[NCTD Retards AML HL60 Cell Proliferation via Targeting Hedgehog/SOX2 axis].

OBJECTIVE: To investigate the effect of norcantharidin (NCTD) to proliferation of leukemia cells through disrupting key regulators of sonic Hedgehog (SHH) pathway and its downstream transcription factor SOX2. METHODS: CCK8 was used to detected the HL60 and NB4 cells after inhibited by NCTD, SMO and GLI1 inhibitor for 24 hours. Expression level of SMO, GLI1 and SOX2 in HL60 cells with NCTD treatment was detected by immunoblot. HL60 cells were transfected with pcDNA3.1 plasmid expressing GLI1 or SOX2. Empty vector and pcDNA3. 1-EGFP were divided into negative and positive control group, respectively. The expression of exogenous GLI1 or SOX2 in HL60 cells was confirmed by immunoblot, and growth curve of HL60 cell was checked by CCK8. Proliferation of genetic modified HL60 cells treated by various dose of NCTD was detected. RESULTS: NCTD, SMO/GLI1 inhibitors could inhibit the proliferation of NB4 and HL60 cells in a dose-dependent manner. Compared with solvent (DMSO)-treated control group, NCTD remarkably decreased protein level of SMO, GLI1 and SOX2. GLI1 and SOX2 were overexpressed in HL60 cells as compared with pcDNA3.1 empty vector-transfected group. Growth curve demonstrated significant proliferative advantage of GLI1/SOX2-transfected cells. CCK8 assay indicated that GLI1/SOX2-overexpressed HL60 cells were more resistant to NCTD treatment. CONCLUSION: NCTD attenuates HL60 proliferation via targeting the Hedgehog/SOX2 axis.

[Effects of IDH2 Gene Mutation on Clinical Characteristics and Prognostic of Patients with Acute Myeloid Leukemia].

OBJECTIVE: To analyze the prevalence, clinical characteristics and prognostic significance of the isocitrate dehydrogenase 2(IDH2) mutations in patients with acute myeloid leukemia(AML). METHODS: The bone marrow samples of 223 patients with newly diagnosed AML confirmed by MICM typing from January 2015 to October 2018 were collected. The mutation of exon 4 of IDH2 gene was detected by direct sequancing of PCR product; the incidence and types of IDH2 gene mutation in AML patients were analyzed; the clinical characteristics of AML patients with IDH2 gene mutation were analyzed and the therapeutic efficacy for these patients was evaluated. RESULTS: In a cohort of 223 AML patients, mutations were detected in 23(10.31％) patients, among them, 15 with R140Q mutations(65.22%) , 6 with R172K mutations(26.09%) and 2 with R140W mutations(8.70%). The median age in IDH2 mutated group was older than that in non.mutated group(P=0.008). The platelet level at initial diagnosis in IDH2 mutated group was higher than that in non.mutated group(P=0.010). There was no significant statistical difference between IDH2 mutated group and non.mutated group in FAB subtypes of AML(P>0.05). But the rate of IDH2 mutation in M4 and M5 was higher. The rate of IDH2 mutations was higher in AML with normal karyotype and in AML with NPM1 mutations. R140Q mutations associated with NPM1 mutations(χ2=8.481，P=0.004), but R172K mutations not associated with NPM1 mutation(P>0.05). IDH2 mutated patients had a lower complete remission rate than non.mutated patients(57.14% vs 80.46%, χ2=5.927，P=0.015). The complete remission rate of R140Q mutated patients was not significantly statistically different from non.mutated patients. The complete remission rate of R172K mutated patients was very significantly lower than non.mutated patients(χ2=7.734，P=0.005). In the patients without NPM1 mutation, the 2 years overall survival in IDH2 mutated group was lower than in non.mutated group(36.36% vs 66.40%,χ2=3.958，P=0.047), the 2 years overall survival of R172K mutated group was significantly lower than non.mutated group(although P>0.05). In all patients, the 2 years overall survival between IDH2 mutated group and non.mutated group was not statistically different(50% vs 66.88%,P>0.05), the 2 years overall survival of R172K mutated group was significantly lower than non.mutated group(although P>0.05). In the patients with normal karyotype or with mutated NPM1, the 2 years overall survival between IDH2 mutated group and non.mutated group was not statistically different(P>0.05). CONCLUSION: IDH2 gene mutations are more common in AML patients at older age, higher platelets level and normal karyotype. The rate of IDH2 mutation in M4 and M5 is higher. IDH2 gene mutations associate with NPMl gene mutations, but R172K mutations not associates with NPM1mutation. IDH2 gene mutations associate with prognosis of AML patients, R140Q mutations have no effect on prognosis of patients, but R172K mutations may be the molecular markers for poor prognosis in AML patients.

[Galectin-3 Expression and Its Clinical Significance in Acute Myeloid Leukemia with Positive AML1/ETO Fusion Gene].

OBJECTIVE: To investigate the mRNA expression of galectin-3 and its clinical significance in acute myeloid leukemia (AML) patients carrying AML1/ETOfusion gene. METHODS: RQ-PCR method was used to detect the expression of galectin-3 mRNA in bone marrow mononuclear cells of 53 AML patients with AML1/ETO+, ELISA was used to detect the expression of galectin-3 protein in peripheral blood, and the correlations of galectin-3 expression with clinical and laboratory features and outcomes were analyzed. RESULTS: The mRNA and protein levels of galectin-3 were significantly higher in newly diagnosed AML1/ETO+ AML patients compared with the control ( P<0.001). Galectin-3 mRNA and protein expressions were positively correlated (r=0.732, P<0.001). Galectin-3 protein was significantly decreased during the period of complete remission (CR)( P<0.001). The mRNA expression of galectin-3 was negatively correlated with the count of white blood cells ( P=0.014), and positively correlated with CD34 expression and additional cytogenetic aberrations (ACA) ( P=0.001, P=0.026). There was no significant difference in CR, partial remission (PR), induction death (early mortality) between galectin-3 high-expression group and low-expression group ( P>0.05), but there was significant difference in recurrence rate between the two groups ( P=0.029). The median overall survival (OS) rate and disease-free survival (DFS) rate were shortened in the high-expression group ( P=0.007, P=0.015) and the cumulative incidence of relapse was increased ( P=0.045), but there was no significant difference in the cumulative incidence of CM(155mm]mortality ( P>0.05). Cox regression analysis suggested galectin-3 mRNA level an independent indicator of OS and DFS in AML1/ETO+ AML patients. CONCLUSION: Bone marrow galectin-3 mRNA level may be an important reference index for evaluating the prognosis and guiding the treatment of AML1/ETO+ AML patients.

Clinical impact of galectin-3 in newly diagnosed t (15;17)(q22;q21)/PML-RARa acute promyelocytic leukemia treated with all-trans retinoic acid and arsenic trioxide-based regimens.

Increased galectin-3 expression has been currently showed to be associated with poor prognosis in some hematological malignancies, such as acute myeloid leukemia, diffuse large B cell lymphoma. However, little is known about the clinical significance of galectin-3 in patients with acute promyelocytic leukemia (APL). We investigated the concentration of serum galectin-3 and characterized the relationship between galectin-3 and outcome in patients with APL. Higher galectin-3 levels were detected in patients with APL compared with the healthy controls (p < 0.001). Higher galectin-3 levels were closely associated with older ages (p < 0.001), the medical history of psoriasis (p = 0.036), coagulopathy (p = 0.042), and CD34 expression (p = 0.004). Compared with patients with lower galectin-3 levels, those with higher galectin-3 levels had significant shorter overall survival (p = 0.028) and relapse-free survival (p = 0.001). Multivariate analysis showed that serum galectin-3 was an independent unfavorable factor for relapse-free survival in patients with APL treated with all-trans retinoic acid and arsenic trioxide-based frontline therapy. Clinical impact of galectin-3 should be further investigated in patients with APL.

Clinical significance of galectin-3 in patients with adult acute myeloid leukemia: a retrospective cohort study with long-term follow-up and formulation of risk scoring system.

Galectin-3 plays an increasingly important role in development and progression of tumor. However, little is known about the clinical impact of galectin-3 in non-acute promyelocytic leukemia (non-M3 AML). Peripheral blood of 298 patients with primary non-M3 AML and 30 normal donors was collected for measurement of galectin-3. Galectin-3 levels were significantly higher compared with the control group (p < .001). Patients with higher galectin-3 levels had lower CR rates (p = .001) and 1-year overall survival (OS) rates (p = .002). The Kaplan-Meier survival analysis showed that higher galectin-3 levels group had significantly shorter OS. Cox regression model revealed high galectin-3 level was an independent poor prognostic factor. A scoring system incorporating galectin-3 and other prognostic factors (age, WBC, karyotype, NPM1/FLT3-ITD, CEBPAdouble-mutation and c-KIT, WT1) was formulated to predict prognosis. In conclusion, galectin-3 may be a reliable prognostic marker in AML patients. The multifactorial scoring system was more powerful than a single factor to predict clinical outcome.

Significance of ETV6 rearrangement in acute promyelocytic leukemia with t(15;17)/promyelocytic leukemia/retinoic acid receptor alpha.

Acute promyelocytic leukemia (APL) is a common subtype of acute myeloid leukemia in China. Since the application of arsenic trioxide and all-trans retinoic acid in the treatment of APL, the prognosis has greatly improved. However, ~20% of patients with APL relapse upon completing chemotherapy. Decreasing the relapse rate and incidence of early mortality may pose the greatest challenges for the future management of APL. Recently, Ets variant 6 (ETV6) was reported to be involved in a variety of translocations associated with hematological malignancies of myeloid and lymphoid origin. To date, little is known about the clinical implication of ETV6 rearrangement in APL. In the present study, ETV6 rearrangement was examined by split-signal fluorescence in situ hybridization in 258 adults with APL, and its association with the clinical features and outcomes of the patients was analyzed. The data suggested that ETV6 rearrangement may be an independent unfavorable prognostic factor for overall survival in APL patients.

Synchronous occurrence of gastrointestinal stromal tumor and acute myeloid leukemia: A case report and review of the literature.

Gastrointestinal stromal tumors (GISTs) originate from the mesenchymal tissue of the gastrointestinal tract. The pathogenesis of GIST is associated with the mutational activation of the receptor tyrosine kinase cluster of differentiation (CD)117 or platelet-derived growth factor receptor-α. Overall, ~60% of GISTs occur in the stomach. Clinically, GISTs may coexist with various types of cancer, including liver cancer, pancreatic tumors and lymphoma, either synchronously or metachronously. The present study reports the case of a patient with the synchronous occurrence of a CD117-positive GIST and acute myeloid leukemia. A 69-year-old man was hospitalized for heart palpitations and dizziness, and was diagnosed with acute myeloid leukemia (AML) by bone marrow aspiration and flow cytometry analysis. An abdominal computed tomograpy and gastroscopy revealed the presence of GIST. The patient received chemotherapy in combination with imatinib (400 mg/day), and the mass was removed 2 months later. To the best of our knowledge, the present study is the first reported case of the synchronous development of a CD117-positive GIST and AML. Additional studies are required in order to understand the association between GIST and hematological malignancies.

Regrowth of Broken Hydroxide Flocs: Effect of Added Fluoride.

Hydrous oxides of Al(III) and Fe(III) play a large part in environmental processes and in the action of coagulants used in water and wastewater treatment. Aggregates (flocs) of hydroxide precipitates can be rather weak and are easily broken by applied shear. It is usually found that broken flocs do not fully regrow under low-shear conditions, and this could be a serious disadvantage in practical applications. The irreversible nature of floc breakage suggests that some form of specific, chemical interaction between precipitate particles must be at least partly responsible. On the basis of experiments reported here and elsewhere, we propose that hydroxyl bridges between particles play a part. When these are broken, there is a reduction in the number of "active" surface groups that are able to form new bridges. When small amounts of fluoride are added during breakage of Al flocs, there can be significant improvement in floc regrowth, although this depends on a number of factors, especially pH. With Fe flocs, fluoride has no noticeable effect. These results can be explained by the formation of soluble Al-F complexes and some dissolution of the Al(OH)3 precipitate. This creates a new surface with more "active" groups that can form new hydroxyl bridges.

Blastic plasmacytoid dendritic cell neoplasm with leukemic manifestation and ETV6 gene rearrangement: A case report.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare malignant tumor of the hemopoietic system that arises from plasmacytoid dendritic cell precursors with a highly aggressive course. BPDCN frequently involves the skin, lymph nodes, peripheral blood and bone marrow. BPDCN is known to develop leukemic dissemination as a feature of myelomonocytic leukemia in the late phase of the disease, which leads to a poorer prognosis. In the present study, a case of BPDCN with leukemic manifestation without cutaneous involvement was reported. In addition, ETS variant gene 6 (ETV6) gene rearrangement was detected in the patient. The patient relapsed soon after complete remisson and had no response to further treatment. To the best of our knowledge, this is the first reported case of BPDCN with ETV6 rearrangement. Following chemotherapy treatment, the patient suffered from severe headache in the complete remission stage; however, brain CT scans showed no significant abnormalities. Several lumbar punctures and intrathecal chemotherapy were performed, and the patient recovered gradually. Therefore, the patient was considered to suffer from central nervous system leukemia. In conclusion, implementation of lumbar punctures and preventive intrathecal chemotherapy are required in BPDCN patients with leukemic manifestation during the remission stage.

