Clinical and gene mutation characteristics of patients with hereditary ellipsocytosis: nine cases report and literature review / 中华血液学杂志

Objective: To report gene mutations in nine patients with hereditary elliptocytosis (HE) and analyze the characteristics of pathogenic gene mutations in HE. Methods: The clinical and gene mutations of nine patients clinically diagnosed with HE at Institute of Hematology & Blood Diseases Hospital from June 2018 to February 2022 were reported and verified by next-generation sequencing to analyze the relationship between gene mutations and clinical phenotypes. Results: Erythrocyte membrane protein gene mutations were detected among nine patients with HE, including six with SPTA1 mutation, one with SPTB mutation, one with EPB41 mutation, and one with chromosome 20 copy deletion. A total of 11 gene mutation sites were involved, including 6 known mutations and 5 novel mutations. The five novel mutations included SPTA1: c.1247A>C (p. K416T) in exon 9, c.1891delG (p. A631fs*17) in exon 15, E6-E12 Del; SPTB: c.154C>T (p. R52W) ; and EPB41: c.1636A>G (p. I546V) . Three of the six patients with the SPTA1 mutation were SPTA1 exon 9 mutation. Conclusion: SPTA1 is the most common mutant gene in patients with HE.

Pharmacokinetic study of anti-human T-cell porcine immunoglobulin combined with cyclosporine A immunosuppressive therapy in patients with severe aplastic anemia / 中华血液学杂志

Objective: To study the metabolic characteristics of anti-human T-cell porcine immunoglobulin (p-ATG) in patients with severe aplastic anemia (SAA) . Methods: For patients with SAA treated with p-ATG combined cyclosporine A (CsA) immunosuppressants between February 2017 and December 2017, the p-ATG dose was 20 mg·kg(-1)·d(-1) over 12 h of intravenous administration for 5 consecutive days. The blood concentration of p-ATG was detected by the three-antibody sandwich ELISA method, the pharmacokinetic analysis software was fitted, and the second-chamber model method was used to calculate the pharmacokinetic parameters and plot the pharmacokinetic curve. Adverse events were recorded and the hematologic reactions were determined at 6 months after treatment. Results: Sixteen patients with SAA treated with p-ATG were enrolled, including 8 females and 8 males, with a median age of 22 years (range, 12 to 49 years) and a median weight of 62.5 kg (range, 37.5 to 82.0 kg) . The pharmacokinetics of p-ATG could be evaluated in 14 cases. p-ATG is distributed in vivo as a two-chamber model, with an average drug concentration peak (T(max)) of (5.786±2.486) days, a peak concentration (C(max)) of (616±452) mg/L, and a half-life of (10.479±8.242) days. The area under the drug time curve (AUC) was (5.807±3.236) mg/L·d. Six months after treatment, 8 of 14 patients received a hematologic response; the AUC (0-t) of the effective group and ineffective groups was (7.50±3.26) mg/L·d vs (4.50±2.18) mg/L·d, and the C(max) was (627±476) mg/L vs (584±382) mg/L, respectively. Conclusion: The plasma concentration of p-ATG reached a peak after 5 days of continuous infusion, and then decreased slowly, with a half-life of 10.479 days, and the residual drug concentration was detected in the body 60 days after administration. A relationship between drug metabolism and efficacy and adverse reactions could not be determined.

Reassessing the six months prognosis of patients with severe or very severe aplastic anemia without hematological responses at three months after immunosuppressive therapy / 中华血液学杂志

Objective: To reassess the predictors for response at 6 months in patients with severe or very severe aplastic anemia (SAA/VSAA) who failed to respond to immunosuppressive therapy (IST) at 3 months. Methods: We retrospectively analyzed the clinical data of 173 patients with SAA/VSAA from 2017 to 2018 who received IST and were classified as nonresponders at 3 months. Univariate and multivariate logistic regression analysis were used to evaluate factors that could predict the response at 6 months. Results: Univariate analysis showed that the 3-month hemoglobin (HGB) level (P=0.017) , platelet (PLT) level (P=0.005) , absolute reticulocyte count (ARC) (P<0.001) , trough cyclosporine concentration (CsA-C0) (P=0.042) , soluble transferrin receptor (sTfR) level (P=0.003) , improved value of reticulocyte count (ARC(△)) (P<0.001) , and improved value of soluble transferrin receptor (sTfR(△)) level (P<0.001) were related to the 6-month response. The results of the multivariate analysis showed that the PLT level (P=0.020) and ARC(△) (P<0.001) were independent prognostic factors for response at 6 months. If the ARC(△) was less than 6.9×10(9)/L, the 6-month hematological response rate was low, regardless of the patient's PLT count. Survival analysis showed that both the 3-year overall survival (OS) [ (80.1±3.9) % vs (97.6±2.6) %, P=0.002] and 3-year event-free survival (EFS) [ (31.4±4.5) % vs (86.5±5.3) %, P<0.001] of the nonresponders at 6 months were significantly lower than those of the response group. Conclusion: Residual hematopoietic indicators at 3 months after IST are prognostic parameters. The improved value of the reticulocyte count could reflect whether the bone marrow hematopoiesis is recovering and the degree of recovery. A second treatment could be performed sooner for patients with a very low ARC(△).

