Poor pretransplantation minimal residual disease clearance as an independent prognostic risk factor for survival in myelodysplastic syndrome with excess blasts: A multicenter, retrospective cohort study.

BACKGROUND: Minimal residual disease (MRD) is an important prognostic factor for survival in adults with acute leukemia. The role of pretransplantation MRD status in myelodysplastic syndrome with excess blasts (MDS-EB) is unknown. This study retrospectively analyzed the relationship between pretransplantation MRD status and long-term survival. MATERIALS AND METHODS: Patients with MDS-EB who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) from March 5, 2005, to November 8, 2020, were included. The relationship between pretransplantation MRD status and long-term survival was analyzed using univariate and multivariate logistic regression models. RESULTS: Of 220 patients with MDS-EB who underwent allo-HSCT, 198 were eligible for inclusion in this multicenter, retrospective cohort study. Complete remission was attained in 121 (61.1%) patients, and 103 patients underwent detection of MRD pretransplantation, with 67 patients being MRD-positive and 36 patients being MRD-negative. The median follow-up time was 16 months, the median age was 41 years (6-65 years), and 58% of the patients were men. The 3-year disease-free survival (DFS) and overall survival (OS) probabilities for all patients were 70.1% and 72.9%, respectively. For patients in complete remission, the 3-year DFS and OS probabilities were 72.2% and 74.8%, respectively. Further analysis found that the 3-year DFS rates of MRD-negative and MRD-positive patients were 85.6% and 66.5% (p = .045), respectively, whereas the 3-year OS rates were 91.3% and 66.4% (p = .035), respectively. Univariate and multivariate analyses showed that poor pretransplantation MRD clearance was an independent prognostic risk factor for DFS and OS. CONCLUSION: Poor pretransplantation MRD clearance is an independent prognostic risk factor for long-term survival after allo-HSCT for patients with MDS-EB. PLAIN LANGUAGE SUMMARY: Poor minimal residual disease clearance pretransplanation is an independent prognostic risk factor for long-term survival after allogeneic hematopoietic stem cell transplantation for patients with myelodysplastic syndrome with excess blasts.

[Expression Changes of Hypoxia-Inducible Factor-1α in G-CSF Induced Hematopoietic Stem Cell Mobilization].

OBJECTIVE: To investigate the expression and its relative mechanism of hypoxia-inducible factor-1α(HIF-1α) in bone marrow(BM) of mice during G-CSF mobilization of hematopoietic stem cells (HSC) . METHODS: Flow cytometry was used to detect the proportion of Lin-Sca-1+ c-kit+ (LSK) cells in peripheral blood of C57BL/6J mice before and after G-CSF mobilization. And the expression of HIF-1α and osteocalcin (OCN) mRNA and protein were detected by RQ-PCR and immunohistochemistry. The number of osteoblasts in bone marrow specimens of mice was counted under the microscope. RESULTS: The proportion of LSK cells in peripheral blood began to increase at day 4 of G-CSF mobilization, and reached the peak at day 5, which was significantly higher than that of control group (P<0.05). There was no distinct difference in the expression of HIF-1α mRNA between bone marrow nucleated cells and osteoblasts of steady-state mice (P=0.073), while OCN mRNA was mainly expressed in osteoblasts, which was higher than that in bone marrow nucleated cells (P=0.034). After mobilization, the expression level of HIF-1α increased, but OCN decreased, and the number of endosteum osteoblasts decreased. The change of HIF-1α expression was later than that of OCN and was consistent with the proportion of LSK cells in peripheral blood. CONCLUSION: The expression of HIF-1α in bone marrow was increased during the mobilization of HSC mediated by G-CSF, and one of the mechanisms may be related to the peripheral migration of HSC induced by osteoblasts inhibition.

[Clinical Analysis of Bloodstream Infection after Hematopoietic Stem Cell Transplantation].