[Hypercoagulable state in patients with multiple myeloma].

OBJECTIVE: This study was to detect the plasma thrombomodulin (TM), D-dimer and fibrinogen in patients with multiple myeloma (MM) and to analyze their relationship with morbid state, and also to investigate the relationship of the expression of coagulation factor with the ratio of myeloma cells. METHODS: ELISA was used to detect the TM level in 45 cases of MM at different stages. The plasma level of D-dimer and fibrinogen was detected by STA automatic coagulation analyser. RESULTS: The level of plasma TM in newly diagnosed patients was higer than that in normal control group and in platform stage group (P < 0.01; P < 0.05). There were significant differences between relapsed or refractory group and normal control group or those reached platform stage group (P < 0.05). Meanwhile, the level of plasma TM in the group of thalidomide combined with chemotherapy was higer than that in newly diagnosed patients (P < 0.05). The level of plasma D-dimer and fibrinogen of MM patients was higher than that in normal controls (P < 0.01;P < 0.05). The expression of D-Dimer in relapsed or refractory group reached the maximum. Also, the level of plasma D-Dimer in group of thalidomide combined chemotherapy was higer than in newly diagnosed patients (P < 0.05). The expression of coagulation factor did not correlate with the ratio of myeloma cells. CONCLUSIONS: Level of plasma TM, D-Dimer and fibrinogen of MM patients is higher than that in control group. The level of plasma TM and D-Dimer can be elevated when thalidomide used, which indirectly suggested the tendency for thrombosis in MM patients.

A phase II trial of post-operative chemoradiotherapy for completely resected gastric cancer with D2 lymphadenectomy.

The optimal post-operative adjuvant treatment for completely resected gastric cancer with D2 lymphadenectomy remains controversial. The present study was a phase II trial on post-operative chemoradiotherapy in 30 patients with gastric cancer. Patients with stage II to IV (M0) gastric cancer received two cycles of chemotherapy prior to and following chemoradiotherapy. The chemotherapy consisted of a 2-h infusion of oxaliplatin (100 mg/m2) and folinic acid (100 mg/m2), which was followed by a 46-h continuous infusion of 5-fluorouracil (5-FU; 2,400 mg/m2) through a portable pump, repeated every 3 weeks. The chemoradiotherapy consisted of 45 Gy of radiotherapy for 5 weeks and 5-FU continuous infusion (350 mg/m2/day). In total, 30 patients were enrolled in this study. All patients underwent the chemoradiotherapy treatment as planned. A total of 10 (33.3%) patients relapsed; two (6.7%) locoregional relapses and mediastinum metastases, four (13.3%) peritoneal relapses, and four (13.3%) distant metastases. The three-year overall survival and disease-free survival rates were 72.7 and 65%, respectively. The toxicities of chemotherapy and radiotherapy, consisting of neutropenia, nausea and hand-foot syndrome, were observed. In conclusion, post-operative chemoradiotherapy following complete resection of gastric cancer with D2 lymphadenectomy is feasible in a significant subset of patients.

A phase II study of preoperative chemotherapy with modified FOLFOX6 followed by surgery and postoperative chemoradiation in patients with localized gastric adenocarcinoma.

The optimal neoadjuvant and adjuvant treatment for gastric cancer remains controversial. We conducted a phase II study using preoperative chemotherapy with modified FOLFOX6 followed by surgical resection and postoperative chemoradiation in patients with gastric carcinoma. Preoperative chemotherapy (two or three cycles) consisted of a 2-h infusion of oxaliplatin (100 mg/m2) and folinic acid (100 mg/m2) followed by a 46-h continuous infusion of 5-fluorouracil (5-FU; 2,400 mg/m2). Surgical resection was planned 4 weeks after the last chemotherapy cycle. Patients underwent postsurgical chemoradiation, receiving a total dose of 45 Gy and 5-FU continuous infusion (350 mg/m2/day). The primary end points were feasibility, overall response rate, and R0 resectability rate after preoperative chemotherapy. The secondary end points were tolerability, treatment-associated complications, disease-free survival, and overall survival. Nineteen patients were enrolled in this study. After neoadjuvant treatment, four patients (21.1%) experienced progressive disease, six patients (31.6%) showed partial remission, and nine patients (47.3%) showed stable disease. In 15 patients (78.9%) R0 resectability could be achieved. Eleven of these patients (73.3%) were able to undergo postoperative chemoradiation. Notably, eight (72.7%) of these patients were disease free and alive at median follow-up of 60 months. Chemotherapy associated neutropenia, neutropenic fever, and anastomotic dehiscence were observed. The combination of preoperative chemotherapy and postoperative chemoradiation is feasible in a significant subset of gastric cancer patients.

