Tissue transglutaminase ELISA positivity in autoimmune disease independent of gluten-sensitive disease.
BACKGROUND
Our aim was to understand why some sera from patients with a broad spectrum of autoimmune diseases or non-autoimmune diseases involving enhanced apoptosis, cell lysis and/or putative secondary autoimmune processes show reactions in the tissue transglutaminase (TGc) ELISA used for diagnosis of gluten-sensitive disease.


METHODS
Sera were compared from groups of patients with autoimmune diseases, diseases involving organ specific enhanced cell death, celiac disease or dermatitis herpetiformis, diseases of non-autoimmune origin, and a group without known disease. IgA antibodies against TGc were detected using human antigen (produced recombinantly in bacterial or human cells) in different systems (non-commercial ELISA with buffers of differing NaCl concentrations, and anti-TGc sandwich ELISA). Anti-gliadin and anti-endomysium antibodies were also determined.


RESULTS
Many sera from patients with autoimmune disorders gave a positive signal in the human TGc ELISAs. The signal appeared related to minor impurities in the recombinant human TGc used and to raised serum IgA antibody levels rather than to the occurrence of TGc specific antibodies in these patients.


CONCLUSIONS
No association of anti-TGc Abs and autoimmune conditions independent of gluten-sensitive disease could be shown. Care should be taken to exclude copurification of chaperones, like heat shock protein 70, where preparing antigens for TGc ELISAs.
Sárdy
Miklós
M
Department of Dermato-Venereology and -Oncology, Semmelweis University, H-1085 Budapest, Mária u. 41., Hungary. sardym@mail.nih.gov
Csikós
Márta
M
Geisen
Christof
C
Preisz
Klaudia
K
Kornseé
Zoltán
Z
Tomsits
Erika
E
Töx
Ulrich
U
Hunzelmann
Nicolas
N
Wieslander
Jörgen
J
Kárpáti
Sarolta
S
Paulsson
Mats
M
Smyth
Neil
N
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001323:Autoantibodies / Q000097:blood; D001327:Autoimmune Diseases / Q000175:diagnosis / Q000201:enzymology* / Q000276:immunology*; D002446:Celiac Disease / Q000175:diagnosis / Q000201:enzymology* / Q000276:immunology*; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000592:standards*; D005189:False Positive Reactions; D005260:Female; D019204:GTP-Binding Proteins / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007223:Infant; D008297:Male; D008875:Middle Aged; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011503:Transglutaminases / Q000276:immunology*
D001323:Autoantibodies; D007070:Immunoglobulin A; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins