INTERLEUKIN-12 EXPRESSION IS FOCALLY ENHANCED IN THE GASTRIC-MUCOSA OF PEDIATRIC-PATIENTS WITH CROHNS-DISEASE

The stomach is frequently involved in children suffering from Crohn's disease (CD). Diagnosis of specific gastritis may be difficult when gr anulomas are absent. We have used in situ hybridization to examine the expression of interleukin (IL)-12, a key cytokine in the Th1 response . IL-12 p35 and p40 antisense probes were used to examine heal specime ns from 9 children with CD and gastric biopsies from 24 children (13 w ith CD, 6 with Helicobacter pylori chronic gastritis, and 5 with a nor mal gastric mucosa). In all patients with CD, many clusters of IL-12-p ositive cells were present in the lamina propria. This was the case In the heal specimens as well as in gastric mucosa showing granulomatous gastritis or nongranulomatous gastritis. The same distribution patter ns were found for the IL-12 p35 and p40. In three patients with Helico bacter pylori gastritis, few scattered IL-12-positive cells were found . No positive cells were found in the normal gastric mucosa. The focal ly enhanced IL-12 expression in the gastric mucosa of pediatric patien ts with CD, with or without specific lesions, suggests that both are i ndeed linked to the disease and supports the major part of IL-12 in in itiating and maintaining of the cascade resulting in the Th1 responses .