Enhanced production of IL-8 in chronic but not in early ileal lesions of Crohn's disease (CD)

Distinct Th1/Th2 patterns have been observed during the evolution of CD. Th e aim of this study was to compare neutrophil involvement and IL-8 mRNA and protein expression during early recurrent lesions and chronic phases of CD . Twenty-nine patients with CD having ileocolonic resection with anastomosi s were studied. Biopsies were obtained during surgery from the non-inflamed ileal mucosa and from chronic ileal lesions. Endoscopic ileal biopsies wer e also taken from early recurrent ileal lesions occurring 3 months after su rgery. Neutrophil counts were performed and mucosal IL-8 levels were evalua ted by competitive reverse transcriptase-polymerase chain reaction and immu nohistochemistry. Early recurrent ileal lesions were characterized by low n eutrophil counts and IL-8 production at the mRNA and protein levels compare d with the ileal chronic lesions. The main cellular sources of IL-8 in the early recurrent lesions were neutrophils, while in chronic lesions the majo rity of IL-8-stained cells were CD3(+) T cells and macrophages. These resul ts confirmed that the nature of the inflammatory infiltrate and the express ion of cytokine profiles may differ between the acute and chronic phases of CD.