الفهرس 
Introduction and aim of the workOnly 14 pages are availabe for public view
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Abstract
In acute lymphoblastic leukemia the level of minimal residual disease (MRD) during clinical remission is one of the most powerful prognostic indicators .Correlative studies have demonstrated that detection of MRD by flow cytometric or polymerase chain reaction (PCR) analysis of leukemiaspecific markers is strongly associated with subsequent relapse and a relative resistance to chemotherapy. Therefore, MRD assays are being introduced into treatment protocols as a tool to evaluate treatment response and aid in the selection of therapeutic strategies.Immunological and molecular techniques have been used to measure minimal residual disease. The conventional bone marrow examination, used to assess hematological remission, can only detect at best 35% leukemia blasts in an otherwise normal bone marrow. Molecular analysis of clone or leukemia specific genes by polymerase chain reaction (PCR) enables detection of 1 leukemia cell in 100.000 to 500.000 normal cells. Commonly used colonal molecular markers includes heavy chain immunoglobulin (IgH) or T cell receptor gamma (TCRgc? sgene rearrangement detected in 80% to 60% of the patients respectively. Aim of the work: The aim of this study is detection and quantitation of MRD by using realtime PCR for by IgH or TCRgc sin childhood acute lymphoblastic leukemia after induction and during maintenance chemotherapy. Methods: This study included 25 children diagnosed as acute lymphoblastic leukemia admitted to hematology and oncology unit in Mansoura university children hospital. They were subjected to: Clinical history, Clinical examination: laboratory investigations: Complete blood count, Bone marrow aspiration and examination, Immunophenotyping. Real time quantitative PCR follow up will be performed using primers specific for clonal antigen receptor gene rearrangements of the heavy chain immunoglobulin (IgH) or T cell receptor gamma (TCRgc? sat diagnosis and at the end of 1st month, 6th months and 18th month after start of chemotherapy using bone marrow samples. Results: Comparison of relapse free survival (24 months) according to MRD level at 1st month; between PCR MRD1 positive (RFS=25%) and PCR MRD1 negative (RFS=100%). There was a statistical significance between both groups (P=0.048 and P=0.040). Non of PCR MRD1 negative patients relapsed . Comparison of relapse free survival (24 months) according to MRD level at 6th month; between PCR MRD6 positive (RFS=0%) and PCR MRD6 negative (RFS=100%). There were a statistical significance between both groups (P=0.048 and P=0.040). The occurrence of individual relapses was not always predicted by PCR. We found that patients who had a relapse had higher level of PCR MRD1 and MRD6 levels (>102) (cases No. 2, 4, 5, 15) and their survival was 0% while patients who stayed in remission PCR MRD1 And MRD6 levels mainly (<102) (cases No. 1, 6, 9, 13 and 18) and their survival was 100% . The applicability and sensitivity of realtime PCR for MRD detection by different probes, using IgH gave positive results in 61.5% as IgH1 (38.5%), IgH2 (23%) while TCRg gave only positive results in 10% Conclusion: PCR MRD1 levels and PCR MRD6 can predict relapse and survival. patients who had a relapse had higher level of PCR MRD1 and MRD6 levels (>102). There was a clonal stability in gene rearrangement at diagnosis and relapse.