Objective To analyze the T- cell receptor excision DNA circles (TRECs) level and evaluate the thymic recent output nave T cells function in patients with acute promyelocytic leukemia (APL). Methods Quantitative detection of TRECs in DNA of peripheral blood mononuclear cells (PBMC) from 9 cases with APL were preformed by real- time PCR (TaqMan) analysis. The TRECs- number was related to the number of T- cells by determination of the number of CD-3 positive cells. 14 normal individuals served as controls. Results In comparison with normal individuals [ (4.10?3.65) copies/1000 PBMC and (6.36?5.28) copies/1000 CD+3 cells], a dramatic reduction of TRECs values in patients with APL [ (0.13?0.22) copies/1000 PBMC and (0.77?1.60) copies/1000 CD+3 cells] could be found (P =0.0004, P =0.0005). Conclusions This is, to our knowledge, the first description of TRECs level which was markedly reduced in APL patients.

AIM:To investigate the role of mesenchymal stem cell-induced regulatory dendritic cells ( MSC-DCregs) in mouse acute graft-versus-host disease( aGVHD) model.METHODS: Bone marrow cells from BALB/c ( H-2 d ) mice were isolated and were induced to differentiate into DCs.The DCs were selected by flow cytometry, and after 10 d co-culture with MSCs, they were induced to be MSC-DCregs.Male 8-week-old C57BL/6 (H-2b) mice were used as do-nor mice.The female 8-week-old BALB/c (H-2d) mice, who had received 100 cm source-skin distance, 30 cm ×30 cm radiation field, 700 cGy total body irradiation (TBI) pretreatment were used as recipient mice.The recipients were divided into 5 groups:control group, TBI group ( injected with medium only) , bone marrow transplantation group ( injected with 1 ×107 bone marrow cells), aGVHD group (injected with 1 ×107 bone marrow cells and 1 ×107 spleen cells), and MSC-DCregs group (injected with 1 ×107 bone marrow cells, 1 ×107 spleen cells and 1 ×106 MSC-DCregs).The white blood cell count, recipients’ chimerism, clinical evaluation of aGVHD, survival analysis and pathological changes were deter-mined.RESULTS:Hematopoieic recovery was seen at 10 d after transplantation.The recipients’ chimerism was parallel to the donors’ at 30 d.The median survival time of the mice in aGVHD group and MSC-DCregs group was 27 d and 33 d, and the survival rates at 30 d were 20% and 100% (P<0.01), respectively.The clinical scores of the mice in MSC-DCregs group were lower than those in aGVHD group ( P<0.01) .Moreover, the pathological changes in the skin and liver of the mice in MSC-DCregs group were less serious than those in aGVHD group.CONCLUSION: The MSC-DCregs in-duce an aGVHD tolerance in vivo, and further research of its mechanism is still in great necessary.

Objective:To investigate the gene expression of TCR V? subfamily T cells and clonality in peripheral blood CD4+ and CD8+ cells from patients with chronic myelogenous leukemia-chronic phase(CML-CP).Methods:The complementarity determining region 3(CDR3)of TCR V? subfamily genes in peripheral blood mononuclear cells(PBMCs),sorted CD4+ and CD8+ cells from 19 CML-CP patients were amplified using RT-PCR,the products were further by genescan analysis to identify the clonality of T cells.Results:Only 1 to 21 V? subfamilies were detected in peripheral blood CD4+ and CD8+ cells from patients with CML.The most frequent expression of V? subfamily was V?13 followed by V?9.Clonal expanded T cells in some V? subfamilies could be identified in both CD4+ and CD8+ cells,especially in CD8+ cells.The clonal expanded of V?21 subfamily in CD4+ cells and V?11 subfamily in CD8+ cells were identified most frequently.Conclusion:The restricted distribution of TCR V? repertoire has been found in CD4+ and CD8+ cells in patients with CML.Clonal expanded CD4+ cells and CD8+ cells have been identified which may relate to host immune response to CML antigen and may play a important role in anti-CML effect.

AIM:To investigate the expression and potential role of complement 5a receptor (C5aR) in chro-nic graft-versus-host disease (cGVHD).METHODS:The expression of C5aR on lymphocytes and the frequency of CD4+CD25+ Foxp3+ regulatory T cells (Tregs) in 20 cGVHD patients and 9 healthy donors was detected by flow cytometry.The correlation between the expression of C5aR and the percentage of Tregs in the cGVHD patients was analyzed.In addition, the splenocytes from the mice were cultured in vitro, and stimulated these splenocytes with recombinant mouse C5a protein (rmC5a).The peripheral blood mononuclear cells (PBMCs) from cGVHD patients were cultured in vitro, which was inhibited by C5aR antagonist (C5aRA).The frequency of Tregs in these splenocytes and the PBMCs were evaluated by flow cytometry.RESULTS:The expression of C5aR on the lymphocytes was significantly increased in the cGVHD patients compared with the healthy donors, while the percentage of Tregs was markedly lower in the cGVHD patients.The expression of C5aR was negatively correlated with the percentage of Tregs.Furthermore, the development of Tregs was suppressed by rmC5a stimulation, but was promoted by C5aRA in vitro.CONCLUSION:C5aR elevation is associated with Treg reduction in cGVHD, indicating that C5aR may play a potential role in suppressing Tregs, resulting in the incidence of cGVHD.

