The case for cytomegalovirus prophylaxis in solid organ transplantation

Comparison of pp65 antigenemia, quantitative PCR and DNA hybrid capture for detection of cytomegalovirus in transplant recipients and AIDS patients

The cytomegalovirus (CMV) antigenemia assay has been used frequently for rapid diagnosis of CMV infection, and antigenemia threshold values are recommended for triggering preemptive therapy. Hybrid capture of CMV's DNA and quantitative polymerase chain reaction (qPCR) are increasingly being adopted for early detection of CMV. The performance of the antigenemia assay, qPCR in plasma and hybrid capture in leukocytes were compared in 110 immunocompromised patients (38 bone-marrow transplants, 50 renal transplants and 22 AIDS patients). The most sensitive test was hybrid capture for transplants, while antigenemia and the qPCR showed similar performance for patients with AIDS. QPCR and hybrid capture thresholds requiring antiviral therapy were calculated using a receiver-operating-characteristic curve for antigenemia values corresponding to 2 positive cells for bone-marrow transplants and to 10 positive cells for renal transplants and AIDS patients. These threshold values varied with the group of patients considered, with corresponding sensitivities higher than 86% and specificities higher than 76% for hybrid capture, and sensitivities higher than 61% and specificities higher than 75% for qPCR in plasma. Hybrid capture in leukocytes can substitute for antigenemia in the case of transplants, and qPCR in plasma can substitute for it in the case of AIDS patients.

Cytomegalovirus hepatitis in normal and immune compromised hosts

Liver biopsies of six previously normal hosts (Group I, NH), with recent or acute CMV infection, and autopsy liver samples of four immunocompromised hosts (Group II, ICH) with overwhelming CMV infection have been studied in an occasional survey. In both groups, portal tract involvement, bile duct inflammation, liver cell degeneration and parenchymal granulomas were present. In Group I, a randomly distributed hepatitis with predominant involvement of the periportal areas was present, including sinusoidal arrays of lymphocytes and lymphohistiocytic aggregates. In contrast, in Group II liver cell damage was more extensive and the inflammatory infiltration only scarce. Intracellular viral inclusion bodies were found only in Group II, both in liver cells and in bile duct epithelium. Morphologically, the presence of viral inclusion bodies correlated well with the immunohistologic demonstration of CMV specific "late" (CMV-LA) or structural antigens. In addition, CMV-specific "early" (CMV-EA) or non-structural antigens were present in liver cell nuclei of 2/6 NH and 2/4 ICH. The possible relations between the inflammation and the lack of structural antigenic viral expression are discussed. It is concluded that ICH with CMV infection have a prominent cytopathogenic effect and widespread lytic viral infection in the liver in the absence of adequate immunologic reactivity, whereas the opposite is found in NH.