[Effect of natural organic matter on coagulation efficiency and characterization of the flocs formed].

Coagulation is an efficient way to remove the natural organic matter in water. Our works primarily focused on the effect of natural organic matter on coagulation and the properties of the flocs formed. PACl25 was used as the coagulant in this research to simulate the process of coagulation, and typical substance of NOM, humic acid and citric acid were used to prepare the model water. The impact of NOM on the size, fractal dimension, Zeta potential of the flocs and residual aluminum in solution was explored. The experiment results showed that as the concentration of humic acid and citric acid increased in the experimental range, the size and growth velocity of flocs, Zeta potential and fractal dimension showed a tendency of decrease (when the concentration of humic acid increased from 0 mg x L(-1) to 10 mg x L(-1), citric acid increased from 0 micromol x L(-1) to 7 micromol x L(-1), the size of flocs before breakage was decreased by 34.2% and 53.1%, respectively, the Zeta potential decreased from about 10 mV to approximately -10 mV and -2.5 mV, the growth velocity of the flocs was decreased by 42.6% and 77.5%, and the fractal dimension declined by 0.08 and 0.094), which showed the occupying of the floc surface by NOM resulted in the decrease of its activity and compactivity. However, the residual aluminum was not affected by the decrease of coagulation efficiency.

Effect of enhanced coagulation by KMnO(4) on the fouling of ultrafiltration membranes.

Pre-coagulation enhanced by KMnO(4) before ultrafiltration (KCUF) was compared with normal pre-coagulation by alum (CUF) in the ultrafiltration of water from the Songhua River, China. The trans-membrane pressure (TMP) with KCUF was much lower than that when alum alone was used. With KCUF a slower increment of TMP occurred, even under conditions of high river water turbidity. The results also showed that the removal of COD, UV(254) and TOC was appreciably higher after adding 0.5mg/L KMnO(4) compared with CUF. Although assimilable organic carbon (AOC) was increased by permanganate treatment, the AOC of the permeate from KCUF was nearly the same as that from CUF, showing that the cake layer on the surface of KCUF membrane could adsorb small molecules more effectively than that of CUF. This result was confirmed by the apparent molecular weight (MW) distribution measured by size exclusion chromatography (SEC). It was shown that flocs formed by KMnO(4) and alum were larger than those formed only by alum, causing higher removal of flocs and higher permeation flux. Lower NOM was found in the permeate from the KCUF systems because oxidation and adsorption of organic matter on the flocs occurred. The membrane was partly clogged by organic matter or other materials including some small flocs.

Effect of two-stage coagulant addition on coagulation-ultrafiltration process for treatment of humic-rich water.

A novel two-stage coagulant addition strategy applied in a coagulation-ultrafiltration (UF) process for treatment of humic-rich water at neutral pH was investigated in this study. When aluminum sulfate (alum) doses were set at a ratio of 3:1 added during rapid mix stage and half way through flocculation stage, the integrated process of two-stage alum addition achieved almost the same organic matter removal as that of conventional one-stage alum addition at the same overall dose. Whereas membrane fouling could be effectively mitigated by the two-stage addition exhibited by trans-membrane pressure (TMP) developments. The TMP developments were found to be primarily attributed to external fouling on membrane surface, which was closely associated with floc characteristics. The results of jar tests indicated that the average size of flocs formed in two-stage addition mode roughly reached one half larger than that in one-stage addition mode, which implied a beneficial effect on membrane fouling reduction. Moreover, the flocs with more irregular structure and lower effective density resulted from the two-stage alum addition, which caused higher porosity of cake layer formed by such flocs on membrane surface. Microscopic observations of membrane surface demonstrated that internal fouling in membrane pores could be also remarkably limited by two-stage alum addition. It is likely that the freshly formed hydroxide precipitates were distinct in surface characteristics from the aged precipitates due to formation of more active groups or adsorption of more labile aluminum species. Consequently, the flocs could further connect and aggregate to contribute to preferable properties for filtration performance of the coagulation-UF process. As a simple and efficient approach, two-stage coagulant addition strategy could have great practical significance in coagulation-membrane processes.

