Integration of measurable residual disease by WT1 gene expression and flow cytometry identifies pediatric patients with high risk of relapse in acute myeloid leukemia.

Background: Molecular testing plays a pivotal role in monitoring measurable residual disease (MRD) in acute myeloid leukemia (AML), aiding in the refinement of risk stratification and treatment guidance. Wilms tumor gene 1 (WT1) is frequently upregulated in pediatric AML and serves as a potential molecular marker for MRD. This study aimed to evaluate WT1 predictive value as an MRD marker and its impact on disease prognosis. Methods: Quantification of WT1 expression levels was analyzed using the standardized European Leukemia Network real-time quantitative polymerase chain reaction assay (qRT-PCR) among a cohort of 146 pediatric AML patients. Post-induction I and intensification I, MRD response by WT1 was assessed. Patients achieving a ≥2 log reduction in WT1MRD were categorized as good responders, while those failing to reach this threshold were classified as poor responders. Results: At diagnosis, WT1 overexpression was observed in 112 out of 146 (76.7%) patients. Significantly high levels were found in patients with M4- FAB subtype (p=0.018) and core binding fusion transcript (CBF) (RUNX1::RUNX1T1, p=0.018, CBFB::MYH11, p=0.016). Following induction treatment, good responders exhibited a reduced risk of relapse (2-year cumulative incidence of relapse [CIR] 7.9% vs 33.2%, p=0.008). Conversely, poor responders' post-intensification I showed significantly lower overall survival (OS) (51% vs 93.2%, p<0.001), event-free survival (EFS) (33.3% vs 82.6%, p<0.001), and higher CIR (66.6% vs 10.6%, p<0.001) at 24 months compared to good responders. Even after adjusting for potential confounders, it remained an independent adverse prognostic factor for OS (p=0.04) and EFS (p=0.008). High concordance rates between WT1-based MRD response and molecular MRD were observed in CBF patients. Furthermore, failure to achieve either a 3-log reduction by RT-PCR or a 2-log reduction by WT1 indicated a high risk of relapse. Combining MFC-based and WT1-based MRD results among the intermediate-risk group identified patients with unfavorable prognosis (positive predictive value [PPV] 100%, negative predictive value [NPV] 85%, and accuracy 87.5%). Conclusion: WT1MRD response post-intensification I serves as an independent prognostic factor for survival in pediatric AML. Integration of WT1 and MFC-based MRD results enhances the reliability of MRD-based prognostic stratification, particularly in patients lacking specific leukemic markers, thereby influencing treatment strategies.

Prognostic Role of CD200 in Acute Lymphoblastic Leukemia Patients.

BACKGROUND: Overexpression of CD200 in ALL patients indicates that it may be useful in the characterization of leukemia initiating cells (LIC). We aim at investigating the expression pattern of CD200 on leukemic B cells and the correlation of CD200 expression with various clinical and laboratory findings in 62 newly diagnosed acute lymphoblastic leukemia patients. METHODS: All patients were subjected to full history taking, a thorough clinical examination, and laboratory investigations, which included complete blood count (CBC), BM aspiration, immunophenotyping of blast cells, and CD200 expression. RESULTS: There is a higher statistically significant mean value of CD200 expression among the cases (66.15 ± 23.08) than the control group (0.37 ± 0.2) (p value ≤ 0.001). CD200 expression shows a significant correlation with total leucocytic count and hemoglobin level (p = 0.001, 0.03, respectively). CONCLUSIONS: This study showed that CD200 expression was expressed in 100% of the patients. Correlations between CD200 expression and different laboratory data of patients revealed that there was an impact of CD200 on different diagnostic findings. After the follow-up of the patients, we found that the use of PRISM function of the software could add value to the detection of minimal residual disease.

Hematopoietic stem cell transplantation from HLA-matched sibling donors in children with acute lymphoblastic leukemia: A report from the Children's Cancer Hospital Egypt.

Introduction: Allogeneic hematopoietic stem cell transplantation (HSCT) is widely used for high-risk acute lymphoblastic leukemia (ALL) patients in their first complete remission (CR1), and for relapsed patients in second complete remission (CR2). Patients and methods: We retrospectively analyzed data for 67 children with ALL, from a cancer center in a low/middle income country, who had undergone HSCT from human leukocyte antigen (HLA)-matched sibling donors (MSDs) using myeloablative conditioning (MAC) regimens, between 2007 and 2020, describing the survival outcome and relapse probability after achieving CR1 and CR2 and determining outcome differences in relation to indications for HSCT in patients transplanted in CR1. All patients had achieved a negative minimal residual disease prior to transplant (<0.01%). Results: Forty-six patients (68.7%) were in CR1; 25 had adverse cytogenetics, including 18 patients with Philadelphia chromosome-positive ALL (Ph-positive ALL), and 21 had poor induction response. The 5-year overall survival (OS), event-free survival (EFS) and cumulative incidence of relapse (CIR) for the whole cohort were 56.1% (95% CI, 42.8%-69.4%), 49% (95% CI, 35.7%-62.3%) and 33.5% (95% CI, 21.7%-45.8%), respectively with better EFS and CIR for CR1 transplants compared to CR2 transplants (P=0.02 and P=0.03, respectively). Patients with Ph-positive ALL had better 5-year OS, EFS and non-relapse mortality (NRM) compared with other CR1 transplants (P=0.015, P=0.009 and P=0.028, respectively). Conclusion: Hematopoietic stem cell transplantation from MSD for ALL in CR1 group had superior outcomes compared to CR2 group and was apparently a curable option for Ph-positive ALL without an increased risk of non-relapse mortality. Poorer survival rates and higher relapse probabilities were associated with HSCT conducted to patients who had a poor response to induction therapy or suffered a relapse.

