Human cytomegalovirus immediate-early mRNA detection by nucleic acid sequence-based amplification as a new parameter for preemptive therapy in bone marrow transplant recipients

Human cytomegalovirus (HCMV) infection was monitored retrospectively by qua litative determination of immediate-early (IE) mRNA by nucleic acid sequenc e-based amplification (NASBA) in a series of 51 bone marrow transplant (BMT ) recipients. The qualitative results for IE mRNA obtained by NASBA were co mpared with those obtained by prospective quantitation of HCMV viremia and antigenemia and retrospective quantitation of DNA in blood (DNAemia) by PCR as well as by qualitative determination of late pp67 mRNA by NASBA, On the whole, of the 39 HCIMV-positive patients tall asymptomatic), HCMV was dete cted in 14 (35.9%) by quantitation of viremia, 15 (38.5%) by detection of p p67 mRNA by NASBA, 32 (82.1%) by quantitation of DNAemia, and 33 (84.6%) by quantitation of antigenemia, while HCMV was detected in 38 (97.4%) patient s by detection of IE mRNA by NASBA, In the immunocompetent host, IE mRNA wa s not detected by NASBA in 100 blood donors or during reactivated infection s in 30 breast-feeding mothers. Likewise, NASBA did not detect IE mRNA in 5 6 solid-organ transplant recipients in the first 21 days after transplantat ion. By using NASBA for detection of IE mRNA as the reference standard for detection of HCMV infection in blood samples, the diagnostic sensitivities were 67.7% for quantitation of DNAemia, 59.0% for quantitation of antigenem ia, 18.3% for detection of pp67 mRNA by NASBA, and 16.0% for quantitation o f viremia. Specificities and negative and positive predictive values were > 90.0, >70.0, and >80.0%, respectively, for all four assays. The mean times to first HCMV detection after bone marrow transplantation were 37.7 +/- 15. 4 days for detection of IE mRNA by NASBA, 39.6 +/- 15.6 days for quantitati on of antigenemia, 40.9 +/- 15.2 days for quantitation of DNAemia, and 43.7 +/- 16.3 or 43.7 +/- 17.5 days for quantitation of viremia and detection o f pp67 mRNA by NASBA, respectively. On the whole, 31 BMT recipients receive d preemptive therapy by using confirmed antigenemia positivity as a cutoff, while 35 patients could have been treated by using NASBA positivity as a c utoff and 31 could have been treated by using quantitation of DNAemia as a cutoff. In single patients, IE mRNA was detected in every episode of active HCMV infection, mostly preceding and sometimes accompanying antigenemia an d DNAemia, whereas pp67 mRNA was detected only concomitantly with the highe st peaks of infection. HCMV IE mRNA detection may represent a useful parame ter for initiation of preemptive therapy in BMT recipients.