QUANTITATION OF CYTOMEGALOVIRUS INFECTION-ASSOCIATED HISTOLOGIC-FINDINGS IN ENDOMYOCARDIAL BIOPSIES OF HEART ALLOGRAFTS

To investigate whether histologic changes in heart allografts may be a ssociated with cytomegalovirus infection, 46 heart transplant recipien ts were monitored for cytomegalovirus. Altogether, 762 endomyocardial biopsy specimens were analyzed. The histologic changes were semiquanti tatively scored from mild to severe, and special attention was paid to inflammatory infiltrates and vascular changes. Cytomegalovirus infect ion occurred in 27 of 46 patients, shown by cytomegalovirus-antigenemi a test. The endomyocardial biopsy findings were investigated in relati on to cytomegalovirus-antigenemia. In the acute phase of cytomegalovir us infection during antigenemia, an inflammatory infiltrate, subendoth elial lymphocytosis, was a characteristic finding in the endomyocardia l biopsy specimens. An intense arteriolar endothelial cell proliferati on and thickening of intima occurred. Long-term histologic findings wi th two years follow-up revealed a cytomegalovirus-associated enhanced vascular intimal thickening that narrowed the lumen of small intramyoc ardial arterioles. Acute rejection episodes were diagnosed in 15 of 27 patients with cytomegalovirus and in 9 of 19 patients free of cytomeg alovirus. The inflammatory infiltrate of acute rejection was more peri pheral to the vessels and did not obscure the findings characteristic to cytomegalovirus infection. The arteriolar endothelial proliferation and intimal thickening were significantly more prominent in cytomegal ovirus infection than in biopsy specimens from patients with rejection only. In long-term follow-up, arteriolar endothelial proliferation de clined, but the intimal thickness persisted and increased. The increas e was significantly higher in patients with cytomegalovirus than in pa tients with rejection. In conclusion, an inflammatory response in vess el walls with alterations of small intramyocardial arterioles leading to narrowing of the vascular lumen of the graft was associated with cy tomegalovirus infection in heart transplant patients.