Cutaneous graft-versus-host reaction: prognostic features seen by light microscopy.

Acute graft-versus-host disease (GVHD) is a severe complication of bone marrow transplantation. The diagnosis may be made and its course followed by serial skin biopsies. The degree of epidermal change has been used as a guideline in grading each biopsy, but great variation may be found within each grade, especially grade 2 (basal cell vacuolization and dyskeratosis). To find a histologic parameter that is prognostic of more severe acute GVHD, we examined retrospectively the serial biopsies of 54 patients. When we studied early cutaneous graft-versus-host reaction (GVHR), represented by the grade 2 biopsies, the number of dermal and epidermal mononuclear inflammatory cells correlated positively with the probability of developing more severe acute GVHD. In addition, the patients who had more severe acute GVHD tended to have an earlier appearance of cutaneous histologic changes. None of the other histologic parameters examined in these grade 2 biopsies were found to be predictive of GVHD progression. In addition, no histopathologic parameters in these grade 2 biopsies were predictive of the subsequent development of chronic GVHD.