Contribution of Flow Cytometry Immunophenotyping in Diagnostic of Acute and Chronic Leukemias

BACKGROUND: Today immunophenotyping by flow cytometry is an useful adjunct to cytomorphologyc analysis to correct diagnostic of leukemias. It provides objective and quantitative data allowing for a high level of sensitivity detection and better characterization of acute and chronic leukemias. The purpose of this study was to demonstrate the contribution of the immunophenotyping by monoclonal antibodies (Mo.Ab.) in leukemic cells from patients with acute and chronic leukemias. METHODS: Analyzed 76 patients with leukemias before the treatment. The diagnostic of leukemias was based on the morphological and immunophenotyping analysis of leukemic cells from peripheral blood and bone morrow. The cytomorphologycal analysis was based on French - American - Britsh criteria (FAB classification) in blood and bone marrow films stain by leishmann and the immunophenotyping by flow cytometry with a panel of Mo.Ab. specific to acute leukemias as: CD1a, CD2, CD3, CD4, CD5, CD8, CD7, CD10, CD13, CD19, CD20, CD103, CD22, CD33, CD34, CD117, CD38, HLADR, TdT, anti-mieloperoxidase, anti-IgM and anti-kappa and lambda light chain. Further clinical and laboratory information as age, sex, presence of tumoral mass, lymphadenopathy, hepatosplenomegaly, hemoglobin determination, total and specific white cell count and cytomorphological analysis of blood film and bone morrow smear. RESULTS: Thirty four patients presented acute myeloid leukemia (AML), twenty acute lymphoblastic leukemia (ALL), nineteen B-cell chronic lymphocytic leukemia (B-CLL), two T-cell chronic lymphocytic leukemia and one case was hairy cell leukemia (HCL). Males were more frequently found in all types of leukemias. ALL were more observed in children (age < 15 years old) and in AML however were more frequently in adults patients. The chronic leukemias were presented in patients with 50 years old or more in all cases. The correlation between the immunophenotyping and clinical pathological profile of these leukemias demonstrated that ALL were more associated to lymphadenopathy, AML to hepatosplenomegaly, and CLL to lymphadenopathy and high count of white cells in peripheral blood. The thrombocytopenia and anemia were found in more cases of acute leukemia. CONCLUSION: This date suggest that today the immunophenotyping by flow cytometry is an important methodology to diagnostic and classification of leukemias. Disclosures No relevant conflicts of interest to declare.

BM-MSC Hhip Induced Microenvironment Protection from Chemotherapy in AML Via Ptch/Smo/Gli Pathwa

Introduction. The mechanism of drug resistance is complicated in acute myeloid leukemia (AML), bone microenvironment provides protection niche for leukemia stem cells (LSC), and considered as an internal environment for AML cells to escape from chemotherapeutics cytotoxicity, but mechanism of drug resistance induced by microenvironment mesenchymal stem cell (MSC) isn't completely clear. In prophase study, it was found that Ptch/Smo/Glis pathway was the key in the network of AML drug resistance. Smo inhibition improved the survival of AML-bearing mice. Low expression of HHIP was found in refractory AML MSC and bone morrow liquid, overexpression of Smo and Gli-1 was verified in AML cells, and negatively correlated with prognosis in AML patients. Chemotherapeutic drug sensitivity was decreased in AML cells after co-cultured with AML MSC in vitro. Methods. Bone morrow samples from AML patients and normal donors were collected to culture MSC cells. HL60/ADM and Kasumi-1 cells as well as HL60、KG-1cells were treated with daunomycin (DNR) or cytosine arabinoside (Ara-C) when cocultured with MSC. Cell cycle and apoptosis were determined by flow cytometry. The expression of HHIP was determined by confocal image and western blotting. Smo and Gli-1 activity was determined by western blotting. Result. We took advantage of AML cells cocultured with MSC to imitate leukemic microenvironment in vitro. Co-culture with AML BM-MSC decreased the sensitivity to DNR or Ara-C compared with normal BM-MSC in HL60/ADM or Kasumi-1 cells. Flow cytometry analysis showed that cells in S phase and percentage of apoptosis cells were increased after co-culture with AML MSC. Western blotting also determined that low expression of HHIP was detected in refractory AML BM-MSC, Smo and Gli-1 expression were increased in HL60/ADM or Kasumi-1 cells after co-cultured with MSC. Confocal analysis also confirmed that the combination of HHIP and Ptch was decreased in AML MSC co-culture, Smo/Gli-1 pathway was activated through decreased inhibition of Shh in refractory AML cells co-cultured with MSC. Samples from AML patients also demonstrated that HHIP expression in AML BM-MSC was lower than that in normal BM-MSC, especially in refractory AML samples. HHIP expression in BM-MSC was negatively related to Smo and Gli-1 activity. Clinic data also showed that AML patients with overexpression of HHIP had a worse prognosis. Conclusion. Our study demonstrated expression of BM-MSC HHIP was negatively related to activity of Ptch/Smo/Glis in AML. Low expression of BM-MSC HHIP resulted in activating Ptch/Smo/Gli pathway, and indicated drug resisitance and bad prognosis in AML. This project is connected with basic research and clinic, and provides support for diagnosis and targeted therapy in AML. Disclosures No relevant conflicts of interest to declare.

