Generation Enzyme-linked Immunosorbent Assay Research Articles

Low prevalence of hepatitis C virus infection in Amerindians from Western Venezuela

Previous studies have not found hepatitis C virus (HCV) infection in Amerindians from Western Venezuela. A survey of 254 Bari and Yukpa natives aged 10-60 years (mean +/- SD age = 35 +/- 5.4 years) from four communities, two Bari and two Yukpa, in this area were studied to assess the prevalence of antibodies to HCV (anti-HCV) and HCV RNA among these indigenous populations. Serum samples were examined initially for anti-HCV by a four generation enzyme-linked immunosorbent assay (ELISA). Reactive samples were then tested using a third generation recombinant immunoblot assay (RIBA-3). Viral RNA was investigated in all immunoblot-reactive samples by a nested polymerase chain reaction (PCR) method. Six (2.3%) of 254 natives were positive by ELISA, one (2.2%) of these reactive samples were positive by RIBA, and four (1.5%) were indeterminate. Only two (0.8%) were positive by PCR, corresponding to 1 (2.1%) of 47 inhabitants of a Yukpa community and to 1 (2.2%) of 45 subjects of a Bari community. Iatrogenic is thought to play a role in acquisition of the infection. The findings indicate a HCV focus of low endemicity and are compatible with a low degree of exposures of the natives to the virus. Studies are necessary to assess the risk factors for infection in these Amerindians.

Hepatitis C and Risk of Lymphoma: Results of the European Multicenter Case-Control Study EPILYMPH

Increasing evidence points toward a role of hepatitis C virus (HCV) infection in the etiology of malignant lymphomas. However, previous epidemiologic studies were limited in size to establish an association between HCV infection and specific lymphoma subtypes. We performed a large, multicenter, case-control study to address this question. The study comprised 5 European countries and included newly diagnosed cases of any lymphoid malignancy recruited between 1998 and 2004. Controls were matched to cases by 5-year age group, sex, and study center. In-person interviews were conducted to collect data on demographic, medical, and family history as well as environmental exposures. Serum samples of 1807 cases and 1788 controls (excluding human immunodeficiency virus-positive and organ-transplantation subjects) were screened for HCV infection using an enzyme immunoassay. Positive as well as randomly selected negative samples were subjected to HCV RNA detection and HCV genotyping. HCV infection was detected in 53 (2.9%) lymphoma cases and in 41 (2.3%) control subjects (odds ratio [OR], 1.42; 95% confidence interval [CI]: 0.93-2.15). Restricted to individuals who tested positive for HCV-RNA (indicating persistent infection and active viral replication), the OR was 1.82 (95% CI: 1.13-2.91). In subtype-specific analyses, HCV prevalence was associated with diffuse large B-cell lymphoma (OR, 2.19; 95% CI: 1.23-3.91) but not with chronic lymphocytic leukemia or follicular, Hodgkin's, or T-cell lymphoma. The sample size was not sufficient to derive any conclusions for rare lymphoma entities such as splenic marginal zone lymphoma. These results support a model that chronic HCV replication contributes to lymphomagenesis and establish a specific role of HCV infection in the pathogenesis of diffuse large B-cell lymphoma.

Evaluation of a new fourth generation enzyme-linked immunosorbent assay, the LG HIV Ag–Ab Plus, with a combined HIV p24 antigen and anti-HIV-1/2/O screening test

The LG HIV Ag–Ab Plus, a new fourth generation diagnostic assay for HIV infection, was evaluated in comparison to the Enzygnost HIV Integral, an established fourth generation HIV assay. The LG assay showed 100% sensitivity with 109 samples with anti-HIV-1, anti-HIV-2 or anti-HIV-1 group O reactivity. It also detected correctly all 51 positives on three BBI performance panels, slightly outperforming the Enzygnost HIV Integral, which detected 50. The specificity of the LG HIV Ag–Ab Plus was 99.9% with 999 sera from healthy blood donors, which was slightly inferior to the performance of the Enzygnost HIV Integral, which had 100% specificity. The LG assay showed 100% specificity with 81 specimens with underlying diseases including hepatitis B, demonstrating a low risk of cross-reactivity with other infections. The reduction of the diagnostic window by the LG HIV Ag–Ab Plus, compared to a third generation HIV assay, was 6.3 days. The LG assay also showed sufficiently high intra-person and inter-person reproducibility. The overall performance of this new fourth generation HIV assay was adequate for screening and diagnosis of HIV infection.

