Quantitation of chemokines (MDC, TARC) expression in mucosa from Crohn's disease and ulcerative colitis.

Chemokines and their receptors are involved in the migration of different mononuclear cells. Among them macrophages-derived chemokines (MDC) and thymus-and activation regulated chemokine (TARC) belong to a new cluster of genes involve in Th2 lymphocytes homing. Cytokines appear to play a significant role in pathogenesis of inflammatory bowel diseases with an excessive Th1 response in chronic lesions of Crohn's disease (CD) and a Th2 pattern in both earlier mucosal CD lesions and in mucosa of ulcerative colitis (UC). Here we demonstrate that RNAm coding for MDC and TARC are expressed in mucosa from CD and UC patients. Using real-time fluorescent RT-PCR, MDC and TARC mRNA were increased in CD inflamed mucosa. Moreover MDC and TARC transcripts were increased in inflamed CD specimen compared to non-involved CD mucosa. These differences both discriminate CD from UC patients. Additionally, MDC protein was produced in isolated mononuclear cells from peripheral blood (PBMC) or mucosa (LPMC) from UC and CD patients: spontaneously, MDC production from PBMC was increased in CD compared to UC patients. MDC production from CD PBMC was also higher than that found in healthy controls. Together, these data indicate that MDC should be involved in the lymphocytes homing in mucosa from CD patients.