Quantum Oscillations, Thermoelectric Coefficients, and the Fermi Surface of Semimetallic WTe2.

We present a study of angle-resolved quantum oscillations of electric and thermoelectric transport coefficients in semimetallic WTe2, which has the particularity of displaying a large B(2) magnetoresistance. The Fermi surface consists of two pairs of electronlike and holelike pockets of equal volumes in a "Russian doll" structure. The carrier density, Fermi energy, mobility, and the mean-free path of the system are quantified. An additional frequency is observed above a threshold field and attributed to the magnetic breakdown across two orbits. In contrast to all other dilute metals, the Nernst signal remains linear in the magnetic field even in the high-field (ωcτ≫1) regime. Surprisingly, none of the pockets extend across the c axis of the first Brillouin zone, making the system a three-dimensional metal with moderate anisotropy in Fermi velocity, yet a large anisotropy in the mean-free path.

Evidence for Half-Metallicity in n-type HgCr2Se4.

High quality HgCr2Se4 single crystals have been investigated by magnetization, electron transport, and Andreev reflection spectroscopy. In the ferromagnetic ground state, the saturation magnetic moment of each unit cell corresponds to an integer number of electron spins (3 µB/Cr3+), and the Hall effect measurements suggest n-type charge carriers. Spin polarizations as high as 97% were obtained from fits of the differential conductance spectra of HgCr2Se4/Pb junctions with the modified Blonder-Tinkham-Klapwijk theory. The temperature and bias-voltage dependencies of the subgap conductance are consistent with recent theoretical calculations based on spin active scatterings at a superconductor-half-metal interface. Our results suggest that n-HgCr2Se4 is a half-metal, in agreement with theoretical calculations that also predict undoped HgCr2Se4 is a magnetic Weyl semimetal.

Incommensurate charge super-modulation and hidden dipole order in layered kitaev material α-RuCl3.

The magnetism of Kitaev materials has been widely studied, but their charge properties and the coupling to other degrees of freedom are less known. Here we investigate the charge states of α-RuCl3, a promising Kitaev quantum spin liquid candidate, in proximity to graphite. We discover that few-layered α-RuCl3 experiences a clear modulation of charge states, where a Mott-insulator to weak charge-transfer-insulator transition in the 2D limit occurs by means of heterointerfacial polarization. More notably, distinct signals of incommensurate charge and lattice super-modulations, regarded as an unconventional charge order, accompanied in the insulator. Our theoretical calculations have reproduced the incommensurate charge order by taking into account the antiferroelectricity of α-RuCl3 that is driven by dipole order in the internal electric fields. The findings imply that there is strong coupling between the charge, spin, and lattice degrees of freedom in layered α-RuCl3 in the heterostructure, which offers an opportunity to electrically access and tune its magnetic interactions inside the Kitaev compounds.

Subtypes of B lymphocytes in patients with autoimmune hemocytopenia.

OBJECTIVE: To investigate the quantities of bone marrow CD5+ B lymphocytes in the patients with autoimmune hemocytopenia and the relationship between quantities of CD5+ B lymphocytes and clinical or laboratorial parameters. METHODS: Quantities of CD5+ B lymphocytes in the bone marrow of 14 patients with autoimmune hemolytic anemia (AIHA) or Evans syndrome, 22 immunorelated pancytopenia (IRP) patients, and 10 normal controls were assayed by flow cytometry. The correlation between their clinical or laboratorial parameters and CD5+ B lymphocytes was analyzed. RESULTS: The quantity of CD5+ B lymphocytes of AIHA/Evans syndrome (34.64% +/- 19.81%) or IRP patients (35.81% +/- 16.83%) was significantly higher than that of normal controls (12.00% +/- 1.97%, P < 0.05). However, there was no significant difference between AIHA/Evans syndrome and IRP patients (P > 0.05). In all hemocytopenic patients, the quantity of bone marrow CD5+ B lymphocytes showed significantly negative correlation with serum complement C3 level (r = -0.416, P < 0.05). In the patients with AIHA/Evans syndrome, the quantity of bone marrow CD5+ B lymphocytes showed significantly positive correlation with serum indirect bilirubin level (r = 1.00, P < 0.05). In Evans syndrome patients, the quantity of CD5+ B lymphocytes in bone marrow showed significantly positive correlation with platelet-associated immunoglobulin G (r = 0.761, P < 0.05) and platelet-associated immunoglobulin M ( r = 0.925, P < 0.05). The quantity of CD5+ B lymphocytes in bone marrow of all hemocytopenic patients showed significantly negative correlation with treatment response (tau-b = -0.289, P < 0.05) , but had no correlation with colony forming unit-erythroid (r = -0.205, P > 0.05) or colony forming unit-granulocyte-macrophage colonies (r = -0.214, P > 0.05). CONCLUSIONS: The quantity of bone marrow CD5+ B lymphocytes in the patients with autoimmune hemocytopenia significantly increases and is correlated with disease severity and clinical response, which suggest that CD5+ B lymphocytes might play an important role in the pathogenesis of autoimmune hemocytopenia.

