Evaluation of COBAS AmpliPrep nucleic acid extraction in conjunction with COBAS AmpliScreen HBV DNA, HCV RNA and HIV-1 RNA amplification and detection.

BACKGROUND AND OBJECTIVES: This report describes the evaluation of the COBAS AmpliPrep instrument for fully automated generic nucleic acid extraction in conjunction with hepatitis B virus (HBV) DNA, hepatitis C virus (HCV) RNA, and human immunodeficiency virus (HIV)-1 RNA COBAS AmpliScreen amplification and detection using serial dilutions of the WHO international standards (IS) and the PeliCheck reference panels. MATERIALS AND METHODS: Serial diluted samples of the WHO IS and the PeliCheck reference panels were tested 24 times to determine the HBV DNA, HCV RNA and HIV-1 RNA detection limits by Probit analysis. The existence and extent of cross-contamination were assessed by testing alternating high titre HBV DNA-positive and -negative samples. The specificity of the AmpliPrep-AmpliScreen test for HBV was determined by testing 232 minipools consisting of six donations, all negative for HCV/HIV-1 nucleic acid testing (NAT) and HBsAg. In addition, a HBV genotypes A-G panel was tested. RESULTS: The respective 95% detection limits (and 95% CI) on the WHO IS and on the PeliCheck reference panels were 6.7 (4.3-13) IU/ml and 123 (68-301) gEq/ml for HBV DNA, 23 (11-106) IU/ml and 126 (84-233) gEq/ml for HCV RNA, and 187 (108-422) IU/ml and 183 (108-434) gEq/ml for HIV-1 RNA. Based on the WHO IS and the PeliCheck reference panels, no significant differences in sensitivity for HBV and HCV were found between AmpliPrep and the licensed MultiPrep extraction method. The sensitivity of AmpliPrep-AmpliScreen for HIV-1 was probably twofold lower as compared to the MultiPrep-AmpliScreen method. No cross contamination was observed. All 232 minipools were HBV NAT-negative. The AmpliPrep-AmpliScreen test for HBV detected HBV genotypes A-G with equal sensitivity. CONCLUSIONS: The AmpliPrep instrument combined with the AmpliScreen assays for HBV, HCV and HIV-1 is robust and suitable for NAT donor screening. The sensitivity criteria for HIV-1 and HCV as defined by the Paul Ehrlich Institute and the Food and Drug Administration for minipool NAT screening are met by this system. SINGLE SENTENCE SUMMARY: Generic COBAS AmpliPrep nucleic acid extraction in conjunction with COBAS AmpliScreen detection for HBV, HCV and HIV-1.

High prevalence of hepatitis G virus after liver transplantation without apparent influence on long-term graft function.

BACKGROUND/AIMS: Hepatitis G virus is a recently characterized transfusion-transmissible RNA virus. Its pathogenicity remains to be established. We studied its prevalence in liver transplant patients and assessed the long-term influence on the liver graft. METHODS: Thirty-nine adult patients without hepatitis B or C were included; median follow-up was 8 years (range 1-17). Serum samples from before and late after transplantation were investigated for the presence of HGV-RNA. HGV-RNA was detected by cDNA-PCR, using primers from the NS3 region of the viral genome. The latest available yearly liver biopsy was assessed in a coded fashion according to established histological criteria. The outcome in the HGV-positive patients was compared with the outcome in the HGV-negative patients with respect to liver tests and liver histology. RESULTS: The prevalence before and after transplantation was 15.4 and 43.6%, respectively. Liver test results and liver histology did not differ between the HGV and non-HGV groups. In both groups more than 50% of the patients showed normal histology. Mild portal and/or lobular inflammation tended to be more prevalent in the non-HGV group (no statistical difference). CONCLUSIONS: HGV infection is highly prevalent in liver transplant patients. In the absence of co-infection with hepatitis B or C virus, no long-term negative influence on the graft occurs.