[The Role of NK Cells in Allogeneic Hematopoietic Stem Cell Micro-Transplantation for Acute Myeloid leukemia]

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.

[Epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023]

Objective: To understand the epidemiological characteristics of human respiratory syncytial virus (HRSV) among acute respiratory infection (ARI) cases in 16 provinces of China from 2009 to 2023. Methods: The data of this study were collected from the ARI surveillance data from 16 provinces in China from 2009 to 2023, with a total of 28 278 ARI cases included in the study. The clinical specimens from ARI cases were screened for HRSV nucleic acid from 2009 to 2023, and differences in virus detection rates among cases of different age groups, regions, and months were analyzed. Results: A total of 28 278 ARI cases were enrolled from January 2009 to September 2023. The age of the cases ranged from<1 month to 112 years, and the age M (Q1, Q3) was 3 years (1 year, 9 years). Among them, 3 062 cases were positive for HRSV nucleic acid, with a total detection rate of 10.83%. From 2009 to 2019, the detection rate of HRSV was 9.33%, and the virus was mainly prevalent in winter and spring. During the Corona Virus Disease 2019 (COVID-19) pandemic, the detection rate of HRSV fluctuated between 6.32% and 18.67%. There was no traditional winter epidemic peak of HRSV from the end of 2022 to the beginning of 2023, and an anti-seasonal epidemic of HRSV occurred from April to May 2023. About 87.95% (2 693/3 062) of positive cases were children under 5 years old, and the difference in the detection rate of HRSV among different age groups was statistically significant (P<0.001), showing a decreasing trend of HRSV detection rate with the increase of age (P<0.001). Among them, the HRSV detection rate (25.69%) was highest in children under 6 months. Compared with 2009-2019, the ranking of HRSV detection rates in different age groups changed from high to low between 2020 and 2023, with the age M (Q1, Q3) of HRSV positive cases increasing from 1 year (6 months, 3 years) to 2 years (11 months, 3 years). Conclusion: Through 15 years of continuous HRSV surveillance analysis, children under 5 years old, especially infants under 6 months old, are the main high-risk population for HRSV infection. During the COVID-19 pandemic, the prevalence and patterns of HRSV in China have changed.

[Analysis on Cellular Immune Function Recovery after HLA Mismatched Allogeneic Hematopoietic Stem Cell Micro-Transp- lantation in Elderly AML Patients]

OBJECTIVE

To investigate the recovery of cellular immunity in elderly patients with acute myeloid leukemia (AML) after micro-transplantation (MST) and the changes of cellular immunity during relapse, as well as their clinical significance.

METHODS

A total of 41 elderly AML patients who received MST treatment in a single center and 25 healthy elderly people were included. Immune function among different age groups in normal population was compared. Furthermore, immune fuction was compared between elderly AML patients of different age groups who achieved continuous complete remission (CR) after MST treatment and normal controls, between high risk group and medium-low risk group, as well as among before diagnosis, after CR, and relapse. Peripheral blood of patients and normal controls was collected, and the percentage of lymphocyte subsets was detected by multi-color flow cytometry.

RESULTS

Thirty-five patients achieved CR after MST treatment while six patients did not. After MST treatment, CD3+ T cells, CD8+T cells and activated T cells in all age groups were higher than normal. Significant recovery of CD3+ and CD8+T cells was observed in both high risk and medium-low risk groups, and the overall recovery of immune cells in medium-low risk group was better. It was also observed that B lymphocytes and NK cells could not return to normal levels within 1 year after MST treatment. The proportion of CD3+ T cells, CD4+ T cells, and CD4/CD8 ratio were significantly decreased during relapse compared with continuous CR after MST (P<0.05).

CONCLUSION

MST treatment can promote the recovery of CD3+T cells, CD8+T cells and other killer cells, so as to improve the cellular immune function of elderly patients, which provides a new immune cell therapy for elderly AML.

Mechanisms of thymic repair of in vitro-induced precursor T cells as a haplo-identical HSCT regimen

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is currently an effective treatment for malignant hematological disease, but the immune deficiency and severe infection triggered by slow immune reconstitution are the main causes of high mortality and transplant failure. One of these outstanding problems is thymus damage, which is associated with graft-versus-host disease (GVHD), and preconditioning including irradiation and chemotherapy. Therefore, rapid repair of damaged thymus and rapid proliferation of thymus-derived donor T cells after transplantation are key to solving the problem. This study is designed to accelerate the recovery of thymus-derived T cells after transplantation. Wild-type mice with normal immunity were used as recipients in a haplo-HSCT mouse model to mimic clinical haplo-HSCT. A modified cell culture system using Notch ligand Delta4 and IL-7 was established that is capable of inducing and amplifying the differentiation and proliferation of hematopoietic stem cells into precursor T (preT) cells in vitro. Haplo-HSCT protocol included the preT and G-CSF mobilized donor splenic mononuclear cells (MNC) co-infusion or MNC alone. Thymic GVHD, thymic repair, and thymus-derived T cell development were compared in two groups by polychromatic immunofluorescence tracking, flow cytometry and detection of T cell receptor Vβ. The thymus homing and T-cell regeneration of allogenic preT cells were observed. The functions of preT cells in accelerating immune reconstitution, restoring thymic architecture, weakening GVH effects, and enhancing immuno-tolerance after transplantation were demonstrated. Further studies revealed that allogeneic preT cells induced by a culture system containing IL7 and Delta4 highly express ccr9 and RANKL. Interestingly, the RANK expression was promoted after preT cells' thymus homing. These results suggested that the RANK/RANKL pathway may play an important role in thymus homing. Our results provide a potential therapeutic option to optimize haplo-HSCT. It further opened up a new field of T cell therapy for artificial induction of allogeneic precursor T cells in vitro to repair the damaged thymus from irradiation and chemotherapy, and to compensate for the recovery of immune function in patients with immune deficiency caused by multiple reasons.

Hematopoietic stem cell microtransplantation in patients aged over 70 with acute myeloid leukemia: a multicenter study

In the era of molecular targeted drugs, elderly patients with acute myeloid leukemia (AML) are still very difficult to treat, especially those older than 70 years. The decline in immune function leads to serious infection and disease recurrence. The microtransplant treatment regimen (MST) chemotherapy combined with allogeneic hematopoietic stem cell infusion is a new cell therapy regimen. The aim of this MST study was to improve the survival of elderly patients by graft versus leukemia action and improving T-cell immune function. From May 2012 to July 2020, one hundred and eleven patients aged 70 to 88 years with de novo AML were analyzed retrospectively. After induction chemotherapy, patients whom complete remission (CR) was achieved were given another 2 cycles of postremission therapy. The MST groups were given allogeneic stem cell infusion after each chemotherapy cycle. CR, leukemia-free survival, and overall survival (OS) were compared between groups. Additionally, the immune function and the T cell receptor (TCR) library of T cells were detected and analyzed. The MST group exhibited an encouragingly high CR rate (63.8%), even in high-risk patients (54%), and this rate was significantly higher than that in the chemotherapy alone group. The 1-year OS of MST patients was 57.7%, and it was 55.9% in the high-risk group. It was only 37.3% in the chemotherapy alone group. Higher numbers of naive T cells were found in the MST population than in the chemotherapy alone group. More updated T-cell clones were observed in MST patients by T-cell receptor repertoire analysis with a next-generation sequencing methodology. These results suggest that MST is a safe and practical regimen conducive to longer-term survival in patients of a highly advanced age with AML. Furthermore, it has broad clinical value in the recovery of immune function in elderly patients.

[Immunophenotypic Features and Clinical Prognosis of Patients with Mixed Phenotype Acute Leukemia]

OBJECTIVE

To retrospectively analyze the laborotary test results and clinical data of 31 patients with mixed phenotype acute leukemia (MPAL) in order to summarize and discuss the biological characteristics, curative effect, and prognosis of each subtype of MPAL based on immunophenotype results.

METHODS

MPAL patients diagnosed and treated in our hospital from July 2013 to January 2019 were selected to analyze the data of cell morphology, immunophenotyping, cytogenetics, molecular biology (MICM), and routine blood at initial diagnosis. Follow-up was carried out until the last discharge time.

