Objective:To explore the role of NK cells in allogeneic hematopoietic stem cell micro-transplantation(MST)in the treatment of patients with acute myeloid leukemia(AML).Methods:Data from 93 AML patients treated with MST at our center from 2013-2018 were retrospectively analyzed.The induction regimen was anthracycline and cytarabine combined with peripheral blood stem cells transplantation mobilization by granulocyte colony stimulating factor(GPBSC),followed by 2-4 courses of intensive treatment with medium to high doses of cytarabine combined with GPBSC after achieving complete remission(CR).The therapeutic effects of one and two courses of MST induction therapy on 42 patients who did not reach CR before transplantation were evaluated.Cox proportional hazards regression analysis was used to analyze the impact of donor NK cell dose and KIR genotype,including KIR ligand mismatch,2DS1,haplotype,and HLA-Cw ligands on survival prognosis of patients.Results:Forty-two patients received MST induction therapy,and the CR rate was 57.1％after 1 course and 73.7％after 2 courses.Multivariate analysis showed that,medium and high doses of NK cells was significantly associated with improved disease-free survival(DFS)of patients(HR=0.27,P=0.005;HR=0.21,P=0.001),and high doses of NK cells was significantly associated with improved overall survival(OS)of patients(HR=0.15,P=0.000).Donor 2DS1 positive significantly increases OS of patients(HR=0.25,P=0.011).For high-risk patients under 60 years old,patients of the donor-recipient KIR ligand mismatch group had longer DFS compared to the nonmismatch group(P=0.036);donor 2DS1 positive significantly prolonged OS of patients(P=0.009).Conclusion:NK cell dose,KIR ligand mismatch and 2DS1 influence the therapeutic effect of MST,improve the survival of AML patients.

Occupational therapists have a significant role in driving rehabilitation by helping clients with disabilities to return to driving. To date, the services for driving rehabilitation are still limited in Malaysia. Furthermore, the current practice of driving rehabilitation in Malaysia is still underreported. Therefore, this study aims to assess occupational therapists’ challenges, attitudes, and skills towards driving rehabilitation, the sociodemographic differences, and associations between the developed constructs. A cross-sectional study was conducted from June to September 2020. A convenience sampling method was used to recruit 177 occupational therapists with at least one year of working experience in Malaysia. The questionnaire consists of three constructs: the challenges, attitudes, and skills related to driving rehabilitation. The content validity of the questionnaire was good (S-CVI/Ave= 0.992; S-CVI/UA= 0.950; modified kappa= 0.812 to 1.000). Based on the Exploratory Factor Analysis (EFA), three items had been deleted due to low communalities. The Cronbach’s alpha for all constructs was acceptable (Cronbach’s alpha > 0.7). Experience in practicing driving rehabilitation, workplace settings, and educational level had significant differences in at least one of the constructs. Age and years graduated had a significant positive correlation with skills. This questionnaire proved to be a tool with good content validity and reliability to assess occupational therapists’ challenges, attitudes, and skills related to driving rehabilitation. In the future, qualitative studies are recommended to better understand the occupational therapists towards driving rehabilitation, especially from their personal experience.

A pre-driving assessment usually involves standardised and non-standardised tests to examine the skills for safe driving of people with disabilities. However, it is still unknown to what extent the pre-driving assessments are being practised among occupational therapists in Malaysia. Therefore, this study aims to investigate the association of challenges, attitudes, and skills of occupational therapists towards practising driving rehabilitation and explore the most used predriving assessment. A cross-sectional study had been conducted from July to September 2020. The convenient sampling method was used to recruit experienced occupational therapists in driving rehabilitation. A total of 53 therapists had completed an online survey. According to the results, the bivariate correlation between skills and challenges was positive and strong (rѕ = 0.680, p < 0.05). A multivariate analysis of variance (MANOVA) indicated that workplace variables had a significant effect on the combined dependent variables of challenges, attitudes, and skills, F(3,49) = 4.521 p = 0.007, partial Ƞ² = 0.217. This study found that the most used standardised assessment was the range of motion (n = 39, 73.6 %) and the right and left discrimination (n = 40, 75.5 %). The findings of this study identified that occupational therapists challenges and attitudes are significantly associated with the skills to practice driving rehabilitation. Malaysian occupational therapists working in the government sector reported better skills than those working in the private sector. Furthermore, numerous types of pre-driving assessments were used and vary from setting to setting. This study hopes to benefit occupational therapists and related rehabilitation practitioners towards a holistic understanding of Malaysia's driving rehabilitation practices.

