ABSTRACT
Recently, the availability of an anti-core antigen [Ag] monoclonal antibody allowed the development of an enzyme linked immunosorbent assay [ELISA] that showed the presence of hepatitis C virus [HCV] core Ag in peripheral blood of HCV- infected patients. The aim of our study was to determine the specificity and sensitivity of HCV-core antigen assay in serum compared to serum HCV-RNA by qualitative and quantitative PCR in diagnosis of HCV infection in children. Our study was performed on fifty children complaining of acute and chronic liver diseases, attending the pediatric department, National Liver Institute, Menoufiya University from May 2002 to October 2003. They were divided into two groups. Group one consists of 25 children with HCV infection, 20 of them with chronic infection and the other 5 with acute infection. Group two consists of 25 children with liver diseases other than HCV as a control group [to with autoimmune hepatitis, 4 with HBV infection, 4 with hepatosplenic shistosomiasis, 4 with fulminant hepatic failure, 2 with venous outflow block and one with congenital hepatic fibrosis]. In our study HCV core antigen assay showed a specificity of 100 % [25/25] compared to PCR in the diagnosis of HCV infection. However, HCV-antibody testing showed 72 % specificity compared to PCR. While sensitivity of HCV core antigen was 88% among all cases, 80 % [44 in diagnosis of acute HCV cases and 90 % [18/20] in diagnosis of chronic HCV cases in children and showed total validity of 94 % in comparison to that of PCR. The 3 negative cases defected by PCR and not by HCV-core Ag were with low viremia with the highest one being 11000 IU/ml. In comparison, HCV- Ab detected one out of the 5 acute cases and 19 out of the 20 chronic ones. In our study, by applying the ROC curve it was found that the best cutoff value of viremia is 15 X 10[3] IU/ml. At that level of HCV- RNA, the sensitivity and specificity of HCV- core Ag assay are 100 %
Conclusion: HCV core antigen assay may obviate many of the problems encountered with the serologic assay of HCV infection and be used in diagnostic settings as if shows comparable specificity and sensitivity to PCR. Moreover, it is simple, of less cost and not prone to contamination as PCR technique. It is also of special value in the window phase of HCV infection before seroconversion. Further study on a larger number of children with HCV infection is recommended to prove its value and its relation to the level of HCV viremia