RESULTS

Among 31 patients, there were 19 males and 12 females, with a median age of 41(12-76) years old. According to the results of immunophenotyping and EGIL score, there were 16 cases of myeloid-T lymphoid mixed phenotype (myeloid-T group), 9 cases of myeloid-B lymphoid mixed phenotype (myeloid-B group), 5 cases of T-B lymphoid mixed phenotype (T-B group), and 1 case of myeloid-T-B lymphoid mixed phenotype. Compared between different subtypes, the antigen expression characteristics were the highest positive rate and expression rate of HLA-DR in myeloid-B group, and the positive rate of CD2 in T-B group was significantly higher than that in the myeloid-T group. Meanwhile, the expression rates of CD7 and cCD3 (cytoplasmic CD3) in T-B group were higher than those in myeloid-T group, and cCD79a was positive in all cases of myeloid-B group and T-B group. The median WBC of T-B group was 81.92×10⁹/L, which was significantly higher than that of the other two groups (P<0.05). The quantitative results of WT1 were higher than 10^-4 in 92.6% of the patients, and the WT1 expression level in myeloid-B group was significantly lower than the other two groups (P<0.01). Among the 9 patients with myeloid-B mixed phenotype, 5 cases showed BCR-ABL positive. Among 28 patients followed up, 21 cases achieved complete remission (CR), the median time to first obtain CR was 32.5(9-75) days, and the median follow-up time was 16 months (range from 21 days to 6 years). The CR rate and median overall survival (OS) time in myeloid-B group were 88.9% and 40 months, which were higher than the other two groups. The CR rate and 3-year OS rate in T-B group were relatively lower (50.0%, 0).

CONCLUSION

WT1 gene is highly expressed in patients with MPAL, and each subgroup of MPAL based on immuophenotype has its unique antigen expression characteristics. Compared with myeloid-T group and T-B group, myeloid-B group can acquire higher remission rate and have better prognosis.

[Analysis of common viral infection in surveillance cases of febrile respiratory syndrome in 9 provinces of China from 2009 to 2021]

Objective: To understand the common viral infection among the surveillance cases of fever respiratory syndrome (FRS) in nine provinces in China. Methods: The research data were obtained from nine provinces (Anhui, Beijing, Guangdong, Hebei, Hunan, Jilin, Shandong, Shaanxi and Xinjiang) in the "Infectious Disease Surveillance Technology Platform Information Management System" of the Chinese Center for Disease Control and Prevention from January 2009 to June 2021. Finally, 8 243 FRS cases with nucleic acid detection results of eight viruses [human influenza virus (HIFV), human respiratory syncytial virus (HRSV), human adenovirus (HAdV), human parainfluenza virus (HPIV), human rhinovirus (HRV), human metapneumovirus (HMPV), human coronavirus (HCoV) and human Boca virus (HBoV)] were included in the study. The χ² test/Fisher exact probability method was used to analyze the difference of virus detection rate in different age groups, regions and seasons. Results The M (Q₁, Q₃) age of 8 243 FRS cases was 4 (1, 18) years old, and 56.56% (4 662 cases) were children under 5 years old. Males accounted for 58.1% (4 792 cases) of all cases. All cases were from outpatient/emergency department (2 043 cases) and inpatient department (6 200 cases). The virus detection rates of FRS cases from high to low were HRSV, HIFV, HPIV, HRV, HAdV, HMPV, HCoV and HBoV. Two or more viruses were detected simultaneously in 524 cases, accounting for 15.66% of virus-positive cases. The difference of the virus detection rate in different age groups was statistically significant (all P values<0.05), and the virus detection rate in children<5 years old was higher (49.96%). The positive rate of any virus in south China was higher than that in north China (P<0.001). The virus-positive FRS cases were detected throughout the year. The detection rate of HRSV was higher in autumn and winter. The detection rate of HIFV was higher in winter. The detection rate of HMPV was higher in winter and spring. The detection rates of HPIV, HRV, HCoV and HBoV were higher in summer and autumn, while there was no significant difference in the detection rate of HAdV in different seasons. Compared with 2009-2019, the detection rate of any virus in 2020-2021 decreased from 41.37% to 37.86%. The detection rate of HIFV decreased sharply from 10.62% to 1.37%. The detection rate of HPIV decreased from 8.24% to 5.88%. The detection rate of HRV and HBoV increased from 5.43% and 1.79% to 9.67% and 3.19%, respectively. Conclusion: HRSV and HIFV infections are more common among FRS cases in nine provinces in China from 2009 to 2021, and the epidemiological characteristics of eight common respiratory viruses vary in different age groups, regions and seasons.

Testing a knowledge-based approach for inferring spatio-temporal characteristics of groundwater in the Australian State of Victoria

Groundwater spatio-temporal characteristics are important information for groundwater development and management. However, such information is usually insufficient or even unavailable in many regions around the world due to insufficient or even lack of in-situ data such as from boreholes. Recently, a knowledge-based approach was proposed to infer 'where' and 'when' to find groundwater using Lake Victoria Basin (LVB) as an example for data-deficient regions. In this knowledge-based approach, groundwater model and inversion analysis of groundwater impact factors are used to infer groundwater storage potential and recharge timing. In the LVB's case, only 10 borehole data were used to test the spatio-temporal behaviours of groundwater, which are insufficient. In this contribution, therefore, using the Australian State of Victoria as an example, with over 15,000 boreholes data, the performance of the same knowledge-based approach is further tested in a well-controlled area. The results indicate that the knowledge-based approach is able to correctly infer regions with large groundwater storage potential suitable for extraction. The recharge timing of groundwater is also correctly indicated as the results show consistency with the borehole data. This provides further evidence of the reliability of the knowledge-based approach for inferring spatio-temporal characteristics of groundwater.

Inference of the spatio-temporal variability and storage potential of groundwater in data-deficient regions through groundwater models and inversion of impact factors on groundwater, as exemplified by the Lake Victoria Basin

Groundwater is an important resource for supporting domestic water use for people's livelihoods and for maintaining ecosystems. Borehole observations provide the first-hand data that characterise the fluctuation, depth, and aquifer conditions of the groundwater. Unfortunately, such observations are not available or are insufficient for scientific use in many regions. Taking the Lake Victoria Basin (LVB) as an example of data-deficient regions, this study proposes a simple knowledge-based approach that uses the Global Land Data Assimilation System (GLDAS) Catchment Land Surface Model (CLSM) for the main data, with rainfall, hydrological, topographical and geological datasets as supports, by which to infer the spatio-temporal variability and storage potential of groundwater. The method is based on analysis and inversion of impact factors on groundwater, and the feasibility of such a method is proven by showing that the groundwater results from GLDAS CLSM can correctly indicate the seasonality, as well as the link to topographical and geological features. For example, both results from the water balance equation (WBE) and GLDAS CLSM indicate that there are two groundwater recharge seasons in the basin, e.g., March to May and September to November. Compared to the eastern side of the LVB, the western side has mountains blocking surface runoff, and thus, reasonably, has larger storage potential estimates in GLDAS CLSM. Due to the low degree of weathering of the basement rocks, it is expected that there is only small storage potential and variation of groundwater in the southeastern parts of the LVB. GLDAS CLSM also correctly reflects this behaviour. Additionally, the largest groundwater storage potential over the LVB is found in regions near the Kagera River and the western shoreline, since it associates with unconsolidated rocks and behaviours of large groundwater recharge from GLDAS CSLM during the wet year of 2006. The major limitation of this knowledge-based method is that the uncertainty in terms of magnitude on GLDAS CLSM groundwater changes cannot be assessed, in addition to the fact that the reliability of the results cannot be quantified in terms of specific numbers. Therefore, the results and interpretation of groundwater behaviours using such methods can only be a guide for 'where' and 'when' to find groundwater.