Characteristics of bone marrow compensatory erythropoiesis in hereditary spherocytosis / 中华血液学杂志

Objective: To reveal the compensatory features of bone marrow (BM) erythropoiesis in hereditary spherocytosis (HS) and to explore the effect of diferent hemoglobin levels on this compensation. Methods: Clinical and laboratory data of patients with HS were collected, and the peripheral blood absolute reticulocytes counts value was taken as the surrogate parameter to evaluate the ability of erythropoiesis compensation. BM erythropoiesis compensation in HS with diferent degrees of anemia were evaluated. Results: ①Three hundred and two patients were enrolled, including 115 with compensated hemolytic disease, 74 with mild anemia, 90 with moderate anemia, and 23 with severe anemia. ②Hemoglobin (HGB) was negatively correlated with serum erythropoietin in the decompensated hemolytic anemia group (EPO; rs=-0.585, P<0.001) . ③The median absolute reticulocyte count (ARC) of HS patients was 0.34 (0.27, 0.44) ×10(12)/L, up to 4.25 times that of normal people. The maximum ARC was 0.81×10(12)/L, about 10 times that of normal people. The median ARC of patients with compensated hemolytic disease was 0.29 (0.22, 0.38) ×10(12)/L, up to 3.63 times that of normal people. The median ARC of patients with hemolytic anemia was 0.38 (0.30, 0.46) ×10(12)/L, which was significantly higher than the patients with compensated hemolytic disease, up to 4.75 times that of normal people (z=4.999, P=0.003) . ④ ARC was negatively correlated with HGB in the compensated hemolytic disease group (rs=-0.177, P=0.002) and positively correlated with HGB in the decompensated hemolytic anemia group (rs=0.191, P=0.009) . There was no significant difference in the ARC among patients with mild, moderate, and severe anemia (χ(2)=4.588, P=0.101) . ⑤The median immature reticulocyte production index of the mild, moderate, and severe anemia groups was 13.1% (9.1%, 18.4%) , 17.0% (13.4%, 20.8%) , and 17.8% (14.6%, 21.8%) , respectively; the mild anemia group had lower index values than the moderate and severe anemia groups (P(adj) values were both<0.05) , but there was no significant difference between the latter groups (P(adj)=1.000) . The median immature reticulocyte count of patients in the mild, moderate, and severe groups was 5.09 (2.60, 7.74) ×10(10)/L, 6.24 (4.34, 8.83) ×10(10)/L, and 7.00 (3.07, 8.22) ×10(10)/L, respectively; there was no significant difference among the groups (χ(2)=3.081, P=0.214) . Conclusion: HGB can be maintained at a normal level through bone marrow erythropoiesis, while red blood cells are reduced in HS. However, once anemia develops, the bone marrow exerts its maximum erythropoiesis capacity and does not increase, regardless of anemia aggravation or serum EPO increase.

Relationship between Changes of Lymphocyte Subsets and Early Hematologic Response in Immunosuppressive Therapy of Severe Aplastic Anemia Patients / 中国实验血液学杂志

OBJECTIVE@#To explore the relationship between the change of lymphocyte subsets before and after immunosuppressive therapy (IST) with disease severity of severe aplastic anemia (SAA) and hematologic response to IST.@*METHODS@#The clinical data of 94 patients with SAA/VSAA treated by r-ATG and CsA in our hospital from December 2009 to October 2011 was analyzed retrospectively. Among them, 26 patients who had sequential data of lymphocyte subsets and cytokines before and after treatment were enrolled. The relationship between lymphocyte subsets, cytokine level before IST and disease severity, as well as the relationship between changes if lymphocyte subsets, changes of cytokine and the HR after IST for 6 months was analyzed.@*RESULTS@#There were no statistical differences in the ratio and absolute count of lymphocyte, the ratio and absolute count of each lymphocyte subsets, including CD3@*CONCLUSION@#The hematopoietic recovery and early hematologic remission may be affected by the intensity of immune suppression reflected from the changes of lymphocyte subsets and the immune reconstruction reflected from the recovery of lymphocyte subsets. The immune reconstruction is most significant within 3 months after IST.