OBJECTIVE: To analyze the clinical characteristics of bloodstream infection (BSI) in patients treated by hematopoietic stem cell transplantation (HSCT). METHODS: The clinical characteristics, distribution of pathogenic bacteria causing BSI and drug sensitivity of 910 patients treated by HSCT in our department from January 2013 to June 2020 were retrospectively analyzed. RESULTS: Among 910 HSCT patients, 111 patients were diagnosed as BSI within 100 days after transplantation, and 98 patients showed BSI during the period of agranulocytosis. Multivariate analysis showed that the usage of anti-thymocyte globulin (ATG), long duration of agranulocytosis and low infusion volume of mononuclear cell (MNC) were the independent risk factors affecting BSI after HSCT. Among 121 pathogenic bacteria isolated, 76 Gram-negative (G-) bacteria (62.8%), 40 Gram-positive (G+) bacteria (33.0%), and 5 fungi (4.1%) were detected out. The top three pathogens were Escherichia coli, Staphylococcus epidermidis and Pseudomonas aeruginosa. The drug-resistance rates of Escherichia coli and Klebsiella pneumoniae to carbapenems was 14.3% and 7.7%, respectively, and Pseudomonas aeruginosa was 66.7%. The susceptibility of G+ bacteria to vancomycin, linezolid and teicoplanin was 97.5%, 100% and 100%, respectively. The crude mortality rate of the patients with BSI at 100 days after HSCT was significantly higher than that of patients without BSI (P<0.001). CONCLUSION: The usage of ATG, long duration of agranulocytosis and low infusion volume of MNC are independent risk factors for BSI after HSCT. The pathogens after HSCT are mainly G- bacteria. Pseudomonas aeruginosa is highly resistant to carbapenems. Key words　　;

Vancomycin population pharmacokinetics and dosing recommendations in haematologic malignancy with augmented renal clearance children.

WHAT IS KNOWN AND OBJECTIVES: Augmented renal clearance (ARC) is characterized by enhanced renal clearance, which leads to insufficient vancomycin exposure and treatment failure. In haematologic malignancy patients, determination of optimal vancomycin dosage is essential because of high stake of life-threatening bacterial infection and increased clearance. The aim of this study was to describe vancomycin pharmacokinetic parameters in haematologic malignancy with augmented renal clearance children and define the appropriate dosing regimen to achieve an AUC0-24h /MIC ≥400. METHODS: Hematologic malignancy with ARC children was enrolled in this retrospective study. The vancomycin PPK model was established by non-linear mixed-effects modelling programme. Goodness-of-fit (GOF) plots, non-parametric bootstrap, normalized prediction distribution error (NPDE) and visual predictive checks (VPCs) were carried out for internal evaluation of the final model. Monte Carlo simulation method was used to stimulate the optimal dosage regimens. RESULTS: Fifty-three patients with 106 samples were included. A one-compartment model with first-order elimination was developed, and the final model was as follows: CL (L/h) = 6.32×（WT/70）0.75  × e0.0467 ; V(L) = 39.6×(WT/70), where WT denotes weight (kg). The internal validation of the model showed a good prediction performance. Monte Carlo simulation results showed that when MIC was 0.5 mg/L or 1 mg/L, the recommended doses to achieve a target of AUC0-24h /MIC ≥400 were 25 to 40 and 50 to 75 mg/kg/d, respectively. With decreasing weight, the recommended dosage to achieve an AUC0-24h /MIC ≥400 increased. WHAT IS NEW AND CONCLUSION: A one-compartment vancomycin PPK model was established in haematologic malignancy with augmented renal clearance children with weight with allometric scaling as a significant covariate. When MIC was 1 mg/L, current recommended paediatric dosages were insufficient in haematologic malignancy with augmented renal clearance children and should be increased.

[Clinical and Bacteriological Analysis of Bacterial Bloodstream Infections in Patients with Acute Leukemial].

