GB virus type C/HGV markers in HCV RNA-positive French blood donors: correlation with HCV genotypes and risk factors

BACKGROUND: Exposure to GB virus type C/HGV (GBV-C/HGV) could be determined by detection either of RNA by RT-PCR or of antibodies of the envelope protein E2. STUDY DESIGN AND METHODS: The aim of the study was to determine the proportion of the GBV-C/HGV markers of infection in a blood donor population infected with HCV and to identify GBV-C/HGV routes of transmission that are associated with HCV genotypes and risk factors. RESULTS: Among 306 HCV RNA-positive blood donors, the proportion of GBV-C/HGV RNA-positive donors and anti-E2-positive donors was 19.3 percent (95% CI = 15.0-24.2%) and 42.1 percent (95% CI = 36.6-47.9%), respectively. Exposure to GBV-C/HGV (RNA or anti-E2) was significantly associated with the risk factor of IV drug use. There was a trend toward association with HCV subtypes 1a and 3a, probably because these HCV subtypes are the most frequent in IV drug users. No correlation was observed between ALT elevation and the presence of GBV-C/HGV RNA. CONCLUSION: In persons with HCV infection, IV drug use seems to be a major route of GBV-C/HGV transmission. Precautions taken to avoid HCV infection will probably also decrease GBV-C/HGV transmission.     

High rate of GB virus type C/HGV transmission from mother to infant: possible implications for the prevalence of infection in blood donors

BACKGROUND: Because GB virus type C(GBV-C)/HGV (GBV-C/HGV) is blood-borne and sexually transmitted, persons at risk of infection with such viruses have a high prevalence of GBV-C/HGV markers. However, adults with no apparent risk factors, such as blood donors, frequently are positive for GBV-C/HGV markers. Mother-to-infant transmission could explain this high prevalence, but it has been studied only through small series of GBV-C/HGV-infected mothers co-infected with HCV or HIV. STUDY DESIGN AND METHODS: To determine the rate of mother-to-infant transmission of GBV-C/HGV RNA in women who are HCV- or HIV-negative, a prospective study was performed in a cohort of 288 mothers screened for viral RNA and in the infants born to GBV-C/HGV-infected mothers. RESULTS: Thirteen mothers (4.5%) were found positive for GBV-C/HGV RNA. Of the infants in whom at least one blood sample was collected between the third and the ninth months of life, 89 percent were positive for viral RNA. The majority of these newborns were negative for GBV-C/HGV RNA at birth and positive after the third month. The viral RNA titers of infants born to GBV-C/HGV-infected mothers appeared as elevated as those of their mothers. All the GBV-C/HGV-infected infants remained positive for viral RNA during the entire study period. No clinical events possibly linked to a primary GBV-C/HGV infection were reported in infants. Serum ALT level and blood count remained within normal values throughout the follow-up of all GBV-C/HGV-infected infants. CONCLUSION: The frequency of mother-to-infant GBV-C/HGV transmission is elevated and could explain the high prevalence of GBV-C/HGV markers (viral RNA and E2 antibody) in adults at low risk for blood-borne or sexually transmitted viruses, such as blood donors.     

Hepatitis C virus and GB virus C/hepatitis G virus viremia in Swedish blood donors with different alanine aminotransferase levels

BACKGROUND: Hepatitis C virus (HCV) is a known blood-borne hepatotropic virus for which antibody screening of blood donors is universally practiced. The newly identified GB virus C (GBV-C) and its strain variant hepatitis G virus (HGV) are of unknown pathogenic significance, and screening of blood donors for this agent has not yet been implemented. Polymerase chain reaction (PCR) is the most sensitive method for detecting HCV viremia and is the only method presently available for the diagnosis of GBV-C/HGV infection. STUDY DESIGN AND METHODS: RNA extracts of sera from 577 anti-HCV-negative blood donors (393 with elevated alanine aminotransferase [ALT] levels, 184 with normal ALT levels) were tested with nested PCR for HCV and GBV-C/HGV directed at the 5'-noncoding regions of the two viruses. RESULTS: One donor with elevated ALT was HCV PCR positive. This donor was anti-HCV negative when recruited to the study but subsequently developed anti- HCV. Of the 19 donors with GBV-C/HGV viremia in the series as a whole, 16 belonged to the group with elevated ALT levels and 3 to the group with normal ALT levels; the group difference in prevalence was nonsignificant (4.1% [16/393] vs. 1.6% [3/184; p = 0.20]). Phylogenetic analysis showed 16 of the GBV-C/HGV isolates to be classifiable as subtype 2a and three as subtype 2b. At follow-up 3 to 5 years later, 11 of 18 donors were still viremic. CONCLUSION: There was no significant difference in GBV-C/HGV viremia in the group with elevated ALT levels and the group with normal ALT levels. The frequency and subtype distribution in the present series were similar to those in other Western countries.     

