[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.

[Efficacy and Prognostic Factors of Nonmyeloablative Allogeneic Hematopoietic Stem Cell Transplantation for Patients with Acute Myeloid Leukemia].

OBJECTIVE: To retrospectively analyze the efficacy and complications of our institution's modified nonmyeloablative allogeneic hematopoietic stem cell transplantation (NST) in treating intermediate-risk acute myeloid leukemia (AML) - first complete remission (CR1) and prognostic factors. METHODS: Clinical data of 50 intermediate-risk AML-CR1 patients who underwent matched related NST at the Fifth Medical Center of Chinese People's Liberation Army General Hospital from August 2004 to April 2021 were collected, the hematopoietic recovery, donor engraftment and complications were observed, and overall survival (OS) rate, leukemia-free survival (LFS) rate, treatment-related mortality (TRM), and cumulative relapse rate were calculated. Statistical analysis of factors affecting prognosis was also preformed. RESULTS: The median times for neutrophil and platelet recovery after transplantation were 10 (6-16) and 13 (6-33) days, respectively. One month after transplantation, 22 patients (44%) achieved full donor chimerism (FDC), and 22 patients (44%) achieved mixed chimerism (MC), among whom 18 cases gradually transited to FDC during 1-11 months, 4 cases maintained MC status. The overall incidence of acute graft-versus-host disease (aGVHD) was 36%, with a rate of 18% for grade II-IV aGVHD and a median onset time of 45 (20-70) days after transplantation. The overall incidence of chronic GVHD (cGVHD) was 34%, with 20% and 14% of patients having limited or extensive cGVHD, respectively. The incidence rates of infections, interstitial pneumonia, and hemorrhagic cystitis were 30%, 10%, and 16%, respectively. The 5-year OS rate, LFS rate, TRM, and cumulative relapse rate were 68%, 64%, 16%, and 20%, respectively. The increase of the number of CD34+ cells infused had shortened the recovery time for neutrophils and platelets (r =0.563, r =0.350). The number of CD34+ cells infused significantly influenced the occurrence of extensive cGVHD (OR =1.36, 95%CI : 1.06-1.84, P =0.024). CONCLUSION: Modified NST is effective in treating intermediate-risk AML-CR1 patients, however, further expansion of sample size is needed to study prognostic factors.

[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.

[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.

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.

[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.

[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.

[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.

[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.

[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.

[Different changes of serum cytokines following HLA-identical and HLA haploidentical non-myeloablative allogeneic hematopoietic stem cell transplantation].

This study was aimed to investigate the expression difference of serum cytokines in 20 patients receiving HLA-identical nonmyeloablative allogeneic hematopoietic stem cell transplantation (iNAHSCT) and HLA-haploidentical nonmyeloablative allogeneic hematopoietic stem cell transplantation (hiNAHSCT). IL-2, IL-4, IL-6, IL-10, TNF-α, γ-IFN and IL-17 were detected by flow cytometric bead array before and on week 1, 2, 4 after transplantation respectively. The results showed that the IL-2 level was found to be up-regulated at week 1 and 2 after transplantation in iNAHSCT group and in hiNAHSCT group respectively, but there was no difference between these two groups (P > 0.05). The γ-IFN levels was up-regulated at week 4 after transplantation in above-mentioned two groups, but no difference was found between these two groups. The IL-4 level increased at week 2 and 1 after transplantation in iNAHSCT and hiNAHCT groups respectively, but the IL-4 level in iNAHSCT group was higher than that in hiNAHSCT group. The IL-6 level rose at week 1 and 2 after transplant in above mentioned groups respectively, and reached to peak level at week 4 after transplantation, but IL-6 level in hiNAHSCT was higher than that in iNAHSCT group (P < 0.02). The IL-10 level was up-regulated at week 1 and 2 in iNAHSCT and hiNAHSCT groups respectively, but the IL-10 level in iNAHSC was higher than that in hiNAHSCT group. The TNF-α level was up-regulated at week 1 in hiNAHSCT group, but at week 2 in iNAHSCT group after transplantation. The TNF-α level in hiNHASCT group was higher than that in iNAHSCT group (P < 0.01). The IL-17 level was up-regulated at week 1 and week 4 after transplantation in hiNAHSCT and iNAHSCT groups respectively, the IL-17 level in hiNAHSCT group was high as compared with that in iNAHSCT group. It is concluded that the serum cytokine levels are obviously up-regulated in iNAHSCT and hiNHASCT groups, and reach to peak level at week 4 after transplantation. The IL-6, TNF-α and IL-17 level up-regulated significantly in hiNAHSCT group, but the IL-4 and IL-10 level up-regulated significantly in iNAHSCT.

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.

[Role of G-CSF in the proliferation, differentiation and cell cycle distribution of mouse thymocytes after acute radiation].