Proteomic: New advances in the diagnosis of rheumatoid arthritis

Background Rheumatoid arthritis (RA) is a chronic autoimmune disease affecting the joints. A number of novel treatment modalities have been introduced over the past years, and rheumatologists are now attempting to institute optimal treatment in recent-onset arthritis. To facilitate diagnosis during the early stages of disease, when often not all clinical symptoms are manifest, a good serological marker is needed. Methods Antibodies directed to citrullinated proteins provide this ability. The most sensitive assay for detecting these antibodies is the so-called anti-cyclic citrullinated peptide, second generation (CCP II) enzyme-linked immunosorbent assay (ELISA). Results The diagnostic and prognostic potential of anti-CCP antibodies and the availability of a fully automated assay method lead us to conclude that the test is satisfactory for routine use as a serological marker of RA. In addition, we consider the potential of multiplex autoantibody assays, including miniaturized, high-throughput microarray technology, to improve diagnosis and prognostication in early onset arthritis patients.

Anti-scl-70

Objective: To develop an overview focusing on the utility of anti-Scl-70 autoantibody determinations in the rheumatic diseases. Methods: Articles from electronic literature searches were retrieved, critiqued and data were extracted and pooled on anti-Scl-70 (topoisomerase I) in relation to history, optimal tests used for its detection, sensitivity, specificity, positive and negative likelihood ratios, indications, interpretation and pitfalls. Results: Anti-Scl 70 antibodies are very useful in distinguishing systemic sclerosis (SSc) patients from healthy controls, from patients with other connective tissue diseases, and from unaffected family members. Among patients with SSc, anti-Scl-70 positivity is useful in predicting those at higher risk for diffuse cutaneous involvement and interstitial fibrosis/restrictive lung disease, though the latter has not been universally observed. Of the four different techniques notably immunodiffusion, immunoblotting, immunoprecipitation and enzyme-linked immunosorbent assay (ELISA) used to assay anti-Scl-70, immunodiffusion has been the most extensively validated. ELISAs are somewhat less specific than other techniques, especially in distinguishing SSc patients from those with other rheumatic diseases, though newer generation ELISAs have been developed to overcome the problem of low specificity inherent with the traditional techniques. As of yet, the need for serial testing of anti-Scl-70 has not been established. Conclusions: Evidence-based guidelines suggest that anti-Scl-70 antibodies are very useful in the diagnosis and clinical management of SSc patients and also to establish prognosis in these patients, particularly those with diffuse skin involvement.

The Diagnostic Utility of Anti‐cyclic Citrullinated Peptide Antibodies, Matrix Metalloproteinase‐3, Rheumatoid Factor, Erythrocyte Sedimentation Rate, and C‐reactive Protein in Patients with Erosive and Non‐erosive Rheumatoid Arthritis