Spatio-temporal groundwater variations associated with climatic and anthropogenic impacts in South-West Western Australia

South-West Western Australia (SWWA) is a critical agricultural region that heavily relies on groundwater for domestic, agricultural and industrial use. However, the behaviours of groundwater associated with climate variability/change and anthropogenic impacts within this region are not well understood. This study investigates the spatio-temporal variability of groundwater in SWWA based on 2997 boreholes over the past 36 years (1980-2015). Results identify the decline in groundwater level (13 mm/month) located in the central coastal region of SWWA (i.e., north and south of Perth) to be caused by anthropogenic impacts (primary factor) and climate variability/change (secondary). In detail, anthropogenic impacts are mainly attributed to substantial groundwater abstraction, e.g., hotspots (identified by above 7 m/month groundwater level change) mostly occur in the central coastal region, as well as close to dams and mines. Impacts of climate variability/change indicate that coupled ENSO and positive IOD cause low-level rainfall in the coastal regions, subsequently, affecting groundwater recharge. In addition, correlation between groundwater and rainfall is significant at 0.748 over entire SWWA (at 95% confidence level). However, groundwater in northeastern mountainous regions hardly changes with rainfall because of very small amounts of rainfall (average 20-30 mm/month) in this region, potentially coupled with terrain and geological impacts. A marked division for groundwater bounded by the Darling and Gingin Scarps is found. This is likely due to the effects of the Darling fault, dams, central mountainous terrain and geology. For the region south of Perth and southern coastal regions, a hypothesis through multi-year analysis is postulated that rainfall of at least 60 and 65-70 mm/month, respectively, are required during the March-October rainfall period to recharge groundwater.

HLA-Mismatched Microtransplant in Older Patients Newly Diagnosed With Acute Myeloid Leukemia: Results From the Microtransplantation Interest Group

Importance

The outcome of older patients with acute myeloid leukemia (AML) remains unsatisfactory. Recent studies have shown that HLA-mismatched microtransplant could improve outcomes in such patients.

Objective

To evaluate outcomes in different age groups among older patients with newly diagnosed AML who receive HLA-mismatched microtransplant.

Design, Setting, and Participants

This multicenter clinical study included 185 patients with de novo AML at 12 centers in China, the United States, and Spain in the Microtransplantation Interest Group. Patients were divided into the following 4 age groups: 60 to 64 years, 65 to 69 years, 70 to 74 years, and 75 to 85 years. The study period was May 1, 2006, to July 31, 2015.

Exposures

Induction chemotherapy and postremission therapy with cytarabine hydrochloride with or without anthracycline, followed by highly HLA-mismatched related or fully mismatched unrelated donor cell infusion. No graft-vs-host disease prophylaxis was used.

Main Outcomes and Measures

The primary end point of the study was to evaluate the complete remission rates, leukemia-free survival, and overall survival in different age groups. Additional end points of the study included hematopoietic recovery, graft-vs-host disease, relapse rate, nonrelapse mortality, and other treatment-related toxicities.

Results

Among 185 patients, the median age was 67 years (range, 60-85 years), and 75 (40.5%) were female. The denominators in adjusted percentages in overall survival, leukemia-free survival, relapse, and nonrelapse mortality are not the sample proportions of observations. The overall complete remission rate was not significantly different among the 4 age groups (75.4% [52 of 69], 70.2% [33 of 47], 79.1% [34 of 43], and 73.1% [19 of 26). The 1-year overall survival rates were 87.7%, 85.8%, and 77.8% in the first 3 age groups, which were much higher than the rate in the fourth age group (51.7%) (P = .004, P = .008, and P = .04, respectively). The 2-year overall survival rates were 63.7% and 66.8% in the first 2 age groups, which were higher than the rates in the last 2 age groups (34.2% and 14.8%) (P = .02, P = .03, P < .001, and P < .001, respectively). The 1-year cumulative incidences of nonrelapse mortality were 10.2%, 0%, 3.4%, and 26.0% in the 4 age groups and 8.1% in all patients. The median times to neutrophil and platelet recovery were 12 days and 14 days after induction chemotherapy, respectively. Five patients had full or mixed donor engraftment, and 30.8% (8 of 26) of patients demonstrated donor microchimerism. Two patients (1.1%) developed severe acute graft-vs-host disease.

Conclusions and Relevance

Microtransplant achieved a high complete remission rate in AML patients aged 60 to 85 years and higher 1-year overall survival in those aged 60 to 74 years.

The newly merged satellite remotely sensed, gauge and reanalysis-based Multi-Source Weighted-Ensemble Precipitation: Evaluation over Australia and Africa (1981-2016)

The Australian and African continents, regions prone to hydroclimate extremes (e.g., droughts and floods), but with sparse distribution of rain-gauge that are limited in time, rely heavily on complementary satellite and reanalysis data to provide important crucial information necessary for informing policies and management. The problem, however, is that satellite products suffer from systematic biases while reanalysis products carry over uncertainties from their forcing parameters. Multi-Source Weighted-Ensemble Precipitation (MSWEP) is a new global rainfall-product that merges satellite, rain-gauge and re-analysis data to exploit their advantages and minimise their disadvantages. Although MSWEP has been validated globally, this product, together with its potential applications, e.g., in water storage fluxes, river discharge and climate impacts studies over Australia and Africa, regions with urgent need of reliable products, has however, not been verified. Using GRACE satellite products, GLDAS model data, GRDC runoff products, and ENSO/IOD climate indices; five rainfall products - FLUXNET, BoM, GPCC, CHIRPS, and AgCFSR; and a suite of statistical methods (Pearson, Kolmogorov-Smirnov, PCA and Three-Corner-Hat (TCH)), this study (i) evaluates monthly MSWEP-V2.1 data (1981-2016), and (ii), assesses its potential applications to water storage flux (within the water balance framework), river discharge analysis, and climate impacts studies. The results show good MSWEP correlations and cumulative distribution with BoM product over most of Australia except in regions with heavy monsoonal rainfall, e.g., northern and north-western Australia where it tends to underestimate. Over Africa, MSWEP has no obvious advantages compared to insitu-GPCC, satellite-CHIRPS or reanalysis-AgCFSR. Furthermore, it is unable to reflect on major hydro-climate extremes over west, east and southern Africa, where it underestimates compared to CHIRPS. Its potential applications to water storage flux, discharge and climate impacts over the two continents show better suitability for water storage flux in Africa, while no advantages are seen compared to other rainfall products on other aspects.

Do We Need Full Donor Chimerism? How Alloreactive Cell Therapies without Substantial Engraftment Might Treat Hematologic Cancers

"Alloreactive cell therapy without substantial engraftment"; (ACT-WiSE) refers to adoptive transfer of natural ("non-engineered") human leukocyte antigen-mismatched lymphocytes to mediate anti-neoplastic alloreactivity in recipients without employing pharmacologic immunosuppression. By definition, ACT-WiSE entails subsequent rejection of most, if not all, donor cells. Macrochimerism is transient and microchimerism may be either short-lived or persistent. This strategy harnesses the anticancer potency of alloreactivity without incurring significant risk of graft-versus-host disease. "Microtransplantation" refers to a form of ACT-WiSE where the donor cell product contains hematopoietic progenitor cells. Microtransplantation therefore accelerates hematopoietic recovery and its immunomodulatory effects may differ from other forms of ACT-WiSE. Recent studies suggest that various forms of ACT-WiSE, including microtransplantation, may improve chemosensitivity in patients with myeloid malignancies, resulting in higher complete remission rates and increased survival. Microtransplantation has also demonstrated promising pilot results in relapsed or refractory Non-Hodgkin and Hodgkin lymphoma. ACT-WiSE and microtransplantation may establish a new class of allogeneic cell therapy of particular relevance to persons not considered candidates for traditional allogeneic hematopoietic cell transplantation (AHCT). Open questions include the optimal timing and cell dose of ACT-WiSE, which donor factors contribute to efficacy, and whether these remissions are durable after eradication of donor cells. We extrapolate from lessons learned in the course of traditional and haploidentical AHCT to propose ways of optimizing ACT-WiSE. We divide these into donor-related strategies (including rational donor selection and boosting NK-cell and T-cell alloreactivity) and patient- related strategies (that may favor development of autologous NK-cell and T-cell mediated anticancer cytotoxicity in the post-ACT-WiSE window).

[Biological characteristics of Microvesicles Derived from Bone Marrow Mesenchymal Stem Cells and Their Capacities Supporting ex vivo Expansion of Hematopoietic Stem Cells]

OBJECTIVE

To 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).

METHODS

The 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.

RESULTS

MSC-MVs are 20-100 nm circular vesicles under electron microscope. About 10 µg protein could be extracted from every 1×10⁶ MSC. 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 CD34⁺ cell 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.

CONCLUSION

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

[Significance of Monitoring Minimal Residual Disease by Flow Cytometry in Acute Leukemia Patients Underwent Nonmyeloablative Allo-HSCT]

OBJECTIVE

To 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.

METHODS

The 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.

RESULTS

Two-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.

CONCLUSION

Dynamically 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.