Predicting early response to immunosuppressive therapy in severe aplastic anemia by soluble transferrin receptor assay / 中华血液学杂志

<p><b>OBJECTIVE</b>To evaluate the value of serum soluble transferrin receptor (sTfR) concentration in predicting early response to immunosuppressive therapy (IST) in severe aplastic anemia (SAA).</p><p><b>METHODS</b>Clinical data and hematologic responses of 140 SAA patients treated with rabbit antithymocyte globulin (rATG) combination with cyclosporine in our hospital were retrospectively analyzed. Correlation of pre-IST baseline of sTfR and IST responses was statistically analyzed and receiver operating characteristic (ROC) curve was used to estimate the sensitivity and specificity of sTfR in prediction of early responses.</p><p><b>RESULTS</b>Serum concentration of sTfR in very SAA (VSAA) patients were significantly lower than SAA and transfusion dependent non-SAA cases (P=0.001). The responders, especially at 3 months, had significantly higher pre- IST baseline of sTfR [median, 0.89 (range, 0.21-2.42) mg/L] than that [median, 0.58 (range, 0.13-1.88) mg/L] of non-responders (P=0.005). The cutoff level of 0.91 mg/L and 0.88 mg/L for predicting responses at 3 and 6 months were established based on the ROC curve, with the degree of accuracy of 65.0% and 60.7% respectively. Multivariate analysis showed that pre-IST baseline of sTfR was the independent factor of predicting response at 3 months (P=0.007) and at 6 months (P=0.021).</p><p><b>CONCLUSION</b>As a indicator of bone marrow failure severity, sTfR could predict early response to IST therapy in aplastic anemia.</p>

High-dose cyclophosphamide for severe aplastic anemia associated with β-thalassemia: a case report and literatures review / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the clinical features and therapeutic method for severe aplastic anemia (SAA) associated with β-thalassemia, and to improve the recognition of the disease.</p><p><b>METHODS</b>One patient hospitalized for pancytopenia was reported and the related literatures were reviewed.</p><p><b>RESULTS</b>A 14-years old girl who presented with anemia from her childhood was hospitalized for acute onset of pancytopenia. Routine blood test showed that WBC count was 1.28×10⁹/L, hemoglobin 65 g/L, platelet count 18×10⁹/L, reticulocyte count 2×10⁹/L, neutrophil count 0.03×10⁹/L and mean corpuscular volume 59.6 fl, respectively. Both bone marrow aspiration and biopsy showed hypoplasia. Her red blood cells presented as microcytic hypochromic and target erythrocytes were common on peripheral blood smear. DNA analysis of the patient and her mother showed exon 17 heterozygous β-thalassemia (c.52 A>T). A diagnosis of SAA associated with β-thalassemia was clarified and high-dose cyclophosphamide (HD-CTX, 1.2 g/d×4 d) plus cyclosporine were offeved, which eventually led to a complete hematologic remission 12 months later.</p><p><b>CONCLUSION</b>This was the first report of SAA associated with β-thalassemia, and the regimen of HD-CTX led to a complete hematologic remission.</p>

Pure red cell aplasia with thymoma/T-cell large granular lymphocyte leukemia: two cases report and literatures review / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the clinical and laboratory features of 2 cases of pure red cell aplasia (PRCA) with thymoma/T-cell large granular lymphocyte leukemia (T-LGLL), and to improve the recognition of the disease and the role of lymphocyte in its mechanism.</p><p><b>METHODS</b>Two cases of PRCA with thymoma/T-LGLL were reported and the related literatures were reviewed.</p><p><b>RESULTS</b>Case 1 was a 63-years old male with hemoglobin level of 54 g/L at admission. Case 2 was a 52-years old female with hemoglobin level of 79 g/L at admission. They were both diagnosed as PRCA with thymoma before admission to our hospital and had no benefit from their thymectomy. Further examinations in our hospital showed that CD3⁺CD4⁻CD8⁺CD57⁺ large granular lymphocytes amplified with clonal TCR rearrangement in their peripheral blood. The diagnosis of PRCA with thymoma/T-LGLL was clarified. Case 1 did not respond to any of the frontline therapies while case 2 responded completely to cyclosporine.</p><p><b>CONCLUSION</b>Both thymoma and T-LGLL could be the cause of secondary PRCA, lymphocyte proliferation may play critical role in the pathogenesis.</p>

