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Objective: To assess the correlation of the multidrug resistance-1 (MDR1) gene single nucleotide polymorphisms (SNP) C1236T, G2677T/A and C3435T with the outcome of induction chemotherapy in patients with de novo acute myeloid leukemia (AML)., Methods: A total of 44 AML patients were enrolled in this study. Genotype of MDR1 C1236T, G2677T/A and C3435T were analyzed with PCR/PFLP assay. Bone marrow smear was made at the end of the first induction chemotherapy to estimate whether complete remission (CR) has been achieved with the clinical characteristics. The Hardy-Weinberg equilibrium for the MDR1 C1236T, G2677T/A and C3435T were tested using a chi(2) analysis. Frequencies of genotype and allele in MDR1 C1236T, G2677T/A and C3435T were compared using a chi(2) test or Fisher's test in terms of the clinical characteristics or achievement of CR., Results: There were significant differences among ethnicities in exon 12, 21, 26, but which were not between healthy chinese volunteers and AML patients. The CR rate of the group with the number of white blood cells (WBC) < 10 x 10(9)/L were significantly higher than that of the group with WBC > 10 x 10(9)/L (chi(2) = 7.207, P = 0.007). There was no correlation between the MDR1 C1236T and C3435T and CR rate (P = 0.349, P = 0.074), but MDR1 G2677T/A genetic polymorphisms were strong associated with the probability of CR (chi(2) = 6.214, P = 0.045). In addition, the CR was lower in G/G genotype at -2677 than non G/G genotype (chi(2) = 6.142, P = 0.013), and was lower in C/T genotype at -3435 than non C/T genotype (chi(2) = 3.991, P = 0.046), even lower than T/T genotype (chi(2) = 5.134, P = 0.023)., Conclusion: With important prognostic significance, MDR1 genetic polymorphisms, such as G2677T/A can predict whether complete remission can be achieved after the first course of induction chemotherapy.

We reported a case of multiple myeloma, who suffered from the acute myelomonocytic leukemia (AML-M4) after the chemotherapy of alkylating agent. The patient had a history of multiple myeloma and was treated with the regimen of including L-Sarcolysinum and cyclophosphamide for 5 years. The multiple myeloma of this patient was proved to have got the remission through bone marrow aspiration, immunofixation electrophoresis of serum, serum protein electrophoresis and detection of urine light chain. However, a pancytopenia of unknown cause was verified to peripheral blood. During the course of supportive treatment only with blood cell and platelet transfusion, WBC count of this patient showed a rising trend and the blast cells (8%-15%) started to occur in the peripheral blood. The further examination discovered that the ratio of blast cell was beyond 30% in bone marrow smear, and the flow cytometry detected the CD45, HLA-DR, CD13, CD33, CD64 to have the positive expressions. Thus, the diagnosis of multiple myeloma in remission and secondary AML-M4 was established. When the chemotherapy regimen to AML was being planned for this patient, she died of massive hemorrhage of gastrointestinal tract due to thrombocytopenia and ineffectiveness.

The purpose of this study was to investigate the expression of Fas, Fas ligand (FasL) and CD80 and function of FasL on the surface of acute myelomonocytic leukemia cells from WEHI-3 line. The expression of Fas, FasL and CD80 on the surface of WEHI-3 were detected by flow cytometry, the apoptosis of YAC-1 cell induced by FasL on the surface of WEHI-3 were detected by (3)H-TdR incorporation. The results showed that the expression rate of Fas, FasL and CD80 on the surface of WEHI-3 cells were (6.75 +/- 2.31)% (n = 5), (63.73 +/- 5.23)% (n = 5) and (5.06 +/- 0.41)% (n = 5) respectively. The apoptosis rate of YAC-1 cells (target cells) co-cultured with WEHI-3 cells (Effector cells) at the rate of 1:3, 1:10 and 1:30 were (26 +/- 4.5)%, (35 +/- 3.2)% and (43 +/- 2.7)% (n = 5) respectively. It is concluded that WEHI-3 cells have high expression of FasL and low expression of Fas and CD80 on their cell membrane, and can induce the apoptosis of Fas(+) YAC-1 cells.

