EXPRESSION OF CD45RO ON CIRCULATING CD19-CELLS IN CROHNS-DISEASE( B)

Crohn's disease is an immunoregulatory disorder of the intestine that can be associated with systemic manifestations. This study analysed B- cell differentiation antigens to identify B-cell subpopulations unique to patients with Crohn's disease. CD45 isoform expression was used as an indicator of B-cell differentiation stage. This work shows that B- cells in blood and gut of patients with Crohn's disease are at an adva nced stage of differentiation based on their unusual presentation of t ransitional (RA+ RO+) and late stage (RO+) CD45 isoforms on lamina pro pria lymphocytes, whereas normal intestinal lamina propria lymphocytes B-cells express primarily CD45RA. Crohn's disease patients had height ened expression of the CD45RO isoform on CD19+ lamina propria lymphocy tes, and was found in a statistically significant proportion of Crohn' s peripheral blood mononuclear cells (PBMC) where CD19+ PBMC had an ex pression pattern affecting an unexpectedly high proportion of these di fferentiated or late stage CD45RO+ B-cells. The expression of CD45RO v aried greatly among CD19+ PBMC from patients with Crohn's disease, so multiple regression analysis was performed between these CD45 isoforms and several clinical parameters. After grouping high and low CD45RO e xpression on CD19+ B-cells, a significant statistical difference was f ound between high Crohn's disease activity index (CDAI) and low CDAI C rohn's disease patients respectively.