Congenital dyserythropoietic anemia type II: a case report and literature review / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the clinical and laboratory features of congenital dyserythropoietic anemia type II (CDA-II) in order to improve the recognition of the disease.</p><p><b>METHODS</b>A case of CDA-II was reported and the related literatures were reviewed.</p><p><b>RESULTS</b>The 32-years old female presented with moderate anemia, jaundice and hepatosplenomegaly from her childhood and was misdiagnosed as hereditary spherocytosis for a long time. There were no increased reticulocytes in the peripheral blood and her bone marrow showed erythroid hyperplasia with 43% of binucleated erythroblasts. Electron microscopy examination revealed stretches of double membrane lining the inner surface of the erythroblast cell membrane.</p><p><b>CONCLUSIONS</b>CDA-II is a rare congenital anemia characterized by ineffective erythropoiesis with unique laboratory features, and is relatively easy to be misdiagnosed. It is necessary to improve the awareness of CDA-II, and to set-up its responsible gene analysis, i.e., CDAN2 gene and SEC23B gene detection.</p>

Effects of concentration of cyclosporine A on the early response to immunosuppressive therapy in severe aplastic anemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To evaluate the effects of cyclosporine A (CsA) whole-blood concentration on the early response to immunosuppressive therapy (IST) in severe and very severe aplastic anemia (SAA/VSAA).</p><p><b>METHODS</b>Ninety SAA/VSAA patients treated with rabbit antithymocyte globulin (ATG) plus CsA as first line therapy in our hospital were retrospectively analysed. CsA levels between the response group and non-response group, and response rates of patients with variant CsA levels were compared respectively.</p><p><b>RESULTS</b>(1) There was no significant difference in the beginning unmodified CsA blood concentration between IST responded and non-responded SAA/VSAA patients. The beginning unmodified C(0) 133.91 ug/L in IST 2-month responders was higher than that of 49.9 ug/L in non-responded SAA patients (P = 0.009); (2) The mean CsA C(0) and C(2) levels during the third month following IST were significantly different in responders and non-responders(197.52 µg/L vs 161.49 µg/L, P = 0.024, and 738.76 µg/L vs 615.46 µg/L, P = 0.009), and no significant difference in other periods of IST (P > 0.05); (3) The response rate (87.5%) was significantly higher in patients with CsA C(0) ≥ 200µg/L the third month following IST than those of 55.6% in patients with CsA C(0) 150 - 200 µg/L (P = 0.023) and 59.3% in patients with CsA C(0) < 150 µg/L (P = 0.046), respectively. The response rate was significantly higher of C(2) ≥ 700 µg/L group than that of C(2) < 700 µg/L group (80.5%vs 55.3%, P = 0.012).</p><p><b>CONCLUSIONS</b>The CsA concentration related to the early IST response. The third month CsA concentrations was the most important for the response and maintaining CsA levels with C(0) ≥ 200 µg/L and C(2) ≥ 700 µg/L may improve the response to IST in SAA/VSAA.</p>

Combination of rabbit antithymocyte globulin and cyclosporine A as first-line therapy for adult severe aplastic anemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the efficacy and side-effects of combination of rabbit antithymocyte globulin (ATG) and cyclosporine A (CsA) as the first-line immunosuppressive therapy (IST) for adult severe aplastic anemia (SAA) patients.</p><p><b>METHODS</b>Adult SAA or very severe aplastic anemia (VSAA) patients treated with rabbit ATG + CsA as first line therapy in our hospital from 2003 to 2008 were retrospectively analysed and the therapeutic response relevant factors were analysed.</p><p><b>RESULTS</b>Seventy-nine patients were enrolled. Of all these patients, 6 died within 3 months after IST. The overall response rate was 82.2% and the median time to transfusion independent was 60 days. The therapeutic response rate in 32 SAA patients (100%) was significantly higher than that in 41 VSAA cases (68.3%) (P = 0.001). Patients with neutrophil response to G-CSF treatment had a higher IST response rate than those without response to G-CSF (100% vs 67.5%, P = 0.001). Sixty-one patients (77.2%) occurred serum sickness reaction. Three patients relapsed and two developed clonal hematological abnormalities after IST. The 3-year overall survival for all the patients was 88.9%.</p><p><b>CONCLUSIONS</b>Rabbit ATG in combination with CsA as first-line IST for adult SAA can lead to excellent treatment outcomes with minor adverse effects.</p>