合肥地区献血员庚型肝炎病毒的分子生物学研究

目的了解台肥地区献血员的庚型肝炎病毒(GBV—C／HGV)感染情况。方法应用酶免疫测定法(EIA)和逆转录一套式多聚酶链反应法(RT—PCR)分别检测献血员中的抗-GBV-C/HGV和GBV-C/HGV RNA。结果 献血员中抗-GBV—C/HGV检出率为1．7％(18／1 050)．抗-GBV—C／HGV阳性血清中GBV／HGV RNA占66.7％(12/18)；男性和低年龄组献血员抗-GBV—C／HGV阳性率分别低于女性和高年龄组．两差异有显性(P<0.05)；抗-GBV—C／HGV阴性的献血员有6名转为阳性，2名抗-GBV-C/HGV和GBV-C／HGV RNA阳性的献血员有1名转为阴性。结论GBV—C／HGV在合肥地区献血员中有较高的感染率；献血员中存在着GBV-C／HGV阳性但ALT正常的献血员，应尽快对献血员进行GBV-C／HGV感染指标的检测。     

Evaluation of RNA and E2 antibodies in prospectively followed recipients of hepatitis G virus-infected blood

BACKGROUND: Hepatitis G virus (HGV) has recently been cloned and tests for HGV RNA and envelope antibodies (anti-E2) have been developed. HGV infection is widespread among blood donors worldwide, but the clinical and serologic outcome of transfusion-associated HGV infection has not been fully characterized. STUDY DESIGN AND METHODS: Consecutive blood donors (n = 2210) were investigated for HGV markers (RNA and anti-E2). The recipients of HGV RNA-positive blood were followed for 1 year after transfusion. RESULTS: Forty-two blood donors (1.9%) were positive for HGV RNA. Eight recipients of HGV RNA-positive blood were retrospectively identified within 2 weeks of transfusion and prospectively followed. In four patients, the presence of anti-E2 before transfusion or an early antibody response protected them from reinfection or prevented HGV persistence, while, in the remaining four patients, transient or persistent viremia was detected shortly after exposure. None of the infected recipients had any evidence of liver disease. CONCLUSION: These results do not support the screening of donors to prevent transfusion-associated HGV infection.     

Testing of individual blood donations for HCV RNA reduces the residual risk of transfusion-transmitted HCV infection

BACKGROUND: To allow cost-effective RNA testing with NAT techniques, the national authorities of several countries have planned or already introduced tests of mixed specimens, that is, plasma pools. STUDY DESIGN AND METHODS: High-throughput extraction, amplification, and detection of HCV RNA from individual blood donations were optimized and validated. The feasibility of the method and the frequency of anti-HCV-negative, HCV RNA-positive donations were determined in a prospective study of 27,745 allogeneic and 792 autologous individual donations. RESULTS: The 50- and 95-percent detection limits of the method were determined at 44 IU per mL and 162 IU per mL, respectively (World Health Organization HCV reference material). When 201 HCV RNA-positive sera were taken as a reference, the sensitivity was 97.5 percent. The assay specificity was determined at 99.77 percent. During a 20-month period, two seronegative blood donors tested positive in HCV PCR. The viral load of these donations was 6 x 10(6) and 3 x 10(7) copies per mL, respectively. Thus, the yield of HCV RNA testing in this study was 7. 63 per 100,000 screened donations (95% CI, 1.25-22.07). In both PCR-positive donors, seroconversion was found in subsequent blood samples. CONCLUSION: This study compares the feasibility of single-donation HCV RNA screening, with the detection of a relatively high percentage of window-phase donations, to data reported from groups using HCV RNA testing of plasma pools. The relative yield of NAT of individual donations versus minipools should be directly investigated in the near future.     