Objective: To compare the diagnostic utility of laboratory variables, including matrix metalloproteinase-3 (MMP-3), anti-cyclic citrullinated peptide (CCP) antibodies, rheumatoid factor (RF), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) in patients with erosive and non-erosive rheumatoid arthritis (RA). Methods: We assembled a training set, consisting of 60 patients with RA, all fulfilling the revised criteria of the American College of Rheumatology. A commercial enzyme linked immunosorbent assay (ELISA) was used both to test for anti-CCP antibodies (second generation ELISA kit) and MMP; RF were detected by latex-enhanced immunonephelometric assay. CRP was measured by latex turbidimetric immunoassay. Results: The levels of anti-CCP antibody titers and ESR were significantly higher in patients with erosive disease than those in non-erosive RA patients (p < 0.001 and 0.0341) respectively. Moreover, a higher frequency of elevated titers of anti-CCP antibodies was found in RA patients with erosions compared to patients with non-erosive RA (78.3% vs. 43.2% respectively). The ROC curves of anti-CCP passed closer to the upper left corner than those other markers and area under the curve (AUC) of anti-CCP was significantly larger than AUC of other markers (0.755 for anti-CCP, 0.660 for ESR, 0.611 for CRP, 0.577 for RF, and 0.484 for MMP-3 female). A positive predictive value was higher for anti-CCP antibodies in comparison to other markers. We did not find significant statistical correlation between anti-CCP antibody titers and inflammatory markers such as ESR or CRP. However, we confirmed the correlation of elevated titers of anti-CCP antibodies and RF in both groups of patients whereas the degree of correlation was more significant in non-erosive patients. Conclusion: The results of our study suggest that the presence of elevated anti-CCP antibody titers have better diagnostic performance than MMP-3, RF, CRP and ESR in patients with erosive RA.

Lichen planus and hepatitis c virus infection: an epidemiologic study

The reported prevalence of hepatitis C virus (HCV) infection in patients with lichen planus (LP) shows variations from different regions. The aim of this study was to investigate the prevalence of HCV infection in patients with LP, in Diyarbakir region of Turkey. A total of 128 patients with LP and 128 healthy controls were detected for HCV infection, using a third generation enzyme-linked immunosorbent assay. Eight of 128 patients (6.25%) with LP were found to have anti-HCV antibodies, whereas only one patient (0.78%) in control group was found to have anti-HCV antibodies. A statistically significant difference was found between LP and control group (p < 0.001). In conclusion, the coexistence of HCV infection and lichen planus is more than coincidental, and it is appropriate to screen all patients with lichen planus for HCV infection.

Frequency of antibodies against the hepatitis C virus in patients with hepatic cirrhosis in Yucatan, Mexico.

To report the prevalence of antibodies against the hepatitis C virus (anti-HCV) in a group of patients with hepatic cirrhosis (HC). A prospective transversal and descriptive study was carried out from March 1998 to May 1999. Study subjects were 153 patients; 117 (76%) male and 36 (24%) female, diagnosed with HC. They were attended at the General Hospital Agustin O'Horan and at Regional Research Center Doctor Hideyo Noguchi, in Merida, Yucatan, Mexico. A clinical-epidemiologic questionnaire completed by interview was used for data collection. Anti-HCV were detected using a 2nd generation enzyme-linked immunosorbent assay (ELISA-2). To confirm diagnosis, a second generation recombining immunoblot assay (RIBA-2) was used. Hepatitis B surface antigen (HbsAg) and antibodies against the hepatitis B core antigen (anti-HBc) were determined using ELISA. The presence of anti-HCV was related to the epidemiologic variables of study subjects. The prevalence of anti-HCV was obtained and the frequency of the characteristics obtained by interview were compared among the positive and negative patients through the chi 2 test and the Fisher's exact test, as needed. Among patients with HC (35/117 (30%) male and 14/36 (39%) female), 32% were positive to anti-HCV. Alcoholism was present in all seroreactive males and absent in all positive females (p < 0.001). Data obtained through an interview were not associated with seropositivity. Anti-HBc was found in 16% of patients positive to anti-HCV and in 12% of seronegatives (p = 0.69). The prevalence found was greater than previous reports in the general population in the Yucatan Peninsula (1.3%). The high prevalence of anti-HCV in these patients suggests that HC is more frequently associated with HCV in Yucatan, Mexico than hepatitis B. Alcoholism probably acts as a cofactor for the development of HC in males.