The clinical and laboratory characteristics of T cell large granular lymphocyte leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the characteristics of T-cell large granular lymphocyte leukemia (T-LGLL).</p><p><b>METHODS</b>Retrospectively analyze the clinical and laboratory data of 27 patients with T-LGLL diagnosed between 1999 and 2007 in our hospital.</p><p><b>RESULTS</b>The median age at diagnosis was 48 years. All patients were symptomatic, mainly complaining of fatigue. Of the 27 patients, 14 (51.9%) had splenomegaly, and 4(14.8%) hepatomegaly. Rheumatoid arthritis was not present in any patients. The most frequent hematological abnormality was anemia (24 patients, 88.9%) with a median Hb level of 57.5 g/L. Pure red cell aplasia was found in 18 patients (66.67%). The median WBC count was 4.24 x 10(9)/L and 19 cases were neutropenia (ANC < 1.5 x 10(9)/L). The median LGL count in peripheral blood was 1.45 x 10(9)/L and most of them (77.8%) were less than 2.0 x 10(9)/L. Twenty-two patients (81.5%) showed the CD3+ CD8+ CD57+ CD56(-) LGL phenotype. With immunosuppressive therapy, 91.3% of patients responded and complete hematological remission rate was 65.2%.</p><p><b>CONCLUSION</b>T-LGLL mainly presented with anemia and complete hematological remission rate was 65.2%. Pure red cell aplasia was commonly associated with the disease. The patients had a good response to immunosuppressive therapy.</p>

Clinical and hematological features of congenital dyserythropoietic anemia type I / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the clinical and laboratory features of patients with congenital dyserythropoietic anemia type I (CDA-I), and improve the clinical diagnostic accuracy.</p><p><b>METHODS</b>The clinical and hematological features of 5 patients diagnosed as CDA-I in our hospital between July 2002 and July 2007 were analyzed retrospectively, and the related literatures was reviewed.</p><p><b>RESULTS</b>Five CDA-I patients, 1 male and 4 females, all had a long history of varied degree of chronic anemia. One patient had congenital malformations, 3 jaundice and 4 hepatosplenomegaly. Bone marrow specimens invariably showed hypercellularity due to erythroid hyperplasia with megaloblastic changes, irregularly shaped nuclear, and chromatin bridges in 0.2% to 0.6% of all erythroblasts. All the 5 patients' bone marrow erythroblasts showed spongy heterochromatin appearances (swiss-cheese) with electron microscopy examination. There was no morphologic abnormality in the granulocytes and megakaryocytes. Serum ferritin levels were increased in 3/4 patients. One patient had been misdiagnosed as hereditary spherocytosis and performed splenectomy in the local hospital with no improvement in Hb level.</p><p><b>CONCLUSIONS</b>CDA-I is a rare congenital anemia characterized by ineffective erythropoiesis, jaundice, hepatosplenomegaly and iron overload, and may be misdiagnosed. Keeping these manifestations in mind should avoid misdiagnosis.</p>

Combination of rabbit antithymocyte globulin plus cyclosporin A as first-line immunosuppressive therapy for the childhood with severe aplastic anemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyse the efficacy and side-effects of rabbit antithymocyte globulin (ATG) and cyclosporin A (CsA) as the first-line therapy for childhood severe aplastic anemia (SAA).</p><p><b>METHODS</b>Seventy-one childhood SAA patients treated with rabbit ATG + CsA as first line therapy were retrospectively analysed.</p><p><b>RESULTS</b>Seventy-one SAA patients, including 38 SAA and 33 very severe aplastic anemia (VSAA), were enrolled. The median age was 12 years. Of these patients, 3 died within 3 months after the immunosuppressive therapy (IST). The overall response rate was 67.6% (46/68) and the median time to transfusion independent was 53 days. Thirty-three patients (48.5%) obtained remission in 3 months after the IST and 45 (67.2%) in 6 months. The response rates were 57.7% (15/26), 56.5% (13/23) and 94.7% (18/19) for patients less than 10 years old, 10 - 15 year-old and 15 - 18 year-old, respectively. Sixty patients suffered from serum sickness on the IST. Three patients relapsed and another 3 unrespond patients received retreatment of IST, and one patient progressed to myelodysplastic syndromes (MDS).</p><p><b>CONCLUSION</b>Rabbit ATG in combination with CsA as first line therapy for childhood SAA/VSAA can lead to overall response rate of 67.6% with minor adverse effects.</p>

