Protein A and protein G ELISA for the detection of IgG autoantibodies against tissue transglutaminase in childhood celiac disease

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Abstract

Objectives: To investigate if the detection of celiac disease (CD) in children was improved by using alternative conjugates for assessment of tissue transglutaminase (tTG) autoantibodies. Methods: Serum samples from 108 biopsy confirmed CD children and 42 control subjects were investigated for the presence of autoantibodies with tTG coated microplates using protein A (PA), protein G (PG), anti-IgG, or anti-IgA as conjugates. Results: Of the 108 CD children, 86 (80%) were IgG-tTG positive, 91 (84%) were positive with the PA-conjugate, 94 (87%) were positive with the PG-conjugate, and 103 (95%) were IgA-tTG positive. Among the 42 controls. 4 (10%) were IgG-tTG positive, 5 (12%) were positive with both the PA- and PG conjugates. whereas 3 (7%) were IgA-tTG positive. Compared with IgG-tTG the concordance was 93% for PA and 95% for PG, with a positive correlation between antibody levels (r=0.967 and r=0.975. p<0.0001). All but one CD child were found positive by combining IgG-tTG and IgA-tTG detection. Conclusions: The sensitivity of IgG-tTG detection with ELISA increased by protein A or protein G conjugates, whereas the specificity was reduced as compared with anti-IgG conjugate. The combined measurement of IgA-tTG and IgG-tTG still seems to be the optimal procedure when screening children for CD. (C) 2008 Elsevier B.V. All rights reserved.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Clinical Laboratory Medicine

Keywords

  • protein A, celiac disease, ELISA, protein G, tissue transglutaminase
Original languageEnglish
Pages (from-to)72-76
JournalClinica Chimica Acta
Volume395
Issue number1-2
Publication statusPublished - 2008
Publication categoryResearch
Peer-reviewedYes