[Effect of Infusion of Recipient Spleen Cells at Different Time after Murine Haploidentical Hematopoietic Stem Cell Transplantation on Graft Versus Host Disease]

OBJECTIVE

To 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.

METHODS

Forty 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 CD3⁺CD4⁺, CD3⁺CD8⁺ cell subsets and FasL in peripheral blood were detected by flow cytometry.

RESULTS

The 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).

CONCLUSION

The +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.

[Biological Characteristics of Microvesicles Secreted by Human Peripheral Blood Hematopoietic Stem Cells]

OBJECTIVE

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

METHODS

PB-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.

RESULTS

The 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 CD11c⁺ cells. The colony-forming experiments revealed that MV and the co-cultured supernatants could facilitate the colony formation.

CONCLUSION

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

[Establishment of Mouse Model of H-2 Haploidentical Hematopoietic Stem Cell Transplantation from Double Donors]

OBJECTIVE

To 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.

METHODS

The recipients CB6F1 of conventional HSCT group were pretreated by 8 Gy total body irradiation(TBI), and received 3×10⁷ donor (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 12×10⁷ spMNC mobilized by G-CSF from 2 donors within 2 hours after TBI, each donor donated 6×10⁷ cells. 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.

RESULTS

The nadir of white blood cell count after conventional HSCT were lower than 1×10⁹/L and lasted for 3 to 5 days, while not less than 3×10⁹/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).

CONCLUSION

A 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.

[Features of Immunophenotypes and Characteristics of Molecular Biology and Cellular Genetics of AML Patients with CD4 and CD7 Expression]

OBJECTIVE

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

METHODS

The 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).

RESULTS

The 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.

CONCLUSION

AML 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.

The long-term outcome of reduced-intensity allogeneic stem cell transplantation from a matched related or unrelated donor, or haploidentical family donor in patients with leukemia: a retrospective analysis of data from the China RIC Cooperative Group

This study compared 6-year follow-up data from patients undergoing reduced-intensity conditioning (RIC) transplantation with an HLA-matched related donor (MRD), an HLA-matched unrelated donor (MUD), or an HLA-haploidentical donor (HID) for leukemia. Four hundred and twenty-seven patients from the China RIC Cooperative Group were enrolled, including 301 in the MRD, 79 in the HID, and 47 in the MUD groups. The conditioning regimen involved fludarabine combined with anti-lymphocyte globulin and cyclophosphamide. Graft-versus-host disease (GVHD) prophylaxis was administered using cyclosporin A (CsA) and mycophenolate mofetil (MMF). Four hundred and nineteen patients achieved stable donor chimerism. The incidence of stage II-IV acute GVHD in the HID group was 44.3 %, significantly higher than that in the MRD (23.6 %) and MUD (19.1 %) groups. The 1-year transplantation-related mortality (TRM) rates were 44.3, 17.6, and 21.3, respectively. Event-free survival (EFS) at 6 years in the HID group was 36.7 %, significantly lower than that of the MRD and MUD groups (59.1 and 66.0 %, P < 0.001 and P = 0.001, respectively). For advanced leukemia, the relapse rate of the HID group was 18.5 %, lower than that of the MRD group (37.5 %, P = 0.05), but the EFS at 6 years was 31.7 and 30.4 % (P > 0.05), respectively. RIC transplantation with MRD and MUD had similar outcome in leukemia which is better than that with HID. RIC transplantation with HID had lower relapsed with higher TRM and GVHD rate, particularly in advanced leukemias. RIC transplantation with MRD and MUD had similar outcomes in leukemia and they were better than those with HID. RIC transplantation with HID had a lower relapse rate but higher TRM and GVHD rates, particularly in cases of advanced leukemia.

[Expression of WT1 Gene in Bone Marrow of Patients with Acute Myeloid Leukemia and Its Influence on Prognosis]

OBJECTIVE

To investigate the expression level of WT1 gene in bone marrow of patients with acute myeloid leukemia (AML) and its relationship with prognosis.

METHODS

The copy numbers of WT1 and internal reference gene in bone marrow samples from 75 newly diagnosed AML patients were detected by using real-time quantitative PCR. The gene WT1 expression level was determined by the ratio of the copy numbers of WT1 to reference gene. And the clinical characteristics, the complete remission (CR) rate after induction chemotherapy, 2-year overall survival (OS) rate and event-free survival (EFS) rate were calculated and analysed.

RESULTS

The expression level of WT1 did not significantly correlate with common clinical parameters such as age, sex, molecular abnormality, FAB classification and risk stratification. The CR rate in the high WT1 expression group before treatment was 65.4%, which was lower than that of 93.9% in the low expression group (χ2=8.25, P<0.01). The 2-year overall survival rate and event-free survival rate of the two groups were statistically significantly different (P<0.05), and the OS and EFS rates in high WT1 expression group were lower than those in low expression group. After the induction chamotheropy for about 1, 3 month and 6 months, the 2-year OS rate significantly increased in patients with decrease of WT1 gene expression level by one log or more (P<0.05).

CONCLUSION

The expression level of WT1 gene in bone marrow may be an effective marker to evaluate therapy efficacy and prognosis for AML patients (non APL).

[Characteristics and Prognosis of 24 Cases of Primary Acute Myeloid Leukemia with Trisomy 8]

OBJECTIVE

To explore the clinical features and prognosis of primary acute myeloid leukemia (AML) with trisomy 8.

METHODS

The clinical data of 24 cases diagnosed as primary AML with trisomy 8 were collected. The clinical characteristics such as sex, age, subtype of FAB, blood routine and bone marrow blast at the first visit were analyzed and the relationship of the characteristics with CR rate and the prognosis was explored.

RESULTS

12 out of 24 AML patients were diagnosed as M5 (50%), while M2, M3, M4 and M6 had 3 cases, respectively (12.5%); one case did not receive the chemotherapy. 23 cases received 1-2 cycles of standard induction chemotherapy. Among them 3 cases of M3 achieved complete response (CR) and survived until the last following up with 100% 5-year OS rate. Among 20 cases of non-M3, 12 cases achieved CR1 (60%), 4 cases achieved partial response (PR) (20%), 4 cases did not respond (NR); 5 cases relapsed in follow-up for 3 years after CR1 (41.7%), 3 cases achieved CR2 after re-induction chemotherapy, and 2 cases remained NR. Among 20 cases of non-M3, 1 case failed to be followed-up after diagnosis within 1 month. The mean follow-up time of 19 cases was 26.2 (1.5-84) months, 9 cases died (6 cases of M5, 1 case of M4 and 2 cases of M2), who achieved PR and NR, or relapsed after CR1; the 3-year DFS and OS were 21%, 31.5% respectively. 2 cases of non-M3 accepted allo-HSCT with HLA-matched sibling donor and kept disease-free survival until the last following up, and survived for 58 and 66 months respectively. Except for 3 cases of M3, 2 cases received allo-HSCT and the cases without chemotherapy, the other 18 cases with initial WBC count less than 10×10(9)/L had OS and DFS longer than those of 10 cases with initial WBC count no less than 10×10(9)/L (P<0.05, P<0.01). The OS of 10 cases with CR1 was longer than OS of those cases without CR1 (P<0.01).

CONCLUSION

The incidence of trisomy 8 in M5 is higher than the other AML subtypes, and the prognosis of M5 is poor. The initial WBC count above 10×10(9)/L is a high-risk factor. M3 with trisomy 8 and RARA gene has a very good prognosis. Trisomy 8 may increase the risk of primary AML except for M3, so allo-HSCT with HLA-matched sibling donor should be carried out as much as possible after CR1. The gene mutation of FLT3, MLL, HOX11, C-kit, NPM1 may possess an important significance on prognosis.