OBJECTIVETo analyze the relationship between the early treatment response and the pregnosis in children with acute lymphoblastic leukemia(ALL).

METHODSTwo hundred and Seventy-eight ALL children diagnosed and treated in Hainan general hospital from March 2013 to March 2017 were collected. All ALL children received therapy with CCLg-ALL-2008 regimen. The 3 year event-free survival (EFS) rate of ALL children in different groups was analyzed in terms of 4 indexes including sensitivity response to prednison at day 8 (D8-SRP), bone marrow remission at day 15 (D15-BMR) and at day 33 (D33-BMR), and minimal residual disease at day 33 (D33-BMR), and minimal residual disease at day 33(D33-MRD). These 4 indexes and other indexes possibly affecting the prognosis of ALL children were enrolled in Cox regression model for analysis of independent factors affecting the prognosis of ALL children.

RESULTSThe D8-SRP test showed that among 269 ALL children, 240(89.22%) cases displayed prednisone poor response (PPR); the 3-year EFS rate in predrisone good response(PGR) group was significantly higher than that in PPR group(P<0.05). The D15-BMR detection showed that among 262 ALL children, the bone marrow remission(BMR) as M1 was observed in 230 cases (87.79%), M2 in 20 cases (7.63%) and M3 in 9 cases (4.58%); the 3-year EFS rate showed as follows:M1 group >M2 group >M3 group(P<0.05). The D33-BMR detection showed that among 257 ALL children, the BMR as M1 was observed in 227 cases (88.33%), M2 in 21 cses(8.17%) and M3 in 9 caes (3.51%); the 3-year EFS rate in 3 groups showed as follows: M1 group >M2 group >M3 group(P<0.05). The D33-MRD detection showed that among 185 ALL children, MRD<10 was found in 128 cases (69.19%), MRD≥10-10 in 43 cases (23.24%), MRD ≥10 in 14 cases (7.57%); the 3-year EFS rate in 3 groups showed as follows: MRD <10 group > MRD≥ 10-10 group>MRD≥10 group. The Cox regression analysis showed that PPR in D8-SRP test, M2 and M3 in D15 and D33 BMR detection, and MRD≥10 in D33 MRD detection as well as T-ALL typing were independent risk factors affecting the prognosis of ALL children.

CONCLUSIONThe early treatment response can predict the prognosis of ALL children, which is an independent prognostic factor for ALL children.

OBJECTIVETo explore the biological characteristics of microvesicles(MV) derived from bone marrow mesenchymal stem cells (BM-MSC) and their capability supporting ex vivo expansion of hematopoietic stem cells(HSC).

METHODSThe MV from cultured BM-MSC supernatant were isolated by multi-step differential velocity contrifugation; the morphological characteristics of MV were observed by electron microscopy with negative staining of samples; the protein level in MV was detected by using Micro-BCA method; the surface markers on MV were analyzed by flow cytometry. The peripheral blood HSC(PB-HSC) were isolated after culture and mobilization; the experiment was diveded into 2 group: in MV group, the 10 mg/L MV was given, while in control group, the same volume of PBS was given; the change of PB-HSC count was observed by cell counting; the change of surface markers on PB-HSC was detected dynamically by flow cytometry; the cell colony culture was used to determin the function change of PB-HSC after co-culture with MV.

RESULTSMSC-MVs are 20-100 nm circular vesicles under electron microscope. About 10 µg protein could be extracted from every 1×10MSC. The flow cytometry showed that CD63 and CD44 were positive with a rate of 96.0% and 50.2%, while the HLA-DR, CD34, CD29 and CD73 etc were negative. When being co-cultured with GPBMNC for 2 days, the cell number of MV groups was 1.49±0.15 times of the control group (P>0.05). When being co-cultured for 4 days, the cell number of MV groups was 2.20±0.24 times of the control group(P<0.05). The CD34cell number of MV groups was 1.76±0.30 times the control group after culture for 2 day and 1.95±0.20 times after culture for 4 day.

CONCLUSIONThe MV has been successfully extracted from MSC culture supernatant by multi-step differential velocity centrifugation. MSC-MV can promote HSC expansion in vitro.

OBJECTIVETo explore the value of dynamically monitoring minimal residual disease (MRD) by flow cytometry before and after non-myeloablative allo-HSCT (NST) for prediction of acute leukemia(AL) relapse after transplantation.