OBJECTIVE: To investigate the clinical characteristics, etiology and drug susceptibility of bacterial bloodstream infections in acute leukemia(AL) patients. METHODS: Clinical data, etiology and drug susceptibility of acute leukemia patients with bacterial bloodstream infections from April 2009 to April 2018 were retrospectively analyzed. RESULTS: A total of 376 strains were isolated, 76.9% was Gram-negative bacterial and 23.1% was Gram-positive bacteria. Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae were listed as the top three of Gram-negative bacteria. The susceptibility of Escherichia coli to the tigacycline, imipenem and meropenem was 100.0%, 98.2% and 98.1%, respectively. The susceptibility of Klebsiella pneumoniae to the tigacycline, imipenem and meropenem were 100.0%, 98.3% and 94.4%, respectively. The adjustment rate for initial use of carbopenems was 3.8%, while the adjustment rate for initial use of noncarbopenems was 74.3% in patients with main Gram-negative bacterial blood stream infection. The susceptibility of Gram-positive bacteria to glycopeptide antibiotics, linezolid and tigacycline was 100.0%. CONCLUSION: Gram-negative bacteria is the majority type of bacteria in AL patients with bacteria blood stream infections. The susceptibility of Gram-negative bacteria to the carbapenems is high, and the treatment adjustment rate is obviously low. The glycopeptide, linezolid and tigacycline are effective for Gram-positive bacteria infections..

Multicenter phase II study of a combination of cyclosporine a, methotrexate and mycophenolate mofetil for GVHD prophylaxis: results of the Chinese Bone Marrow Transplant Cooperative Group (CBMTCG).

BACKGROUND: Improvement of current GVHD prophylactic therapies remains an important goal in the allo-HSCT. We have described a novel prophylaxis regimen in a single institution trial. The Chinese Bone Marrow Transplant Cooperative Group (CBMTCG) initiated a phase II multicenter study. METHODS: The study was designed as a prospective, single arm phase II open-label, multicenter clinical trial. The primary endpoint was improvement of aGVHD by 25% over historical control (40%) in Chinese patients. 508 patients were enrolled. All of the patients received cyclosporine A (CsA), methotrexate (MTX) and mycophenolate mofetil (MMF) (0.5-1.0 g daily for 30 days) as GVHD prophylaxis regimen. RESULTS: The primary endpoint was met with cumulative incidences of grades 2 to 4 and grades 3 to 4 aGVHD of 23.2% and 10.3%, respectively. Incidence for cGVHD was 67.4%. The non-relapse mortality (NRM) rate was 18.4% at 2 years. The probabilities of leukemia free survival (LFS) for non-advanced stage and advanced stage patients at 2 years were 69.7% and 44.8% respectively (p = 0.000). Recipient age ≥ 40 years, advanced stage and Busulfan-Fludarabine(BuFlu) conditioning regimen were identified as major risk factors for aGVHD. Recipient age ≥ 40 years, BuFlu conditioning regimens, female donor/male recipient and prior aGVHD were associated with cGVHD. Despite lower RM (relapse mortality), patients with grade 2-4 aGVHD had higher NRM and worse OS and LFS compared to patients with grade 0-1 aGVHD. In contrast, patients with cGVHD had better OS and LFS and lower RM compared to patients without cGVHD. CONCLUSION: The novel GVHD regimen decreased the risk for aGVHD by 42% without improving the risk for cGVHD compared to historical controls. Development of aGVHD was associated with worse OS and LFS as well as higher NRM. In contrast, cGVHD was associated with improved OS and LFS likely attributed to a GVL effect.

[Clinical outcomes of different regimens for non-Hodgkin's lymphoma with bone marrow involvement: analysis of 148 cases].

OBJECTIVE: To investigate the effects of different treatment protocols on non-Hodgkin's lymphoma (NHL) with bone marrow involvement (BMI). METHODS: The clinical data of 148 patients of NHL with BMI, 108 undergoing CHOP regimen, 51 undergoing dose-intensive CHOP regimens, 13 undergoing CHOP regimen + rituximab, and 27 undergoing hemopoietic stem cell transplantation (HSCT) after CHOP protocol with remission. The curative effects were retrospectively analyzed. RESULTS: (1) The response rate (RR) for the whole group was 80.4%, with a complete remission (CR) rate of 60.7%. The response rate of the patients treated with the dose-intensive regimens (dose-intensive group) was 84.3%, significantly higher than that of the patients treated with standard CHOP regimen (64.1%, P < 0.05). (2) The 3- and 5-year overall survival (OS) rates and progress-free survival (PFS) of the B-cell NHL patients who underwent HSCT + Rituximab treatment (Rituximab combined with chemotherapy) were significantly higher than those of the dose-intensive group and CHOP group, and the 3- and 5-year OS rates and PFS of the dose-intensive group were all significantly higher than those of the CHOP group (all P < 0.05). (3) The 3- and 5-year OS rates, and PFS of the T-cell NHL patients who underwent HSCT group and dose-intensive CHOP were all significantly higher than those patients who underwent CHOP regimen (all P < 0.05). CONCLUSION: Superior survival may benefit from Dose-intensive regimens and HSCT, may be good choices for the patients with NHLBMI, a group of heterogeneous malignancies with poor prognosis. And combined chemotherapy with Rituximab treatment remarkably raises the effect for CD20(+) B-cell NHLBMI.

