T-CELLS SELECTIVELY INFILTRATE BONE-MARROW AREAS WITH RESIDUAL HEMATOPOIESIS OF PATIENTS WITH ACQUIRED APLASTIC-ANEMIA

Aplastic anaemia (All) is characterized by pancytopenia and bone marro w (BM) hypocellularity. In some patients AA may be mediated by T cells . To localize inflammatory cell infiltrates, we carried out a quantita tive immunohistochemical analysis of BM biopsies of AA patients, In fi ve out of eight biopsies, significantly higher numbers T cells were fo und in the areas with residual haemopoiesis (RH). The significantly in creased numbers of CD3(+) T cells in areas with RH supports the hypoth esis of a site-directed infiltration and/or a local proliferation of T cells in;he BM of patients with AA.