Superconductivity emerging from a suppressed large magnetoresistant state in tungsten ditelluride.

The recent discovery of large magnetoresistance in tungsten ditelluride provides a unique playground to find new phenomena and significant perspective for potential applications. The large magnetoresistance effect originates from a perfect balance of hole and electron carriers, which is sensitive to external pressure. Here we report the suppression of the large magnetoresistance and emergence of superconductivity in pressurized tungsten ditelluride via high-pressure synchrotron X-ray diffraction, electrical resistance, magnetoresistance and alternating current magnetic susceptibility measurements. Upon increasing pressure, the positive large magnetoresistance effect is gradually suppressed and turned off at a critical pressure of 10.5 GPa, where superconductivity accordingly emerges. No structural phase transition is observed under the pressure investigated. In situ high-pressure Hall coefficient measurements at low temperatures demonstrate that elevating pressure decreases the population of hole carriers but increases that of the electron ones. Significantly, at the critical pressure, a sign change of the Hall coefficient is observed.

Endogenous erythroid colony assay in patients with polycythemia vera and its clinical significance.

BACKGROUND: Polycythemia vera (PV) is a malignant disorder of hemaopoietic stem cells which is characterized by clonal hyperproliferation and a low rate of apoptosis. This study was to assess endogenous erythroid colony (EEC) formation in the bone marrow of PV patients and determine its clinical significance. METHODS: The bone marrow mononuclear cells of 26 patients with PV, 2 patients with secondary erythrocytosis (SE), and 19 normal controls were cultured by Marsh's method for EEC evaluation, and the clinical significance was evaluated. RESULTS: EECs appeared in 25 patients with PV but not in 2 patients with SE and 19 normal controls. The number of EECs and the EEC ratio [EEC/erythropoietin (EPO)-dependent colony forming unit-erythroid (CFU-E)] in PV patients positively correlated with hemoglobin (Hb) levels. Their EEC number did not correlate with white blood cell (WBC) counts, platelet (PLT) counts, or leukocyte alkaline phosphatase (LAP) scores. Their EEC did not correlate with serum EPO levels. Fifteen patients with PV were treated with hydroxyurea (Hu) and/or interferon-alpha (IFN-alpha). Their EEC ratio before treatment positively correlated with the treatment time required for complete remission (CR) and negatively correlated with the time before relapse. The EEC numbers of 7 PV patients treated with Hu/IFN-alpha decreased after the blood cell counts dropped to normal levels. There was a positive correlation between the EEC ratio and the incidence of attacks of vascular thrombosis in PV patients. The numbers of apoptosised bone marrow mononuclear cells in PV patients were lower than those in normal controls. The EEC numbers of PV patients negatively correlated with the rate of apoptosis of bone marrow mononuclear cells. CONCLUSIONS: EEC formation is characteristic in PV patients. EEC number in PV patients positively correlates with Hb levels, the time required for CR, and the incidence of attacks of vascular thrombosis. EEC number negatively correlates with the time before relapse. Bone marrow suppressive treatment might decrease EEC number. Thus, EEC number is a sensitive and specific parameter reflecting the abnormal hematopoietic clone burden induced by polycythemia vera. EEC number is an important diagnostic parameter for PV patients.

