Tissue transglutaminase autoantibodies and human leucocyte antigen in Down's syndrome patients with coeliac disease.
The association between autoantibodies against tissue transglutaminase (tTG) and human leucocyte antigen (HLA)-DQB1 alleles was tested in Down's syndrome (DS) patients with and without coeliac disease (CD). Immunoglobulin A (IgA) and G (IgG) anti-tTG were measured in radioligand binding assays and compared with conventionally analysed IgA antibodies against gliadin (AGA) and IgA autoantibodies against endomysium (EMA) in 48 DS patients. HLA-DQB1 typing was carried out by polymerase chain reaction and hybridization with allele-specific probes in 41/48 patients. Both IgA-tTG and IgG-tTG, as well as EMA, were detected in 7/48 and AGA in 15/48 patients. Intestinal biopsy showed histopathological changes consistent with CD in 9/16 patients. HLA-DQB1 typing, available for 8/9 patients with and for 33/39 without CD, demonstrated that 5/8 with CD had DQB1*02 compared with 7/33 of those without (p = 0.0345). In patients with anti-tTG, 5/6 had the DQB1*02 allele compared with 7/35 of those without (p = 0.0053).


CONCLUSIONS
Anti-tTG are HLA-DQB1*02-associated autoantibodies which together could be useful screening tests for silent CD in DS patients. In patients with gastrointestinal symptoms or clinical signs of malabsorption, anti-tTG should be combined with AGA to detect other forms of enteropathies and CD.
Agardh
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Department of Paediatrics, Malmö University Hospital, Sweden. daniel.agardh@home.se
Nilsson
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A
Carlsson
A
A
Kockum
I
I
Lernmark
A
A
Ivarsson
S A
SA
D000293:Adolescent; D001323:Autoantibodies / Q000032:analysis* / Q000276:immunology; D015415:Biomarkers; D001707:Biopsy, Needle; D016022:Case-Control Studies; D002446:Celiac Disease / Q000150:complications / Q000276:immunology* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D004314:Down Syndrome / Q000150:complications / Q000276:immunology* / Q000473:pathology; D005260:Female; D006683:HLA-DQ Antigens / Q000032:analysis* / Q000276:immunology; D006801:Humans; D008297:Male; D011336:Probability; D012016:Reference Values; D012042:Registries; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D011503:Transglutaminases / Q000032:analysis* / Q000276:immunology
D001323:Autoantibodies; D015415:Biomarkers; D006683:HLA-DQ Antigens; D011503:Transglutaminases