الفهرس 
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Abstract
AML is a hematopoietic stem cell disorder characterized by a block in differentiation of hematopoiesis resulting in growth of a clonal population of neoplastic blast cells with loss of normal hematopoietic function. Furthermore, AML is heterogenous regarding the disease outcome which is dependent upon several factors, including patient age, karyotype, mutational status, and comorbid conditions. The accurate diagnosis of AML is important for appropriate treatment and management. Morphology and cytochemistry are not sufficiently precise to diagnose all cases of AML. MPO is considered to be one of the main markers of myeloid lineage, and plays an important role in diagnosis of AML.
MPO is a heme protein exclusively synthesized by normal neutrophil and monocyte precursor cells. MPO functions not only in host defense by mediating efficient microbial killing but also can contribute to progressive tissue damage.
Conventional cytochemical staining, electron microscope cytochemistry, immunocytochemistry and flow cytometry have been used to assay the activity or expression of MPO. Measurement of plasma MPO by ELISA is considered very sensitive, usually allowing protein detection in the nanogram to picogram range, and highly specific as it is not influenced by enzyme activity or inhibitors.
The aim of this work was to assess plasma MPO level in de-novo AML patients in relation to clinical and laboratory parameters and to evaluate it s prognostic impact on the disease outcome.
The present study was carried out on 30 newly diagnosed AML patients attending the Hematology/ Oncology Unit of Ain Shams University Hospitals. They were 16 males and 14 females with a male to female ratio of 1.1:1, and their ages ranged from 17 to 64 years with a mean age of 35.2±12.7yrs. All patients were subjected to complete history taking, thorough clinical examination and laboratory investigations including: CBC, BM aspiration with examination of Leishman stained PB and BM smears, immunophenotyping and assessment of plasma MPO level using Quantikine Human MPO ELISA kit. Follow up of these patients was done over a period of 6 months. Ten healthy subjects were included as a control group.
The present study demonstrated a highly significant plasma MPO level in AML patients when compared to control group. Neither the patients’ clinical nor laboratory parameters showed a significant difference in relation to the plasma MPO level, with the exception of the initial Hb concentration, as well as cytoplasmic MPO detected by FCM, where both revealed a highly significant association with plasma MPO level.
Regarding disease outcome, patients were divided into two groups; good and poor where 21 (70%) patients showed good outcome and 9 (30%) patients showed poor outcome. Although mean value of plasma MPO level was much higher in patients with poor outcome over patients with good outcome, a significant statistical difference could not be achieved.
Concerning the patients’ OS, 21 (70%) patients showed a survival of 24 weeks, while the remaining 9 (30%) patients showed a survival of <24 weeks. No significant difference was detected in this study upon comparing patients’ OS to plasma MPO concentration.
On comparing patients’ clinical and laboratory parameters to disease outcome, no significant statistical difference was detected except for presence of lymphadenopathy and the patients’ OS where 90.5% of patients with good prognosis were presented without lymphadenopathy and had an OS 24 weeks.
A discrepancy in the MPO level among different AML FAB subtypes was observed in this study, where patients classified as M0 and M6 had lower MPO levels than patients classified as M2, M3 and M4.
Study of diagnostic performance and ROC curve analysis of plasma MPO in AML assigned 780ng/ml as the best cutoff value for discriminating between AML patients and control subjects with a 66% sensitivity and 71% specificity.
In conclusion, the significantly elevated plasma MPO level in AML patients suggests a diagnostic value for plasma MPO in AML, yet impact on the disease outcome could not yet be verified. Quantitation of MPO in plasma by ELISA is considered quite specific and sensitive in diagnosis of AML. It also overcomes the disadvantages of the conventional methods used for MPO detection.