Previous studies of monozygotic twins with inflammatory bowel disease (IBD) suggest genetic mucin alteration in ulcerative colitis.
In this study, researchers from Europe evaluated mucosal expression of the oncofetal carbohydrate antigen TF (galactose ß1, 3 N-acetylgalactosamine alpha-) in twins.
The team studied formalin fixed paraffin embedded rectal biopsies from 22 monozygotic twin pairs with IBD.
Of these, 8 had ulcerative colitis and 14 had Crohn's disease.
Overall, 6 pairs were concordant for disease and 16 had unaffected twin siblings.
Closely adjacent sections were assessed for TF expression and nuclear factor kappa B (NF kappa B) activation; investigators were blinded to the diagnosis.
The team found that unaffected twins were almost all TF positive, compared with the controls.
Furthermore, unaffected ulcerative colitis and Crohn's disease twins were similarly TF positive.
The team determined that TF positivity was confined mainly to the superficial epithelium and absent from the stem cell compartment of the lower crypts. This suggested that glycosylation changes are acquired rather than genetically determined.
|Unaffected twins were almost all TF positive.|
They also found that activated NF kappa B was present in the surface epithelium of mucosal biopsies nearly all unaffected IBD twins, compared with controls.
The researchers found that all 22 affected IBD twins were TF positive and 18 were positive for activated NF kappa B.
Dr Bodger's team concluded, "Altered mucosal glycosylation in unaffected identical twins of IBD patients was confirmed in this study".
"This occurred in both ulcerative colitis and Crohn's disease twins".
"The changes are probably acquired rather than congenital and may reflect "preinflammatory" NF kappa B activation".