الفهرس 
Introduction
Acute Lymphoblastic Leukemia (ALL)Only 14 pages are availabe for public view
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Abstract
Huge advances occurred in the treatment guidelines of ALL. The remission rate is mostly around 80% but the risk of relapse remains the most important cause of treatment failure. Relapse occurs due to the persistence of minimal amount of leukemic cells inside the bone marrow of the patient although he seems to be in clinical remission, this termed minimal residual disease ”MRD”. The morphological detection of this small amount of leukemic cells among huge BM normal hematopoietic cells is difficult and with low sensitivity, this explains discrepancy between hematological remission and true molecular remission. The aim of this work is to assess detection of MRD in all patients by real time PCR, allowing early detection of relapsed cases with very high sensitivity than that obtained by morphologic assessment alone, and stratification of all patients according to the MRD assessment as a prognostic marker independent and superior to other risk factors in ALL. In this study 30 patients were included, 15 females and 15 males of newly diagnosed ALL, with an age ranged from 1 to 25 years with the mean age 8.16 and sample standard deviation 6.48. BM aspirate samples were withdrawn from patients twice, first sample at time of diagnosis and second sample after patients received induction chemotherapy. The diagnosis of all was based on both clinical and laboratory aspects which includes: Morphological, cytochemical and immunophenotyping diagnosis. The DNA extraction and molecular assessment was performed for both the diagnosis BM sample and after induction chemotherapy BM sample. IgH or TCR gene rearrangement of the all patients was studied using RQ- PCR at time of diagnosis and after induction chemotherapy. Quantitative real time PCR with clone specific primers combined with a general detection method using SYBR Green1 dye which gives a bright fluorescence when bound to a double stranded DNA was used to detect the clonal IgH /TCR gene rearrangements. The study revealed the following: Regarding the clinical data, the commonest clinical presentation was fever found in 63.3% patients followed by lymphadenopathy in 53% of patients and 50 % were presented with pallor. Laboratory assessment of the study group patients at diagnosis evaluating the haemogram and bone marrow, revealed TLC with mean ± SE= (44.18+ 15.30).and low Hb level with mean ± SE = (7.9+ 0.38).and low plt count with mean ± SE = (81.3+ 14.57).The bone marrow blast percent ranged from 24% to 98 % . Cytochemical analysis of the study group all bone marrow smears showed that SBB (Sudan black-B) were negative in all of the 30 all patients. PAS (Periodic acid –Schiff) showed positivity in (56.7%)Patient risk classification were done according to NCI (National cancer institute sponsored workshop 1993) in the basis of their age and WBC at diagnosis and separated into high risk group (50 %) and standard risk group (50%). The study revealed that 3 out of 4 of the MRD negative cases by PCR were of patients stratified as high risk group according to age and WBC, while only one of the MRD negative cases was of patients stratified as standard risk group according to age and WBC. Immunophenotyping study allowed classification of studied patient into precursor Pre B-ALL (73.3%), Common B-ALL (10 %) and T-ALL (16.7%). After induction chemotherapy, patients BM was evaluated and examined morphologically for remission status based on 5 % blast index. The morphological non-remission status (> 5% blast) were identified in 8 cases (26.7 %), while 22 cases (73.3%) were identified as morphologic remission (<5% blast) and RQ-PCR for IGH/TCR gene rearrangements were done for the 30 patients .Out of the 22 cases who showed morphological remission there were 18 cases (81.8 %) with MRD positive (i.e. not in molecular remission) and 4 cases (18.2 %) were MRD negative (i.e. molecular remission). Patients showed non remission morphologically (8 cases) were confirmed to be MRD positive. Relating patients variables as ”age, gender, TLC and all immunophenotype” to the results of MRD by RQ-PCR, none of them have been identified as predictors of MRD risk. Conclusion from our study we concluded that application of PCR in detection of MRD by using IgH/TCR gene rearrangements allows better definition of remission status based on MRD assessment by molecular techniques rather than remission based on morphological and clinical assessment. The molecular assessment of MRD allows evaluation of efficacy of chemotherapy and early detection of relapse thus gives a chance of intervention and managing treatment plans. from our work, there is no relation between MRD results and risk stratification in all according to age and WBC at diagnosis; this confirms that detection of MRD of leukemic cells can be considered a superior prognostic marker of relapse independent from conventional prognostic factors.