Effect of primer selection on estimates of GB virus C (GBV-C) prevalence and response to antiretroviral therapy for optimal testing for GBV-C viremia.
GB virus C (GBV-C; also called hepatitis G virus) is a common cause of infection associated with prolonged survival among HIV-infected individuals. The prevalences of GBV-C viremia vary widely in different studies, and there has been poor agreement among different laboratories performing GBV-C RNA detection in quality control studies. To determine the optimal method of measuring GBV-C RNA in clinical samples, samples obtained from 939 HIV-infected subjects were studied using reverse transcription (RT)-PCR methods amplifying four separate regions of the GBV-C genome. Primers amplifying the E2 coding region were 100% specific; however, their sensitivity was only 76.6%. In contrast, primers amplifying three additional conserved regions of the GBV-C genome (the 5' nontranslated region and the nonstructural protein-coding regions 3 and 5A) were more sensitive but produced higher rates of false-positive results. Using low-specificity primer sets influenced the significance of association between GBV-C viremia and response to antiretroviral therapy. Using a quantitative GBV-C RNA method, the GBV-C RNA concentration did not correlate with baseline or set point HIV RNA levels; however, a correlation between negative, low, and high GBV-C RNA levels and increasing reduction in HIV RNA following antiretroviral therapy was observed. Subjects with both GBV-C E2 antibody and viremia had significantly lower GBV-C RNA levels than did viremic subjects without E2 antibody. These studies demonstrate that accurate detection of GBV-C RNA by nested RT-PCR requires the use of primers representing multiple genome regions. Analyses based on testing with single primers do not lead to reliable conclusions about the association between GBV-C infection and clinical outcomes.
Souza
I E
IE
Department of Internal Medicine, SW54-15, GH, University of Iowa, 200 Hawkins Drive, Iowa City, 52242, USA.
Allen
J B
JB
Xiang
J
J
Klinzman
D
D
Diaz
R
R
Zhang
S
S
Chaloner
K
K
Zdunek
D
D
Hess
G
G
Williams
C F
CF
Benning
L
L
Stapleton
J T
JT
D019380:Anti-HIV Agents / Q000627:therapeutic use; D000914:Antibodies, Viral / Q000097:blood; D017931:DNA Primers; D004359:Drug Therapy, Combination; D005260:Female; D018178:Flaviviridae Infections / Q000188:drug therapy* / Q000453:epidemiology* / Q000821:virology; D029407:GB virus C / Q000235:genetics / Q000302:isolation & purification*; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy; D006801:Humans; D015995:Prevalence; D012367:RNA, Viral / Q000032:analysis / Q000302:isolation & purification; D018894:Reverse Transcriptase Inhibitors / Q000627:therapeutic use; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology; D014766:Viremia / Q000188:drug therapy* / Q000453:epidemiology* / Q000821:virology
D019380:Anti-HIV Agents; D000914:Antibodies, Viral; D017931:DNA Primers; D012367:RNA, Viral; D018894:Reverse Transcriptase Inhibitors; D014759:Viral Envelope Proteins; C107619:glycoprotein E2, GB virus C