Inflammatory cells in graft-versus-host disease on the rectum: immunopathologic analysis.

The inflammatory infiltrate of acute rectal graft-versus-host disease (GVHD) was investigated by indirect immunofluorescence. Twenty biopsies from 11 allogeneic bone marrow transplant recipients were studied in four groups: biopsies before transplantation; biopsies after transplantation without GVHD; biopsies from patients with extra-intestinal GVHD only; and biopsies from patients with intestinal GVHD. Total T cell numbers (CD2+, CD3+) in the lamina propria differed little in the four groups. CD4+ lymphocytes appeared to be decreased in GVHD while CD8+ lymphocytes were significantly increased (p less than 0.01), thus significantly lowering the CD4/CD8 ratio. In pre-transplant patients and in those without GVHD this ratio resembled that in normal peripheral blood (1.44 +/- 0.5 and 2.46 +/- 1.3, respectively) but was significantly lower in both extraintestinal (0.71 +/- 0.08) and intestinal GVHD (0.56 +/- 0.08) (p less than 0.05). Acute intestinal GVHD was marked by a fourfold increase in CD57+ lymphoid cells within the epithelium and the lamina propria (p less than 0.05). The recognition of CD57+ cells, which may include natural killer-like cells, within rectal lymphoid infiltrates suggests a possible role for non-HLA restricted effector cells in GVHD of the rectum.