Td. Horn et al., REAPPRAISAL OF HISTOLOGIC FEATURES OF THE ACUTE CUTANEOUS GRAFT-VERSUS-HOST REACTION-BASED ON AN ALLOGENEIC RODENT MODEL, Journal of investigative dermatology, 103(2), 1994, pp. 206-210
We employed a rat model of complete major histocompatibility complex-m
ismatched allogeneic bone marrow transplantation to better characteriz
e the histologic expression of the acute cutaneous graft-versus-host r
eaction (GVHR), compared with changes due to the preparative regimen.
Cyclosporin A abolished the development of this GVHR. Low levels of dy
skeratotic cells were present in all groups (allogeneic and syngeneic
transplants with and without cyclosporin A) and, alone, were insuffici
ent to diagnose a cutaneous GVHR. A consistent histologic feature of t
he GVHR was significant lymphoid infiltration of the dermis. The patte
rn of cytotoxic folliculitis involved follicular epithelium above the
entry of sebaceous glands. Immunostain for major histocompatability co
mplex class II, IA, and IE antigens revealed that dendritic cells with
in the follicle were limited to this upper region and that lower folli
cular epithelium did not upregulate expression with evolution of the G
VHR. Based on this model,we conclude 1) that the diagnostic scheme for
the acute cutaneous GVHR should include lymphoid infiltration of the
dermis, 2) that the preparative regimen (including total body irradiat
ion) induces persistent low levels of dyskeratotic cells (two to three
cells/linear mm of epidermis), and 3) that the pattern of follicular
involvement may relate to the distribution of dendritic cells and to a
n inability of lower follicular epithelium to upregulate major histoco
mpatability complex class II antigens.