Leukemia Stem Cell Frequency at Diagnosis Correlates With Measurable/Minimal Residual Disease and Impacts Survival in Adult Acute Myeloid Leukemia.

Acute myeloid leukemia (AML) is a heterogenous disease in which the initiation and maintenance of the malignant clone is blamed on a rare population of leukemia stem cells (LSCs). The persistence of such a malignant population is referred to as measurable/minimal residual disease (MRD). Evaluation of MRD is the gold standard for follow-up of therapy and constitutes an independent prognostic parameter. As LSCs are the main contributor to the persistence of MRD, then MRD should correlate with the bulk of LSCs at the individual case level. MRD is measured at defined time points during therapy. However, LSCs can be evaluated at diagnosis, which ensures the advantage of early prediction of high-risk patients and allows for early therapeutic decisions. Using two simple four-color monoclonal antibody combinations (CD38/CD123/CD34/CD45 and CD90/CD133/CD45/CD33) and the prism function of the Coulter Navios flow cytometer, the frequency of LSC subsets was evaluated in 84 newly diagnosed adult AML patients. For each panel, 16 possible combinations were detected. Our results showed that there was extreme variability in the percentage of the LSC fraction between different cases, as well as at the individual case level. For each LSC subset, the median value was used to divide cases into low and high expressors. LSC subsets that showed an impact on overall survival (OS) and disease-free survival (DFS) included CD123+, CD 123+/CD34-, CD34-/CD38+/CD123+, CD34+/CD38-/CD123+, CD133+, and CD133+/CD33-. On multivariate analysis, only CD123 (p ≤ 0.001, SE = 0.266, HR = 2.8, 95% CI = 1.74.7) and CD133+/CD33- (p = 0.017, SE = 0.263, HR = 1.9, 95% CI = 1.1-3.1) retained their significance for OS. Likewise, only CD34+/CD38-/CD123+ (p ≤ 0.001, HR 2.3, SE: 0.499, 95% CI: 2.4-17.4) and CD133 (p = 0.015, HR 2.3, SE 0.34, 95% CI: 1.2-4.4) retained their statistical significance for DFS. The LSC frequency at diagnosis showed a moderate to strong correlation with MRD status at day 14 and day 28. In conclusion, the level of LSCs at diagnosis correlated with MRD status at day 14 and day 28 in AML patients and had a deleterious impact on OS and DFS. It may be used as an early marker for high-risk patients allowing for early therapeutic decisions.

Prognostic value of detection of CD99+ , CD45- cells in peripheral blood by flow cytometry in children with Ewing sarcoma.

BACKGROUND: Early detection of metastasis and recurrence of Ewing sarcoma (ES) is important for early management. This work aimed to detect CD99+ , CD45- cells in peripheral blood by flow cytometry (FC) before and during chemotherapy and evaluate their prognostic significance. PROCEDURE: This prospective cohort study was carried out on 60 children newly diagnosed with ES at Children Cancer Hospital-Egypt 57357 and 40 healthy children control group. Detection of CD99+ , CD45- cells in peripheral blood was accomplished by FC at baseline before treatment and after five cycles of chemotherapy. Samples were classified as positive if they had more than the upper limit of cells observed in the control cases. Correlation between FC results and relapse and overall survival (OS) after one year was performed. RESULTS: Median percentage of CD99+ , CD45- cells was significantly increased in patients compared with controls (0.002% vs 0%, respectively, P < 0.001). Post-cycle 5 CD99+ , CD45- cells were increased in 12 patients, of them 11 patients' disease had either relapsed or progressed. Post-cycle 5 CD99+ ; CD45- cells had a 73.3% sensitivity and 97.8% specificity for predicting relapse or progression, whereas baseline only had 6.7% sensitivity and 77.8% specificity. The hazard ratio for mortality in the post-cycle 5 positive group was 18.4 [95% confidence interval (1.86 to 181.46)] times that of the negative group. One year OS was 91.67%. CONCLUSION: Post-cycle 5 CD99+ , CD45- cells in peripheral blood by FC is a strong predictor for relapse, progression, and mortality whereas baseline is a poor predictor in newly diagnosed patients with ES.

Neutrophil-mediated oxidative stress and albumin structural damage predict COVID-19-associated mortality.