[Retrospective analysis of 54 patients with high risk aggressive T-cell non-Hodgkin lymphomas].

OBJECTIVE: To analyse the clinical characteristics, treatments and prognosis of patients with T-cell non-Hodgkins lymphoma (NHL) in intermediate-high and high risk. METHODS: Fifty-four patients with T-cell NHL classified intermediate-high and high risk were retrospectively analyzed. RESULTS: According to WHO classification criteria, there were 12 cases of T-lymphoblastic lymphoma (TLBL), 31 peripheral T-cell lymphoma unspecified (PTCL-U), and 11 hepatosplenic T-cell lymphoma (HSTCL). The IPI were 12 cases of intermediate-high risk and 42 high risk. Of them, 49 cases were bone marrow affected and 7 CNS affected. The response rate (RR) for the whole group was 86.5%, complete remission (CR) rate 67.3%, and 3-year survival rate 16.0%. The 3-year survival rates for haematopoietic stem cell transplantation and chemotherapy groups were 44.4% and 8.3%, respectively. Multi-factor analysis showed that choice of therapy modality, and achievement of remission were significant factors for overall survival. CONCLUSION: T-NHL is a group of heterogeneous malignancies. The response rate of intermediate-high and high risk T- NHL, especially PTCL-U and LTBL, is not low, but its long-term outcome is poor. New treatment modality needs to be explored for these patients, and autologous HSCT is perhaps a good choice.

[The role of stromal cell-derived factor and its receptor-CXCR4 in G-CSF-induced hematopoietic stem cell mobilization].

OBJECTIVE: To explore the role of stromal cell-derived factor (SDF-1) and its specific receptor CXCR4 in the G-CSF-induced hematopoietic stem/progenitor cells (HSPCs) mobilization in human healthy donor. METHODS: The changes of SDF-1/CXCR4 in bone marrow (BM) and peripheral blood (PB) of healthy donors during G-CSF-induced mobilization were detected by enzyme-linked immunosorbent assay (ELISA), immunohistological staining and flow cytometry. SDF-1 neutralizing antibody wes injected into BALB/c mice to further test its effect on mobilization. RESULTS: SDF-1 concentration in mobilized BM (mBM), steady state BM (ssBM) and PB were(7.23 +/- 0.66) microg/L, (5.43 +/- 0.35) microg/L and (5.42 +/- 0.52) microg/L, respectively. SDF-1 protein levels were decreased in the BM (P < 0.05) after 5-day G-CSF injection, and its concentration gradient between BM and PB disappeared (P > 0.05). Significant up-regulation of CXCR4 expression was observed on mBM CD34 cells in healthy donors. The rate of CXCR4 expression on CD34 cells in ssBM, mBM and mobilized PB were (40.98 +/- 21.56)%, (65.80 +/- 24.68)% and (27.54 +/- 26.03)%, respectively. Comparing with that in ssBM and mBM, CXCR4 expression on mobilized PB CD34+ cells were significantly decreased (P < 0.05). Inhibition of SDF-1 signal by blocking monoclonal antibodies significantly reduced G-CSF-induced mobilization in BALB/c mice. This resulted in significant decrease of white blood cell count and progenitors mobilized into peripheral circulation. CONCLUSION: G-CSF induces HSPCs mobilization by decreasing bone marrow SDF-1 and down-regulating CXCR4 expression on HSPCs.

[Real-time quantitative PCR detecting B7-H1 gene expression in leukemia cells and its clinical implications].