Characterization of organic membrane foulants in a submerged membrane bioreactor with pre-ozonation using three-dimensional excitation-emission matrix fluorescence spectroscopy.

This study focuses on organic membrane foulants in a submerged membrane bioreactor (MBR) process with pre-ozonation compared to an individual MBR using three-dimensional excitation-emission matrix (EEM) fluorescence spectroscopy. While the influent was continuously ozonated at a normal dosage, preferable organic matter removal was achieved in subsequent MBR, and trans-membrane pressure increased at a much lower rate than that of the individual MBR. EEM fluorescence spectroscopy was employed to characterize the dissolved organic matter (DOM) samples, extracellular polymeric substance (EPS) samples and membrane foulants. Four main peaks could be identified from the EEM fluorescence spectra of the DOM samples in both MBRs. Two peaks were associated with the protein-like fluorophores, and the other ones were related to the humic-like fluorophores. The results indicated that pre-ozonation decreased fluorescence intensities of all peaks in the EEM spectra of influent DOM especially for protein-like substances and caused red shifts of all fluorescence peaks to different extents. The peak intensities of the protein-like substances represented by Peak T(1) and T(2) in EPS spectra were obviously decreased as a result of pre-ozonation. Both external and internal fouling could be effectively mitigated by the pre-ozonation. The most primary component of external foulants was humic acid-like substance (Peak C) in the MBR with pre-ozonation and protein-like substance (Peak T(1)) in the individual MBR, respectively. The content decrease of protein-like substances and structural change of humic-like substances were observed in external foulants from EEM fluorescence spectra due to pre-ozonation. However, it could be seen that ozonation resulted in significant reduction of intensities but little location shift of all peaks in EEM fluorescence spectra of internal foulants.

Breakage and regrowth of Al-humic flocs--effect of additional coagulant dosage.

The growth, breakage and regrowth of flocs formed by aluminum sulfate (alum) with humic acid (HA) in water at neutral pH was investigated by jar testing with continuous optical monitoring. Various initial dosages of alum and different breakage shears were investigated to compare the floc strengths and to explore the growth of flocs and regrowth of broken flocs. In all cases there was significant irreversibility of floc breakage when no additional coagulant was added. On the other hand, when a small additional dosage of alum was added to the suspension during floc breakage, the size of regrown flocs was higher than that before breakage. The result did not change with the variation of the initial dosage of alum, and the intensity and duration of floc breakage, provided that the additional coagulant was added shortly before the end of the breakage process. It seems that aluminum hydroxide is better able to form flocs, when newly precipitated, rather than after an extended period of high shear.

[The effects of B7H4 on human bone marrow mesenchymal stem cell inhibiting proliferation of PHA activated T cells].

OBJECTIVE: To investigate the effects of B7H4 on human bone marrow mesenchymal stem cells (HBMSC) mediating immune suppression. METHODS: The expression of the negative immunoregulatory factor B7H4 on HBMSC were analyzed by RT-PCR and flow cytometry (FCM), respectively. The blocking experiment was used to detect the effects of B7H4 on HBMSC mediating suppression on PHA induced T cell activation, proliferation and cell cycle. HBMSC inhibiting T cell proliferation was examined by transwell cell culture system. RESULTS: B7H4 was highly expressed on HBMSC. Blocking the B7H4 expression by B7H4mAb significantly attenuated the inhibitory effects of HBMSC on T cell proliferation. Compared with that of the unblocking group, T cell stimulator index (SI) of the B7H4 blocked group was significantly increased (53 +/- 5 vs 15 +/- 8, P < 0.01) and the inhibitory effects of HBMSC on T cell cycle were weakened significantly through down-regulating the cell number in G(0)/G(1) phase \[(85.6 +/- 9.9)% vs (95.8 +/- 9.9)%\] and up-regulating those in S phase\[(5.8 +/- 3.2)% vs (2.3 +/- 2.2)%, P < 0.05\]. The suppressive effects of HBMSC on T cell proliferation were significantly weakened after separating HBMSC from T cells by transwell cell culture system. Compared with the cell to cell contact group, T cell SI was significantly increased (27 +/- 17 vs 15 +/- 3, P < 0.01). CONCLUSION: HBMSC highly express B7H4, which plays an important role in the suppressive effects of HBMSC on T cell proliferation.