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

Aims-To define the immunopathological profile of transfusion associated graft versus host disease (TA-GvHD) to elucidate its pathophysiology and to determine if any features are of diagnostic value. Methods-Nine patients (age range 14-61 years) who developed histologically confirmed TA-GVHD between 1989 and 1992 were studied. Immunohistochemical analysis of frozen and formalin fixed skin biopsy tissue was performed. Sections were stained with antibodies to CD3, CDS, CD4 and HLA-DR, using a routine streptavidin-biotin technique with standard diaminobenzidine 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 focal. In all biopsy specimens T cells had infiltrated the dermis and epidermis. In all nine cases CD4 + T helper/inducer cells were the predominant T cells. Discussion-Immunohistochemical studies are of value in the diagnosis of TA-GVHD. Aberrant keratinocyte expression of HLA-DR and dermal and epidermal infiltration of CD4 + T cells are immunopathological features of TA-GvHD. Immunohistochemical analysis of skin biopsy tissue using antibodies to these markers is thus a useful investigation in pancytopenic patients presenting with unexplained rashes.