The clinical characteristics of T cell large granular lymphocyte leukemia associated with pure red cell aplasia / 中华血液学杂志

<p><b>OBJECTIVE</b>To analyze the characteristics of acquired pure red cell aplasia (PRCA) secondary to T cell large granular lymphocyte leukemia (T-LGLL).</p><p><b>METHODS</b>Fourteen patients with T-LGLL associated with PRCA between 2000 and 2006 in our hospital were retrospectively analyzed.</p><p><b>RESULTS</b>The median age at diagnosis was 61 years with equal gender distribution. The PRCA had indolent process, mainly presenting with anemia. Of the 14 patients, 9 had mild to moderate splenomegaly, one hepatomegaly and one lymphadenopathy. The median Hb level was 61.5 g/L and the median WBC count 4.3 x 10(9)/L. The median percentage and count of LGL in peripheral blood were 0.36 and 1.9 x 10(9)/L respectively. The median percentage of LGL in BM was 0.165 (0.085 - 0.410). Some patients had serologic abnormalities. All the 12 cases with available bone marrow cell cytogenetics showed normal karyotypes. With cyclosporine A or glucocorticoid immunosuppressive therapy, the overall response was 91%.</p><p><b>CONCLUSION</b>T-LGLL was one of the major causes of acquired PRCA. This type of PRCA has the similar clinical and laboratory feature to that of other type of PRCA and has a good response to immunosuppressive therapy.</p>

Study on the Characteristics of cell cycle and proliferation of CD34+ hematopoietic stem cells in myelodysplastic syndromes / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the characteristics of cell cycle and proliferation of CD34+ hematopoietic stem cells in patients with myelodysplastic syndromes (MDS).</p><p><b>METHODS</b>Propidium iodide staining was used to examine cell cycle parameters (G(0)/G(1), S and G(2)/M) of bone marrow mononuclear cells (BMMNCs) while immunofluorescent double staining and FACS techniques were used to measure Ki67 expression in BM CD34+ cells from normal control, patients with MDS, acute myeloid leukemia preceded by MDS (MDS-AML) and primary AML.</p><p><b>RESULTS</b>There was a statistical up-tendency in G(0)/G(1) phase proportion of BMMNCs whereas a statistical down-tendency in S and G(2)/M phase proportions among normal control, MDS and primary AML. Compared to primary AML, MDS-AML had significantly higher ratios of S (P < 0.05), G(2)/M (P < 0.05) and S + G(2)/M (P < 0.05) phase cells while lower ratio of G(0)/G(1) phase cells (P < 0.05). The proportion of CD34+Ki67+ cells in MDS patients was significantly higher than that in normal control (P = 0.004). So were the percentages of CD34+Ki67+ cells in low-risk [(0.54 +/- 0.49)%, P < 0.05] and high-risk MDS patients [(1.69 +/- 1.66)%, P = 0.022]. Furthermore, there was statistical difference between low-risk and high-risk MDS (P < 0.05). Compared to normal control and primary AML, MDS-patients had the highest proportion of CD34+Ki67+ cells [(16.75 +/- 13.58)%, P < 0.05]. The proportion of CD34+Ki67+ cells in CD34+ cells in MDS patients [(48.50 +/- 20.49)%] was significantly higher than that in normal control [(27.71 +/- 16.04)%, P < 0.01]. So were the low-risk [(51.85 +/- 21.80)%, P = 0.002] and high-risk MDS [(43.93 +/- 18.57)%, P < 0.05]. The proportion of CD34+Ki67+ cells in CD34+ cells in MDS-AML patients [(60.92 +/- 30.12)%] was the highest, and was statistically higher than that in both normal control (P < 0.01) and primary AML patients [(17.01 +/- 15.93)%, P < 0.001]. The proportion of CD34+Ki67+ cells in Ki67+ cells in MDS patients [(4.91 +/- 4.68)%, P < 0.01] was significantly higher than that [(2.43 +/- 2.37)%] in normal controls. In the low-risk MDS group it was (4.11 +/- 3.94)%, (P > 0.05) and in high-risk MDS group it was (5.76 +/- 5.38)%, (P < 0.05).</p><p><b>CONCLUSION</b>High proportion of G(0)/G(1) cells and G(1) phase arrest occurred in MDS. High proliferation capacity of MDS clone, especially that derived from CD34+ cells, might play an important role in the clonal expansion, diseases deterioration and worse prognosis of MDS.</p>