A Study of Human Leukocyte Antigen Mismatched Cellular Therapy (Stem Cell Microtransplantation) in High-Risk Myelodysplastic Syndrome or Transformed Acute Myelogenous Leukemia

The treatment outcomes of myelodysplastic syndrome (MDS) and transformed acute myelogenous leukemia (tAML) remain very unsatisfactory. We designed a combination of human leukocyte antigen (HLA)-mismatched hematopoietic stem cell microtransplantation (MST) with chemotherapy for patients with MDS and tAML and evaluated its effects and toxicity. Patients were between 13 and 79 years old. Patients with MDS (n=21) were given HLA-mismatched MST combined with decitabine and cytarabine; patients with tAML (n=22) were given HLA-mismatched MST combined with decitabine and cytarabine, and also mitoxantrone. Patients in complete remission (CR) also received MST plus decitabine and medium-dose cytarabine chemotherapy without graft-versus-host disease (GVHD) prophylaxis. The overall response rate of the patients with MDS was significantly higher than that of those with tAML (81% vs. 50%; p=.03). The CR rates were 52.4% and 36.4% in the two groups, respectively. There was no difference in the cytogenetic CR rate between the MDS and tAML groups (85.7% vs. 70%, respectively; p=.7). The 24-month overall survival of the patients with MDS was significantly higher than that of the patients with tAML (84.7% and 34.1%, respectively; p=.003). The median recovery times of neutrophils and platelets were, respectively, 14 and 17 days in the patients with MDS, and 16 and 19 days in those with tAML. The treatment-related mortality rates were 4.8% and 18.2%, respectively, in the MDS and tAML groups (p=.34). No GVHD was observed in any patient. Microtransplantation combined with decitabine and chemotherapy may provide a novel, effective, and safe treatment for high-risk MDS and tAML.

SIGNIFICANCE

Microtransplantation (MST) refers to regular chemotherapy combined with granulocyte colony-stimulating factor-mobilized peripheral blood stem cell infusion of human leukocyte antigen-mismatched donor cells without using immunosuppressive agents. It aims to support hematopoietic recovery and perform graft-versus-leukemia (GVL) effects but differs from traditional allogeneic stem cell transplantation because the rate of donor cell chimerism is low and there is and no graft-versus-host disease (GVHD) risk. Thus, a trial was designed to evaluate the safety and efficacy of MST in patients with myelodysplastic syndrome and those with transformed acute myelogenous leukemia. Higher complete remission and cytogenetic complete response rates were observed, and the treatment improved disease progress-free survival, sped hematopoietic recovery, and avoided GVHD.

[Efficacy of Nonmyeloablative Allogeneic Hematopoietic Stem Cells for 14 Case of Severe Acquired Aplastic Anemia]

OBJECTIVE

To investigate the therapeutic efficacy of nonmyeloablative allogeneic hematopoietic stem cells transplantation for severe acquired aplastic anemia (SAA).

METHODS

Fourteen patients with severe acquired aplastic anemia received nonmyeloablative allogeneic hematopoietic stem cells transplantation from HLA matched sibling donors, among them 8 cases were dagnosed as SAA-I, 6 cases were diagnosed as SAA-II. The conditioning regimen consisted of fludarabine (FIUD), cyclophosphamide (CTX) and anti-thymocyte globulin (ATG/ALG). The prophylaxis for graft-versus-host disease (GVHD) was performed with cyclosporine (CsA) combined with mycophenolate mofetil (MMF) or tacrolimus (FK506).

RESULTS

All the patients gained a quick successfully engraftment of donor hametopoietic cells. The mean recovery time for neutrophil and platelet was 9 d and 13 d respectively. All the patients have acquired a full donor chimerism before 14 d. There were only 2 cases of GVHD: one out of them was acute skin GVHD (grade I) at day 70 after transplantation and the other was chronic liver GVHD (grade I) in 1 years after transplantation, the GVHD more than degree II did not coccur in all patients, 9 patients with bacterial and fungal mixed infection and (or) virus infection were observed, and improved after anti-infection therapy. The median follow-up time were 54.5 months (ranged between 5-144 months), and 12 patients remain disease-free survival currently, only 2 patients died of fungal infectin.

CONCLUSION

Transplantation of nonmyeloablative allogeneic hematopoietic stem cell is safe and effective for the treatment of severe acquired aplastic, but the prevention, treatment and monitoring of infection need to be enhance.

[Clinical efficacy of switching to 2nd generation of tyrosine kinase inhibitor on CML patients at poor responses to imatinib]

OBJECTIVE

This study was to investigate the timing and clinical efficacy of switching to the 2nd generation of tyrosine kinase inhibitor (TKI) for CML patients at poor response to imatinib (dissatifed efficacy or intolerance).

METHODS

The therapeatic efficacy and side reaction of switched 2nd TKI in patients with newly diagnsed CML-CP who poorly responded to imatinib were observed, anong them 3 cases were intolerant, 6 cases did not acquire satisfied efficacy.

RESULTS

After switching to 2nd generation TKI, 3 patients with intolerance achieved complete cytogenetic remission (CCyR) in 3 months, and major molecular remission (MMR) in 3-6 months. All of them achieved optimal efficacy according to European Leukemia Network (ELN), but the pleural effusion appeared in 1 case after use of 2nd generation of TKI for 3 months, and the dadatinib was stoped temporally, and the curative efficacy still was maintained. Among 6 cases with poor efficacy by treatment with imatinib, 2 cases with BCR/ABL mutation progressed after switching 2nd generation of TKI, out of them 1 case with poor tolerance progeressed to the accelerated phase, but was cured by haploidentical allogeneic hematopoictic stem cell transplantation, 1 case progressed to blastic crisis and died of serious infection; the another 4 cases achieved MMR in 3-12 months after using 2nd generation of TKI, and maintained CMR for 12-36 months.

CONCLUSION

CML-CP patients without the optimal response to imatinib should be treated by switching to 2nd generation of TKI as soon as possible, and thereby patients may acquired satisfactory therapentic efficacy.

[Risk factors analysis of cytomegalovirus infection after nonmyeloablative allogeneic peripheral blood stem cell transplantation]

The aim of this study was to analyze the risk factors of cytomegalovirus (CMV) infection and CMV disease after nonmyeloablative allogeneic hematopoietic stem cell transplantation(NST) and develop a rational strategy for the diagnosis, monitoring and preemptive treatment of CMV infection. The Clinical data of 80 patients undergoing NST from November 2009 to November 2012 in the hospital 307 were retrospectively analyzed. The cytomegalovirus load in peripheral blood of patients was detected by using RT-PCR. The results indicated that the incidence of CMV infection was 77.5% (62/80), and the median time for the positive CMV-DNA firstly detected by RT-PCR was day 35 (17-133) after NST. The total of 100-day cumulative incidence of CMV disease was 11.3%(9/80) after early preemptive therapy. Both univariate and multivariate analysis showed thymoglobulin (ATG) used in preconditioning regimen, other herpesvirus infection and fungal infection in medical history before NST were the risk factors of CMV infection after NST.Univariate analysis revealed that CMV viremia and ATG used in preconditioning regimen were the risk factors for CMV disease, while the same result was not found in the multivariate analysis.The incidence of CMV infection in patients with II-IV grade of aGVHD was 91.3%,while the incidence of CMV infection in patients with 0-1 grade of aGVHD was 71.9% (P = 0.06), it seems that II-IV grade of aGVHD was not the risk factor of CMV infection for NST. It is concluded that the ATG used in preconditioning regimen may increase the incidence of both CMV infection and CMV disease after NST. CMV infection easily accompanies by other herpesvirus infection and fungal infection.Therefore other herpesvirus infection and fungal infection should be attentively monitored and prevented after trans-plantation.

[Establishment and identification of a H-2 completely mismatched microtransplantation model of leukemia mouse]

This study was purposed to establish and identify a H-2 completely mismatched microtransplantation model of leukemia mouse. The recipients were female BALB/c mice, while donors were male C57BL/6J mice. Recipients were inoculated intravenously with 1×10(6) of WEHI-3 cells, a cell line of myelomonocytic leukemia. Donors received 100 µg/kg G-CSF mobilization through hypodermic injection, every 12 hours, and it last 5 days. Chemotherapy regimens was MA (mitoxantrone+cytarabine), and it last 4 days. Recipients were given chemotherapy conditioning without GVHD prophylaxis after inoculation of leukemic cells for 2 days, and within 8 hours after last chemotherapy received donor mobilized spleen mononuclear cells (sMNC). The number of sMNC was (3, 6, 12) ×10(7), respectively. The early death rate, recovery level of WBC in peripheral blood and leukemia load were compared between chemotherapy and microtransplantation groups. The donor chimerism was detected by RT-PCR. From the clinical manifestation and pathological features, the GVHD in recipients was evaluated. The results showed that the early mortality in chemotherapy group was 25%, meanwhile those in the (3, 6, 12)×10(7) groups were 16.67%, 8.33%, 8.33%, respectively. The(3, 6)×10(7) groups has a stronger hematopoietic recovery capability than that in chemotherapy and 12×10(7) groups (P < 0.05) . There were more leukemic cells in chemotherapy mice than that in microtransplantation mice (P < 0.01) , and (12, 6)×10(7) groups had lower leukemia load than that in 3×10(7) group (P < 0.05) . No signs of GVHD were observed in microtransplantation mice. The donor microchimerism could be discovered at eraly 2 weeks after donor cell transfusion. It is concluded that a H-2 completely mismatched microtransplantation model of leukemia mouse has been successfully established, and it will provide a experimental base for studying microtransplantation in clinic.

