Hematopoietic progenitor cell count as a potential quantitative marker in apheresis products during allogeneic stem cell transplantation.

BACKGROUND: The quality and quantity of hematopoietic stem cells in apheresis products are essential to the success of peripheral blood hematopoietic stem cell transplantation (PB-HSCT). While the flow cytometry measurement of CD34+ cells as a golden standard for stem cell count is labor and cost-intensive, hematopoietic progenitor cell number evaluated by XN Sysmex series automated hematology analyzers (XN-HPC) is suggested as a surrogate marker. MATERIALS AND METHODS: We evaluated the correlation and consistency of XN-HPC and CD34+ cell count in apheresis samples from both allogeneic donors and autologous patients during PB-HSCT. RESULTS: Good correlation and consistency were observed between XN-HPC and CD34+ cell counts in harvests collected from healthy donors (R = .852) rather than autologous patients (R = .375). Subgroup analysis showed that the correlation was especially poor when autologous patients used plerixafor as an additional mobilizer or were diagnosed with multiple myeloma (MM). In the setting of allogeneic transplantation, the correlation coefficients were even better in samples from non-first-round apheresis (R = .951), with high white blood cell (WBC) counts (R = .941), or having successful engraftment within 2 weeks (R = .895). ROC analysis suggested that an optimal XN-HPC count of 1127 × 106 /L best predicted a sufficient yield of CD34+ stem cells, with diagnostic sensitivity and specificity being 92% and 72%, respectively (AUC = 0.852). CONCLUSIONS: XN-HPC is a sufficient quantitative marker for stem cell assessment of harvest yield in allogeneic but not autologous HSCT.

[Expression of cMPO in 502 cases of acute myeloid leukemia (AML) and its diagnosis significance in AML subtypes].

OBJECTIVE: To investigate the myeloperoxidase (cMPO) expression pattern by flow cytometry (FCM) in patients with acute myeloid leukemia (AML) and its role in classifying AML. METHODS: Eight- color multiparametric FCM with CD45/SSC gating was used to determine the cMPO expression in 502 AML patients. RESULTS: The positive rate of cMPO in all patients was 58.0%, in which the proportion of normal positivity, dim positivity and partial positivity was 21.5%, 34.1% and 2.4%, respectively. The remaining case (42.0%) were all negative. In AML with t (15;17）(q22;q12)/PMLRARα, the positive rate was the highest (100%) and the intensity was similar to that of the normal granular leukocytes, followed by AML with t (8;21（q22;q22/RUNX1-RUNX1T1, the positive rate was 91.4% and the intensity was mostly dim. AML with minimal differentiation and acute megakaryoblastic leukemia were all cMPO negative. The positive rates of cMPO in the remaining subtypes were between 22.7% and 76.2%. CONCLUSION: The positive rate and intensity of cMPO were significantly different among different subtypes of AML.

[Production and property identification of monoclonal antibodies against DAF molecules by DNA immunization followed by a single boost with cell antigen].

AIM: To produce mAb against DAF by DNA immunization followed by a single boost with cell antigen and to characterize its property. METHODS: Recombinant plasmid pcDNA3.1/DAF was constructed by molecular cloning technique and injected into mice quadriceps muscle of thigh. To boost the DAF immunized mice, HPB-All cell antigen were injected on day 3 before cell fusion. The affinity and property of mAb to natural membrane protein and denatured protein were identified by FCM, fluorescence microscope and Western blot. RESULTS: Two mAb against DAF were obtained, namely 2B6B and 2B6E. The affinity constant of 2B6E was 1.81x10(-7) mol/L. The isotype of the two mAbs were IgG2a, and the epitope of them was different. FCM, fluorescence microscope and Western blot indicated that the obtained mAb had affinity to natural membrane protein and denatured protein with high specificity. CONCLUSION: This study indicates that the DNA immunization and cell antigen boost method enables mice to produce mAb against DAF. The low frequency of nonspecific mAb is one of the advantages of this method compared to the conventional cell immunization method. Moreover the mAb generated by this method has satisfactory binding activity and specificity.