Evaluation of an enzyme immunoassay for hepatitis C virus antibody detection using a recombinant protein derived from the core region of hepatitis C virus genome

This study was undertaken to evaluate an enzyme immunoassay (EIA) for hepatitis C virus antibody detection (anti-HCV), using just one antigen. Anti-HCV EIA was designed to detect anti-HCV IgG using on the solid-phase a recombinant C22 antigen localized at the N-terminal end of the core region of HCV genome, produced by BioMérieux. The serum samples diluted in phosphate buffer saline were added to wells coated with the C22, and incubated. After washings, the wells were loaded with conjugated anti-IgG, and read in a microtiter plate reader (492 nm). Serum samples of 145 patients were divided in two groups: a control group of 39 patients with non-C hepatitis (10 acute hepatitis A, 10 acute hepatitis B, 9 chronic hepatitis B, and 10 autoimmune hepatitis) and a study group consisting of 106 patients with chronic HCV hepatitis. In the study group all patients had anti-HCV detected by a commercially available EIA (Abbott(r)), specific for HCV structural and nonstructural polypeptides, alanine aminotransferase elevation or positive serum HCV-RNA detected by nested-PCR. They also had a liver biopsy compatible with chronic hepatitis. The test was positive in 101 of the 106 (95 percent) sera from patients in the study group and negative in 38 of the 39 (97 percent) sera from those in the control group, showing an accuracy of 96 percent. According to these results, our EIA could be used to detect anti-HCV in the serum of patients infected with hepatitis C virus.

In vitro induced antibody production for the diagnosis of herpes simplex virus infection in immunosuppressed patients

We developed and evaluated a specific test for herpes simplex virus (HSV) infection based on the secretion of HSV-specific antibodies by lymphocytes stimulated in vitro with HSV-1 antigens. The in vitro induced antibody production (IVIAP) test was used for the diagnosis of HSV infection in 43 seropositive selected subjects: 9 healthy subjects (controls), 30 symptomatic patients (26 of them immunocompromised and 4 immunocompetent) and 4 patients with varicella zoster infection. Anti-HSV antibodies were detected by an immune assay using an anti-human IgG peroxidase conjugate. The test showed a sensitivity of 93 per cent (15/16) and specificity of 92 per cent (1/13) which were confirmed by positive culture or clinical and laboratory follow-up. One AIDS patient had a false-negative result and one false-positive result (1/9) was obtained among the healthy subjects. All patients infected with varicella zoster virus were negative to the IVIAP test. The test is rapid, inexpensive, easy to interpret and can be used for the diagnosis of HSV infections, especially in immunocompromised patients.