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

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.

• Authors: Ingrid Dahlbom, Daniel Agardh, Tony Hansson
• Journal: Clinica chimica acta; international journal of clinical chemistry (Clin Chim Acta) Vol. 395 Issue 1-2 Pg. 72-6 (Sep 2008) ISSN: 0009-8981 [Print] Netherlands
• PMID: 18514068 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Autoantibodies
• G-substrate
• Immunoglobulin A
• Immunoglobulin G
• Nerve Tissue Proteins
• Staphylococcal Protein A
• Protein Glutamine gamma Glutamyltransferase 2
• Transglutaminases
• GTP-Binding Proteins

Topics

• Adolescent
• Adult
• Autoantibodies (blood)
• Celiac Disease (blood, immunology)
• Child
• Child, Preschool
• Enzyme-Linked Immunosorbent Assay (methods)
• Female
• GTP-Binding Proteins (immunology)
• Humans
• Immunoglobulin A (blood)
• Immunoglobulin G (blood)
• Infant
• Male
• Nerve Tissue Proteins (chemistry)
• Protein Glutamine gamma Glutamyltransferase 2
• Reproducibility of Results
• Retrospective Studies
• Sensitivity and Specificity
• Staphylococcal Protein A (chemistry)
• Transglutaminases (immunology)