Mother-to-infant transmission of GB virus type C/HGV

BACKGROUND: The potentially hepatotropic flavivirus-like virus, GB virus type C (GBV-C)/HGV, has been detected in a few patients with acute and chronic hepatitis and in a certain proportion of blood donors and recipients of blood or blood components. STUDY DESIGN AND METHODS: Sera from 2979 pregnant Japanese women were examined for the presence of GBV-C/HGV RNA by nested RT-PCR. Mothers who were positive for viral RNA and their 34 infants were followed and tested for infection. RESULTS: Of the 2979 women, 32 (1.1%) were positive for GBV-C/HGV RNA. Twenty-six (76.5%) of 34 babies born to these women were positive for the virus when first tested. A significantly higher titer of viral RNA was observed in mothers whose infants were infected than in those whose infants were uninfected (mean +/- SD, 10(6.3 +/- 0.9) vs. 10(4.6 +/- 0.9)/mL; p<0.001). Twenty-three (96%) of 24 babies born to mothers whose serum viral titers were 10(6) mL or more were infected with the virus. Infants delivered by elective caesarean section had a lower risk (OR, 0.13; 95% CI, 0.02-0.82) than those delivered vaginally or by emergency caesarean section. No other risk factors for mother-to-infant transmission were confirmed. CONCLUSIONS: GBV-C/HGV is frequently transmitted from mothers to infants in the general population. The most critical factor is the titer of viral RNA in the maternal serum. By the use of elective caesarean section in women with high titers of viral RNA, vertical transmission of the virus may be lessened.     

Efficacy of HCV core antigen detection during the preseroconversion period

BACKGROUND: The purpose of this study was to compare the performances of HCV core antigen (HCV Ag) testing with HCV RNA detection during the preseroconversion period. STUDY DESIGN AND METHODS: Six HCV antibody (HCV Ab)-negative and HCV RNA-positive blood samples from 6 donors and 135 serial samples from 28 patients who had undergone hemodialysis, collected a mean of 90 days before the detection of HCV Ab, were tested by ELISA for the detection of HCV Ag and by PCR to quantify HCV RNA. RESULTS: Five of the six donors were positive for HCV Ag. The donor with a negative HCV Ag test had the lowest viral load. In the hemodialysis patients, the 43 first specimens of the series were HCV RNA negative. Of the 92 specimens that were HCV RNA positive, 81 (88%) were positive for HCV Ag. Among the 74 samples with more than 10(5) RNA copies, 71 (96%) were HCV Ag positive. Average time from first viremic bleed to first HCV Ag-positive bleed was estimated at 2.0 days and that to first HCV Ab-positive bleed at 50.8 days. CONCLUSION: HCV Ag testing permits the detection of an HCV infection about 1.5 months earlier than the HCV Ab screening tests and an average of only 2 days later than quantitative HCV RNA detection in individual specimens.     

Routine HCV PCR screening of blood donations to identify early HCV infection in blood donors lacking antibodies to HCV

BACKGROUND: Detection of early hepatitis C infection of blood donors is still a major problem for blood transfusion. Common anti-HCV screening assays show differences in sensitivity and specificity. The often mild symptoms of acute hepatitis C also cause difficulties in the identification of early HCV infection. The feasibility and efficacy of routine screening of blood donations for HCV RNA were investigated. STUDY DESIGN AND METHODS: Blood donations (n = 251,737) were screened for HCV RNA over 4 years. RNA extraction, amplification, and detection were done by two commercial HCV PCR kits (HCV Cobas Amplicor and HCV Cobas Amplicor 2.0, Roche Diagnostics). Screening was done by pool testing with a maximum pool size of 40 serum samples. RESULTS: Three donations out of 251,737 were HCV RNA positive and anti-HCV negative. ALT levels of these donations were 271, 32, and 10 U per L. The HCV infection of a fourth HCV RNA-positive donor could not be identified by routine, second-generation HCV EIA (Abbott Diagnostika). In this case, two previous donations were also HCV RNA positive, and three second-generation test systems (Abbott) could not detect anti-HCV, whereas third-generation anti-HCV screening assays detected antibody with different sensitivity. The first HCV RNA-positive donation was identified only by the HCV ELISA 3.0 (Ortho Diagnostic Systems). The results of confirmatory assays like RIBA HCV 3.0 (Ortho) and Matrix (Abbott) indicate a restricted immune response to NS3 only. CONCLUSION: HCV RNA detection by PCR can be carried out routinely in blood donor screening without significant delay of release of the components. The residual risk of transmission can be reduced by identification of early infection, which can lead to an improved safety of blood components. RNA screening can also be advantageous in cases of incomplete or lack of antibody response to HCV.     

