Graft-versus-host disease in extremity transplantation: digital image analysis of bone marrow in situ.

ABSTRACT

The development of either unstable immune chimerism and lethal graft-versus-host disease or stable immune chimerism and alloimmune tolerance can result from extremity transplantation. LBN rats served as recipients of Lewis vascularized extremity (limb) transplants. Recipients received no immune suppression and were immunologically unmodified. The bone marrow of transplanted and contralateral limbs was analyzed in situ for distribution of nuclei, nuclear area, and staining intensity by digital image analysis and computerized morphometry. Cellularity was significantly increased, and fat content was significantly decreased in the graft-versus-host disease animals' marrow versus the tolerant animals' marrow for both the transplanted and contralateral limbs. Tolerant animals demonstrated significantly increased nuclear staining compared with graft-versus-host disease animals for both transplanted and contralateral limbs. Additionally, there were significant changes between the host and the transplanted limbs for marrow intensity and cellularity within tolerant and graft-versus-host disease groups. The significant differences in the graft-versus-host disease-positive recipients suggested that both autoimmune dysregulation and alloimmune reactions were in effect for both donor and host bone marrow compartments. Cellular alterations in the tolerant recipients' marrow were suggestive of subtle subclinical graft-versus-host responses.