OBJECTIVETo investigate the accuracy and consistency of the detection of BCR-ABL tyrosine kinase domain point mutation among different laboratories.

METHODSEvery one of 6 laboratories prepared 10 cDNA samples from tyrosine kinase inhibitors resistant BCR-ABL (P210 or P190) positive patients'bone marrow or peripheral blood. Each cDNA sample was divided into 6 aliquots and delivered to the laboratories. All 6 laboratories tested BCR-ABL point mutations of 60 samples according to their own protocols. Peking University People's Hospital analyzed the comparison results based on both the reports and sequencing chromatogram from all laboratories.

RESULTSAll laboratories reported the same nucleotide and corresponding amino acid mutations in 37 samples (61.7%）. Of 60 samples, 53 had confirmed mutation types, and a total of 23 types were included; 1 had no mutation; mutation types of 6 samples could not be determined because of the big differences among chromatograms from different laboratories. Low percentages of mutants were significantly related to results inconsistency (P=0.008). Inconsistent result of one sample was caused by the unique chromatogram of the mutant L248V, and one by the non-coverage amplification of PCR product from different laboratories. Amplification was failed in 3 samples. Testing or sequencing mistakes occurred in 7 samples. The differences in the mutant percentages among laboratories were less than 20% in the 80.6% of samples with confirmed results. Low internal control gene copies (ABL<10 000) were significantly related to both failed amplification and big differences among chromatograms from different laboratories (P=0.005 and <0.001, respectively).

CONCLUSIONProblems in the clinical routine detection of BCR-ABL point mutation could be exposed and improvement could be achieved by sample exchange and comparison. Low percentage of mutant is the main reason which causes the discrepancy of BCR-ABL point mutation results among different laboratories.

OBJECTIVE To investigate the effect of amifostine(Amf)on the differentiation of human megakaryocyte cell line-Dami. METHODS Dami cells were treated with Amf 0.01-5.0 mmol · L-1 for 12 d. Dami cells were counted every day for the growth curve:only cells with a diameter>20μm. The platelet demarcation membrane system was observed by transmission electron microscopy. The expression of CD33,CD34,CD41a and DNA ploidy was detected by flow cytometry. RESULTS Amf 0.1-1.0 mmol · L-1 promoted the differentiation of Dami cells ,but inhibited their proliferation at a concentration>1.0 mmol · L-1. When these cells were treated with Amf 1.0 mmol · L-1 for 12 d,the platelet demarcation membrane system was observed,the percentage of cells with a diameter >20 μm was increased by 24.6%(P<0.01),the expression of CD41a was increased by 11.9%,while the expression of CD33 was decreased by 13.6%(P<0.05). Polyploidy cells(16N)were observed,and 4N,8N and 16N cells were increased to 31.56%,8.83% and 3.43%,respectively(P<0.05). CONCLUSION Amf 0.1-1.0 mmol · L-1 can promote the differentiation of Dami cells,but inhibit their proliferation at a high concentration(>1.0 mmol·L-1).

Objective: To investigate the effects of artesunate treatment on chronic graft-versus-host disease (cGVHD). Methods: Recipient BALB/c mice received 8 × 10⁶ bone marrow cells with 8×10⁶ spleen cells from B10D2 mice. Artesunate solubilized in acetone was injected intraperitoneally every day at the dose of 1 mg/kg at Day 28 after BMT. The clinical scores, survival and histopathological damage were analyzed. The frequency of Th17 and Tregs in PB and spleens from the mice were evaluated by flow cytometry. In addition, CD4⁺ T cells from the spleens of mice were cultured in vitro, then stimulated with artesunate, the frequency of Th17 and Tregs in these splenocytes were evaluated by flow cytometry. Results: Artesunate administration diminished clinical and histopathological damage, and improved the survival of cGVHD mice[(46.57±7.83)% vs (55.71±6.99)%, χ²=5.457, P=0.020]; Artesunate contributed to Tregs development [(4.45±0.04)% vs (8.40±0.23)%, t=15.679, P<0.001; (6.62±0.24)% vs (10.48±0.48)%, t=6.587, P=0.003] while decreased Th17 cells [(1.51±0.18)% vs (0.58±0.19)%, t=7.233, P<0.001; (1.48±0.38)% vs (0.71±0.18)%, t=3.653, P=0.011] expressions in both PB and spleens, and decreased the Th17/Treg ratio (0.34±0.05 vs 0.09±0.03, t=7.621, P=0.002; 0.19±0.03 vs 0.06±0.02, t=6.993, P=0.002). Moreover, artesunate suppressed the Th17 cells expressions [(0.82±0.37) % vs (3.39±1.22) %, t=4.044, P=0.007] and contributed to Tregs development [(34.63±1.29) % vs (14.28±1.69) %, t=19.119, P<0.001], and also decreased the Th17/Treg ratio (0.24±0.09 vs 0.02±0.01, t=4.780, P=0.003) in vitro. Conclusions Artesunate suppressed the Th17 cells expressions and contributed to Tregs development, which provided new sights into the development of a novel drug for cGVHD, e.g., artemisinin.