[Research on expansion of CD34+ cells from umbilical cord blood using different cytokine groups in vitro].

OBJECTIVE: To investigate the expansion of the CD34+ cells of umbilical cord blood in vitro culture comprising different cytokines and the potential hematopoiesis function of the expanded CD34+ cells. METHOD: Expanding the purified CD34+ cells from the fresh umbilical cord blood for 6 days in vitro with the use of different combination of FL, SCF, TPO, IL-3 and IL-6. Getting one better combination by analyses of the results from flowcytometry, LTC-IC, and progenitor clonogenic assays. RESULTS: The numbers of CD34+ cells expanded by use of different combination of cytokines were 3.1-8.6 times as large as the numbers of ordinary ones, thus making 16 cases of insufficient CD34+ cells become able to satisfy the needs of the adults weighing 50 kg. No significant difference was observed between the function of the expanded cells and the original ones in hematopoiesis. Meanwhile, it was proved that TPO in combination with other cytokines could strengthen the expansion of CD34+ cells, but using TPO alone for long time culture would cause more CD34+ cells to be megalocaryocytes. CONCLUSION: The combination of FST36 cytokines can expand the CD34+ cells of the umbilical cord blood to meet the adults' needs in laboratory's methods.

[The clinical features of hepatitis associated aplastic anemia].

OBJECTIVE: To analyse the proportion of hepatitis associated aplastic anemia (HAAA) in severe aplastic anemia (SAA) and its clinical features of HAAA. METHODS: All newly diagnosed SAA cases in our department in the recent 5 years were analyzed. A case-control study was undertaken to investigate the differences of clinical and laboratory features between HAAA and non-hepatitis associated SAA (non-HASAA) patients. RESULTS: The proportion of HAAA in SAA was 3.3%. There was no significant difference in PB cell counts, bone marrow hematopoiesis status and the amount of blood transfusion between HAAA and non-HASAA patients. Sera from 13 patients with HAAA were tested for antibodies to hepatitis viruses A, B, and C and hepatitis B surface antigen. Twelve (92.3%) of them had negative serologic results for the tests and only one (7.7%) had a positive result for HBsAg and HBeAg. Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were decreased prior to the diagnosis in twelve (92.3%) of the 13 HAAA patients. The percentage of CD4(+) cells in HAAA patients was significantly lower than that in non-HASAA patients (P < 0.05). HAAA patients had higher percentages of CD8(+) cells (P < 0.05) and lower ratios of CD4(+)/CD8(+) (P < 0.05). The early infection rate of the HAAA patients was significantly higher than that of non-HASAA patients (84.6% vs 42.3%, P < 0.05), with different mortalities (61.5% vs 15.4%, P < 0.05). The 2-year survival rate of HAAA patients was significantly lower than that of non-HASAA patients (16.6% vs 83.2%, P < 0.01). CONCLUSION: The proportion of HAAA in SAA was 3.3%. Most of HAAA were associated with non-A, non-B and non-C hepatitis virus. Compared with that of non-HASAA, the abnormality of T cell immunity of HAAA was more severe, with a higher frequency of early infection and a higher mortality rate.

[Study of Th cell subsets in bone marrow of myelodysplastic syndromes patients].