This study was purposed to investigate the effect of G-CSF on the proliferation, differentiation, and cell cycle distribution of thymocytes in sublethally irradiated mice. Female BALB/c mice were exposed to 6.0 Gy γ-ray irradiation and then randomly divided into control and G-CSF treatment group. In the treatment group rhG-CSF 100 µg/(kg·d) was given subcutaneously for 14 continuous days and to make sure the first injection was given within 1 hour after irradiation. Cell cycle distribution and apoptosis of thymocytes were detected within 72 hours after irradiation. Subpopulations of CD4(-)CD8(-) cells and sequential changes in the distribution of CD4(+)CD8(+), CD8(+)CD4(-), CD8(-)CD4(+) cells were detected by a three-color flow cytometry during a four-weeks period after irradiation. The results showed that in G-CSF treatment group marked increase of cells in G(0)/G(1) phase (G-CSF vs control: 82.0 ± 5.0% vs 75.9 ± 2.8%) (p < 0.05) and a decrease of cells in S phase (G-CSF vs control: 10.2 ± 4.8% vs 15.7 ± 2.3%) (p < 0.05)could be observed as early as 6 hours after irradiation, but G-CSF seems have no evident effects on the cells in G(2)/M phase. G-CSF could also protect thymocytes against apoptosis. 6 and 12 hours after irradiation the apoptosis rates of thymic cells in G-CSF treatment group were 11.5 ± 2.4% and 15.5 ± 3.3% respectively, while in the control group the apoptosis rates were 16.5 ± 2.2% and 22.6 ± 0.7% respectively. Comparison between the two group demonstrated significant difference (p < 0.05). CD4(-)CD8(-) double negative thymocytes (DN)can be defined as DN1-4 according to their maturation. G-CSF treatment resulted in a significant increase in DN1 thymocytes and promoted their proliferation and differentiation to a more mature DN3 and DN4 stage. G-CSF could enhance the recovery of CD4(+)CD8(+) thymocytes and mitigate their relapse during reconstitution. The percentage of CD4(+)CD8(+) thymocytes in the G-CSF treatment group 28 days after irradiation was significantly higher than that of the control group (71.0 ± 6.3% vs 25.5 ± 6.3%) (p < 0.05). It is concluded that G-CSF has a positive effects on the thymic cell cycle distribution, proliferation and differentiation, which may contribute to the reconstitution of central immune system after acute irradiation.

[Relationship between WT1-specific T-cell subsets and graft-versus-host disease after nonmyeloablative allogeneic transplantation].

OBJECTIVE: To explore the relationship between WT1-induced T-cell subsets and graft-versus-host disease (GVHD) after nonmyeloablative allogeneic hematopoietic stem cell transplantation (NST). METHODS: Peripheral blood mononucleated cells (PBMCs) from 19 patients who expressed WT1 and developed GVHD after NST were simulated by WT1126-134 peptide in vitro, and proportions of WT1-induced-T-cell subsets (Tc1, Tc2, Th1, Th2 cells) before and after transplant were detected by intracellular cytokine staining (ICCS) assay. WT1-specific CD8(+) CTLs of 14 patients with HLA-A*0201 were detected by HLA-A*0201/WT1 pentamer. RESULTS: (1) 17 of 19 patients developed GVHD, among whom proportions of Tc1 and Th1 cells, achieved peak value in 16 patients at occurrence of GVHD (P = 0.039); (2) The peak proportions of Tc1 and Th1 cells in patients with aGVHD above grade II were higher than those with grade I, but being no statistical difference (P = 0.900 and P = 0.140, respectively); (3) The peak proportion of Th1 cells (P = 0.004), but not Tc1 cells (P = 0.060) in patients with extensive cGVHD was significantly higher than that in patients with limited one; (4) Proportions of Tc1, Th1 and WT1(+)CD8(+)CTL in patients without GVHD were similar to those in patients with Grade I aGVHD, but lower than those in aGVHD above grade II. CONCLUSION: GVHD promotes the generation of WT1-induced GVL effect, and the intensity of the latter maybe correlated with the intensity of GVHD, especially cGVHD. Th1 cells play a more important role in the enhancement of WT1-induced GVL effect in extensive cGVHD patient than in limited cGVHD patients.

[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 IL-21 alone or in combination with IL-15/IL-2 on proliferation and anti-tumor activity of G-CSF-mobilized peripheral blood mononuclear cells in vitro].

This study was purposed to investigate the proliferation and antitumor activity of rhG-CSF-mobilized peripheral blood mononuclear cells (G-PBMNCs) activated by interleukin 21 (IL-21) alone or in combination with interleukin 15 (IL-15)/interleukin 2 (IL-2) and to evaluate the feasibility and value of tumor immunotherapy with cytokine combinations. G-PBMNCs were activated by IL-21 alone or in combination with IL-15/IL-2 in vitro, and the proliferation of the activated G-PBMNCs was analyzed by CCK-8 assay. The cytotoxicity of the activated G-PBMNC to the K562 cells was studied by the test principle which is based on target cell labeling with 5-(6)-carboxy-fluorescein succinimidyl ester (CFSE) and subsequent DNA-labeling with propidium iodide (PI) for identification of target cells with compromised cell membranes. The phenotypes of the activated G-PBMNCs were assayed by flow cytometry. The results showed that the cytotoxicity of IL-21 group had no difference from which of IL-2 group. When G-PBMNCs were exposed to the combinations of IL21+IL15/IL21+IL15+IL2, the cytotoxicity was significantly enhanced at E:T ratio of 25:1, as compared with combination of IL21+IL2 (p<0.05). The cytotoxicity of the cytokines combinations was significantly higher than that in cytokine used alone at E:T ratio of 50:1 (p<0.05). The cryopreservative and resuscitative G-PBMNCs showed the same result with the fresh G-PBMNCs in cytotoxicity test. The proportions of CD3+ and CD8+ T cells were increased when G-PBMNCs were incubated with cytokines for 72 hours. CD4, CD3-56+ and CD3+56+ counts were significantly elevated when G-PBMNCs were exposed to IL21 + IL15 (p<0.05). It is concluded that IL-21 alone enhance the antitumor activity of G-PBMNCs, which further strengthens when IL-21 combinated with IL-15.