[Abnormality of blood coagulation indexes in patients with de novo acute leukemia and its clinical significance]

To explore hemorrhage risk and the clinical significance of abnormal change of prothrombin time (PT), activated partial thromboplastin time (APTT), plasma fibrinogen (FIB), plasma thrombin time (TT) and d-dimer (D-D) in de novo acute leukemia (except for APL), the different bleeding manifestations of 114 cases of de novo acute leukemia with different coagulation indexes were analyzed retrospectively. The correlation between these blood coagulation indexes and the possible correlative clinical characteristics were analysed, including age, sex, type of acute leukemia, initial white blood cell(WBC) and platelet(Plt) count, the proportion of blast cells in bone marrow and cytogenetic abnormality of patients at diagnosis. The results indicated that the incidence of abnormal blood coagulation was as high as 78.1% for de novo AL patients. These patients with 5 normal blood coagulation indexes may have mild bleeding manifestation, but the more abnormal indexes, the more severe bleeding. Both PT and D-D were sensitive indexes for diagnosis of level II bleeding. Incidence of abnormal blood coagulation significantly correlates with the proportion of blast cells in bone marrow (χ(2) = 4.184, OR = 1.021, P < 0.05) and more with D-D (P < 0.01), while age, sex, type of AL, WBC count, Plt count and abnormality of cytogenetics did not correlate with abnormal blood coagulation. It is concluded that the coagulation and fibrinolysis are abnormal in most patients with de novo acute leukemia. More abnormal indexes indicate more severe bleeding, and both PT and D-D are sensitive indexes for diagnosis of level II bleeding. Higher proportion of blast cells in bone marrow predicts higher incidence of abnormal blood clotting. Acute leukemia with elderly age, high white blood cell count and adverse cytogenetics do not predict severer abnormal blood clotting. Detection of PT, APTT, TT, FIB, and D-D may help to judge whether the patients are in a state of hypercoagulability or disseminated intravenous coagulation, which will provide experiment evidences for early intervention and medication.

HLA-mismatched stem-cell microtransplantation as postremission therapy for acute myeloid leukemia: long-term follow-up

PURPOSE

Despite best current therapies, approximately half of patients with acute myeloid leukemia in first complete remission (AML-CR1) with no HLA-identical donors experience relapse. Whether HLA-mismatched stem-cell microtransplantation as a novel postremission therapy in these patients will improve survival and avoid graft-versus-host disease (GVHD) is still unknown.

PATIENTS AND METHODS

One hundred one patients with AML-CR1 (9 to 65 years old) from four treatment centers received programmed infusions of G-CSF-mobilized HLA-mismatched donor peripheral-blood stem cells after each of three cycles of high-dose cytarabine conditioning without GVHD prophylaxis. Donor chimerism and microchimerism and WT1+CD8+ T cells were analyzed.

RESULTS

The 6-year leukemia-free survival (LFS) and overall survival (OS) rates were 84.4% and 89.5%, respectively, in the low-risk group, which were similar to the rates in the intermediate-risk group (59.2% and 65.2%, respectively; P=.272 and P=.308). The 6-year LFS and OS were 76.4% and 82.1%, respectively, in patients who received a high dose of donor CD3+ T cells (≥1.1×10(8)/kg) in each infusion, which were significantly higher than the LFS and OS in patients who received a lower dose (<1.1×10(8)/kg) of donor CD3+ T cells (49.5% and 55.3%, respectively; P=.091 and P=.041). No GVHD was observed in any of the patients. Donor microchimerism (2 to 1,020 days) was detected in 20 of the 23 female patients who were available for Y chromosome analysis. A significant increase in WT1+CD8+ T cells (from 0.2% to 4.56%) was observed in 33 of 39 patients with positive HLA-A*02:01 antigen by a pentamer analysis.

CONCLUSION

Microtransplantation as a postremission therapy may improve outcomes and avoid GVHD in patients with AML-CR1.

[Effects of IAT and MAT chemotherapeutic regimens in patients with refractory or relapsed acute myeloid leukemia]

The aim of this study was to investigate effects of IAT and MAT chemotherapeutic regimens treating patients with refractory and relapsed acute myeloid leukemia (AML). 99 patients with refractory and relapsed AML received IAT regimen or MAT regimen as study objects were retrospectively analyzed (56 patients with refractory AML and 43 patients with relapsed AML). Among of them, 28 patients were treated with IAT regimen, and 71 patients received with MAT regimen. The results showed that in 2 groups mentioned above the OR was 65.7%, CR was 49.5%, PR was 16.2%; in IAT group the OR was 64.3%, CR was 46.4%; in MAT group the OR was 66.2%, CR was 50.7%, no statistical difference was found between these 2 groups; The 2 years overall survival was 25% in IAT group and 15.5% in MAT group. Serious infection in IAT and MAT regime groups was 25% and 9.9%, respectively. It is concluded that both IAT and MAT regimens are effective methods for inducing CR in patients with refractory of relapsed AML. IAT and MAT regimens can be used in treatment of the refractory or relapsed MAL patients who were not respond to other regimen.

[Clinical study of bortezomib for treating multiple myeloma with renal impairment]

This study was purposed to analyze the clinical characteristics of multiple myeloma (MM) patients with and without renal impairment (RI) and to investigate the effect of bortezomib (Bor) on MM with RI. Clinical data of 39 MM patients (15 cases with RI, 24 cases without RI) received treatment of Bor in department of hematology in our hospital from Jan 2007 to Aug 2011 were collect and analyzed in term of clinical characteristics, curative efficacy, outcome of renal impairment and toxic reaction associated to chemotherapy. The results showed that (1) the obvious difference of the disease type, the creatinine, uric acid, serum calcium and β2-microglobulin levels existed in patients with and without RI, while there were no significant difference in hemoglobin and globin levels; (2) there were no significant difference in overall reaction rate and overall survival rate between MM patients with and without RI, however the median survival time of patients without RI was longer than that of patients with RI; (3) the RI could be reversed after the treatment with Bor, and the effect was most obvious after the first cycle. 20% MM patients with RI had recovered from RI after the first cycle; and the recovery rate from RI got up to 38.4% after the second cycle. The decline of creatinine levels had no difference between MM patients with or without RI after the second cycle. (4) The adverse events included gastrointestinal symptoms, peripheral neuropathy, thrombocytopenia and infection. There was also no difference between the 2 groups. It is concluded that Bor-based regimens for the MM patients with RI are effective and safe, and the renal function would be reversed after 2 cycle of Bor-based regimen.

[Transfection of recombinant adenoviral vector with co-expressing keratinocyte growth factor and enhanced green fluorescent protein to murine bone marrow mesenchymal stem cells]

To construct the adenoviral vector with co-expressing keratinocyte growth factor (KGF) and enhanced green fluorescent protein (EGFP) for transfection into the mesenchymal stem cells (MSC), the target gene KGF was cloned into the shuttle plasmid with the report gene EGFP, then the recombinant shuttle plasmid was transformed into DH5a bacteria to recombine with backbone vector pAdxsi. Next, the plasmid pAd-EGFP-mKGF was amplified in H293 cells and the viral titer was determined. The MSC were separated and enriched by using bone marrow adherent culture and identified in vitro to observe the efficiency of transfection. The results indicated that the recombinant shuttle plasmid pShuttle-EGFP-mKGF digested with restriction endonucleases was confirmed by two products which length was about 0.6 kb and 5.1 kb, respectively; the recombinant plasmid pAdxsi-EGFP-mKGF digested with restriction endonucleases was confirmed by 7 products; recombinant adenoviral vector Ad-EGFP-mKGF was amplified to titer of 1.6 × 10(10) pfu/ml. At 10 h after transfecting MSC began to express fluorescence at 6 to 8 days later, the fluorescence reached to the peak with infection rate of 92.3, at 28 days the expression of fluorescence was still observed. It is concluded that the recombinant adenoviral vector Ad-EGFP-mKGF is successfully constructed and can transfect MSC effectively and safely.

