ADA and colitis: Various authors have reported a significant increase in adenosine-deaminase expression and activity in inflamed tissues, including intestinal ones and the association of a defective adenosine production, with chronicization of the phlogistic conditions.[26] In a model of experimental colitis induced by dinitrobenzene sulphonic acid (DNBS), the results indicated that the blockade of adenosine conversion into inosine, promoted by inhibition of adenosine deaminase, was able to protect the colonic tissues from inflammatory injury.