Synthetic peptide-based immunoassay as a supplemental test for HCV infection

Introduction: Hepatitis C virus (HCV) is a single strand RNA hepatotrophic virus infecting 170 millions around the world and 20% of Egyptian blood donors. Although there has been significant improvement in the enzyme immunoassays (EIAs) in population screening of HCV infection, the development of a low variability, easy to automate and inexpensive supplemental test to support the current immunoassays was of a major concern to several laboratories. Objectives: In the current study, we embarked on a systematic study to analyze by DNA sequencing several HCV isolates to identify conserved core protein sequences and perform explorative analysis of five synthetic peptides from the core/E1 region in anti-HCV antibody assays. Methods: We designed four synthetic-core specific peptides and an E1-specific peptide. These peptides were used to screen HCV antibodies in sera of 100 HCV positive patients and 100 HCV negative subjects and compared the results with those obtained by the commercial systems based on second and third generation enzyme-linked immunosorbent assays. Results: Our results showed that all peptides detect HCV antibodies in infected sera to varying degrees. The synthetic peptide (a.a. 21–40) of the core protein had 99% sensitivity, 100% specificity and was highly reproducible. Conclusion: The above findings make this core peptide a candidate product for developing a supplemental test for chronic HCV infection in the Egyptian population.

The seroprevalence of varicella zoster antibodies in Behçet's and other skin diseases.

The purpose of this study was to investigate the association of the varicella zoster virus (VZV) IgG, and IgM antibodies with Behçet's and other skin diseases (group 1: recurrent aphthos stomatitis, fungal infections, psoriasis; group 2: vitiligo, lichen planus). Twenty eight patients with Behçet's disease (BD), and 117 patients with dermatological disorders other than BD were evaluated for specific VZV IgG and IgM antibodies by using a third generation enzyme-linked immunosorbent assay (ELISA). The Mantel Heizshel chi2 method was used to adjust the confounding of age and sex of the patients. The serological positivity for VZV IgG and IgM antibodies in BD was not statistically different from other skin diseases. When we considered the age of the patients, chi2 = 2.64, CI (0.27-1.65), odds ratio (1, 1.25, 2.21) (p = 0.10) and when we considered the sex of the patients, chi2 = 0.31, CI (0.81-1.28), odds ratio (1, 1.45, 1.41), (p = 0.57).

Timing and interpretation of tests for diagnosing perinatally acquired hepatitis C virus infection.

The diagnosis of hepatitis C virus (HCV) infection in children born to HCV-infected women is based on serologic assays and HCV RNA measurement by PCR. Interpretation of the results of these tests is hampered by uncertainty about the age distribution of loss of maternal antibody and the sensitivity and specificity of PCR at different ages. On the basis of findings from a recent vertical transmission study, we estimated the posttest probability of a child's being infected or uninfected under several test result scenarios. These estimates may assist clinicians in assessing the likelihood of infection in an individual child and in using the currently available assays cost effectively.

Hepatitis C virus infection mimicking systemic lupus erythematosus: study of hepatitis C virus infection in a series of 134 Spanish patients with systemic lupus erythematosus.

To determine the prevalence and clinical significance of hepatitis C virus (HCV) infection in patients with systemic lupus erythematosus (SLE). We investigated 134 consecutive SLE patients (121 women and 13 men; mean age 35 years) who fulfilled the 1982 revised criteria for SLE of the American College of Rheumatology. Two hundred consecutive volunteer blood donors were also studied. Serum from all patients and controls was tested for antibodies to HCV (by third generation enzyme-linked immunosorbent assay and confirmed by third generation recombinant immunoblot assay [RIBA-3]). Antibodies to HCV were present in 18 patients with SLE (13%) and in 2 (1%) of the blood donors studied. Among the anti-HCV-positive group, HCV infection was confirmed (by RIBA-3 and polymerase chain reaction) in 15 SLE patients (11%) and in the 2 blood donors (1%) (P < 0.001). We observed a lower frequency of cutaneous SLE features (40% versus 76%; P = 0.01) and positivity for anti-double-stranded DNA (anti-dsDNA) (33% versus 81%; P < 0.001), and a higher frequency of hepatic involvement (93% versus 2%; P < 0.001), low C4 levels (73% versus 39%; P = 0.002), low CH50 levels (73% versus 44%; P = 0.03), and cryoglobulins (60% versus 22%; P = 0.02) in SLE patients with HCV infection compared with SLE patients without infection. The prevalence of HCV infection in SLE patients was higher than in blood donors from the same geographic area. SLE HCV-positive patients showed a lower frequency of cutaneous SLE features and anti-dsDNA antibodies, and a higher prevalence of liver involvement, hypocomplementemia, and cryoglobulinemia. HCV testing should be considered in the diagnosis of SLE, especially in patients who lack the typical cutaneous features of SLE or who have low titers of autoantibodies, cryoglobulinemia, or liver involvement.

Hepatitis C virus prevalence among an immigrant community to the southern Amazon, Brazil.

A community-based random survey was conducted in a southern Brazilian Amazonian county aiming to investigate hepatitis C virus (HCV) infection prevalence and the association of demographic variables and lifestyle behaviours. Seven hundred eighty individuals were serologically screened with a third generation enzyme-linked immunosorbent assay to detect anti-HCV antibodies between 1994/1995. Positive samples were retested for confirmation with a line immunoassay (LIA, Inno-LIA HCV Ab III). Most of these subjects were low income and came from southern Brazilian states (65.8). Two point four percent (IC 95% 1.2%- 4.6%) of the subjects had LIA-confirmed anti-HCV antibodies reactivity. The age-specific prevalence of HCV antibodies slightly increased with age, with the highest prevalence after the age of 40 years. The results of multivariate analysis indicate a strong association between HCV antibodies and previous surgery and history of intravenous drug use. There were no apparent association with gender, hepatitis B virus markers, blood transfusion, and sexual activity. Mean time living in Amazon did not differ between confirmed and negative anti-HCV individuals. The present data point out an intermediate endemicity of HCV infection among this immigrant community to the Amazon region and that few HCV infected participants presented known risk factors.

Assessment of the Prognostic Relevance of Serum Anti-p53 Antibodies in Epithelial Ovarian Cancer

The objective of this study was to assess the prognostic relevance of preoperative serum anti-p53 antibodies in epithelial ovarian cancer. These autoantibodies were detected with a new generation enzyme-linked immunosorbent assay in blood samples preoperatively drawn from 86 patients with this malignancy. Serum anti-p53 antibodies were found in 3 (10.0%) of the 30 patients with stage I–II and 15 (26.8%) of the 56 patients with stage III–IV epithelial ovarian cancer (P= 0.09). We assessed in detail 44 patients with stage III–IV disease who underwent six cycles of first-line platinum-based chemotherapy. A pathological complete response at second-look was achieved by none of the 15 patients with serum anti-p53 antibodies compared to 24.1% of the 29 patients without autoantibodies (P= 0.09). However, the preoperative serum anti-p53 antibody status had no prognostic relevance for progression-free survival and survival. In conclusion, the assessment of preoperative serum anti-p53 antibodies seems to have a limited clinical value in the management of patients with advanced epithelial ovarian cancer.

Universal precautions prevent hepatitis C virus transmission: A 54 month follow-up of the Belgian multicenter study

The isolation of anti-hepatitis C virus (HCV) in hemodialyzed (HD) patients has been repeatedly advocated to prevent nosocomial HCV transmission. We evaluated the incidence of seroconversion for HCV in Belgian HD patients, and demonstrate the complete prevention of HCV transmission by adherence to the universal precautions advocated by the Centers for Disease Control (Atlanta, GA, USA). All (N = 963) HD patients from 15 units, none of which isolates anti-HCV positive patients, were tested by a second or third generation enzyme-linked immunosorbent assay (with confirmation by a second- or third-generation recombinant immunoblot assay or the polymerase chain reaction) every 18 months from May 1991 to November 1995. Follow-up was available in 488 patients (drop-outs resulting from death or transplantation mainly). The yearly incidence of seroconversion for HCV over the initial 18 months was 1.41%, with evidence suggestive of nosocomial HCV transmission. Universal precautions were therefore reinforced. The incidence of seroconversion subsequently fell to 0.56% and 0%, respectively (P = 0.014), despite the facts that the average transfusion load and the proportion of patients with dialyzer reuse or with monitors disinfected after each session did not change significantly. We conclude that the strict enforcement of universal precautions fully prevents HCV transmission to HD patients. The isolation of anti-HCV positive patients is not warranted.

Second generation hepatitis C virus antibody-positive rate in children: investigation of the route of hepatitis C virus infection in children with no history of transfusion.

Hepatitis C virus (HCV) antibody and HCV-RNA screening was undertaken in 1864 children, aged from 0 to 15 years who did not have a history of transfusion. Anti-HCV was tested by the second generation enzyme-linked immunosorbent assay (ELISA). HCV RNA was examined by reverse transcriptase-nested polymerase chain reaction (PCR). Two of the 1864 children were positive for serum HCV RNA. They had no history of transfusion, no episodes of horizontal transmission, but the mother in each case was positive for serum HCV RNA, implying mother-to-infant infection. Eleven children who were positive for HCV antibody with low values and negative for serum HCV RNA were classified as belonging to the high bovine milk (composed primarily of casein)-specific IgG4 value group. This suggested that many of the children who were falsely positive for HCV antibody using ELISA had antibodies to casein.

Hepatitis C and G Virus Infection and Liver Dysfunction After Allogeneic Bone Marrow Transplantation: Results From a Prospective Study

Acute and chronic liver dysfunction is common after allogeneic bone marrow transplantation (BMT). Although toxicity, graft versus-host disease (GVHD), and viral infections are the major causes, etiologic diagnosis is difficult and often remains unknown. We conducted a prospective study to establish the role of the infection with both the hepatitis C virus (HCV) and the recently discovered hepatitis G virus (HGV) in liver dysfunction after BMT. From January 1994 to December 1995, 59 patients who had undergone an allogeneic BMT at our institution were enrolled in the study. HGV-RNA was identified in serum by nested polymerase chain reaction (PCR), and HCV was studied by the presence of second generation enzyme-linked immunosorbent assay (ELISA)-antibodies and HCV-RNA by nested PCR. HGV-RNA was detected in 25 patients (42%) (before BMT in 18 and after BMT in 7). HCV-RNA was present in 12 patients (20%) (before BMT in 11 and after BMT in one). The presence of HCV-RNA and HGV-RNA was clearly associated with a previous history of blood transfusions. No significant association was found between viral infection and acute liver toxicity. Some degree of liver dysfunction was present 6 months after BMT in 25 of 40 evaluable patients (62%). Long-term liver dysfunction was more common among patients infected with HCV alone (3 of 4) or with both HCV and HGV (3 of 3) than in those infected with either HGV alone (eight of 13) or with no virus infection (10 of 20). We found a high prevalence of HGV infection in our BMT population. However, no role for HGV in liver disease could be established in this study, and the relationship between HGV infection and liver dysfunction requires further clarification.

Hepatitis C and G Virus Infection and Liver Dysfunction After Allogeneic Bone Marrow Transplantation: Results From a Prospective Study

