Evaluation of human cytomegalovirus gene expression in thoracic organ transplant recipients using nucleic acid sequence-based amplification

Background Human cytomegalovirus (CMV) infection is a major cause of morbid ity in transplant patients. Early diagnosis and treatment have been shown t o improve outcome. We evaluated the suitability of CMV immediate early, ear ly, and late gene expression detected by nucleic acid sequence-based amplif ication (NASBA) as markers of CMV infection. Methods. Blood samples were taken immediately before transplant and every o ne to two weeks after transplantation for 12 weeks from 50 patients undergo ing thoracic organ transplantation. CMV-NASBA was performed and results com pared with serology, CMV pp65 antigenaemia (CMV-AG) and the development of clinical CMV infection. Patients received '''preemptive" anti-CMV therapy w ith ganciclovir based on the CMV-AG results. Results. CMV immediate early and early gene expression were detected in 87 and 47%, respectively, of patients without other evidence of CMV infection. CMV late gene expression had a sensitivity of 97% for infection (compared with 83% for CMV-AG P=0,06) and a specificity of 93% (compared with 100% P= NS), Late gene expression occurred at the same time as CMV antigenaemia but 1.1 weeks earlier than the threshold of antigenaemia (CMV-AG>10) used to i nitiate preemptive therapy. Conclusion. NASBA provided a standardized tool for the detection of CMV tra nscripts with a greater sensitivity than the standard antigenemia test. Det ection of immediate early and early gene transcripts was not specific for s ubsequent infection. CMV late gene expression determined by NASBA was an ac curate and early marker of CMV infection. Detection of CMV late gene expres sion could be used to trigger "preemptive" anti-CMV therapy.