Application of a new enzyme-linked immunosorbent assay for detection of total hepatitis C virus core antigen in blood donors

Recent studies have shown that total hepatitis C virus (HCV) core antigen, both free and antibody bound, is an accurate indirect marker of viral replication that can be used in clinical practice. The aim of the present study was to evaluate the performance of a new total HCV core antigen enzyme-linked immunosorbent assay (ELISA) for detection and quantification of total core antigen in blood donors, testing positive for anti-HCV antibodies and for prospective low-risk population screening. A population comprising 257 samples, from blood donors detected reactive for anti-HCV antibodies [137 recombinant immunoblot assay (RIBA) positive and 120 RIBA indeterminate], were tested by using a new total HCV core antigen ELISA. HCV-RNA was quantified by using quantitative polymerase chain reaction (PCR) assays in all RIBA-positive samples and RIBA-indeterminate samples that were positive for the total core antigen. Specificity of the assay was studied in 1070 healthy blood donors negative for anti-HCV antibodies. Compared with quantitative PCR assays, the total HCV core antigen assay showed 97.37% sensitivity. The three HCV-RNA-positive samples, which tested negative for the total core antigen, had a low viral load (< 1.4 x 10(4) IU mL(-1)). All samples with more than 1.4 x 10(4) IU mL(-1) of viral RNA were positive for total core antigen, independent of the HCV genotype. Concentration of total core antigen correlated significantly with those of HCV-RNA (r = 0.614, P < 0.0001). Overall specificity in freshly collected blood donor specimens was 99.63%. Our data indicate that the total HCV core antigen ELISA has a sensitivity close to PCR assays in diagnosing HCV infection in blood donors with anti-HCV antibodies and shows an excellent specificity in volunteer donors. This assay, in combination with anti-HCV antibodies screening tests, could be an alternative to molecular assays for HCV infection screening in blood donors.     

High prevalence of GBV-C/HGV among relatives of GBV-C/HGV-positive blood donors in blood recipients and in patients with aplastic anemia

BACKGROUND: The prevalence of GB virus C (GBV-C)/HGV is high in individuals with parenteral risk factors. The frequency of GBV-C/HGV in blood donors is significantly lower, however it is still far above other parenterally transmitted viruses like HBV and HCV. Therefore, transmission routes apart from parenteral transmission must be considered. STUDY DESIGN AND METHODS: The purpose of the study was to evaluate the prevalence of GBV-C/HGV in blood donors and relatives of GBV-C/HGV-positive and -negative blood donors. Prevalence was also analyzed in aplastic anemia patients. Samples were tested by RT-PCR and partially by ELISA. Positive isolates were sequenced and phylogenetically analyzed. RESULTS: A total of 5733 blood donors were PCR tested and 90 were positive (1.6%). Of these, 98 relatives could be tested. Viremia was found in 14.3 percent and anti-E2 in 29.5 percent, whereas only 1.1 percent of the relatives of PCR-negative donors were viremic and 8.5 percent were anti-E2 positive. Probable virus transmission could be shown in two couples and in six mother-child pairs by sequencing of isolates indicating horizontal and vertical virus transmission, respectively. Recipients of GBV-C/HGV RNA-positive blood products were shown to be infected at a rate of 58 percent (18/31). Aplastic anemia patients were positive at a rate of 32 percent (17/53). CONCLUSION: The high percentage of 14.3 percent of GBV-C/HGV PCR-positive relatives of GBV-C/HGV-positive blood donors suggests intrafamilial transmission. Sequence analyses revealed vertical and horizontal transmission. Although parenteral transmission is highly efficient for GBV-C/HGV (58% of recipients of GBV-C/HGV RNA-positive blood products and 32% of aplastic anemia patients), it appears that sexual and vertical transmission are the most common transmission routes.     

Donor levels of serum alanine aminotransferase activity and antibody to hepatitis B core antigen associated with recipient hepatitis C and non- B, non-C outcomes

BACKGROUND: Hepatitis virus(es) that are neither hepatitis B (HBV) nor hepatitis C (HCV) (non-B, non-C [NBNC]) may be transmitted by transfusion. The present study assessed donor values for alanine aminotransferase (ALT) and antibody to hepatitis B core antigen (anti- HBc) for their association with HCV and NBNC hepatitis outcomes among allogeneic blood recipients. STUDY DESIGN AND METHODS: Data on blood donors and recipients enrolled in the Transfusion- Transmitted Viruses Study in four United States cities from 1974 through 1980 were supplemented by anti-HBc testing of donors and anti-HCV evaluation of recipients. Two statistical approaches estimated the value of these indirect tests in detecting donors associated with HCV seroconversion and NBNC hepatitis in recipients. RESULTS: For HCV cases, donor ALT alone (at > or = 60 IU/L) had a sensitivity and a specificity of 30 and 96 percent, respectively, and anti-HBc alone (at > or = 60% inhibition) had a sensitivity and specificity of 53 and 86 percent, respectively. The two markers combined had a sensitivity and a specificity of 69 and 83 percent. For NBNC hepatitis cases, each measure had low sensitivity (20%) that was not improved by using both (28%) [corrected]. CONCLUSION: The indirect tests proved to be equal in sensitivity to the first-generation anti-HCV tests. The positive predictive power of these indirect tests in the 1980s was sufficient to affect HCV incidence in studies during that period. Improved anti-HCV assays, however, replaced the need for indirect tests. The sensitivity of indirect tests for NBNC hepatitis contributed little.     

