Performance of two commercial ELISAs for detecting IgA anti-human and anti-guinea pig tissue transglutaminase antibodies.
BACKGROUND
Sensitivity and specificity of anti-human tissue transglutaminase antibodies (anti-htTGA) seem to be superior to those of anti-tissue transglutaminase of guinea pig (anti-gptTGA) for screening patients with celiac disease (CD), but there are still controversies. The aim of this study was to evaluate the performance of two INOVA ELISA kits to detect IgA anti-htTGA and anti-gptTGA in patients with and without CD.


METHODS
The study groups were comprised of 49 anti-endomysial antibody (EMA)-positive untreated-CD, and 123 controls (EMA-negative treated CD, EMA-negative chronic diarrhea, autoimmune hepatitis, inflammatory bowel disease and healthy people).


RESULTS
The agreement between the two ELISAs was statistically significant in all study groups and there was no significant difference between them (92.7% agreement; kappa = 0.70; kappa p = 0.001; McNemar p = 1). All patients with serum reactivity of more than 100 units had histologic diagnosis of CD. In seven of 10 patients with treated-CD who had control biopsies, villous atrophy was still present in four who tested positive by both kits. Two of three celiacs with histologic remission tested positive for both anti-tTGA.


CONCLUSIONS
the anti-gptTGA and anti-htTGA determination were equally efficient in identifying patients with untreated-CD with high titers of EMA. Whatever the anti-tTGA ELISA used, the reactivity above 100 units was always related to active CD diagnosed by histologic alterations in intestinal biopsies. The anti-tTGA reactivity by both kits was not only similar in determining histologic activity in the follow-up of CD after a gluten free diet, but also in identifying positive sera from the control groups, regardless if CD has been confirmed by duodenal biopsies.
Abrantes-Lemos
Clarice Pires
CP
Laboratory of Immunopathology of Schistosomiasis (LIM 06), Institute of Tropical Medicine, University of São Paulo School of Medicine, Sao Paulo, Brazil.
Nakhle
Maria Cristina
MC
Damiao
Aderson Omar Mourao Cintra
AO
Sipahi
Aytan Miranda
AM
Carrilho
Flair José
FJ
Cancado
Eduardo Luiz R
EL
D000328:Adult; D000818:Animals; D000906:Antibodies / Q000097:blood*; D002446:Celiac Disease / Q000097:blood / Q000276:immunology; D002908:Chronic Disease; D003967:Diarrhea / Q000097:blood / Q000201:enzymology / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D026122:Factor XIIIa / Q000276:immunology*; D005260:Female; D006168:Guinea Pigs; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D043183:Irritable Bowel Syndrome / Q000097:blood / Q000201:enzymology / Q000276:immunology; D008297:Male
D000906:Antibodies; D007070:Immunoglobulin A; D026122:Factor XIIIa