Antibodies to wheat high molecular weight glutenin sub-units in patients with coeliac disease

BACKGROUND: Wheat gluten comprises gliadins and glutenins. The high-molecular-weight (HMW) glutenin subunits (GS)-1Dy10 are toxic for patients with celiac disease (CD). This study aimed to assess whether CD patients Mount a serological response to HMW-GS-1Dy10.
METHODS: Recombinant HMW-GS-1 DY 10 was deamidated using human recombinant tissue transglutaminase. MALDI-TOF was performed to compare the level of deamidation of glultamine residues between material before and after treatment. Enzyme-linked immunosorbent assays were developed. Sera from patients with untreated CD and gastrointestinal disease controls were tested and receiver operator characteristics were used to calculate cutoffs.
RESULTS: MALDI-TOF revelead a number of fragments matching known HMW-GS-1Dy10 sequences within both the deamidated and non-deamidated material. Evidence of deamidation of glutamine residues was found only within th ehuman transglutaminase-treated material. Patients with untreated CD had significantly increased levels of serum antibodies to HMV-GS-1Dy10 compared to controls. Undeamidated HMW-GS-1Dy10 IgA antibodies had sensitivities and specificities of 72.5 and 78.26%, respectively. Deamitated HMW-GS-1Dy10 IgA antibodies had sensitivities and specificies of 76.8 and 65.2%. Undeamidated HMW-GS-1Dy10 IgG antibodies had sensitivities and specificities of 75.3 and 68.1%. Deamidated HMW-GS-1Dy10 IgG antibodies has sensitivities and specificities of 36.2 and 92.8%.
CONCLUSIONS: Patients with untreated CD have raised antibody levels to HMW-GS-1Dy10, indicating the participation of these proteins in the adaptive immune response to gluten. Discrimination between CD patients and controls is not enhanced by deamidation of HMW-GS-1Dy10. Thus antibodies to these proteins are not useful markers for CD detection.