Cytomegalovirus infection-associated generalized immune activation in heart allograft recipients: a study of cellular events in peripheral blood and endomyocardial biopsy specimens.

An association between cytomegalovirus (CMV) infection, heart allograft rejection, and arteriosclerosis has been reported. To investigate the mechanisms of this association, the cellular immune response in peripheral blood and the inflammation in heart allografts during antigenemia were studied. CMV antigenemia occurred in 13 recipients. In recipients with severe CMV infection, a significantly weaker immune response was recorded in peripheral blood: fewer lymphoid blast cells (max. 2.4% +/- 0.4%) and large granular lymphocytes (LGL; max. 9.3% +/- 1.4%) were seen than in patients with mild or asymptomatic CMV infection (lymphoid blast cells max. 6.5% +/- 0.8% P < 0.01 and LGLs max. 20% +/- 2.3%, P < 0.05). Thus, a strong immune response with lymphoid activation was associated with clinically good outcome of CMV infection. In heart allograft histology, subendothelial inflammation of small intramyocardial vessels was a characteristic finding during CMV antigenemia compared to CMV-free recipients (at the peak P < 0.01). However, no difference in this mild and short-lived inflammatory response was observed between clinically mild or severe CMV infection. The CMV-linked generalized immune activation and inflammation of the vascular structures might contribute to the initiation of allograft vasculopathy and to the pathogenesis of chronic heart allograft rejection.