Functional Studies of Ex Vivo Expanded Hematopoietic Stem Cells in Mice and Monkeys

Hematopoietic stem cell (HSC) transplantation has been widely applied for the treatment of malignant blood diseases. However, obtaining sufficient HLA-matched stem/progenitors for cell transplantation is an obstacle for clinical applications. We reported here that an optimal cytokine cocktail in a modified IMDM basal medium was developed that contained stem cell factor, Flt-3 ligand, thrombopoietin, interleukin 3, G-CSF and GM-CSF. Up to 7.3 folds of expanded CD34+ cells with 66.3% CD34+ of whole cells were obtained after 4 days' culture from human umbilical cord blood. Colony-forming unit (CFU) assays showed that expanded CD34+ cells retained the same renewal ability as the pre-expanded counterparts. To test the repopulating ability of the expanded CD34+ in vivo, sixteen NOD/SCID mice were divided to four groups and injected with saline (group 1), 0.4 million pre-expanded CD34+ cells (group 2), 0.4 million 4-day expanded CD34+ cells (group 3), and 2.9 million expanded CD34+ cells (group 4), respectively. Multi-lineage differentiations in the peripheral blood were assessed by flow cytometry with antibodies against a panel of human cell surface markers. In week 3, human CD34+ cells were decreased below 1% in groups 2 and 3, and 1.717%±0.65% in group 4. Whereas, human CD45+ was increased up to 3.831%±1.54%, 3.108%±1.18% and 10.408%±3.27% for groups 2, 3 and 4, respectively. The other human CD41+, CD71+ and CD15+ were also increased in groups 2-4. No expression of any human cell lineage markers was detected in group 1, indicating that expanded human CD34+ cells possessed the repopulating viability of HSCs in vivo. Furthermore, in week 12, the human CD34+ cells were re-isolated from the bone morrow of the mice (one mouse from each group). The isolated human CD34+ cells were again transfused into new NOD/SCID mice for the secondary transplantation. In week 6, human CD45+, CD15+ and CD19+ were observed from the bone morrow cells of sacrificed mice. On the other hand, human CD45+, CD15+ and CD19+ were also detectable in bone morrow cells for all remaining mice in week 24, suggesting that the expanded CD34+ cells could be successfully engrafted into mice in a long term. In addition, the cytokine cocktail was further evaluated for its safety and efficacy in primates. The CD34+ cells were isolated from the peripheral blood of cynomolgus monkeys and expanded for about 8 folds were obtained on day 9. Harvested CD34+ cells were transducted with the gene of green fluorescent protein (GFP). These cynomolgus monkeys (n=11) were administered with cyclophosphamide via intravenous injection at a dose of 50 mg/kg/day for two days. The myelo-suppressed monkeys were randomly divided into three groups as follows: a control group treated with saline (n=3), a group with autologous CD34- cells (n=3), and a group treated with GFP-labeled, expanded autologous CD34+ cells (n=5), respectively. After autologous transplantation, routine blood tests and flow cytometry analysis were performed to determine the proportion of GFP+ cells in the peripheral blood. The flow cytometry analysis revealed that the white blood cells (WBC), neutrophil (NEU) and platelets (PLT) in peripheral blood of cynomolgus monkeys were completely recovered to the normal levels on days 12, 11 and 10 post autologous transplantation of expended CD34+ cells, respectively. For the control groups, WBC, NEU and PLT returned to the normal on days 22, 22 and 12 for the saline treatment and on days 20, 20 and 12 for the CD34- group, respectively. Similarly, the lymphocytes of cynomolgus monkeys were recovered completely on day 20 post autologous CD34+ cell transplantation compared with the saline control (day 25) and the CD34- group (day 22). On day 30 after the autologous transplantation, the GFP+ ratio in CD45+ populations was around 2% in the peripheral blood. GFP+ cells (ranging from 1.8% to 4.1%) were also detected in bone morrow of cynomolgus monkeys. All primates transplanted with the expanded autologous CD34+ cells have survived for 18 months without any noticeable abnormalities. In conclusion, our results indicate that expanded CD34+ cells can be safely and efficiently used for repopulating stem cell compartment in mice and primates, underscoring the potential applications in the clinic. Furthermore, the results from successful autologous transplantation of cynomolgus CD34+ cells strongly suggest a possible application for personalized treatment of blood diseases. Disclosures Qin: Biopharmagen. corp: Employment. Ren:Biopharmagen corp: Employment.