliacs, with the same in-vivo potential for damage.

Influence of age and genetic risk on anti-tissue transglutaminase IgA titers

OBJECTIVES

False-positive results of anti-tissue-transglutaminase (tTG) IgA autoantibodies have been reported in subjects with a genetic risk for celiac disease (CD). The aims of this retrospective study were to assess the prevalence of false-positive tTG titers in patients at risk of CD compared with symptomatic children and to evaluate the influence of age and indication for testing on tTG titers.

PATIENTS AND METHODS

All tTG results measured in our institution during a 33-month period were evaluated. Patients with known CD were excluded. Indications for testing were either symptoms suggestive of CD (group 1) or history of being at risk for CD (group 2). Duodenal biopsies were recommended if titers were positive (> or =10 U/mL) and offered if borderline (> or =4 to <10 U/mL).

RESULTS

The final analysis included 2056 patients, 1707 belonged to group 1, and 349 to group 2. All 65 patients with positive tTG results underwent biopsy (group 1: 57, group 2: 8). Celiac disease was confirmed in 61 subjects (median titer: 107.8 U/mL, range 12.0-1748 mL, NS between group 1 and 2), whereas 4 had normal histology (10.2-25.2 U/mL). Three out of 16 patients with borderline results underwent biopsy and had normal histology. Borderline titers were more common in group 2 patients (2.6% vs 0.4%, P<0.001). Multiple regression analysis in patients with negative tTG results (n=1975) revealed that titers were independently related to age (P<0.05) and indication for testing (P<0.001).

CONCLUSIONS

The influence of age and genetic predisposition/risk has to be taken into account when interpreting tTG results.

Celiac disease diagnosed in the elderly

BACKGROUND AND AIMS

In the past 20 years, a growing proportion of new cases of celiac disease (CD) are diagnosed in adults and in patients with extraintestinal manifestations. Our understanding of the extremely wide spectra of manifestations and the profound effects on elderly patients is improving. Nevertheless, CD is still underdiagnosed in elderly patients. In this study, we describe a case series of CD patients diagnosed after the age of 60.

METHODS

A retrospective chart review was preformed in cases of CD diagnosed after the age of 60. Patients were included if they had positive serology and histologic findings compatible with CD. Eligible patients were reinterviewed, and demographic, clinical, and laboratory information were recorded.

RESULTS

During the study period, 7 patients with CD diagnosed after the age of 60 were identified. The most common presenting findings were weight loss, iron deficiency anemia, and diarrhea. Two patients suffered from severe early osteoperosis and 2 additional patients had elevated liver function tests. Neurologic manifestation was suspected in 3 cases. Two female patients presented with cognitive decline that was attributed to Alzheimer dementia but ameliorated after the initiation of gluten-free diet. The third patient had peripheral neuropathy that completely resolved after the initiation of gluten-free diet. Median lag in diagnosis was 8 years. Diet treatment led to complete resolution of symptoms in most cases and a significant weight gain (median 7.75 kg, range 5 to 11). One patient developed a fatal intestinal T-cell lymphoma.

CONCLUSIONS

In this case series, we have described several cases of CD in patients over the age of 60 with a varied spectrum of manifestations. We have also found a significant lag in diagnosis and treatment. We believe that it is important to promote the identification of CD as a possible culprit in varied clinical conditions in the elderly population.