Expression of 70-kDa heat-shock protein during acute graft-versus-host disease

Acute lethal graft-versus-host disease (GVHD) was induced in unirradiated (LEW x DA)F1 rats by injection of DA parental lymphoid cells. Control rats received the same dose of (LEW x DA)F1 cells. The level of hsp70 at different stages of GVHD was examined in the spleen, lymph nodes, thymus, liver, lung, kidney, heart, and skeletal muscles of GVHD and control animals. Hsp70 was present in all organs analyzed in both groups and, with the exception of the spleen and lymph nodes, detectable levels remained constant during the disease. However, the spleen and lymph nodes of GVHD rats showed distinct changes in the hsp70 levels throughout the course of the disease. Expression of hsp70 in spleen and lymph nodes was augmented 7 and 14 days after induction of the disease. During the last stages of GVHD, 18-21 days after the induction, expression of hsp70 diminished to a level similar to that in untreated and control animals. Elevated levels of hsp70 in lymphoid organs during GVHD suggest an involvement of hsp70 in the pathology of the disease.