In vitro assessment of the intra luminal phase of gliadin digestion in coeliac disease: gamma-glutamyl transpeptidase-like activity in saliva.

gamma-Glutamyl transpeptidase (GGTP) is an enzyme of potential relevance to the digestion of dietary gliadin, and hence of possible importance in the development of coeliac disease (CD). We have confirmed that human saliva has GGTP-like activity. Comparison of this activity between treated CD patients in long-term remission, age- and sex-matched normal control subjects, and unaffected relatives of CD patients did not show statistically significant differences. Although our results have not demonstrated a primary abnormality of this particular enzyme activity in CD, the intraluminal phase of gliadin processing is potentially important in the aetiology and pathogenesis of CD and thus deserves further study.