الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The World Health Organization estimates 150 million individuals worldwide are infected with Hepatitis C virus (HCV) (1).Egypt has the highest prevalence of HCV worldwide which is considered a major cause of chronic hepatitis, liver cirrhosis, hepatocellular carcinoma and liver transplantation in the country.
Several methods are currently in use for the detection of HCV. Nucleic acid amplications tests (NAT) allow the detection of HCV much earlier in the course of infection. Unfortunately, NAT is more expensive than ELISA, thus its routine use as a screening tool for blood products or in clinical practice is limited.
The aim of this study was to compare between TaqMan probe technique and SYBR green method regarding sensitivity and specificity in diagnosis and follow up of HCV patients.
The present study included 220 anti-HCV positive patients. All relevant information was collected from patients. The following laboratory investigations were done for each patient; ALT, prothrombin activity and platelet count. The patients were tested for HCV- RNA positivity by the two real time PCR techniques namely SYBR green and TaqMan probe technique.
Out of the 220 anti-HCV positive patients 194(88.2%) were HCV-RNA positive by SYBR Green technique. Amplification was followed by melting curve. In the present study, two different melting curve peaks were observed at 82o C or 88oC, and both were associated with amplification plots. The characteristic band of 251 base pair was obtained in relation to both curves indicating that the reason of obtaining two melting curves was due to different GC content with the same amplicon size.
In the present study HCV-RNA was detected in 196 (89.1%) cases out of 220 chronic anti-HCV positive patients, 156 (70.9%) by TaqMan probe technique compared to 194 (88.2%) by SYBR green technique.
Among the 220 HCV patient 154 (70%) were HCV-RNA positive by both techniques, while 24 (10.9%) were negative by both techniques. On the other hand 40 (18.2%) cases were HCVRNA positive by SYBR green technique only , and 2 (0.9%) by TaqMan probe technique only.
In the present study 40 cases (20.4%) out of 196 chronic HCV cases were HCV-RNA positive by SYBR green and negative by TaqMan probe Technique , 11 cases (27.5%) out of them had a viral load less than 104 IU / ml
On the other hand 29 (72.5%) out of the 40 cases negative by TaqMan technique were of high viral load ranging from higher than 104 IU to higher than 108 IU.
In the present study only two cases out of 196 HCV-RNA positive cases were missed by SYBR green Technique, which can be explained by intermittent RNA positivity in samples with low levels of viral load.
In the present study, no correlation was found between serum HCV RNA positivity either by SYBR green or Taqman real time PCR techniques or with positivity by both techniques and liver parameters including ALT prothrombin activity and platelets count. Meanwhile, normal platelets count was associated with negative HCV RNA by both techniques.
In conclusion, SYBR green could be used for screening HCV RNA positivity. TaqMan probe technique should be confirmed by another molecular technique conventional nested PCR should be tried in cases with discrepancies between both real time PCR techniques.