A prospective study of cellular and immunologic changes in skin of allogeneic bone marrow recipients. Relationship to clinical and histologic features of acute graft-versus-host disease.

The inflammation-associated molecules intercellular adhesion molecule (ICAM)-1, endothelial lymphocyte adhesion molecule (ELAM)-1, vascular cell adhesion molecule (VCAM)-1, human leukocyte antigen (HLA)-DR, interleukin (IL)-2R (CD25), CD34, alpha-1-antichymotrypsin (alpha 1-ACT), and L1 antigen were studied in skin from marrow recipients to determine the timing and distribution of their expression in relation to the clinical and histologic evolution of graft-versus-host disease (GvHD). Four phases were recognized: 1. pretransplant with no immunohistologic change; 2. posttransplant with no evidence of GvHD when dermal alpha 1-ACT + macrophages were increased; 3. posttransplant with clinical, but not histologic, evidence of GvHD with increased keratinocyte HLA-DR and ICAM-1 expression and increased numbers of VCAM-1+ dermal cells; and 4. posttransplant with clinical and histologic evidence of GvHD characterized by an infiltrate of CD25+ T cells, L1+, alpha 1-ACT+ and VCAM-1+ macrophages, L1 antigen expression on keratinocytes accompanied by further increases in HLA-DR and ICAM-1, and increased endothelial ELAM-1 staining with a reciprocal decrease in CD34. A sequential accumulation of cellular and molecular changes, therefore, occurs in the evolution of acute GvHD, and immunostaining for HLA-DR, ICAM-1, and VCAM-1 may be helpful in diagnosing early disease.