OBJECTIVE: To detect the expression of B7-H1 gene in bone marrow mononuclear cells (BMMNCs) from leukemia patients and explore its clinical implications. METHODS: The B7-H1 mRNA expression levels of BMMNCs from 74 newly diagnosed leukemia patients and 10 normal volunteers were detected by real-time quantitative PCR. At the same time, BMMNCs from 12 patients in complete remission (CR) after chemotherapy and 5 in relapse were followed up. The correlation between the clinical features of 74 de novo leukemia patients and the expression level of B7-H1 gene was analyzed. RESULTS: The mRNA expression level of B7-H1 gene in BMMNCs from de novo leukemia patients (RQ = 0.125) was lower than that from normal control (RQ=1). When patients achieved CR the gene expression level (RQ = 69.07) was significantly higher than that before CR (P = 0.001). After relapsed, its level (RQ=4) was still higher than that before CR (P > 0.05). No clinical parameters such as gender, age, peripheral white blood count, blast cells ratio in BM, CD34 positive cells were significantly correlated with the expression level of B7-H1 except the response to therapy. The initial expression level of B7-H1 gene in non CR patients after therapy was significantly higher than that in CR patients (RQ = 26. 91, P = 0.005). CONCLUSION: The mRNA expression level of B7-H1 gene in newly diagnosed leukemia patients is lower than that in normal controls, and is higher in CR patients than in newly diagnosed patients. There is a correlation between the gene expression level and responsiveness to therapy.

[Related factors affecting the isolation of multipotent non-hematopoietic adult stem cells from umbilical cord blood].

To investigate the related factors affecting the isolation of multipotent non-hematopoietic adult stem cells (MNASCs) from human umbilical cord blood in low serum (2%) condition, the isolation conditions were optimized and the yield of MNASCs was improved. MNASCs from human umbilical cord blood samples were isolated, and the effects of medium component, medium exchange time and initial plating density for isolation of MNASCs were studied. Then, the MNASCs were isolated and cultured in optimal condition, the surface antigen expression and differentiation potential of MNASCs were detected. The result showed that the medium of DMEM/F12 was better than IMDM and DMEM-LG for MNASCs culture in low serum condition. The optimal yield of MNASCs was obtained when mononuclear cells were cultured at a initial plating density of 1 x 10(6) cells/cm2 and the medium was exchanged to remove the nonadherent cells after 72 hours of inoculation. MNASCs isolated and cultured under the above-mentioned conditions maintained a homogenous morphology, high potential ability of expansion and differentiation. It is concluded that culture conditions with low serum defined in this study is optimal for the successful isolation and expansion of umbilical cord blood MNASCs with high numbers for subsequent cellular therapeutic approaches.

[Long-term survival analysis in 170 cases of acute promyelocytic leukemia].

This study was aimed to investigate various factors influencing long-term survival in patients with acute promyelocytic leukemia. A single institutional retrospective study with long-term follow-up was performed to better define the prognostic factors and a rationale for the use of ATRA, chemotherapy, and As(2)O(3) in the treatment of newly diagnosed APL patients. Newly diagnosed patients with APL entering complete remission (CR) were followed up for 6 to 185 months (n = 170) from January 1990 to December 2004. Univariate and multivariate analysis of 8 potential factors influencing survival and prognosis were carried out with Log-Rank and Cox regression method, including sex, age, initial WBC count, the level of lactic hydrogenase (LDH), first induction regimen, time from induction therapy to CR, post-remission therapy, negative or positive rate of PML-RAR alpha and follow-up of reverse transcription-polymerase chain reaction (RT-PCR). The results showed that the estimated 5-year overall survival (OS) and relapse-free survival (RFS) were 80.9% +/- 4.0% and 71.0% +/- 4.0% respectively. The 23 patients relapsed at the median time of 15 months (6 - 70) after CR. Univariate analysis revealed that initial WBC count, first induction regimen, time from induction therapy to CR, type of post-remission therapy and persistent negative RT-PCR in remission were important prognostic factors for long-term survival. Multivariate study demonstrated that only type of post-remission therapy was associated with RFS and OS. It is concluded that the post-remission treatment combining ATRA, As(2)O(3) and chemotherapy would significantly improve the long-term survival of APL patients entering CR(1).

