SKIN BIOPSY IN ALLOGENEIC AND AUTOLOGOUS BONE-MARROW TRANSPLANT PATIENTS - A HISTOLOGIC AND IMMUNOHISTOCHEMICAL STUDY AND REVIEW OF THE LITERATURE

Histologic criteria and grading system for diagnosis of cutaneous mani festations of graft vs. host disease (GvHD) have been established, and the diagnosis of high-grade GVHD is readily made by pathologists. The re have been, however, increasing reports of skin rash occurring in pa tients treated with autologous bone marrow transplant (aBMT) that cann ot be distinguished clinically or histologically from GvHD following a llogeneic bone marrow transplant (alloBMT). We studied the histologic and immunohistochemical features of 25 skin biopsy specimens obtained from 22 patients with skin rashes who had undergone either aBMT or all oBMT, or who suffered from a malignancy. Tissue sections were immunore acted with pan-T lymphocyte- associated antibody Leu 22 (CD43); pan-B antibody L26 (CD20); macrophage/myeloid antibody for CD68 antigens; an d LN-3 antibody specific for HLA Class II antigens. The clinical suspi cion of GvHD was confirmed in 8 of 10 alloBMT patients. Seven of the 1 0 aBMT patients also clinically diagnosed to have GvHD, had histologic changes consistent with Grades I, II, or III. The rest of the patient s showed changes consistent with drug reaction. T-cell lymphocytes (Le u22), macrophages (CD68), and HLA-DR expression on Langerhans cells we re in general more prominent in allogeneic chronic GvHD, but this was not statistically significant. No significant differences were seen in the degree of HLA-DR expression on endothelial cells and keratinocyte s in any of the groups. The current histologic criteria are inadequate to differentiate cutaneous GvHD following alloBMT from the skin rash occurring in the setting of aBMT. Additionally, and contrary to previo us reports, immunohistochemical studies are of no additional help as a djuvants in the differential diagnosis of these conditions.