HUMAN CD8+ INTRAEPITHELIAL LYMPHOCYTES-T ARE MAINLY CD45RA-RB+ AND SHOW INCREASED COEXPRESSION OF CD45R0 IN CELIAC-DISEASE

Expression of various CD45 isoforms (RA, RB and R0) on CD3+, CD4+ and CD8+ intraepithelial and lamina propria T cells was examined in situ by a three‐color immunofluorescence technique in jejunal biopsy specimens from 32 patients with celiac disease and 18 controls. The median percentage of CD3+ intraepithelial lymphocytes (IEL) that expressed CD45R0 increased from 52% in controls to 69% in untreated celiac disease (p < 0.01). Furthermore, the percentages of CD4+ and CD8+ IEL strongly positive for CD45R0 rose respectively from 94% and 24% in controls to 100% and 55% in untreated celiac disease. Conversely, CD45R0 was strongy expressed on most CD3+ lamina propria lymphocytes (LPL) both in control (81%) and diseased (77%–81%) mucosa. A variable fraction of the intraepithelial and lamina propria CD3+ T cells expressed mainly CD45RB (controls, 46% and 20%, respectively; celiac disease, 29% and 15%). Only 2% IEL and 4% LPL were positive for CD45RA. Expression of different CD45R isoforms thus identified three distinct CD8+ T cell subsets in human intestinal mucosa. In addition, our results suggested that antigen‐primed CD8+CD45R0+ memory cells accumulate in the jejunal epithelium of patients with untreated celiac disease. Copyright © 1990 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim