PubMed Health⌕ Search

Biomedical subjects

A Polito

Publications and source records attributed to A Polito.

At least 55 records · Page 3Linked to original sources
PubMed1995

Increased detection of hepatitis C virus infection in commercial plasma donors by a third-generation screening assay.

BACKGROUND: Routine screening of blood donations with second-generation hepatitis hepatitis C virus (HCV) assays has substantially reduced the occurrence of posttransfusion hepatitis. However, following the development of third-generation assays, several studies indicated that these assays may identify HCV-infected individuals who are not identified by second-generation assays. STUDY DESIGN AND METHODS: The sensitivity of a third-generation HCV enzyme-linked immunosorbent assay (ELISA-3) was compared with a second-generation ELISA (ELISA-2) in a side-by-side study of 9936 commercial blood donors. ELISA-reactive specimens were subjected to supplemental analysis by third-generation recombinant immunoblot assay and polymerase chain reaction. RESULTS: ELISA-3 demonstrated greater sensitivity than ELISA-2, detecting 1 additional recombinant immunoblot assay-positive specimen per 2000 tested. ELISA-3 also detected 1 additional HCV-infectious polymerase chain reaction-positive unit among approximately 10,000 units screened. CONCLUSION: The incremental sensitivity achieved with ELISA-3 can be expected to eliminate approximately 20 infectious donations per week among those made by commercial donors in the United States. In accordance with previous studies, most of the improved sensitivity of ELISA-3 derives from its increased detection of anti-c33c (NS3), rather than from the inclusion of HCV antigen NS5.

Blood Donors↗
PubMed1994

Evaluation of indeterminate c22-3 reactivity in volunteer blood donors.

BACKGROUND: Approximately 25 percent of blood donor sera that are repeatably reactive for hepatitis C virus (HCV) on second-generation enzyme immunoassay (EIA 2.0) are indeterminate on second-generation recombinant immunoblot assay (RIBA 2.0), and over 76 percent of these results are due to single reactivity to the HCV recombinant antigen c22-3. STUDY DESIGN AND METHODS: Data are presented on 46 volunteer allogeneic blood donors who were reactive on EIA2.0 and c22-3 indeterminate in RIBA 2.0. Index and follow-up samples were evaluated by using a panel of five synthetic peptide EIAs, a prototype strip immunoblot assay that uses synthetic peptides in addition to recombinant protein (RIBA 3.0), and polymerase chain reaction (PCR) for HCV RNA. RESULTS: All 46 donations had normal alanine aminotransferase values; only 2 (4.3%) reacted for antibody to hepatitis B core antigen. With a panel of 12 synthetic peptides spanning the entire sequence of the c22-3 recombinant antigen, 33 plasmas (72%) reacted to one peptide or none, including 19 plasmas with reactivity restricted entirely to the N-terminal peptide (1-15 amino acids) of c22-3. With RIBA 3.0, 28 donations (61%) were nonreactive, including 25 that reacted with one peptide or none in EIA. Of these 25 plasmas, 18 reacted with the N-terminal sequence only. All 46 index donations were tested by PCR; the single PCR-positive unit reacted with four HCV peptides, was positive by RIBA 3.0, and reacted for antibody to hepatitis B core antigen. Twenty-six index donors were successfully recalled 3 to 7 months after their index donation. None seroconverted to positivity in RIBA 2.0, 1 was nonreactive, and 25 remained positive for c22-3 only. The restricted epitope reactivity in peptide EIA and RIBA 3.0 was maintained over time in all cases. All 26 of the follow-up samples tested negative by PCR. CONCLUSION: On the basis of the restricted peptide reactivity and PCR negativity of index and follow-up samples, it is concluded that the majority of c22-3 RIBA 2.0-indeterminate results are due to nonspecific cross-reactivity to restricted (principally, N-terminal) regions of HCV core antigen.

Alanine Transaminase↗
PubMed1994

Hepatitis C in HIV-infected patients with and without AIDS: prevalence and relationship to patient survival.

BACKGROUND: Limited information is available about the prevalence of hepatitis C virus in patients with human immunodeficiency virus in relation to specific risk factors or about the influence of hepatitis C virus coinfection on survival. This retrospective study addressed these questions. METHODS: The study population consisted of 512 predominantly non-intravenous drug-using male homosexuals, 224 of whom had AIDS. Samples positive for hepatitis C virus antibody by second-generation enzyme immunoassay were further tested by means of strip immunoblot assay, and for hepatitis C virus RNA by means of polymerase chain reaction amplification. A randomly selected set of enzyme immunoassay-negative samples was also tested for hepatitis C virus RNA and, if hepatitis C virus RNA positive, by a second-generation recombinant immunoblot assay. RESULTS: The prevalence of hepatitis C virus infection unaccounted for by intravenous drug use or transfusion was 11.7% by enzyme immunoassay, and 87% of sera positive by enzyme immunoassay were also positive by second-generation recombinant immunoblot assay or hepatitis C virus RNA analysis. Hepatitis C virus RNA was detectable in 53% of enzyme immunoassay-positive samples but in only about 1% of enzyme immunoassay-negative samples. Hepatitis C virus coinfection did not influence survival of HIV-infected patients with or without manifestations of AIDS. CONCLUSIONS: Hepatitis C virus infection in nontransfused, non-intravenous drug-using patients with HIV infection is several times more prevalent than in volunteer blood donors, suggesting homosexual transmission of hepatitis C virus. About half of patients seropositive for hepatitis C virus antibody have detectable hepatitis C virus RNA, and serologically occult hepatitis C virus viremia is rare. Hepatitis C virus coinfection does not appear to adversely influence survival.

Acquired Immunodeficiency Syndrome↗
PubMed1993

A pattern of 5-1-1 and c100-3 only on hepatitis C virus (HCV) recombinant immunoblot assay does not reflect HCV infection in blood donors.

Current criteria for a reactive (positive) interpretation on hepatitis C virus (HCV) recombinant immunoblot assay (RIBA) require > or = 1+ reactivity to at least two of the four HCV antigens present in the assay. Given that 5-1-1 is a subcomponent of c100-3, there is concern that donor samples reacting only with these two antigens (and not with c22-3 or c33c) could be incorrectly classified as positive on the basis of limited reactivity to only one HCV gene product. It is determined that 0.23 to 0.44 percent of HCV enzyme immunoassay-repeatably reactive donor sera demonstrate a pattern of 5-1-1 and c100-3 only on RIBA. Evaluation of six such donor sera using peptide enzyme immunoassays spanning the c100-3 antigen showed highly restricted reactivity to the 5-1-1 N-terminal region of c100-3, in contrast to broad 5-1-1 and c100-3 C-terminal peptide reactivity observed in the majority of donor sera with other positive RIBA patterns. HCV polymerase chain reaction and follow-up serologic evaluations of four of these donors indicated the absence of viremia or evolving seroconversion in all cases. It is concluded that, in the blood donor setting, a pattern of only 5-1-1 and c100-3 reactivity is typically not indicative of HCV infection. To avoid overinterpretation, it is recommended that RIBA grading criteria be revised to require reactivity to two or more HCV-encoded gene products.

Amino Acid Sequence↗
PubMed1993

Hepatitis C virus antibodies in patients with chronic liver disease: ELISA and RIBA HCV strip immunoblot assay results.

In a study using the current first generation Ortho ELISA, a second generation Ortho ELISA, and the RIBA HCV strip immunoblot assay, all patients who were strongly positive for antihepatitis C virus (HCV) on ELISAs (OD490 > 3) were reactive to RIBA for multiple bands. While all ELISA false positive samples had low or intermediate OD490 values, RIBA confirmed HCV reactivity in 50% of the patients reactive to ELISA with a low suspicion of HCV infection, thus suggesting that RIBA HCV strip immunoblot assay will be most useful for patients who react weakly positive or intermediate to ELISA.

Chronic Disease↗
PubMed1993

Epidemiology of hepatitis C among veterans with alcoholic liver disease. The VA Cooperative Study Group 275.

Of 288 patients with alcoholism and various stages of alcoholic hepatitis, 18.4% (53 of 288) reacted serologically for hepatitis C (HCV). An evaluation of the risk factors associated with HCV indicated that parenteral drug use, even in the distant past, increased the risk for infection 10.1-fold (p = 0.0001). Ethnicity was also a significant, independent risk factor. Minorities (i.e., African-Americans or Hispanic-Americans) had a 2.4-fold increase (p = 0.038). Prior blood transfusions, even if multiple, showed only a tendency toward increased infections (p = 0.088) in this population. An interaction between age and contact with parenteral drug users was demonstrated such that the risk of HCV infection was increased by contact with drug users. This was further increased with increasing age (p = 0.006). There was no relationship between HCV reactivity and the severity of the liver disease; however, the liver injury appeared to be accelerated since it occurred at a younger age (p = 0.0001) and was associated with more frequent hospitalizations (p = 0.0005).

Hepatitis C↗
PubMed1992

Improved detection of hepatitis C virus antibodies in high-risk populations.

Sera from 483 patients at high (group 1, n = 313) and lower (group 2, n = 170) risk for exposure to hepatitis C were tested for antibodies to hepatitis C using first-generation (c100-3) and second-generation enzyme-linked immunosorbent assays and four-antigen recombinant immunoblot assay. The second-generation enzyme-linked immunosorbent assay and nitrocellulose-based immunoblot assay differ from c100-3-based systems in the addition of expression products from the NS3/NS4 (c33c, c200) and putative nucleocapsid (c22-3) region of the hepatitis C genome. In group 1, the sensitivity of detection of hepatitis C antibodies was 45%, 55% and 46% by the first- and second-generation enzyme-linked immunosorbent assays and recombinant immunoblot assay, respectively. In group 2, antibodies were detected by each test system in 26%, 32% and 7% of patients, respectively. Most sera (99%) reactive with the first-generation enzyme-linked immunosorbent assay were reactive with the second-generation enzyme-linked immunosorbent assay (in group 1, 89% of these specimens demonstrated reactivity to at least one antigen with the immunoblot assay, compared with only 31% in group 2). An additional 12% (group 1) and 6% (group 2) of specimens demonstrated reactivity with the second-generation enzyme-linked immunosorbent assay only (of these, 75% [group 1] and 9% [group 2] demonstrated reactivity to at least one antigen with the immunoblot assay). Ninety-eight percent of specimens not reactive with both enzyme-linked immunosorbent assay test systems were also nonreactive by recombinant immunoblot assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Hepatocellular↗
PubMed1992

Improved detection of antibodies to hepatitis C virus using a second generation ELISA.

A screening assay for the detection of antibodies to hepatitis C virus (HCV); ORTHO HCV ELISA Test System, Second Generation, was compared with the currently licensed c100-3 based test (ORTHO HCV ELISA Test System). The second generation ELISA differs from the c100-3 based assay in that it detects circulating antibodies to both structural (nucleocapsid) and non-structural (NS3/NS4) HCV proteins. Specimens tested consisted of a cohort of 35 patients diagnosed with non-A, non-B hepatitis (NANBH) and 3971 presumably healthy volunteer blood donors. Second generation ELISA demonstrated significantly greater clinical sensitivity in patients with acute phase NANBH (80% vs. 60%) as well as chronic disease (88% vs. 72%). Additional specimens reactive only in second generation ELISA, demonstrated reactivity to HCV antigens c33c and/or c22-3 in supplemental testing by the Chiron HCV RIBA Assay System. The second generation ELISA also detected additional RIBA reactive volunteer blood donors (0.18% of the population tested) that were nonreactive in first generation ELISA. This data indicated that second generation ELISA would detect approximately 2 additional anti-HCV reactive donors per 1,000 screened. Specificities obtained with this low risk population were 99.6% for first generation and 99.7% for second generation ELISA.

Blood Donors↗
PubMed1992

Comparative evaluation of supplemental hepatitis C virus antibody test systems.

Implementation of routine blood donor screening using anti-hepatitis C virus (HCV) enzyme immunoassay (EIA) has resulted in an urgent need for well-characterized supplemental assays to confirm the presence of HCV antibodies. A comparative study of four commercially available supplemental assays is reported here: first- and second-generation versions of a strip recombinant immunoblot assay (RIBA-1 and RIBA-2), an HCV neutralization EIA, and HCV neutralization plus synthetic peptide EIA. Three hundred sixty-seven blood donor specimens that were repeatedly reactive on HCV EIA were studied. Most specimens (93%) were also evaluated by radioimmunoassay (RIA) with a six-antigen panel, and 60 selected specimens were tested for HCV RNA by the polymerase chain reaction (PCR). RIBA-1 and RIBA-2 gave concordant results with 86 percent of specimens, while an additional 13 percent were correctly classified by RIBA-2 but not RIBA-1. Neutralization EIA alone correctly identified 94 percent of the study group, while the remaining 6 percent required the peptide EIA or the combined neutralization-peptide assay system for correct classification. The RIBA-2 and neutralization-peptide assay system for correct classification. The RIBA-2 and neutralization-peptide assay systems yielded identical results for 86 percent of specimens, and these results were supported by RIA and selected PCR testing. Only 2 specimens (0.5%) were frankly discrepant, while 51 specimens were indeterminate on either (47) or both (4) assays. When either the RIBA-2 or neutralization-peptide assay yielded an indeterminate interpretation, the other system correctly classified the specimen (based on concordance with RIA and PCR data) in a high proportion (92%) of cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Viral↗
PubMed1992

Early antihepatitis C virus response with second-generation C200/C22 ELISA.

Detection of early antibody to hepatitis C virus (HCV) by a new second-generation C200/C22 anti-HCV enzyme-linked immunosorbent assay (ELISA) and a four-antigen recombinant immunoblot assay (4-RIBA) was compared with the first-generation anti-HCV C100 ELISA using sequential serum samples of 9 recipients who were infected with HCV, as detected by polymerase chain reaction after transfusion of blood products. Within 26 weeks after transfusion, 9/9 (100%) recipients seroconverted with C200/22 ELISA, and 6/9 (67%) seroconverted with C100 ELISA. Compared with C100 ELISA, C200/C22 ELISA seroconversion occurred simultaneously in 3 cases, 5-6 weeks earlier in 3 other cases, and 20 weeks earlier in 1 case. Seven of 9 (78%) recipients became positive, and 2/9 (22%) became indeterminate with 4-RIBA. In 8 cases with clinical posttransfusion hepatitis non-A, non-B (PTH-NANB), anti-HCV C200/C22 ELISA seroconversion occurred 2-17 (mean 6) weeks after the onset of hepatitis. In 6 cases of PTH-NANB, anti-HCV C100 ELISA seroconversion occurred 2-26 (mean 9) weeks after the onset of hepatitis. It is concluded that the second-generation C200/C22 ELISA is more sensitive than the C100 ELISA for the detection of antibody during early HCV infection. Indeterminate 4-RIBA results are found in the early phase of HCV infection.

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Interferon alpha therapy in patients with chronic type C hepatitis: changes of serum ALT, anti-HCV & HCV-RNA.

BACKGROUND: After the discovery of type C hepatitis virus, the studies on this virus are extensively progressing. The treatment of this viral infection is also widely progressing. Among many agents, recombinant interferon alpha therapy is generally accepted as an effective single agent. To evaluate the efficacy of interferon and to observe the changes of serum aminotransferase (ALT), antibody to hepatitis C virus (anti-HCV) and HCV ribonucleic acid (HCV-RNA), we treated 10 patients with chronic type C hepatitis for 6 months. METHODS: Patients were randomly divided into 2 groups: 5 patients in group A received interferon and the other 5 in group B received no therapy. Interferon was administered at a dose of 3 million units (MU) daily for the first month and thrice weekly for the following 5 months, and followed up for 2 years. RESULTS: In group A, serum ALT returned to normal in 4: 3, starting at the first month and one at the 3rd month of therapy and maintained normal throughout the follow-up period. In contrast, serum ALT level persistently fluctuated in 4 patients in group B. In one patient, serum ALT returned to normal one and a half years later. Regardless of therapy, serum anti-HCV titer remained unchanged in all patients. However, HCV-RNA, using polymerized chain reaction (PCR), became undetectable in all responded patients and in one untreated patient whose serum ALT returned to normal spontaneously. CONCLUSION: This study suggested that interferon alpha therapy in patients with chronic type C hepatitis may be clinically effective. Our study also indicated that the detection of HCV-RNA by PCR is useful to predict the prognosis of chronic type C hepatitis.

Adult↗
PubMed1991

The use of a recombinant immunoblot assay in the interpretation of anti-hepatitis C virus reactivity among prospectively followed patients, implicated donors, and random donors.

Samples from prospectively followed recipients, their respective donors, and a cohort of random donors were used to evaluate the specificity and efficacy of a recombinant immunoblot assay (RIBA) as an adjunct to anti-hepatitis C virus (HCV) testing by enzyme immunoassay (EIA). RIBA reacted (RIBA+) in 100 percent of patients who developed hepatitis associated with anti-HCV seroconversion documented by EIA and in 100 percent of the EIA-positive (EIA+) donors implicated in these cases. In contrast, RIBA reacted in none of 10 recipients who were EIA+ but did not develop hepatitis, in none of 7 EIA+ patients with hepatitis B or cytomegalovirus infection, in 33 percent of EIA+ donors who were not implicated in hepatitis transmission, and in 37 percent of EIA+ random donors. Hence, the vast majority of EIA+ individuals who have ancillary evidence of HCV infection react on RIBA, whereas the majority of EIA+ individuals in low-risk settings do not react (RIBA-negative, or RIBA-). There was a strong association between RIBA reactivity and the presence of a surrogate marker (elevated alanine aminotransferase [ALT] and/or antibody to hepatitis B core antigen); 43 percent of RIBA+ implicated donors had a surrogate marker as compared to none of 14 EIA+, RIBA- donors. Among EIA+ random donors, 77 percent of those with a surrogate marker were RIBA+, as compared with 29 percent of those without a surrogate marker. In addition, in EIA+ donors, RIBA reactivity correlated with the extent of ALT elevation; 86 percent of those with an ALT greater than 135 IU per L were RIBA+ compared with 18 percent of those with an ALT less than 30 IU per L.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood↗
PubMed1991

Risk factors in hepatitis C virus-infected blood donors.

Risk factors of parenteral and nonparenteral exposure to hepatitis C virus (HCV) infection were studied in 125 blood donors in The Netherlands who were positive for anti-HCV on enzyme-linked immunosorbent assay (ELISA). Risk factors were related to confirmatory test results of four-antigen recombinant immunoblot assay (4-RIBA) and polymerase chain reaction (PCR) of the HCV 5' untranslated region. Twelve (10%) of the 125 anti-HCV C100 ELISA-positive blood donors were 4-RIBA positive. Eleven (92%) of 12 4-RIBA-positive blood donors were PCR positive, and all 113 remaining 4-RIBA-negative or -indeterminate donors were PCR negative. Eleven (92%) of 12 4-RIBA-positive blood donors had a risk factor of parenteral exposure, as compared to 17 (15%) of 113 4-RIBA-negative or -indeterminate donors. The prevalence of confirmed HCV infection among Amsterdam blood donors is calculated at 0.04 percent; parenteral exposure appears to be the major risk factor for HCV infection.

Blood Donors↗