Determination of Epstein-Barr virus (EBV) DNA load as a Marker to Follow up EBV related Hodgkin’s and non Hodgkin’s Lymphoma Patients using Quantitative Competitive Polymerase Chain Reaction Technique

number: 
2109
إنجليزية
Degree: 
Imprint: 
Medicine
Author: 
Elham A. Alaswad
Supervisor: 
Dr.Nidhal Abdul Mohymen
Dr. Layla Al-Omer
year: 
2008

Abstract:

The Epstein -Barr virus (EBV) is the first Human virus implicated in carcinogenesis. It infects greater than 90% of the world’s populations. The symptomatic consequence of the different susceptibility to EBV related tumors like Hodgkin’s Lymphoma and Non Hodgkin’s Lymphoma, In this study EBV DNA considered as target in the effective diagnosis and monitoring of EBV associated HL and NHL patients. Highly advanced method called Quantitative Competitive PCR (QC-PCR) can be used; it will yield two products that can be distinguished by hybridization with specific oligonucleotide. QC-PCR used to quantitate the EBV DNA load in 18 patients pre and post therapy and 9 healthy individuals.Blood was aspirated from each patient before and after treatment. DNA extracted from these samples by silica based extraction method. Wild type EBV DNA (WT) prepared by transformation of Escherichia coli (E. coli) MM 294 to be used in optimization of EBNA-1 QC-PCR. Linear regression correlation was detected in the estimation of standard dilution curve for WT EBV DNA through amplification of different dilution of this WT EBV DNA, the curve was used to quantitate qualitatively patients EBV DNA copy numbers which is found to be102-4-106 copies /ml of blood.
EBV WT DNA and Internal standard DNA (IS) which will be used to compete with targeted DNA assay was confirmed when copy number detected by ELISA is 102.9 which is nearly same as 10 3 copy number used as input in the amplification reaction . Controls and patients pre and post therapy was estimated by using QC-PCR. The EBV DNA load in controls found to be 7- 1.99 × 103 copy number per ml of blood while the viral load in patients at time of diagnosis ranged from zero to 1.936×109 copy numbers per ml of blood which was significantly differ from controls p = 0.011 . High viral load was detected in 66.7% of HL patients and 44.5 % of NHL patient pre therapy, after chemotherapy, the viral load shows significant decrease by 60%in HL patients and by 100% in NHL patients. P=0.036
Among the 18 patients 55.5% of patients of them were having viral DNA load above the cut off value but after chemotherapy treatment 16.6% of them continue to have high viral DNA load ( Above cutoff value ) compared to control group . We found that 38.3% of the patients showed a response to chemotherapy by decreasing the viral load below cut off value .While 11.1 % continue to have a viral DNA load above cut off value. One patient (5.5%) showed an elevation of viral DNA load after completion of chemotherapy. DNA load estimated by QC -PCR with ELISA detection system considered as valuable promising tumor biomarker in the diagnosis and monitoring of EBV related HL and NHL patients.