Advanced

Calcium activation of tissue transglutaminase in radioligand binding and enzyme-linked autoantibody immunoassays in childhood celiac disease.

Agardh, Daniel LU ; Roth, Bodil LU ; Lernmark, Åke LU and Stenberg, Pål (2005) In Clinica Chimica Acta 358(1-2). p.95-103
Abstract
Background



Conflicting data have been published concerning the effect of calcium on binding of autoantibodies to tissue transglutaminase (tTG) in celiac disease (CD).

Methods



IgA-tTG and IgG-tTG were measured with radioligand binding assays (RBA) using human recombinant (hr) 35S-tTG produced in lysate of rabbit reticulocytes and with guinea pig (gp) tTG ELISA in 51 CD children (median: 5.7 years) and 35 controls (median: 2.2 years). Assays were performed with and without calcium.

Results



In hr-tTG RBA, IgA-tTG levels remained unchanged after calcium detecting 50/51 CD children and 1/35 controls (p < 0.0001). IgG-tTG levels decreased with calcium (p < 0.0001)... (More)
Background



Conflicting data have been published concerning the effect of calcium on binding of autoantibodies to tissue transglutaminase (tTG) in celiac disease (CD).

Methods



IgA-tTG and IgG-tTG were measured with radioligand binding assays (RBA) using human recombinant (hr) 35S-tTG produced in lysate of rabbit reticulocytes and with guinea pig (gp) tTG ELISA in 51 CD children (median: 5.7 years) and 35 controls (median: 2.2 years). Assays were performed with and without calcium.

Results



In hr-tTG RBA, IgA-tTG levels remained unchanged after calcium detecting 50/51 CD children and 1/35 controls (p < 0.0001). IgG-tTG levels decreased with calcium (p < 0.0001) in CD children and detected 48/51 with and 49/51 without calcium as compared to 1/35 controls (p < 0.0001). In gp-tTG ELISA, levels increased with calcium (p < 0.0001) making it possible to detect an additional three to a total of 50/51 with IgA-tTG and 13 to 39/51 CD children with IgG-tTG compared to 4/35 and 8/35 controls (respectively, p < 0.0001). Rabbit reticulocytes displayed calcium-dependent tTG activity.

Conclusions



Calcium increased binding of IgA-tTG and IgG-tTG in the ELISA test. The reverse effect observed in RBA may be explained by competitive binding between calcium activated native rabbit reticulocyte tTG and hr 35S-tTG. tTG autoantibody assays may need taking calcium into account for accurate diagnostic sensitivity and specificity for CD. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Calcium, Celiac disease, Radioimmunoassays, Tissue transglutaminase
in
Clinica Chimica Acta
volume
358
issue
1-2
pages
95 - 103
publisher
Elsevier
external identifiers
  • wos:000231001600010
  • pmid:15946660
  • scopus:22144488118
ISSN
0009-8981
DOI
10.1016/j.cccn.2005.02.027
language
English
LU publication?
yes
id
87bff488-385d-405f-a6aa-39899590e853 (old id 140151)
date added to LUP
2007-07-09 15:33:28
date last changed
2017-02-05 03:29:17
@article{87bff488-385d-405f-a6aa-39899590e853,
  abstract     = {Background<br/><br>
<br/><br>
Conflicting data have been published concerning the effect of calcium on binding of autoantibodies to tissue transglutaminase (tTG) in celiac disease (CD).<br/><br>
Methods<br/><br>
<br/><br>
IgA-tTG and IgG-tTG were measured with radioligand binding assays (RBA) using human recombinant (hr) 35S-tTG produced in lysate of rabbit reticulocytes and with guinea pig (gp) tTG ELISA in 51 CD children (median: 5.7 years) and 35 controls (median: 2.2 years). Assays were performed with and without calcium.<br/><br>
Results<br/><br>
<br/><br>
In hr-tTG RBA, IgA-tTG levels remained unchanged after calcium detecting 50/51 CD children and 1/35 controls (p &lt; 0.0001). IgG-tTG levels decreased with calcium (p &lt; 0.0001) in CD children and detected 48/51 with and 49/51 without calcium as compared to 1/35 controls (p &lt; 0.0001). In gp-tTG ELISA, levels increased with calcium (p &lt; 0.0001) making it possible to detect an additional three to a total of 50/51 with IgA-tTG and 13 to 39/51 CD children with IgG-tTG compared to 4/35 and 8/35 controls (respectively, p &lt; 0.0001). Rabbit reticulocytes displayed calcium-dependent tTG activity.<br/><br>
Conclusions<br/><br>
<br/><br>
Calcium increased binding of IgA-tTG and IgG-tTG in the ELISA test. The reverse effect observed in RBA may be explained by competitive binding between calcium activated native rabbit reticulocyte tTG and hr 35S-tTG. tTG autoantibody assays may need taking calcium into account for accurate diagnostic sensitivity and specificity for CD.},
  author       = {Agardh, Daniel and Roth, Bodil and Lernmark, Åke and Stenberg, Pål},
  issn         = {0009-8981},
  keyword      = {Calcium,Celiac disease,Radioimmunoassays,Tissue transglutaminase},
  language     = {eng},
  number       = {1-2},
  pages        = {95--103},
  publisher    = {Elsevier},
  series       = {Clinica Chimica Acta},
  title        = {Calcium activation of tissue transglutaminase in radioligand binding and enzyme-linked autoantibody immunoassays in childhood celiac disease.},
  url          = {http://dx.doi.org/10.1016/j.cccn.2005.02.027},
  volume       = {358},
  year         = {2005},
}