OBJECTIVE: To study the quantity and ratio of Th1, Th2 cells in the bone marrow of myelodysplastic syndromes (MDS) patients, and to evaluate the correlation between the ratio of the blast cells and the number of the Th1 cells in the bone marrow of MDS patients. METHODS: By FACS, the quantity and ratio of IFN-gamma producing CD4(+) T cell (Th1) and IL-4 producing CD4(+) T cell (Th2) cells in the bone marrow were detected in 21 MDS patients, 18 normal controls and 13 severe aplastic anemia (SAA) patients respectively. The karyotypes of 18 MDS patients and 15 normal controls were assayed. The correlation between the ratio of the blast cells in the bone marrow and the number of the Th1 cells in the MDS patients were analyzed. RESULTS: The percentages of Th1 cells, Th2 cells and ratio of Th1/Th2 in the bone marrow of normal controls were (0.48 +/- 0.10)%, (0.24 +/- 0.19)% and 2.31 +/- 0.76 respectively, while those of the MDS patients were (0.36 +/- 0.11)%, (0.76 +/- 0.35)% and 0.51 +/- 0.13. The percentage of Th1 cells of patients with MDS was reduced and the Th1/Th2 ratio was significantly lower than that of normal controls (P < 0.01). Those of the patients with SAA were (4.75 +/- 0.49)%, (0.40 +/- 0.28)% and 26.5 +/- 8.79 respectively, their Th1 cells and Th1/Th2 ratio were markedly higher than those of normal controls (P < 0.01). In all of the 15 normal controls the karyotypes were normal, but that of MDS patients was (50.00 +/- 0.10)%. The lower ratio of the Th1 cells in the bone marrow of the patients with MDS and the AML which progressed from MDS was negatively correlated with the higher percentage of the blast cells (r = -0.563, P < 0.01). CONCLUSIONS: (1) The immune function of T lymphocytes in MDS is abnormal: the balance between Th1 and Th2 cells is broken. (2) With descending of the number of Th1 cells in the bone marrow of the MDS patients, the disease is progressing to leukemia.

[A Nude Mouse Model for Human Umbilical Cord Blood Transplantation]

To evaluate the hematopoietic potentiality and the migration and homing routine of separated as well as cryopreserved umbilical cord blood hematopoietic cells, the BALB/cnu(+) mice were used to establish a murine model. This can prepare for the clinical transplantation and the establishment of a large-scale cord blood bank. The result indicated that the hydroxyethyl starch (HES) sedimentation and DMSO step-by-step cryopreservation procedure resulted in only less losses of hematopoietic progenitor cells and also unharmful to the hematopietic potentiality. We can found evidence for successful transplantation in each mouse which received (1.0 - 2.0) x 10(7) separated or cryopresered hematopoietic cells from cord blood, which lasted for about fifty days. The results demonstrated that (1) HES sedimentation and DMSO cryopreservation procedure can keep the hematopoietic potentiality of cord blood, and so can be used to clinical transplantation or establishment of a cord blood bank; (2) Rich hematopoietic stem cells in human cord blood can cross the xenogenetic barriers and successfully engraft mice; (3) The hematopoietic cells migrated among bone marrow, liver, spleen, lung and kidney in the mice and homed to bone marrow by the end. Cryopreservation may influence the adhesion molecule on the hematopoietic cells and the homing behaviour, but not influence their hematopoietic potentiality.

[Effect of T3 on the expression of transferrin receptor and ferritin in K562 cells and its possible mechanism].

OBJECTIVE: To explore the effect of T(3) on the expression of transferrin receptor (TfR) and ferritin (Fn) in K562 cells and its possible mechanism. METHODS: Flow cytometry was used for the detection of TfR expression, radioimmunoassay for Fn expression, RNA/protein band shift assay for the binding activity of iron regulatory protein (IRP) and iron responsive elements (IRE), and RT-PCR for TfR and Fn mRNA levels. RESULTS: Different concentration of T(3) significantly increased Fn expression of K562 cells, especially at 100 nmol/L and 200 nmol/L (p < 0.05). However, T(3) had no effect on TfR expression. T(3) decreased the binding activity between IRP and IRE, particularly at concentration of 50 nmol/L. Different concentration of T(3) increased Fn-H mRNA level at different time point while it had no effect on TfR mRNA level. CONCLUSION: T(3) increased Fn expression of K562 cells through the possible mechanisms of either the post-transcriptional regulation or transcriptional modulation.

