الفهرس 
Hepatitis C virusOnly 14 pages are availabe for public view
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Abstract
CHC infection is a global public health problem, with approximately 170 million persons chronically infected. They are at an increased risk of morbidity and mortality, due to liver cirrhosis, HCC, and extra hepatic complications that develop. Adequate screening of individuals with an active infection is a crucial issue in areas where HCV is endemic. In clinical practice, diagnosis of HCV infection in hospitals is usually based on the detection of anti-HCV in the serum. Several anti-HCV assays have been used as the common serological marker for HCV infection for more than 20 years. Detection of anti-HCV is a simple, inexpensive and rapid test but has a low sensitivity in the first 6 - 8 weeks of infection or in several clinical conditions, such as chronic immunosuppression or hemodialysis. It is also unable to distinguish between active and past infection.
Detection and quantification of HCV RNA is the essential tool in the management of chronic HCV infected patients. However, PCR based assays are rather expensive and relatively complex so the availability of an accurate, cheaper test would be important.
The detection of the HCVcAg can be used for the detection of HCV infection in the window period by a conventional ELISA because it appears in the serum about 1 day following the appearance of HCV RNA, and 45 days sooner than HCV antibodies. It is also more stable after freezing or heating than HCV RNA. An early HCVcAg decrease down to undetectable levels within four weeks may be predictive of a sustained virologic response (SVR) after commencing combination therapy, and a detectable HCVcAg at 12 weeks has a positive predictive value of 100% for non-SVR.
The aim of the present work was to investigate the use of HCVcAg assay for diagnosis of hepatitis C infection.
This study was carried out through the period from December 2011 to November 2012. It included 150 subjects referred to some private laboratories in Alexandria for different investigations and for follow up of hepatitis C IFN therapy. Both sexes were included and their ages ranged from 18 to 76 years. Subjects were subdivided according to the presence or absence of HCV RNA into 2 groups; (1) 75 HCV RNA negative subjects and (2) 75 HCV RNA positive subjects. Out of the 75 HCV RNA positive subjects 30 under IFN therapy were selected. Viral response was monitored by quantitative PCR and the antigen testing three months after start of treatment. A sheet was fulfilled for each subject in this study, including the important personal data (e.g. age, sex, history of blood transfusion and history of elevated ALT Level).
from each subject, blood sample was collected and tested for HCV RNA by real time PCR (Cobas ampliprep/Cobas Taqman), HCV core antigen, anti HCV antibodies, by ELISA and liver enzyme ALT by Roch / Hitachi Cobas C system.
Summary and Conclusion
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The main results of the study are:
1. Out of 75 HCV RNA positive subjects, 73(97.3%) were positive and 2(2.7%) were negative for HCVcAg, while among 75 HCV RNA negative subjects only one was positive for HCVcAg. The results were statistically significant (p<0.05). The diagnostic sensitivity and specificity, of the HCVcAg assay compared to the HCV RNA test were 97.3 %, and 98.6%, respectively.
2. In the two cases negative for HCVcAg, the HCV RNA was below 103 IU/ml
3. Among 75 HCV RNA positive subjects, 14 (18.7%) aged 20 –, 57 (76.0%) aged 40- and 4 (5.3%) were aged ≥60 years of age. Out of 75 HCV RNA negative subjects, 4 (5.3%) aged <20, 38 (50.7%) aged 20 –, 29 (38.7%) aged 40- and 4 (5.3%) were aged ≥60 years of age. There was a statistically significant increase in age in relation to HCV RNA positivity (p<0.05).
4. The mean ALT level was significantly higher among HCV RNA positive subjects than HCV RNA negative subjects (59.53 ± 25.12 vs 26.87 ± 16.76)
5. No statistical significant relation between the HCV antibody and HCVcAg (p> 0.05) with slight agreement between the two tests (Kappa = 0.021).
6. A statistical significant relation between the HCV antibody and HCV RNA (p≤ 0.05). The sensitivity and specificity, of the HCV Ab assay compared to the HCV RNA test were 97.3 %, and 44.0%, respectively with moderate agreement (Kappa = 0.413).
7. HCV Ab and HCVcAg had no statistical significant relation with age, sex or ALT levels.
8. In follow up subjects, there was a significant statistical relation between the presence of HCVcAg and HCV RNA after and before treatment. The sensitivity of the detection of HCVcAg in HCV RNA positive subjects was 81.25 % and specificity was 100.0 % after 3 months of treatment. The overall agreement between HCVcAg and HCV RNA among follow up subjects was perfect (kappa =0.802).
from the study it could be concluded that:
1- There was a statistical significant increase in age in relation to HCV RNA positivity, with the highest positivity rates among those aged 40- years.
2- A statistical significant relation was found between HCVcAg and HCV RNA, with a perfect agreement between the two tests.
3- HCVcAg was not detected in subjects with HCV RNA level below 103 IU/ml.
Recommendation
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RECOMMENDATIONS
1- HCVcAg had a perfect agreement with HCV RNA testing. In a resource limited setting, where HCV RNA testing might be impossible, HCVcAg testing would allow for a compromise.
2- HCVcAg testing should be considered as an integral part of the HCV screening program.
3- All anti-HCV positive results should be refluxed to HCVcAg testing, to confirm or exclude an active infection and additional HCV RNA testing should only be required if HCVcAg would be negative.
4- HCVcAg may be more reliable test than HCV antibodies assays in diagnosis of HCV in specific group of populations, when HCV antibody may be false negative as in immunocompromised patients and those on hemodialysis.
5- Further studies are required to test if kits manufactured with higher sensitivity of HCVcAg could be an alternative tool to HCV RNA to monitor antiviral therapy.