[Clinical analysis of invasive fungal infections in patients with hematologic malignancies]

The aim of this study was to investigate the clinical situation of invasive fungal infections in patients with hematological malignancies, and discuss the susceptible factors and precautions. 541 patients with hematological malignancies from 2008 Jan to 2011 Dec in hospital 307 of Chinese PLA were statistically retrospectively analyzed in term of clinical manifestation, image examination, culture results of secretions, therapy and so on. The results showed that 63 out of 541 patients got invasive fungal infections. The respiratory tract and intestinal tract were the most common infection sites (62.34 and 19.48, respectively); Candida albicans (66.67) and Candida glabrata (12.82) were the most common pathogens. It is concluded that the main risk factors are as follows: primary diseases, chemotherapy, glucocorticoid, leukopenia after chemotherapy, applications of broad-spectrum antibiotics and aging. It is suggested that a stratification of risk factors is helpful in preventing and treating invasive fungal infections.

[Effect of G-CSF on murine thymocyte emigration and cell cycle alteration after a sublethal dose of irradiation]

This study was aimed to investigate the effect of recombinant human granulocyte colony-stimulating factor(G-CSF) on murine thymocyte emigration and cell cycle alteration after a sublethal dose of gamma-irradiation. Female BALB/c mice were given 6.0 Gy γ-ray total body irradiation and then randomly divided into G-CSF and control groups. Mice in the G-CSF group were injected recombinant human G-CSF 100 µg/(kg·d) subcutaneously once daily for 14 consecutive days and mice in the control group were given the same volume of phosphate buffered solution. Thymocyte cycle alteration and the proportion of apoptosis cells were detected by flow cytometry within 72 hours after irradiation. Real-time PCR was used for detection and quantitation of murine T cell receptor rearrangement excision circles (sjTREC) of the thymic cells at 30 and 60 day after the irradiation. The results showed that at 6 hour after irradiation G-CSF could significantly increase the thymic cells in G(0)/G(1) phase, G-CSF vs control: (82.0 ± 5.0)% vs (75.9 ± 2.8)% (p < 0.05), and decrease the thymic cells in S phase, G-CSF vs control: (10.2 ± 4.8)% vs (15.7 ± 2.3)% (p < 0.05), but G-CSF seemed have no evident effects on the percentage of thymic cells in G(2)/M phase. G-CSF could also protect thymocytes from apoptosis at 6 hour and 12 hour after irradiation the percentages of apoptosis cells in G-CSF group were (11.5 ± 2.4)% and (15.5 ± 3.3)%, respectively, which were significantly lower than that of the control group (16.5 ± 2.2)% and (22.6 ± 0.7)%, respectively (p < 0.05). The sjTREC copy amount was conspicuously higher in G-CSF group than that in the control at 30 day after irradiation (p < 0.01), but the preponderance disappeared 60 days later. It is concluded that G-CSF has a positive effect on the thymic cell cycle alteration to protect thymocytes from apoptosis and enhance the recent thymocyte emigration, which may contribute to the central immune reconstitution after irradiation.

[Expression of NOV and BNIP3 gene in mouse myelomonocytic leukemia and its significance]

This study was aimed to investigate the expression level of NOV and BNIP3 mRNA in mice myelomonocytic leukemia (AML-M(4)) and its significance. The mice were inoculated intravenously with myelomonocytic leukemia cells of WEHI-3, and divided randomly into chemotherapy group and control (untreated) group. Bone marrow samples were then collected from both groups at different times. The NOV and BNIP3 mRNA expression were detected by TaqMan quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR), and the relationship between these expression levels and clinical significance in leukemia incidence and progression were analyzed with β-actin as the housekeeping gene. The results showed that the mean values of NOV and BNIP3 increased gradually from 2 weeks after inoculation and achieved highest level at death in control group. Expression level of NOV increased from 1.85E-05 before inoculation to 3.57E-02 at death (p < 0.05), and BNIP3 from 3.44E-03 to 3.48E-02. While 2 gene expression in the chemotherapy group decreased quickly to 2.51E-05 and 1.58E-03 (p < 0.05) respectively after chemotherapy, which were close to the level before inoculation (p > 0.05). The 2 gene expressions again rose at relapse, and difference of expression level between 2 group at death were no statistically significant (p > 0.05). It is concluded that the expression of NOV and BNIP3 in leukemia AML-M(4) is significantly higher than that in normal controls, of which high level expression is an important factor in the development of leukemia. Close relation between the therapeutic effect and expression level of these two genes suggests the great value in prognostic evaluation and MRD detection.

The radiation protection and therapy effects of mesenchymal stem cells in mice with acute radiation injury

The aim of this study was to investigate the effects and mechanisms of mesenchymal stem cells (MSCs) on haematopoietic reconstitution in reducing bone marrow cell apoptosis effects in irradiated mice, and to research the safe and effective dosage of MSCs in mice with total body irradiation (TBI). After BALB/c mice were irradiated with 5.5 Gy cobalt-60 gamma-rays, the following were observed: peripheral blood cell count, apoptosis rate, cell cycle, colony-forming unit-granulocyte macrophage (CFU-GM) and colony-forming unit-fibroblast (CFU-F) counts of bone marrow cells and pathological changes in the medulla. The survival of mice infused with three doses of MSCs after 8.0 Gy or 10 Gy TBI was examined. The blood cells recovered rapidly in the MSC groups. The apoptotic ratio of bone marrow cells in the control group was higher at 24 h after radiation. A lower ratio of G0/G1 cell cycle phases and a higher ratio of G2/M and S phases, as well as a greater number of haematopoietic islands and megalokaryocytes in the bone marrow, were observed in the MSC-treated groups. MSCs induced recovery of CFU-GM and CFU-GM and improved the survival of mice after 8 Gy TBI, but 1.5 x 10(8) kg(-1) of MSCs increased mortality. These results indicate that MSCs protected and treated irradiated mice by inducing haematopoiesis and reducing apoptosis. MSCs may be a succedaneous or intensive method of haematopoietic stem cell transplantation under certain radiation dosages, and could provide a valuable strategy for acute radiation syndrome.

[Application of HLA-A*0201/WT1 pentamer combined with intracellular IFNgamma+ staining in detecting circulating WT1 specific T cells in leukemia]

This study was purposed to investigate the value of combination of pentamer and intracellular IFNgamma staining in the qualitative and quantitative detection of circulating antigen-specific T cells. WT1 expressions in 14 HLA-A*0201+ patients and their matched donors were detected by RT-PCR, and circulating WT1 specific T cells were assayed by HLA-A*0201/WT1 pentamer combined with intracellular IFNgamma+ staining. The results showed that the low level of WT1 expression was found only in 2 cases out of 14 donors, but different levels of WT1 expression could be observed in all leukemic patients. The WT1+CD8+ CTL and WT1+IFNgamma+ cells did not detected in all 14 donors, but WT1+CD8+ CTL cells in 2 patients and WT1+IFNgamma+ cells in 3 patients could be detected before transplantation respectively, there was no significant difference between them, while the WT1+CD8+ CTL cells and WT1+IFNgamma+ cells both could be detected in all 14 patients after transplantation, the positive detection rate after transplantation was obviously higher than that before transplantation. The WT1+CD8+ and WT1+ IFNgamma+ cells could be detected within 30 days after transplantation, but the positive detection rate of WT1+IFNgamma+ cells was higher than that of WT1+CD8+ CTL cells (p=0.014). The median peak value of WT1+CD8+ CTL cells was 0.18% in 14 patients, and the median peak value of WT1+IFNgamma+ cells was 0.83% in 14 patients, the later was significantly higher than former. The median peak time of WT1+CD8+ CTL cells was 75 days after transplantation, while the WT1+IFNgamma+ cells was 105 days after transplantation, there was no significant difference between them. It is concluded that pentamer and intracellular IFNgamma staining may effectively detect circulating WT1 specific T cells in leukemic patients, and the combination of these two methods profit to the exact qualitation and quantitation of circulating antigen-specific T cells.