[Giant Tumor Cells in the Bone Marrow and Their Significance]

Giant tumor cells and their varieties in the bone marrow were found in 7 patients with abnomal hematopoiesis phenomena. These cells were artificially devided into 5 kinds according to the difference of their morphology. Most of these cells were corresponding to lymphoid-monocytoid-macrophagocytoid cells with Wright's staining, cytochemical stainings, immunocytochemical stainings, flow cytometry examination, electron microscopy and pathologic study. The bone marrows were hypercellular and marked dysplastic hematopoiesis phenomena. Two of the 7 cases were diagnosed as malignant lymphoma with bone marrow biopsy. All cases characteristically showed no lymph node enlargement or hepatosplenomegaly or any local tumor mass. As to the prognosis of these cases, two patients died with survival time of 8 and 17 months, respectively, one was on critical condition at course of 10 months, and the other 4 cases were in comparatively stable condition with courses of 2.5 to 24 months. These patients seem to be a group of rare malignant lymphoid-monocytoid-macrophagocytoid proliferative diseases.

[Role of Th1 cell in the pathogenesis of aplastic anemia].

OBJECTIVE: To detect the quantity, proportion and function of producing cytokines of Th1 and Th2 cells in aplastic anemia (AA) patients and their contribution to the hematopoietic failure. METHODS: (1) Eleven patients with severe aplastic anemia (SAA) at diagnosis were observed by Marsh's method for the CFU-E, BFU-E and CFU-GM before and after depletion of CD(4)(+) T lymphocytes from bone marrow mononuclear cells (BMMNC); (2) Th1 (CD(4)(+) IFN-gamma(+)) and Th2 (CD(4)(+) IL-4(+)) cells in peripheral blood mononuclear cells (PBMNC) of 21 SAA patients and 17 normal controls were counted by FACS. (3) mRNA expression of IFN-gamma and IL-4 gene in unstimulated BMMNC from 16 SAA patients, 11 chronic aplastic anemia (CAA) patients, 26 other hematological diseases patients and 11 normal controls were measured by reverse transcriptase polymerase chain reaction (RT-PCR). RESULT: (1) CFU-E, CFU-GM and BFU-E increased significantly after depletion of CD(4)(+) T lymphocytes from BMMNC of SAA patients. (2) The percentage of IFN-gamma producing CD(4)(+) T cell (Th1) of SAA patients was significantly higher than that of controls, the percentages of IL-4 producing CD(4)(+) T cells (Th2) had no difference between SAA patients and normal controls. (3) IFN-gamma mRNA was detected in unstimulated BMMNC in 13 of 16 SAA patients, 6 of 11 CAA patients and one of 6 paroxysmal nocturnal hemoglobinuria (PNH) patients. The IFN-gamma mRNA was not detected in unstimulated BMMNC of 11 normal controls and other hematological diseases patients. CONCLUSIONS: Disbalance of CD(4)(+) T lymphocytes subsets and increases in quantity and IFN-gamma producing function of Th1 cells might be important for the development of bone marrow failure in AA and in distinguishing AA from other kinds of pancytopenic diseases.

[Clinical analysis of 185 patients with polycythemia vera].

OBJECTIVE: To understand the clinical feature and natural course of polycythemia vera (PV). METHODS: The clinical symptoms, signs, laboratory examination and prognosis of 185 patients with PV were analysed. RESULTS: There are 122 males and 63 females. The mean age was (52.7 +/- 14.1) years. The mean hemoglobin level was (208.3 +/- 21.2) g/L. Pancytosis was displayed in 74 (40%) cases, excess of red blood cells in 33 (17.8%), excess of red blood cells and granulocytes in 67 (36.2%) and excess of red blood cell and platelets in 11 (5.9%). Splenomegaly was found in 123 (66.5%) patients and hepatomegaly in 30 (16.2%). Quantitative assess of serum Epo was done in 25 patients. The level was low in 16 (64.2%) and normal in 9 (36.0%). Hematopoietic progenitor culture yields was elevated in 11 patients, endogenous erythroid colonies (EEC) formation was found in 10 cases (90.9%). Eighty two patients (44.3%) had 101 attacks of vascular thrombotic incidents, 7 patients developed myelofibrosis (MF). Secondary cancer occurred in 1 patient. Two patients died of thrombosis. CONCLUSION: PV is an elderly adult myeloproliferative disease with a high frequency of thrombosis. EEC can be found out in PV patients. The serum Epo level is not increased in PV patients. The main sequelae of PV is MF.

