Celiac.com 11/03/2008 - Blood testing for radioimmunoassay (RIA) tissue transglutaminase auto-antibodies (tTG-Abs) has proven to be a sensitive test for celiac disease follow-up. Recent studies have shown that RIA can accurately detect tTG-Abs in human saliva. However, not much is known about reliability of this method for monitoring the progress of celiac disease over time in patients who are attempting to follow a gluten-free diet.

A team of researchers recently set out to assess salivary RIA tTG-Abs in celiac children on gluten-free diet. The research team included doctors M. Bonamico, R. Nenna, R.P.L. Luparia, C. Perricone, M. Montuori, F. Lucantoni, A. Castronovo, S. Mura; A. Turchetti, P. Strappini, and C. Tiberti.

The team evaluated blood and saliva samples taken from 109 children at the time of their diagnosis for celiac disease. The first group included 71 females, with an average age of 9.4 years. A second group included 58 people who were following a gluten-free diet. The second group was broken into two subgroups: group 2a with 36 patients assessed at 3-6 months; and group 2b with 34 patients at 9 months or more (group 2b).

The research team also included two control groups matched for age and sex. Group 3 included 89 gastroenterological patients, while group 4 included 49 healthy subjects. The team used RIA to detect tTG-Abs in saliva and blood, and compared the results against two other established tests: serum tTG-Abs ELISA and IgA anti-endomysium antibodies (EMA).

The team detected salivary RIA tTG-Abs in 94.5% of patients from group 1, 66.7% of celiac patients from group 2a, and 50.0% from 2b. They detected blood RIA tTG-Abs in 98.2% of patients from group 1, 72.2% of celiac patients from group 2a, and 50.0% from 2b. The longer patients were on a gluten-free diet, the more the tTG-Abs decreased. The research team also found a correlation between saliva and serum levels (r = 0.75, P = 0.0001). A celiac disease follow-up showed comparable salivary and serum RIA sensitivities, and higher levels for EMA and ELISA methods.

The research team concluded that it is possible to measure salivary tTG-Abs with a high level of accuracy; both at initial diagnosis for celiac disease, and also while patients are following a gluten-free diet.

This discovery means that doctors treating people with celiac disease might soon be able to use a simple saliva test to monitor the progress of their patients’ gluten-free diets. Such a development might take remove much of the guesswork for celiacs who are trying to follow a gluten-free diet, and would be particularly useful for patients who might be asymptomatic, or who are at risk for celiac-associated conditions.

Aliment Pharmacol Ther.  2008; 28(3): 364-370.

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