DIAGNOSTIC FEATURES OF TRANSFUSION-ASSOCIATED GRAFT-VERSUS-HOST DISEASE

Aims-To define the immunopathological profile of transfusion associate d graft versus host disease (TA-GvHD) to elucidate its pathophysiology and to determine if any features are of diagnostic value. Methods-Nin e patients (age range 14-61 years) who developed histologically confir med TA-GVHD between 1989 and 1992 were studied. Immunohistochemical an alysis of frozen and formalin fixed skin biopsy tissue was performed. Sections were stained with antibodies to CD3, CDS, CD4 and HLA-DR, usi ng a routine streptavidin-biotin technique with standard diaminobenzid ine development. Results-All biopsy specimens showed aberrant positive expression of HLA-DR by epidermal keratinocytes. In four patients, ah of whom died, HLA-DR was diffusely expressed throughout the epidermis ; in the other five cases keratinocyte expression of HLA-DR was more f ocal. In all biopsy specimens T cells had infiltrated the dermis and e pidermis. In all nine cases CD4 + T helper/inducer cells were the pred ominant T cells. Discussion-Immunohistochemical studies are of value i n the diagnosis of TA-GVHD. Aberrant keratinocyte expression of HLA-DR and dermal and epidermal infiltration of CD4 + T cells are immunopath ological features of TA-GvHD. Immunohistochemical analysis of skin bio psy tissue using antibodies to these markers is thus a useful investig ation in pancytopenic patients presenting with unexplained rashes.