[Quantitative and functional changes of T helper cell subsets in the bone marrow of severe aplastic anemia patients].

OBJECTIVE: To evaluate the quantitative and functional changes of T helper (Th) cell subsets in the bone marrow of severe aplastic anemia (SAA) patients and the relationship between these changes and the patients hematopoietic function. METHODS: By FACS, the quantity and ratio of Th1 and Th2 cells, the percentage of CD3(+)CD8(+) cells in the bone marrow were detected in 24 patients with SAA at active phase, 15 patients with SAA at recovery phase, and 16 normal controls. By radioimmunoassay, the serum levels of TNF-alpha, or IL-4 in 20 SAA patients at active phase, 12 at recovery phase and 16 normal controls were measured. The relationships between CD3(+)CD8(+) cells, TNF-alpha and Ret, ANC; and between Th1 cells and CD3(+)CD8(+) cells, TNF-alpha or Ret, ANC; between IL-4, balance of Th1/Th2 and Ret, ANC were evaluated. RESULTS: The percentages of Th1 and Th2 cells, and ratio of Th1/Th2 in bone marrow of SAA patients at active phase were (4.87 +/- 2.64)%, (0.41 +/- 0.26)% and 21.22 +/- 5.07, respectively, being higher than those of normal controls [(0.42 +/- 0.30)% (P < 0.01), (0.24 +/- 0.17)% (P < 0.05) and (1.57 +/- 0.93) (P < 0.01), respectively] and all of them reduced to normal levels of SAA at recovery phase (P > 0.05). The percentage of CD3(+)CD8(+) cells significantly decreased from (32.32 +/- 8.69)% at active phase to (13.76 +/- 2.96)% at recovery phase (P < 0.01). The serum levels of TNF-alpha and IL-4 at active phase was (4.29 +/- 3.15) microg/L and (1.24 +/- 0.73) microg/L, respectively, being higher than those of normal controls (1.21 +/- 1.16) microg/L, (1.18 +/- 0.97) microg/L, but only the difference of TNF-alpha was statistically significant (P < 0.01). In recovery SAA patients, the serum levels of TNF-alpha significantly decreased to (1.46 +/- 1.41) microg/L (P < 0.01), and the levels of IL-4 increased markedly to (3.05 +/- 1.94) microg/L. The CD3(+)CD8(+) cells and TNF-alpha of patients negatively correlated with Ret (P < 0.05; P < 0.05) and ANC (P < 0.05; P < 0.05), Th1 cells correlated with CD3(+)CD8(+) cells and TNF-alpha positively (P < 0.01; P < 0.05), the Ret and ANC negatively (P < 0.01; P < 0.01), IL-4 and the balance of Th1/Th2 positively correlated with Ret and ANC (P < 0.05, P < 0.01; P < 0.01, P < 0.01). CONCLUSION: The bone marrow failure in SAA might be caused not only by the increase of Th1 cells, Th1 type effector cells and cytokines, but also by insufficient compensation of Th2 cells and Th2 type cytokines, which shifted the balance of Th1/Th2 favorable to Th1.

[Expression of apoptosis related proteins in CD34 positive bone marrow cells of patients with polycythemia vera].

