Relationship Between Immunological Characteristics And Prognosis In Patients With Acute Myeloid Leukemia

BackgroundAcute myeloid leukemia (AML) is a hematopoietic stem cell disease characterized by a block in differentiation of hematopoiesis and with its biological characteristics of highly heterogeneous. A large variety of clinical and biological parameters, including age of the patients,cytogenetics, immunophenotyping and clinical characteristics have been claimed to correlate with response to treatment and survival in AML. Age and cytogenetics are considered the most important prognostic factors that affect the prognosis of acute myeloid leukaemia patients. The prognosis is very poor in elderly patients with AML, however, the clinical outcome varies greatly in the patients with same age. Prognosis and cytogenetics of AML are tightly linked. Risk stratification based on cytogenetics divides patients into three main groups, those with favorable, intermediate, and unfavorable cytogenetics,which has important value to guide therapeutic decisions and predict treatment response or survival in AML. However, adult AML chromosomal abnormality rate is about 52%-78% by conventional cytogenetic analysis at present. There are still about 45% of cases with normal karyotype,and some patients failed to get the cytogenetic information because of lack of Mitotic figures. Thus, stratified diagnosis can not be done on those patients with AML. As a result, additional markers with prognostic significance are needed to identify clinical relevant subgroups of AML patients with a normal karyotype and those who failed to get the cytogenetic information. In addition to cytogenetics, flow cytometric immunophenotyping is a routinely used technique for the diagnosis and characterization of AML. It is a widely used method, complementing morphology, cytochemistry and karyotype analysis to make more precise diagnosis and classification of AML. Evaluation of surface and intracellular antigens with a panel of antibodies allows identification of specific cell lineage as well as maturation stage in the leukemic process. The diagnostic value of immunophenotyping in adult AML is clear, particularly in the differentiation of AML from lymphoid leukemias. However,the prognostic relevance of surface antigen expression is still unclear. Its prognostic value in AML remains controversial. Several reports suggested a relationship between some antigens (e.g., CD7, CD11b, CD13,CD14, CD15, CD34, CD56, CD117,HLA-DR) and prognosis, while others have failed to show any significant association between immunophenotype and the response to chemotherapy and survival. To our best knowledge,domestic clinical research(sample size>300cases) is few. In this report, we examined the prognostic significance of immunophenotypic markers in patients with de novo AML diagnosed and treated at our institute. We also compare the results with other known prognostic features.Objective1.To investigate the immunophenotyping of patients with acute myeloid leukemia and its association with the clinical effect.2. To investigate the cytogenetics features of patients with acute myeloid leukemia and its association with the clinical effect.3.To explore the relationship between age, WBC, PLT, Hb and the clinical effect in acute myeloid leukemia. Methodsl.From January 2000 through December 2009,510 untreated patients with de novo AML diagnosed in a single institute were enrolled in this study. Immunophenotyping,cytomorphology angd cytochemistry were performed in all patients. Chromosome analysis were performed in 465 patients.2.The data of the included cases were studied restrospectively. The clinical characteristics of patients, including:Age, immunophenotyping, cytogenetics,WBC, Hb and PLT were recorded, and the possible prognos tic factors were analyzed.3. Prognostic indicators:(1)the response to chemotherapy:complete remission (CR) rate;(2) survival time;(3)early death.4. Statistical analysis:ALL the data were analyzed by SPSS software 13.0 version.Relationship of marker expression and other factors to patient's response to treatment were was analyzed withχ2 test (Pearson Chi-Square or Fisher's Exact Test). On the basis of univariate analysis, the variables(P<0.05) were analyzed with binary Logistic regression analysis. The survival time was analyzed with Kaplan-Meier method. Cox's proportional harzard regression model was used for overall survival. Significance was defined as P<0.05.Results1. General material characteristics of the patients.Of the 510 de novo acute myeloid leukemia, male 295 cases(57.8%), female 215 cases (42.2%), age 12-83 years, median age 36 years;FAB subtypes:M1 26 cases,M2 147cases, M3 78 cases, M4 60cases, M5 109 cases,M6 10 cases, M7 5-cases, AML-ND(not determined) 75 cases.2. Cytogenetic features(1) Cytogenetics were available in 422 cases,and revealed abnormal karyotypes in 68.2%,complex abnormal karyotypes in 14.0%, non-complex abnormal karyotypes in 54.2%. The most common anomalies is t(15;17), and then t(8;21). According to WHO risk stratification of caryotype, we classified cytogenetics into three risk groups: "favourable" 106cases (25.1%),"intermediate" 214cases(50.7%), "unfavorable" 102cases(24.2%).(2)The relationship between karyotype and age:the detection rate of complex abnormal karytypes was 11.9% in patients<50 years old,and 21.3% in patients≥50 years old, the difference was statistically significant (χ2=5.352,P=0.021).3. ImmunophenotypingThe myeloid lineage antigens expression in AML patients:CD 13 was detected in 86.3% of evaluable cases, CD33 in 79.4%, CD117 in 55.4%,CD64 in 45.8%,CD11b in 23.4%,CD15 in 11.6%, and CD14 in 8.4%. The lymphoid lineage antigens expression in AML:37.6% of our cases expressed lymphoid lineage antigens, including CD7 in 29.2%, CD56 in 18.9%, CD 10 in 12.5%,CD2 in 8.7% and CD19 in 8.5%. The hematopoietic progenitor cell antigens:CD34 in 58.9% and HLA-DR 66.9%. CD34 and HLA-DR were expressed in a lower percentage in APL patients, and as the lymphoid lineage antigens.4. Clinical prognosis and early death analysisThe cohort included 78 cases of APL and the statistical analyses of prognosis were performed on the sample excluding these APL cases. Of the 432 non-APL patients, early death 27cases (6.3%),364 cases (84.2%) received standard induction chemotherapy, while 41 cases (9.5%) failed to receive standard induction chemotherapy for various cause. The 364 patients had a CR rates of 62.4%.4.1 Early death analysis(1)M4 and M5 have higher early death rate; (2) Age is an important factor of early death,≥60 years AML patients with higher early early death rate;(3) Early death was associated with the WBC count of the AML patients , Patient with high white blood cell have high early death rate;(4)The early death rate was higher in petients with lower PLT count(<20G/L);(5)Patients with complex caryotype have higher early death rate, while patients with t(8;21) have lower early death rate;(6) Correlations between early death and immunophenotype were not found in our cases;(7) The TA program of induction chemotherapy is of higher early death rate.4.2 Clinical prognosis analysis(1 Relationship Between FAB subtypes and response to chemotherapy: Patients with M1 had a significantly lower CR rates than the other FAB subtypes,while patients with M2 had a higher CR rates than the other FAB subtypes. There was statistical significances between FAB subtypes and response to chemotherapy(χ2=13.041,P=0.023)(2) Patients older than 50 had a significantly lower CR rates (χ2=4.125,p=0.042) and shorter OS (χ2=4.142,p=0.040).(3) Patients with WBC> 50G/L had a significantly lower CR rates (χ2=13.896,P<0.001) and shorter OS (χ2=7.462,P=0.006). Patients with PLT> 50G/L had a significantly lower CR rates (χ2=4.948,P=0.026), but there was no statistical significances in OS between this two groups(χ2=0.582,P= 0.445).(4) Correlations between cytogenetics and Prognosis:1) Patients with t(8;21) had a significantly higher CR rates and longer OS, while patients with 5/7 chromosome abnormality and complex abnormal karytypes had a significantly lower CR rates and shorter OS. Patients with normal karyotypes and Simple abnormal karytypes had a medial CR rates and OS. There were statistical significances in either CR rates or OS between this five groups(P= 0.001 and P=0.000).2) According to MRC AML10 trial:cytogenetics were classified Into three risk groups. The patients with favourable karytypes had a significantly higher CR rates and longer OS, while the patients with unfavorable kartypes had had a significantly lower CR rates and shorter OS. The patients with intermediate kartypes had a medial prognosis. There were statistical significances in either CR rates or OS between this three groups(P=0.000 and P=0.002).(5) Relationship Between Immunophenotype and response or survival:1) According to cutoff point 20%, an antigen was considered positive when expressed by more than 20% of the blast cells.On univariate analysis, CD10 and CD11b negative cases had a higher CR rates than CD10,CD11b positive cases (P= 0.001 and 0.043), but there was no statistical significances in OS between this two groups(P= 0.129 and 0.325).The OS was significantly shorter in patients expressing both CD13 and CD34 than in cases expressing only CD13 or CD34 or both negative (χ2=4.154,P=0.042). but there was no statistical significances in CR rates between this two groups(χ2=2.176,P=0.140). 2) According to cutoff point 50%, an antigen was considered high level expression when expressed by more than 50% of the blast cells. On univariate analysis, patients with high level expression of CD 13 or CD34 had a significantly lower CR rates(P=0.024 and 0.038) and shorter OS (P=0.020 and 0.047).(6) Binary Logistic regression analysis indentified three independent risk factor of CR rates:CD10,CD34 and cytogentics. Cox regression analysis showed outcome after the first induction course and cytogenetics were independent factors for overall survival.ConclusionAge, WBC and cytogenetics are the most important prognostic factors that affect the prognosis of AML patients. Age, WBC, PLT and cytogenetics are associated with early death. PLT is associated with CR rate. CD10, CD11b, CD13, CD34 is associated with the prognosis of the patients with AML.Immunophenotyping is not only helpful for diagnosis but is of important significance for prognosis, and may be useful for risk stratification in AML patients.