ADA and triple-A syndrome: The mechanism of developing such a loss of response (LOR) is involved in the production of anti-drug antibodies and the decrease in the serum level (trough level) of anti-TNF-α due to the undetectability of anti-TNF-α; both serum ADA trough level and anti-ADA antibodies (AAA) have been reported to be associated with mucosal healing and LOR [11].