Human serum albumin (HSA) is the frontline antioxidant protein in blood with established anti-inflammatory and anticoagulation functions. Here, we report that COVID-19-induced oxidative stress inflicts structural damages to HSA and is linked with mortality outcome in critically ill patients. We recruited 39 patients who were followed up for a median of 12.5 days (1-35 days), among them 23 had died. Analyzing blood samples from patients and healthy individuals (n=11), we provide evidence that neutrophils are major sources of oxidative stress in blood and that hydrogen peroxide is highly accumulated in plasmas of non-survivors. We then analyzed electron paramagnetic resonance spectra of spin-labeled fatty acids (SLFAs) bound with HSA in whole blood of control, survivor, and non-survivor subjects (n=10-11). Non-survivors' HSA showed dramatically reduced protein packing order parameter, faster SLFA correlational rotational time, and smaller S/W ratio (strong-binding/weak-binding sites within HSA), all reflecting remarkably fluid protein microenvironments. Following loading/unloading of 16-DSA, we show that the transport function of HSA may be impaired in severe patients. Stratified at the means, Kaplan-Meier survival analysis indicated that lower values of S/W ratio and accumulated H2O2 in plasma significantly predicted in-hospital mortality (S/W≤0.15, 81.8% (18/22) vs. S/W>0.15, 18.2% (4/22), p=0.023; plasma [H2O2]>8.6 µM, 65.2% (15/23) vs. 34.8% (8/23), p=0.043). When we combined these two parameters as the ratio ((S/W)/[H2O2]) to derive a risk score, the resultant risk score lower than the mean (<0.019) predicted mortality with high fidelity (95.5% (21/22) vs. 4.5% (1/22), log-rank χ2=12.1, p=4.9×10-4). The derived parameters may provide a surrogate marker to assess new candidates for COVID-19 treatments targeting HSA replacements and/or oxidative stress.

IL12 and IFNγ secretion by donor mononuclear cells in response to host antigens may predict acute GVHD after HSCT.

One persistent problem of allogeneic hematopoietic stem cell transplantation (HSCT) is acute graft versus host disease (GVHD). The role of cytokines in the pathogenesis of GVHD has been acknowledged. We aimed, in the current study, to investigate the possibility of prediction of acute GVHD through investigating the pattern of interleukin 12 (IL12) and interferon gamma (IFNγ) production of both patients' origin and donors' origin. A total of 45 patients, receiving allogeneic peripheral blood (PB) stem cells from an identical sibling, were included in the study. Patients' plasma was collected after conditioning, during aplastic phase (representing patients' origin) and after engraftment (representing donors' origin). In addition an aliquot from the graft was used as responders in mixed lymphocyte culture (MLC) for 3 days with patients' mitomycin-treated mononuclear cells as stimulators. Culture supernatant was used for detection of IL12 and IFNγ of donors' origin. Fourteen patients developed acute GVHD. In culture supernatant, IL12 was detectable in 7/14 cases with and in none of 31 cases without acute GVHD (p= <0.001). The corresponding figures for IFNγ were 10/14 and 3/31 with significantly higher IFNγ level in cases with than in cases without acute GVHD (p = 0.001). At engraftment the corresponding figures were 7/14 and 5/31 for IL12 and 11/14 and 7/31 for IFNγ with significantly higher cytokine levels in cases with acute GVHD (p = 0.008 and p = 0.001 respectively). At a cutoff of 0.89 pg/ml, IL12 in culture supernatant may predict acute GVHD with absolute specificity of 100% and a sensitivity of 50%. In conclusion, IL12 and IFNγ of donors' origin not of patients' origin may predict the occurrence of acute GVHD. The MLC model may allow prediction of acute GVHD upfront before conditioning of the patient or mobilization of the donor.

Impact of FLT3 Receptor (CD135) Detection by Flow Cytometry on Clinical Outcome of Adult Acute Myeloid Leukemia Patients.

BACKGROUND: The significance of FMS-like tyrosine kinase 3 (FLT3)-ITD mutation in acute myeloid leukemia (AML) prognosis has been well established. The aims of this study were to investigate the prognostic impact of the FLT3 protein (CD135) expression and its association with FLT3-ITD mutation, and to identify its role in minimal residual disease. PATIENTS AND METHODS: CD135 was measured by flow cytometry on leukemic blasts of 257 adults with de novo AML. High expression of CD135 ≥ 20% was correlated with clinical, laboratory, and other prognostic factors that influenced treatment outcome. FLT3-ITD mutation was tested by PCR. RESULTS: The frequency of CD135 expression was 138 (53.7%) of 257. FLT3-ITD was detected in (21.4%). Positive CD135 expression was associated with high total leukocyte count (P = .006), platelet count (P = .003), monocytic leukemia (P < .001), and CD34 (P = .008) and CD117 (P = .006) expression. CD135 expression ≥ 25% was a predictor of FLT3-ITD mutation (P = .03). CD135 overexpression was a negative predictor of complete remission and of postinduction minimal residual disease at days 14 and 28 (P < .001). CD135 had an adverse impact on overall and disease-free survival (68.5% vs. 15%, P = .002). Multivariate analysis indicated CD135 was the sole independent prognostic factor for overall survival (hazard ratio = 2.49; 95% confidence interval, 1.855-3.345; P < .001). CONCLUSION: CD135 is emerging as a prognostic factor, a new marker for minimal residual disease, and a potential novel therapeutic target of AML.