[Changes of lymphocyte subsets in acute leukemia patients after HLA-mismatched nonmyeloablative hematopoietic stem cell transplantation]

This study was purposed to investigate the reconstitution of immune system in patients with acute lymphocyte leukemia (ALL) or acute myeloid leukemia (AML) after HLA-mismatched nonmyeloablative hematopoietic stem cell transplantation (NHSCT) and its relation with infection and GVHD. 6 ALL and 4 AML patients having HLA-mismatched related donors received the nonmyeloablative precondition regimen composed of fludarabine (Fln), ATG, Ara-C, CTX and total body irradiation (TBI) in dose 2 Gy. The GVHD was prevented and treated by CsA, anti-CD25 antibody and mycophenolic mofetil (MMF) before and after transplantation. The flow cytometry was used to detect the changes of total T cells, help/inducer T cells, suppressor/killer T cells, gamma/delta T cells, B cells, NK cells, NKT cells, regulatory T cells, activated T cells, naive T cells, memory T cells and ratio of CD4/CD8 in patients with remission resulting from chemotherapy before transplantation, and analyse the relation of immunofunctional cells to infection and GVHD after transplantation, compare the difference in recovery of immune system of ALL and AML patients. The results showed that the recovery of total lymphocytes and lymphocyte subsets displayed one's own regular pattern. As compared with patients without GVHD, the counts of lymphocyte subsets in patients with GVHD was higher, while the counts of gamma/delta T cells, regulatory T cells, NK cells, the counts of B cells, NK cells, naive cells and CD4/CD8 ratio as well as the counts of B cells, naive T cells and NK cells were lower at 1 month, 2 - 3 months and 6 - 8 months after transplantation respectively. The total T cells and subsets recovered slowly, but NK cells and NKT cells recovered rapidly in patients with infection at early period after transplantation, the B cells and naive B cells recovered rapidly at 3 months after transplantation. There was no difference in lymphocyte recovery between ALL and AML patients. It is concluded that the analysis of each lymphocyte subsets may indirectly show the recovery of thymus function in patients, the changes of NK cells, B cells and naive T cells have an important significance for identifying and forecasting the GVHD and infection.

[Effects of mesenchymal stem cells on cell cycle and apoptosis of hematopoietic tissue cells in irradiated mice]

The aim of this study was to investigate the effect of mesenchymal stem cells (MSCs) on cell cycle and apoptosis of thymus, spleen and bone marrow cells in mice totally irradiated with sublethal dose, and to explore its mechanisms. BALB/c mice irradiated with 5.5 Gy 60Co gamma-ray were randomly divided into control group and MSC group. Mice in MSC group were infused with 0.4 ml containing 2.5x10(7)/kg of MSCs through tail vein at 1 hour after irradiation. Mice in control group were infused with 0.4 ml normal saline. The cell apoptosis and cell cycle of thymus, spleen and bone marrow cells were detected by flow cytometry at 6, 12, 24 and 72 hours after irradiation and the P53 protein expressions in thymus and bone marrow cells were assayed by immunohistochemistry at 12 hours after irradiation. The results showed that the arrest of cells in G0/G1 and G2/M phase, and decrease of cells in S phase appeared at 6 hours after irradiation, those reached peak respectively at 12 hours in thymus cells, 6 hours in spleen and 24 hours in bone marrow, then the cell counts in G0/G1 phase decreased and the cell counts in S and G2/M phases increased. At 72 hours the cell counts in G0/G1 phase were less than the normal level and the cell counts in S phase were more than the normal level. The above changes of cell cycle in thymus and spleen were more rapid in spleen and more obvious in amplitude than that in bone marrow, the change of cell cycle in MSC group was more rapid and obvious than those in control group. After irradiation the apoptosis cells increased from 6 hours, reached the highest level at 12 hours and decreased to the normal level gradually after 24 hours in two groups; the apoptosis rates in spleen and thymus cells were higher than that in bone marrow cells. In comparison with the control group, the apoptosis rate in thymus cells at 12 hours, in spleen cells at 12 and 24 hours, and in bone marrow cells at 24 hours were fewer in MSC group. The cells expressing P53 protein in control group were more than that in MSC group. It is concluded that the MSCs accelerate the running of cell cycle in these hematopoietic tissue cells of irradiated mice, reduce the cell apoptosis and promote the recovery from injuries in hematopietic and immunological organs, thus protect the irradiated mice at early stage.

[Kinetic study of various cytokine mRNA expressions in rhesus treated with haploidentical peripheral blood stem cell transplantation]

This study was aimed to analyze the mRNA expression of cytokines (TGF-beta, IL-2, IL-6, IL-10, IFN-gamma, TNF-alpha, FAS-L) in five rhesus treated with haploidentical peripheral blood stem cell transplantation after nonmyeloablative preparative regimens and to explore the role of these cytokines in the development and pathology of acute graft-versus-host-disease (aGVHD). Five rhesus monkeys received nonmyeloablative haploidentical peripheral blood stem cells transplantation. Semi-quantitative reversed transcription polymerase chain reaction (RT-PCR) was used to analyze the kinetics of cytokine mRNA expression in the transplantation and aGVHD. The results showed that five rhesus monkeys acquired hematopoietic reconstitution successfully. The graft was rejected in one monkey which survived without disease, the other four achieved mixed chimerism and full donor chimerism. Chimerism of low centigrade in one monkey achieved high centigrade at 35 days after donor stem cell infusion. Intestinal aGVHD grade III developed in one monkey. Cytokines of Th1 and Th2 changed after transplantation. In period of aGVHD, expression of TGF-beta decreased but all others increased in various levels. When donor chimerism decreased, the cytokines decreased accordingly. It is concluded that the decrease of TGF-beta mRNA may be an indicator to predict aGVHD, and can be used as a differential diagnostic indicator for intestinal GVHD.

[Establishment and application of a method for assessing hemopoietic chimerism in rhesus after allogeneic stem cell transplantation]

Monitoring engraftment of donor cells after allogeneic transplantation is the key of assessing successful establishment of animal transplantation model. The purpose of this study was to establish a method for analysis of chimerism in rhesus transplantation model. Y-specific sequence in rhesus was amplified by the polymerase chain reaction (PCR), method for analysis of chimerism in rhesus after sex-mismatched transplantation was established; the feasibility and sensitivity of the approach were tested by using serial DNA mixtures of sex-mismatched individuals; the accuracy of results was confirmed by chromosome karyotype analysis simultaneously; Chimerisms of one rhesus received allogeneic stem cell transplantation and the other received mesenchymal stem cells (MSC) transfusion were detected by this method. The results showed that a 176 bp long sequence of PCR product was gained in male rhesus, while no product was gained in female rhesus. The sensitivity of this method was up to 0.05% (male/female DNA ratio). Male donor chimerism were found on day 7 and 14 after allogeneic stem cell transplantation by Y-specific sequence and chromosome karyotype analysis. Otherwise, male donor chimerism was found in peripheral blood at 1 hour and in bone marrow on day 30 after MSC transfusion by this method, but no male donor chimerism was found after MSC transfusion using chromosome karyotype analysis. In conclusion, this rapid, sensitive approach can used to assess chimerism in experiments of rhesus alloorgan transplantation and cell transfusion.

[Establishment of rhesus model for haploidentical hematopoietic stem cell transplantation with nonmyeloablative conditioning]

To study if rhesus haploidentical hematopoietic stem cell transplantation model can be established by non-myeloablative conditioning, parent monkeys were used as donors, offspring monkeys were used as recipients. The recipient monkeys received a nonmyeloablative conditioning consisting of fludarabine, cyclophosphamide, total body irradiation and rabbit anti-human thymocyte globulin. Cyclosporine, mycophenolate mofetil and anti CD25 antibody were used for GVHD prevention. Donor mobilized peripheral blood stem cells were transplantated on day 0. Hematopoietic recovery, chimerism level, GVHD were assessed regularly. The results indicated that hematopoietic recoveries in all 4 cases were observed within 8 days after transplantation. Donor hematopoietic chimerism could be induced in all cases, chimerism analysis showed full donor chimerism (FDC) in case 3 and 4, and II to III grade GVHD developed on day 12 and 14. In case 1, only low level donor chimerism was detected on day 7, and transplantation rejection happened eventually. Unfortunately, kidney failure happened in case 2 after conditioning and died several days later, chimerism analysis showed 50% donor rate on day 7. It is concluded that the rhesus transplantation model was successfully established by nonmyeloablative conditioning for striding over the MHC barrier. This rhesus monkey model would provide a basis for future research.