OBJECTIVE: To investigate the expression of apoptosis receptor FAS (CD95) and apoptosis related protein Bcl-2 and Bax in CD34 positive bone marrow cells of the patients with polycythemia vera (PV). METHODS: The expressions of apoptosis receptor FAS (CD95) and apoptosis related protein Bcl-2 and Bax in bone marrow CD34(+) cells from 21 PV patients, 8 essential thrombocythemia (ET) and 11 normal persons were assessed by bicolor flow cytometry (FCM), and the expressions of Bcl-2 and Bax mRNA were assessed by RT-PCR, and their correlation was analysed. RESULTS: There was no difference between the expressions of CD95 in CD34(+) bone marrow cells of PV patients (42.65 +/- 15.56)%, and that of ET patients (45.31 +/- 17.62)% and of normal person (37.55 +/- 15.19)% (P > 0.05). There was no difference between the expression of Bax in CD34(+) bone marrow cells of PV patients (35.83 +/- 9.33)% and of normal persons (41.65 +/- 9.04)% (P > 0.05). The expression of Bcl-2 in CD34(+) bone marrow cells of PV patients (79.35 +/- 14.43)% was significantly higher than that of normal controls (55.84 +/- 13.43)% (P < 0.01). The ratio of Bax/Bcl-2 of PV patients (0.47 +/- 0.14) was significantly lower than that in normal controls (0.76 +/- 0.24) (P < 0.01). The expression of Bcl-2 mRNA in PV patients' bone marrow hematopoietic cells was higher than that of normal controls (P < 0.01). There was no difference between the expression of Bax mRNA in bone marrow hematopoietic cells of PV patients and that of normal controls. Bcl-2 expression was negatively correlated with Annexin V expression in CD34(+) bone marrow cells of PV patients. CONCLUSION: Over-expression of Bcl-2, one of anti-apoptosis genes, in CD34(+) bone marrow cells might be involved in the lower apoptosis of PV patients.

[A long-term follow-up study of 50 patients with severe aplastic anemia who have survived more than 3 years after immunosuppressive therapy].

OBJECTIVE: To evaluate the long-term outcome of immunosuppressive therapy (IST) in patients with severe aplastic anemia (SAA). METHODS: Hematopoietic recovery (peripheral blood cell counts, bone marrow aspirates, bone marrow biopsy, in vitro culture of hematopoietic progenitors), immunity of T lymphocyte, quality of life and side-effects of the therapy were assessed in 50 SAA patients who have survived more than 3 years after IST. RESULTS: At 3 years, 4 years and 5 years follow-up, 81.5% (13 cases), 86.7% (13 cases) and 89.5% (17 cases) of the SAA patients reached and maintained normal peripheral blood cell counts, 93.4% (15 cases), 93.3% (14 cases) and 94.7% (18 cases) showed normal bone marrow pictures, and 37.5% (6 cases), 40.0% (6 cases) and 73.7% (14 cases) had normal yields of bone marrow cell culture, respectively. Overall, 86.0% (43 cases), 94.0% (47 cases) and 52.0% (26 cases) of the total SAA patients were normalized in peripheral blood counts, bone marrow picture and culture of hematopoietic progenitor yields, respectively. During the follow-up, 88.0% (44 cases) of the patients achieved 100 of Karnofsky scores; 26 of the 31 patients (83.9%) who received bone marrow biopsy showed normal histological pictures, and 29 of 37 patients (78.4%) tested had normal subsets of T lymphocytes. No clonal disease was found. The late side-effects of IST were mild. All of the parameters tested were normal in 24 patients. CONCLUSION: After IST, the hematopoietic function of bone marrow, the immunity of the T lymphocyte and the life quality were normalized with few side-effects in patients with SAA. These patients would probably be cured.

[Apoptosis and proliferation of CD34 positive bone marrow cells in patients with polycythemia vera].