OBJECTIVETo revalidate the conversion factor（CF）for the conversion of BCR-ABL （P210）transcript levels to the international scale（BCR- ABLIS）in chronic myeloid leukemia（CML） which validated before.

METHODSPeking University People's Hospital（PKUPH）prepared the exchange samples for revalidation of CFs of 15 laboratories which validated nine or eighteen months ago. The fresh BCR-ABL（P210）（+）bone morrow or peripheral blood nucleated cells were diluted with BCR-ABL （P210）（-）cells to achieve different BCR- ABL levels, totally 16 sets and 24 samples per set were prepared. TRIzol reagent was added in each tube. Each laboratory tested BCR-ABL transcript levels of one set of samples. Agreement between BCR-ABLIS of each laboratory and PKUPH was assessed by the Bland- Altman method. For laboratories which did not meet the criteria of revalidation, linear regression equation was derived after the samples with maximum BCR-ABL deviation were removed until R²>0.98, then new CF was calculated.

RESULTS10 laboratories met the revalidation criteria with both bias within ±1.4 fold and 95% limits of agreement within ±6 folds, and their CFs still could be used for accurately conversion of BCR-ABLIS. New CFs were recalculated as of 1.8-6.3 folds of their previous CFs in 5 laboratories not met the criteria.

CONCLUSIONRevalidation of CF by sample exchange among laboratories was necessary for accurate and continuous application of BCR-ABLIS, which not only tested the validity of CF acquired before but also calculated new available CFs for those with invalid CFs.

Objective To investigate the levels of γδ T cells and their subpopulations in bone marrow(BM)of patients with myelodysplastic syndrome(MDS),it aims to explore the immune deficiency status of BM microenvi-ronment in MDS patients.Methods BM samples were collected from MDS patients before and after treatment,as well as from normal donors.Multicolor flow cytometry was utilized to detect bone marrow γδ T cells and subpopulation levels.The changes of the T cell subsets after treatment were also analyzed.Results The levels of BM γδ T cells and follicular helper γδ T cells from MDS patients were significantly lower than those of normal donors(P<0.05).Among γδ T cells at different stages of differentiation,only the frequencies of na?ve γδ T cells from MDS patients decreased significantly(P = 0.037),and there was no significant difference observed about central memory,effector memory,and terminally differentiated γδ T cells in MDS patients compared to normal donors(P>0.05).Although there was a slight decrease in PD1+γδ T cells and an increase in TIM3+γδ T cells,these differences were not statistically significant(P>0.05).In patients who achieved a curative effect,the proportions of γδ T cells and naive γδ T cells increased significantly after treatment,and the effector memory γδ T cells decreased significantly after treatment(P<0.05).After treatment,85.71%(6/7)of MDS patients showed a decrease in γδ+TIM3+ T cell levels to varying degrees.Conclusions The levels of γδ T cells and their subpopulations in the BM microenvironment of patients with MDS exhibit varying degrees of abnormalities.However,in patients who receive effective treatment,these abnormal γδ T cells can recover.By detecting the levels of γδ T cells and subpopulations,we can gain insights into the immune deficiency status of MDS.This information might serve as an indicator to assess treatment efficacy and provide valuable insights for anti-tumor immunotherapy.

OBJECTIVETo validate the conversion factor (CF) for the conversion of BCR-ABL (P210) transcript levels to the international scale in chronic myeloid leukemia (CML).

METHODSIn 2012, the international reference laboratory in Adelaide, Australia (IMVS) sent two batches of RNA samples, 30 samples per batch, to Peking University People's Hospital (PKUPH). By comparing BCRABL (P210) transcript levels reported by the two laboratories, CF of PKUPH was calculated and validated by IMVS. In 2013, PKUPH prepared the exchange samples for validation of CF of 9 hospitals who have calculated CFs before. The fresh BCR-ABL (P210) (+) cells were serially diluted by BCR-ABL (P210) (-) cells to prepare 22 kinds of samples with different BCR-ABL transcript levels, each kind had 10 parallel samples. Trizol reagent was added in each tube. Ten hospitals tested BCR-ABL transcript levels of one set of 22 samples. Agreement between BCR-ABL transcript levels of each laboratory and PKUPH was assessed by the Bland-Altman method.

RESULTSPKUPH successfully validated its CF with bias 1.1 fold and 95% limits of agreement between -4.7 and 4.9 fold. Of 9 hospitals whose validation performed by sample exchanges with PKUPH, 6 hospitals successfully validated their CF with bias ≤±1.4 fold and 95% limits of agreement within ±6 fold.

CONCLUSIONValidation of CF examined the stability of the detection of BCR-ABL (P210) transcript levels, which was necessary for the valid conversion of BCR-ABL (P210) transcript levels to the international scale in CML.