Immunohistology of graft-versus-host disease mediated skin lesions and its correlation to a large granular lymphocyte surface phenotype and function.

Skin lesions of five patients presenting with acute and chronic Gvhd after bone marrow transplantation were analyzed on frozen tissue sections using selected monoclonal antibodies against various T-cell determinants and HLA-antigens in order to define immunological phenomena characteristic for cutaneous damage seen in various GvHD states. Four of these patients showed marked increase of a certain T-cell subpopulation positive for HLA-D region products in the upper dermis. A considerable number of these T-cells seemed to show cytotoxic reactivity on the basal cell layers of the epithelium and to correlate with the appearance of an OKT4-, OKT8+, HLA-DR+ T-cell subset in the peripheral blood presenting natural killer (NK) cell like activity on various targets. Ia antigen expression on keratinocytes observed in one patient with chronic GvHD could result from a rapid and irregular turnover of epidermal cells affected by continuous stimuli of these T-cells. Further immunological studies on skin biopsies of patients with different states of GvHD and autoimmune diseases may lead to valuable diagnostic criteria for an early and accurate assessment of various skin lesions in patients after bone marrow transplantation.