OBJECTIVE: To study the apoptosis and proliferation of CD(34) positive (CD(34)(+)) bone marrow cells (BMC) in patients with polycythemia vera (PV). METHODS: The expression of Annexin V and Ki67 of the CD(34)(+) BMC in 20 PV patients and control cases [10 essential thrombocythemia (ET), 12 normal persons] were assessed by bicolor flow cytometry (FCM), and the correlation between apoptosis and clinical situation was analysed in PV patients. RESULTS: The Annexin V expressions of CD(34)(+) BMC were (15.96 +/- 1.45)% in PV patients and (15.53 +/- 1.76)% in ET patients which were lower than that in normal subjects [(23.61 +/- 3.89)%, (P < 0.05)]. The Ki67 expression of CD(34)(+) BMC was (48.79 +/- 11.68)% in PV patients and (49.60 +/- 9.98)% in ET patients, which were significantly higher than that in normal controls (33.87 +/- 6.82)%. The ratio of apoptosis/proliferation in PV patients was 0.33 +/- 0.10 and in ET patients 0.32 +/- 0.02 which were significantly lower than that in normal controls 0.72 +/- 0.11 (P < 0.01). The apoptosis of CD(34)(+) BMC was negatively correlated with the hemoglobin (Hb) levels (r = -0.481, P = 0.037), white blood cells (WBC) (r = -0.538, P = 0.026) and the numbers of endogenous erythroid colony (EEC) (r = -0.632, P = 0.50), and the ratio of apoptosis/proliferation was negatively correlated with the Hb (r = -0.537, P = 0.018) and WBC (r = -0.667, P = 0.003) in PV patients. CONCLUSION: There were lower apoptosis and higher proliferation in CD(34)(+) BMC of PV patients. Lower apoptosis was correlated with the severity of the disease.

[Proliferation of bone marrow hematopoietic stem cells and function of T helper lymphocytes of patients with immuno-related pancytopenia].

OBJECTIVES: To explore the proliferative capacity of bone marrow hematopoietic stem cells and the function of T helper (Th) lymphocytes of patients with immuno-related pancytopenia (IRP). METHODS: Twenty-five untreated IRP patients, 15 IRP patients in complete remission (CR) and 10 normal controls were studied for in vitro yields of CFU-GM, CFU-E and BFU-E from bone marrow mononuclear cells (BMMNC). The mRNA expressions of IL-4, IL-10, IFN-gamma and IL-2 genes in unstimulated BMMNC from 25 untreated IRP patients,15 IRP patients in CR, 19 patients with other hematological diseases presenting pancytopenia and 10 normal controls were detected by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: There was no significant difference of the yields of CFU-E, CFU-GM or BFU-E among the untreated, and in CR IRP patients and normal controls (P > 0.05). The mRNA expressions of IL-4 and IL-10 of Th2 cells were significantly higher in untreated IRP patients than in the other groups. The mRNA expressions of IFN-gamma and IL-2 of the Th1 cells in all IRP patients were not higher than those in the other groups. CONCLUSIONS: The cytopenia of IRP patients was not caused by the qualitative abnormality of the hematopoietic stem cells but by the destruction or suppression of hematopoietic stem cells from certain extrinsic insults. The imbalance of Th lymphocytes subtypes and overfunction of Th2 lymphocytes played important roles in the pathogenetic mechanism of IRP leading to increased and overfunctional B lymphocytes, which produced autoantibodies destructing or suppressing hematopoiesis in IRP.

[The clinical features of severe aplastic anemia patients with complication of infection].

OBJECTIVE: To study the clinical features of severe aplastic anemia (SAA) patients with complication of infection. METHODS: A retrospective analysis of prevalence of infection occurring in 229 SAA patients, their bacterial spectrum, and the effect of GM-CSF or G-CSF on the infection were done. RESULT: The prevalence of infection in SAA patients was 86.0%, among which 54.2% was infected with gram-positive organisms, 40.0% with gram-negative bacilli and 5.8% with fungal infections. Septicemia occurred mostly with E. coli and Pseudomonas infection. Patient's neutropenia was significantly related to the infection. The patients with neutrophil count less than 0.2 x 10(9)/L had more frequent and severe infection. Age, hemoglobin level, subtype of T lymphocytes and antithymocyte globulin therapy were not related to infection. Prophylaxis usage of floxacin could not reduce patient' gastrointestinal infection. The total mortality of SAA patients with infection was 23.1%. Pulmonary infection and septicemia increased mortality, and GM-CSF/G-CSF therapy reduce mortality. CONCLUSION: SAA patients were at high risk of infection which was significantly associated with severe neutropenia. GM-CSF or G-CSF therapy exerts an assistant role to antibiotics in controlling the infections.