[Effects of stromal cell-derived factor 1 and platelet factor 4 on the adhesion characteristics and chemotactic function of ex vivo expanded umbilical cord blood CD34+ cells].

To investigate the effects of stromal cell-derived factor 1 (SDF-1) and platelet factor 4 (PF4) on the homing-related function of expanded ex vivo umbilical cord blood CD34(+) cells, purified cord blood CD34(+) cells were cultured in serum-free medium containing a HGF combination of FL + SCF + TPO (FST) with either 100 ng/ml SDF-1 alone, 100 ng/ml PF4 alone, or both of these 2 cytokines. The expansion rate of CD34(+) cells, colony formation, homing-related functions including expression of homing-related adhesion molecules of expanded CD34(+) cell, adhesion activity and chemotactic function of the re-selected expanded CD34(+) cells were evaluated at different time points. The results showed that expansion rate of CD34(+) cells and expansion multiple of CFU in SDF-1 groups were higher than those in control. The expression of CD49e on the expanded CD34(+) cells was remarkable up-regulated, in contrast, expression of CXCR-4 on the expanded CD34(+) cells was remarkable down-regulated in SDF-1 groups. The expression of CD49e, CD54 and CXCR-4 on the expanded CD34(+) cells were remarkably up-regulated in the PF4 groups. In all the SDF-1 group, PF4 group and SDF-1 plus PF4 group, the ability of expanded CD34(+) cells adhering to fibronectin layer were higher than those in the control on day 10. Spontaneous migration rate of expanded CD34(+) cells in SDF-1 groups were higher than those in control, while SDF-1-induced migration rate were lower than those in control on day 10. SDF-1-induced migration rate in PF4 groups were higher than those in control on day 10. Spontaneous and SDF-1-induced migration rate of expanded CD34(+) cells in the SDF-1 plus PF4 groups were higher than those in control on day 10. It is concluded that, SDF-1 and PF4 can up-regulate expression of adhesion molecules on expanded CD34(+) cells, and retain the adherent and migration ability of expanded CD34(+) cells, which is helpful for the homing of expanded CD34(+) cells. In short, SDF-1 and PF4 are helpful for the homing-related function of the expanded UCB HSPC.

[Comparison of expanding dendritic cells derived from cord blood and mobilized peripheral blood by two-step culture method].

To compare the expansion efficiency and function of dendritic cells derived from CB-CD34+ cells and MPB-CD34+ cells by using two-step culture method, enriched CB-CD34+ cells or MPB-CD34+ cells with immunoadsorption were primarily cultured in the presence of FL, SCF, TPO, GM-CSF for 10 days, and then further cultured with a combination of GM-CSF, IL-4, TNF-alpha, CD40Ab and PGE2 to induce DC. The DC phenotypes were detected by flow cytometry, the expansion efficiency and cell function were evaluated by mix-lymphocyte reaction (MLR), IL-12 level was detected by using ELISA and the chemotactic function mediated by secondary lymphoid tissue chemokine (SLC) was determined with Transwell plate. The results indicated that after 10 days of expansion, there were no significant difference in the percentage of CD14+CD1a- cells between CB and MPB [(40.48 +/- 16.85)% vs (28.07 +/- 23.19)%, P > 0.05], but the expansion of total cells in CB was higher than that in MPB (388.88 +/- 84.63-fold vs 79.67 +/- 10.32-fold, P < 0.01), so the yield of CD14+CD1a- cells from CB was significantly higher than that from MPB too (189.42 +/- 25.02-fold vs 28.74 +/- 23.27-fold, P < 0.01). The percentage of CD83+ DCs cultured with CD40Ab/PGE2 derived from CB were higher than those cultured with TNF-alpha derived from MPB respectively [(34.52 +/- 11.22)% vs (3.70 +/- 2.27)% and (36.69 +/- 13.36)% vs (7.34 +/- 3.364)% respectively, P < 0.01]. In the same circumstance, the yield of CD83+ DCs derived from CB was much more than that from MPB (198.72 +/- 117.53 times vs 33.95 +/- 6.19 times, P < 0.01). There were no difference in stimulating capacity, IL-12 secretion and migration capacity between DCs derived from CB and MPB. It is concluded that DCs induced from CB-CD34+ cells by two-step culture possess similar functions with that from MPB-CD34+ cells, but the yield of DCs from CB CD34+ cells is much more than that from MPB CD34+ cells.