METHODSThe clinical data of 51 AL patients underwent NST were analyzed retrospectively in Department of Hematology of Affiliated Hospital of Academy of Military Medical Sciences from January 2011 to December 2015. All AL patients achieved the morphologic complete remission of bone marrow before transplantation. The bone marrow samples were collected for monitoring of MRD within 35 days before transplant, every month till 3 months after transplant, every 3 months till 24 months after transplant, and then every 6 months after 2 years of transplant. According to the MRD cutoff value of 0.2%, the AL patients were divided into high level MRD group (18 cases) which was defined as MRD≥0.2% after transplantantion at least for 1 time, and low level MRD group (33 cases) which was defined as MRD<0.2% after transplant all the time. 2 year cumulative relapse rate in 2 groups were compared.

RESULTSTwo-year relapse rates were 6.1% and 50% in low-level MRD group and high-level MRD group post NST(P=0.001)respectively. Multivariate analysis indicated that the risk of relapse in high level MRD group was 5.84 times of low level MRD group(P=0.036). MRD≥0.2% post transplant was an independent risk factor for leukemia relapse post NST. The mortality rate was 81.8% and 46.3%(P<0.05) in relapse and non-relapse groups respectively.

CONCLUSIONDynamically monitoring MRD by FCM is a crucial tool for early relapse estimation of acute leukemia in adult patients after allogeneic nonmyeloablative hematopoietic stem cell transplantation. MRD≥0.2% after transplant can be used as a early valuable evidence for predicting relapse and guiding active medical intervention.

OBJECTIVETo explore the effect of infusing G-CSF mobilized recipient spleen cells at different time after haploidentical stem cell transplantation(HSCT) on graft-versus-host disease (GVHD) in mice and its possible mechanism.

METHODSForty mice after HSCT were randomly divided into 4 groups (n=10): GVHD positive control group (control group), 1st d recipient cell infusion group after transplantation (+1 d group), 4th d recipient cell infusion group after transplantation(+4 d group), 7th d recipient cell infusion group after transplantation(+7 d group). The mice in control group were injected the normal saline of same equivalent with experimental group which were given the same amount of G-CSF-mobilized recipient spleen cells. The general manifestation and pathological change of GVHD were observed. The expression changes of CD3CD4, CD3CD8cell subsets and FasL in peripheral blood were detected by flow cytometry.

RESULTSThe incidence of GVHD was significantly decreased in +4 d group and the median survival time was longer than 60 days, which was significantly higher than that of control group (24 d), +1 d group (21 d), +7 d group (28 d). (P<0.01, P<0.01, P<0.01). The Fasl expression of peripheral blood T lymphocytes in +4 d group were significantly lower than that in the other 3 groups(P<0.05).

CONCLUSIONThe +4 d infusion of G-CSF mobilized recipient spleen cells on 4th day after haploidentical HSC transplantation can inhibit the expression of FasL in donor T lymphocytes, and significantly reduce the incidence of GVHD.

OBJECTIVETo investigate the effects of microvesicles(MV) isolated from human peripheral blood hematopoietic stem cells(PB-HSC) on immune regulation and hematopoiesis.

METHODSPB-HSCs were separated by density-gradient centrifugation and cultrued. The supernatants of PB-HSC at 48 h were harvested for isolation and purification of MV by using ultracentrifugation. The electron microscopy was used to observe the morphology of MV. The protein level in MV was quantified through bicinchoninic acid(BCA) protein assay. Flow cytometry was used to detect the immunophenotype of MV. Human peripheral blood mononuclear cells(PB-MNC) were isolated from healthy donor and treated with isolated MV. After being co-cultured for 12 h, confocal microscopy was used to observe the action mode of MV on PB-MNC. After being co-cultured for 48 h, the levels of IL-2, IL-6, IL-8, IL-10, IFN-γ and TNF-α were detected by ELISA. Flow cytometry was used to detect the changes of T cell subsets and the activation of T cell subsets as well as intracellular cytokine staining after co-culture for 48 h. The methylcellulose was used to assess the hematopoiesis-supportive function of MV as well as co-cultured supernatants.

RESULTSThe eletron microscopy revealed that MV were elliptical membrane vesicles. The protein amount in MV ranges from 29 to 110 µg. Flow cytometry showed that MV expressed mix markers on the surface, especially highly expressed MV specific marker CD63(85.86%) and hematopoietic stem cell marker CD34(33.52%). After being co-cultured for 12 h, confocal microscopy showed that MV were merged with PB-MNC. After being co-cultured for 48 h, ELISA showed that the secretion of cytokines IL-6,IL-8, IL-10 as well as TNF-α was increased while the level of IL-2 and IFN-γ was not changed much. The results of flow cytometry showed that there was no significant change in T cell subsets and T cell activation. Staining of intracellular factor showed that IL-8 was increased significantly in CD11ccells. The colony-forming experiments revealed that MV and the co-cultured supernatants could facilitate the colony formation.

