Israel Medical Association Journal

Background: Anti-endomysial antibodies are sensitive and specific markers for celiac disease. This antibody has recently been identified as an antibody to tissue transglutaminase, an enzyme that cross-links and stabilizes extracellular matrix proteins.

Objectives: To evaluate the clinical usefulness of an enzyme-linked immunoassay for anti-transglutaminase antibodies, and to compare the results with those of AEA, the current gold standard serological test for celiac disease.

Methods: Serum samples were collected from 33 patients with biopsy-proven celiac disease and AEA tests were performed. Control samples for anti-transglutaminase were obtained from 155 patients. An ELISA test for immunoglobulin A anti-transglutaminase utilizing guinea pig liver transglutaminase was developed and performed on all sera.  Cutoff values for the test were performed using logistic regression and receiver operating curves analysis.

Results: An optical density cutoff value of 0.34 was established for the assay. The mean value was 0.18±0.19 optical density for controls, and 1.65±1.14 for patients with celiac disease (P<0.001). Sensitivity and specificity of the assay were both 90%, while AEA had a sensitivity and specificity of 100% and 94%, respectively.

Conclusions: A tissue transglutaminase-based ELISA test is both sensitive and specific for  detection of celiac disease.

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AEA = anti-endomysial antibody

Background: There is an increasing number of reports of pertussis among older children and adults. The development and licensure of an acellular pertussis vaccine offer the possibility of adult vaccination against the disease. Information on immunity to pertussis in this age group is needed before any vaccination policy can be considered.

Objectives: To study the seroepidemiology of pertussis antibodies in a random sample of adolescents.

Methods: Serum IgG antibodies to whole-cell lysate of Bordetella pertussis were measured by enzyme-linked immunosorbent assay in sera of 533 Israeli military recruits aged 17–18 years. Epidemiologic variables were collected by a questionnaire and analyzed for correlation with pertussis antibodies.  

Results: Of the sera tested 58.6% were positive for pertussis IgG antibodies, while 35.4% were negative and 6% were borderline. The seropositivity rate was significantly higher among females and non-smokers than among males and smokers. Serum samples of subjects found negative to Bordetella pertussis on recruitment were tested again, using the same ELISA assay, 2–3 years later.  Seroconversion during the 3 year military service was detected in 12.5% of 40 subjects. Using the pertussis toxin as the antigen in a subsample of 160 sera, the seroprevalence was lower than that detected by the whole-cell lysate on the same sera (45% vs. 58%).

Conclusions: A significant part of the adolescent population in Israel has low titer of serum IgG antibodies to the multiple antigens of B. pertussis. The relatively low concentration of anti-pertussis antibodies, together with the serological evidence of exposure to the disease indicates that booster immunization with the acellular pertussis vaccine of military recruits should be considered after more information on the incidence of clinical cases of pertussis will be available.

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ELISA = enzyme-linked immunosorbent assay