[The effect of matrix metalloproteinase-9 in granulocyte colony stimulation factor-induced stem cell mobilization].

OBJECTIVE: To investigate the effects of matrix metalloproteinase-9 (MMP-9) on granulocyte colony stimulation factor (G-CSF)-induced hematopoietic stem/progenitor cell (HSPC) mobilization in healthy donors of hematopoietic stem cells. METHODS: Peripheral blood (PB) samples and bone marrow (BM) blood samples were collected from 12 healthy donors of hematopoietic stem cell before and 5 days after G-CSF-induced mobilization. CD34(+) cells were isolated and purified. ELISA was used to detect the protein expression of MMP-9 in the peripheral blood and BM blood of the healthy donors. The protein expression of MMP-9 in the BM blood was detected by ELISA and immunohistochemistry, and the stromal cell-derived factor-1 (SDF-1) level in the BM blood was detected by ELISA. The mRNA expression of MMP-9 in the BM blood samples was detected by RT-PCR. HT1080 cells rich in MMP-9 were cultured. CD34(+) cells were co-cultured with the supernatant of HT1080 cell culture fluid. CD34(+) cells cultured in Iscove's modified Dulbecco's medium were used as control group. Fluorescence-activated cell sorter was used to detect the CXCR4 expression on the surface of the CD34(+) cells. In the transwell experiment CD34(+) cells were divided into 4 groups: control group, o-phenanthroline (MMP-9 chemical inhibitor, MPI) group, HT1080 sup group, and HT1080 + MPI group to be co-cultured with buffer, o-phenanthroline, supernatant of culture fluid of HT1080 cells, or supernatant of culture fluid of HT1080 cells Flow cytometry was used to calculate the cell migration capacity. RESULTS: The MMP-9 level of BM and PB of the healthy donors 5 days after G-CSF mobilization were 278 ng/ml +/- 34 ng/ml and 392 ng/ml +/- 284 ng/ml respectively, both significantly higher than those before G-CSF mobilization (42 ng/ml +/- 17 ng/ml and 27 ng/ml +/- 12 ng/ml respectively (P < 0.01 and P < 0.05). Western blotting showed that the SDF-1 level in the supernatant 5 days after G-CSF mobilization was 5.9 ng/ml +/- 1.0 ng/ml, significantly lower than that before G-CSF mobilization (7.2 ng/ml +/- 0.7 ng/ml, P < 0.05). The CXCR4 levels of the CD34(+) cell from both PB and BM blood were up-regulated after co-culture with the supernatant of HT1080 cells (both P < 0.05). The migration capacity of CD34(+) cells cultured in the supernatant of HT1080 cells was increased significantly (P < 0.05), however, this effect could be inhibited by MIP (P < 0.05). The PB WBC numbers of the G-CSF group and G-CSF + MPI group were 14.9 x 10(6)/L +/- 4.3 x 10(6)/L and 12.3 x 10(6)/L +/- 1.2 x 10(6)/L respectively, the PB WBC numbers of the G-CSF + MPI group was significantly lower than that of the G-CSF group (P < 0.05), however, significantly higher than that of the negative control group (6.8 x 10(6)/L +/- 2.5 x 10(6)/L, P < 0.05). The CFU of the G-CSF group was (84 +/- 10) U/2 x 10(5) MNC, significantly higher than that of the G-CSF + MPI group, (69 +/- 3) U/2 x 10(5) MNC (P < 0.05). The BM MNC number of the G-CSF group was 12.7 x 10(6)/L +/- 0.7 x 10(6)/L, not significantly different from that of the G-CSF + MPI groups (13.1 x 10(6)/L +/- 1.3 x 10(6)/L; P > 0.05). CONCLUSION: MMP-9 probably facilitates HSPC mobilization by degrading SDF-1, up-regulating CXCR4 expression on the CD34(+) cells, and increasing the migration ability of CD34(+) cells.