CONCLUSIONMV isolated from PB-HSC have immune-regulatery function and can prornote hematopoiesis.

OBJECTIVETo establish a new mouse model of H-2 haploidentical stem cell transplantation from double donors (DHSCT) and compare with conventional haploidentical hematopoietic stem cell transplantation (HSCT) so as to alleviate transplant-related complications.

METHODSThe recipients CB6F1 of conventional HSCT group were pretreated by 8 Gy total body irradiation(TBI), and received 3×10donor (male C57) spleen mononuclear cells (spMNC) mobilized by G-CSF within 2 hours after TBI. Recipients CB6F1 of D-HSCT groups accepted 2 Gy TBI, and received total 12×10spMNC mobilized by G-CSF from 2 donors within 2 hours after TBI, each donor donated 6×10cells. According to the different strains and sex of donors, DHSCT were divided into 3 groups: in group A, the stem cells were from male C57 and female BALB/c; in group B, stem cells were from male C57 and male BALB/c, while the stem cells in group C were from male C57 and male C3H. Hematopoietic reconstruction, engraftment, GVHD and survival were observed among these 4 groups.

RESULTSThe nadir of white blood cell count after conventional HSCT were lower than 1×10/L and lasted for 3 to 5 days, while not less than 3×10/L after D-HSCT among either group A, B or C. The complete chimerism (CC) in conventional HSCT group was achieved quickly within only 1 week in peripheral blood. Mixed chimerism (MC) in peripheral blood was found within the first week after DHSCT among either group A, B or C, and transformed into stable CC within the second week eventually. Both GVHD morbidity and mortality of conventional HSCT were 100% at 34th day after transplantation.Among DHSCT groups,the overall GVHD morbidity and mortality at 34th day after transplant were 49.6% and 50%(P<0.01,P<0.05), respectively,and 60.4% and 81.2% at 50th day after transplant. Overall survival of 50 days was 50.9% that indicated a long survival in such mice DHSCT. The differences of hematopoietic reconstruction, donor cell engraftment, GVHD incidence, GVHD mortality and OS were not statistically significant among group A, B and C(P>0.05).

CONCLUSIONA new mouse model of H-2 haploidentical peripheral blood stem cell transplantation from double donors (DHSCT) has been successfully established by reducing conditioning intensity and increasing graft cell numbers from double haploidentical donors without GVHD prophylaxis. DHSCT successfully achieved stable complete chimerism, less GVHD morbidity and mortality and longer OS without hematopoietic suppression. This study provides experimental evidence for clinical application of HLA haploidentical peripheral blood stem cell transplantation from double donors.

OBJECTIVETo explore the features of immunophenotypes and the characteristics of molecular biology and cellular genetics of AML patients with CD7 and CD4 expression.

METHODSThe immunophenotypical markers of AML cells were detected by multiple parameter flow cytometry; the expression of WT1, MDK, ETO, PML-RaRa and BCR-ABL were detected by RT-PCR; and cellular features were analyzed by R-band in 304 patients. The patients were divided into three groups according to their immunophenotypes: AML with CD7 expression (CD7 group), AML with CD4 expression(CD4 group) and AML without CD7 and CD4 expression (common AML group).

RESULTSThe expression rate and level of HLA-DR in CD7 group were higher than those in the common AML group, and the expression rate of CD33 and CD34 was higher than that in the other two groups. The expression rate and level of CD15, CD64 in the CD4 group were higher than those in the other 2 groups, and the expression rate and level of CD33 were higher than those in the common AML group. WT1 expression in the CD7 group was lower than that in the common AML group. PML-RaRa was not detected in the CD7 group. AML with co-expression of CD4 or CD7 showed more normal karyotype. (15;17) was not found in AML with CD7 expression.

CONCLUSIONAML cells with CD7 expression originate from precursor cells and are blocked in the early phase of hematological development; AML cells with CD4 expression originate from more mature stage of hematological devevelopment and with CD33, CD64 and CD15 high expression; AML cells with CD7 and CD4 expression are characterized by no-specific change of cellular genetics. According to the expression level and intesity of CD4 and CD7, and together with other specific lineage markers, the MRD in AML patients can be quantitatively detected.