A search for hepatitis C virus polymerase chain reaction-positive but seronegative subjects among blood donors with elevated alanine aminotransferase

BACKGROUND: Previous studies reported the existence of hepatitis C virus (HCV) polymerase chain reaction (PCR)-positive but seronegative sera. This is not surprising in the case of window-phase specimens, because PCR can detect HCV RNA many weeks before the appearance of antibody. To determine whether such sera can also be found in chronically infected subjects, a high-risk population of blood donors with elevated alanine aminotransferase was studied. STUDY DESIGN AND METHODS: Freshly frozen plasma from 301 donors with alanine aminotransferase > 100 IU per L was tested with PCR assays that were rigidly controlled for specificity and contamination, and with current and newer versions of assays for anti-HCV. Sera were classified as seropositive if positive in two screening assays and one supplemental assay or if positive in two screening assays and PCR. RESULTS: New versions of screening assays detected 100 percent of seropositive samples. A second-generation immunoblot assay detected 98 percent of seropositive sera, a second-generation recombinant immunoblot assay detected 96 percent, and an enzyme immunoassay for antibody to the envelope protein of HCV detected 98 percent. Fifty-one of 54 seropositive sera were PCR positive. None of the 247 seronegative samples was reproducibly positive on PCR. CONCLUSION: No PCR-positive but seronegative donors were found in this high-risk donor population. The possible benefit of PCR screening of blood donors can be determined only by large-scale comparative testing of donor populations and may be limited to the detection of window-phase infections.     

Safety and efficacy of hepatitis C virus antibody screening of blood donors with two sequential screening assays

BACKGROUND: Reactive samples in hepatitis C virus (HCV) antibody screening of blood donors are currently referred for a confirmatory assay. This scheme is not optimally efficient and is expensive because of the lack of specificity and cost of confirmatory tests, as well as the need to discard false-positive donations. As in some human immunodeficiency virus antibody-confirmatory schemes, the safety and efficacy of confirming anti-HCV with two sequential screening assays were evaluated. STUDY DESIGN AND METHODS: Three combinations of two anti-HCV screening assays were used to test 75,874 blood donors. Results were compared with the routine testing scheme and HCV RNA detection in any enzyme immunoassay-repeatably reactive samples. RESULTS: The use of an alternative screening assay for repeat testing decreased the proportion of enzyme immunoassay-positive donors from 0.28 to 0.05 percent. All samples that were "confirmed" as positive by the standard combination of immunoassays and all HCV RNA-positive samples were detected by the sequential screening assays. No samples that had discordant results on primary and secondary screening assays were confirmed by recombinant immunoblot assay or were found to contain detectable HCV RNA. CONCLUSION: The combination of screening assays for anti-HCV confirmation was as safe as, cheaper than, and nearly as efficient as the standard testing scheme.     

病毒核酸检测在献血者血液筛查中的应用

目的　建立献血者血液混合核酸检测方法 ,调查北京现有检测体系下血液的残余风险度 ,评估核酸检测 (NAT)的必要性和可行性。方法　用世界卫生组织标准品对国产丙型肝炎病毒(HCV)和人免疫缺陷病毒 (HIV)荧光 聚合酶链反应核酸扩增检测试剂进行灵敏度、重复性和精密度试验 ;对 2 0 0 2年 2～ 10月 34373份常规血清学检测 (ALT、HBsAg、抗 HCV、抗 HIV、梅毒抗体 )合格的献血者血样进行HCVRNA和HIV 1RNA核酸扩增分析。采取 2 4人份混合血样测定 ,超离心浓缩病毒 ,Roche核酸提取柱提取病毒核酸。结果　扩增系统能 10 0 %检出 5 0IU/mlHCV及 5 0IU/mlHIV 1标准品核酸 (n =16 ) ;常规血清学检测合格的献血者血液中 ,没有检出HCV或HIVNAT阳性。结论　该核酸检测体系适用于献血者血液病毒筛查 ;北京市血液的病毒安全性已有相当高的保障。为更准确地评估NAT检测项目的可行性和必要性 ,检测标本量尚待增加。