PERSISTENT CLONAL EXPANSIONS OF PERIPHERAL-BLOOD CD4(-DISEASE() LYMPHOCYTES IN CHRONIC INFLAMMATORY BOWEL)

It is increasingly recognized that chronic Ag exposure may lead to clo nal expansions of T cells, including those within the peripheral blood . Inflammatory bowel disease is a chronic, multisystemic disease of un known origin that predominantly affects the intestine. We sought to de termine whether clonal expansions of T cells are present in the periph eral blood of patients with inflammatory bowel disease by an examinati on of TCR usage. Positively selected CD4(+) and CD8(+) peripheral bloo d T cells were isolated from subjects with active ulcerative colitis, Crohn's disease, and diverticulitis and from normal controls. Analysis of complementarity determining region 3 lengths of 24 TCR-beta chain V region families from CD4(+) and CD8(+) peripheral blood T cells show ed a skewed distribution in the three inflammatory groups, consistent with expansion of T cell clones, in comparison to the normally distrib uted pattern observed among the control donors. Random sequencing of t he PCR amplification products of CD4(+) peripheral blood T cells from the subjects with ulcerative colitis, Crohn's disease, and diverticuli tis revealed reiterative TCR-beta chain sequences that were not found in the normal donors. In subjects with Crohn's disease, the reiterativ e TCR-beta chain sequences from the CD4(+) peripheral blood T cells we re persistent over at least a l-yr period. The persistently expanded T CR-beta chain sequences of CD4(+) peripheral blood T cells were identi fiable in genomic DNA isolated from archival tissue of intestine from subjects with Crohn's disease and ulcerative colitis by Southern blott ing and direct DNA sequencing. An identical twin pair, concordant for Crohn's disease, shared the same reiterative TCR-P chain sequences in their CD4(+) peripheral blood T cells. These studies show that chronic intestinal inflammation is associated with expansions of CD4(+) perip heral blood T cells. Furthermore, in inflammatory bowel disease these T cell clonal expansions are persistent and shared among HLA-identical individuals, implicating a response to specific, persistent, and stim ulating Ags in these diseases.