AbstractAcute and chronic liver dysfunction is common after allogeneic bone marrow transplantation (BMT). Although toxicity, graft versus-host disease (GVHD), and viral infections are the major causes, etiologic diagnosis is difficult and often remains unknown. We conducted a prospective study to establish the role of the infection with both the hepatitis C virus (HCV) and the recently discovered hepatitis G virus (HGV) in liver dysfunction after BMT. From January 1994 to December 1995, 59 patients who had undergone an allogeneic BMT at our institution were enrolled in the study. HGV-RNA was identified in serum by nested polymerase chain reaction (PCR), and HCV was studied by the presence of second generation enzyme-linked immunosorbent assay (ELISA)-antibodies and HCV-RNA by nested PCR. HGV-RNA was detected in 25 patients (42%) (before BMT in 18 and after BMT in 7). HCV-RNA was present in 12 patients (20%) (before BMT in 11 and after BMT in one). The presence of HCV-RNA and HGV-RNA was clearly associated with a previous history of blood transfusions. No significant association was found between viral infection and acute liver toxicity. Some degree of liver dysfunction was present 6 months after BMT in 25 of 40 evaluable patients (62%). Long-term liver dysfunction was more common among patients infected with HCV alone (3 of 4) or with both HCV and HGV (3 of 3) than in those infected with either HGV alone (eight of 13) or with no virus infection (10 of 20). We found a high prevalence of HGV infection in our BMT population. However, no role for HGV in liver disease could be established in this study, and the relationship between HGV infection and liver dysfunction requires further clarification.

Vertical transmission of hepatitis C virus: an epidemiological study on 2,980 pregnant women in Italy.

The risk of mother-to-infant transmission of hepatitis C virus (HCV) varies according to the population studied and the tests used. Aim of the current study was to investigate HCV vertical transmission rate in children born to 30 HCV positive/HIV negative pregnant women in Italy. We investigated the potential vertical transmission of HCV by identifying HCV antibody seropositive pregnant women, by analyzing HCV-RNA in the peripheral blood using PCR and by prospectively following their offspring until 24 months of age. During the third trimester, 2,980 consecutive pregnant women were examined for anti-HCV antibodies by a second generation Enzyme-Linked Immunosorbent Assay (EIA2) and re-assayed by a second generation Recombinant Immunoblot Assay (RIBA2). A total of 32 mothers (1.07%) were positive for EIA2 test; 30 out of 32 had a reactive confirmatory RIBA2 test for HCV. All anti-HCV positive mothers were negative for HIV. These 30 mothers and their 30 babies formed the study cohort. Of the 30 anti-HCV positive mothers, 10 were also positive for serum HCV-RNA by PCR. All the babies born to the 30 anti-HCV positive mothers were initially negative for HCV-RNA (cord blood specimens), but three babies became positive at three months of age and remained positive thereafter. These babies had been born to 3 of the 10 mothers with viremia during the third trimester of pregnancy. These results suggest that HCV vertical transmission is possible in 10% of anti-HCV positives and in about 33% of the HCV-RNA seropositive mothers.

Genotypes of hepatitis C virus in Nigeria.

A pilot survey of hepatitis C virus (HCV) infection in Nigeria was carried out on healthy adult blood donors and children of preschool age. Sixteen of 200 (8%) donors were positive for antibodies using a second generation enzyme-linked immunosorbent assay (ELISA) but all of the children were negative. Supplementary testing of the ELISA-positives using a recombinant immunoblot assay (RIBA-2) confirmed the presence of antibody in four and two others were indeterminate. Four of the anti-HCV-positive sera and one found positive by ELISA but which was negative by RIBA-2 were found to be positive for HCV RNA using reverse transcriptase-polymerase chain reaction (RT-PCR) and primers specific for the 5' untranslated region (5'UTR) of the HCV genome. The NS5 and core regions also were amplified and the PCR products from all three regions were sequenced. Sequences from the 5'UTR could be divided into two groups: one group comprised three isolates with greater than 95% sequence identity with published sequences of genotype 1 and the other comprised two isolates with greater than 93% sequence identity with genotype 4. Analysis of three sequences amplified from the NS5 region confirmed this assignment to genotypes 1 and 4. Pairwise comparisons of the NS5 region sequences with representatives of 1a, 1b, 1c (for the first group) and 4a-4h (for the second group) show the first group to include subtypes classifiable as 1a and a novel sequence and the second group to include a novel sequence within genotype 4. Sequence analysis of the core region was consistent with this interpretation. These data confirm the presence of at least two major HCV genotypes in Nigeria (genotypes 1 and 4) and we report two novel sequences which have been designated provisionally as genotypes 1d and 4i.