Objective: To study Fas expression regulation of cytotoxic T lymphocyte(CTL)via anti-Fas ribozyme, increasing of CD80 epitope on the surface of acute myelomonocytic leukemia cells by CD80-IgG fusion protein and their effects on the apoptosis and killing ability against acute myelomonocytic leukemia cells of CTL., Methods: A hammerhead ribozyme gene targeting the Fas mRNA was synthesized and its expression vector pEGFP-RZ596 was constructed and transfected into the mouse spleen T cells via electroporation. The Fas expression on T cells was detected by RT-PCR and Western bloting. In the meantime the eukaryotic expression vector pcDNA/CD80-IgG was constructed by gene recombinant technique and transfected into ovarian cells of hamster of the line CHO. The CD80-IgG fusion protein was purified from the supernatant of G418-selected CHO cells by Protein G affinity chromatography method. Then allogeneic mixed lymphocytes culture between the mouse spleen T cells transfected with pEGFP-RZ596 and WEHI-3 cells (mouse acute myelomonocyte leukemia cell line) incubated with CD80-IgG fusion protein was performed. The apoptosis rate of the T cells was detected with annexin V-FITC. The proliferation and killing ability in vitro against WEHI-3 cells of the T cells were detected by MTT colorimetry., Results: The luminance of Fas Western bloting results from the mouse spleen T cells negative control, transfected with pEGFPC1 and transfected with pEGFP-RZ596 were separately 1, 0.98 and 0.45 (P < 0.01). After being cocultured with WEHI-3 cells, which has higher expression of Fas ligand (64% +/- 3%), the apoptosis rate and the killing ability against WEHI-3 cells of the mouse spleen T cells transfected with pEGFP-RZ596 were separately 37% and 67%. Whereas that of the mouse spleen T cells negative control and transfected with pEGFPC1 were separately 88%, 84% (P < 0.01) and 32%, 31% (P <0.01). The CD80 positive expression rate of WEHI-3 cells was upregulated from 5.1% +/- 0.4% to 27.4% +/- 2.2% after these cells were preincubated with CD80-IgG fusion protein (P < 0.01). The killing ability of the mouse spleen T cells against WEHI-3 cells preincubated and not preincubated with CD80-IgG fusion protein were separately 64% and 49% (P <0.01), but that of the mouse spleen T cells, which were transfected with pEGFP-RZ596, was further promoted to 82% (P < 0.01), Conclusion: The apoptosis of mouse CTL inducing by FasL-Fas pathway could be avoided and the killing ability of mouse CTL against WEHI-3 cells can be significantly promoted at the same time by combining anti-Fas ribozyme and CD80-IgG fusion protein.

To investigate the expression of HoxA(10) mRNA in acute leukemia patients and its significance, HoxA(10) level was detected by reverse transcription polymerase chain reaction (RT-PCR) in 50 patients with acute leukemias, 7 healthy volunteers and 3 patients with ITP (idiopathic thrombocytopenic purpura). The regularity of the expression of HoxA(10) gene in acute leukemia and the relationship between HoxA(10) level and the prognosis of leukemia was explored. The results showed that HoxA(10) was expressed in all types of acute myelogenous leukemia; HoxA(10) message was also observed in acute lymphoblastic leukemia patients and part of control groups. 3 normal donors were found not to express HoxA(10). The level of HoxA(10) mRNA of acute myelogenous leukemia patients was significantly higher than that of acute lymphoblastic leukemia patients and controls (P < 0.01). HoxA(10) gene appeared to be more strongly expressed in AML-M(1) and -M(2) subtypes than in AML-M(4) and -M(5) subtypes, and the gene was notable high expressed in acute promyelocytic leukemia. The number of blast and promyeloid cells in the bone marrow was positive related with the level of HoxA (r = 0.635, P < 0.01). The level of HoxA(10) of 9 non-responsive patients was higher than that of 8 remission patients, but there was no significant difference between them (P = 0.258). HoxA(10) was overexpressed in acute myelogenous leukemia. It is concluded that HoxA(10) is a major transcription factor regulating hematopoiesis and a mark to differentiate lymphoid leukemia and myelogenous leukemia, but not a specific gene of cancer. The level of HoxA(10) is related with load of leukemic cells and curative effect, and can affect occurrence and development of leukemia in combination with many cytokines, HoxA(10) may facilitate the leukemia progression with another cofactors.

To explore CD34(+) antigen expression in new diagnosed acute myeloid leukemia (AML) and analyze the prognosis for CD34(+) AML patients, the expression of antigen CD34 in 238 AML patients was detected by indirect immunofluorescence assay. The results showed that CD34 in 92 out of the 238 patients (38.7%) were positive, there was relationship between the CD34(+) expression and FAB subtypes (M(0), M(1)), and no CD34(+) expression was observed in M(3) subtypes. The complete remission rate of CD34(+) AML patients was 32%, which was lower than that of CD34(-) AML (61%). The lymphoid-associated antigen (CD7) was significantly increased in CD34(+) AML patients, compared with CD34(-) patients (P < 0.05). It is concluded that CD34(+) AML patients show poor prognosis and lower CR rate. The detection of CD34 expression is of some value in predicting prognosis in AML.

Immunotherapy of tumor is extensively attentioned as an important part of combined therapy of tumor in recent years. Dendritic cell (DC) is the most powerful antigen presenting cell (APC) by now which not only activates auto-immunity to attack tumor cells, but also does help to enhance antitumor effect for allogenic bodies. To explore the feasibility and safety of clinical therapy application of peripheral blood derived DC cultured ex vivo, and analyze the influence of DC-inducing-immunotherapy upon long-term survival of ANLL patients accepted autologous bone marrow transplantation, peripheral blood mononuclear cells (PBMNC) of 13 ANLL patients after autologous bone marrow transplantation were collected by using CS3000Plus. DC immunotherapy was administered after cultivation of PBMNC ex vivo for 2 weeks, desease-free survival time was observed after therapy for long time follow-up. The results showed that no any severe adverse event associated with DC therapy was observed, the survival analysis of Kaplan-Meier suggested that five year survival rate was 75.52% in DC group while 45.71% in non-DC group. DC group surpassed non-DC group in accumulative survival rate. It is concluded that the ex vivo cultivation and clinical therapy application of DC derived from peripheral blood are feasible and safe, DC immunotherapy in patients with acute non-lymphocytic leukemia after autologous bone marrow transplantation prolongs desease-free survival time and enhances long-term survival rate.

In order to evaluate the effects of FLAG regimen in treatment of refractory and relapsed acute myeloid leukemia (AML), 27 patients with refractory or relapsed acute myeloid leukemia (10 refractory AML patients, 17 relapsed AML patients) were treated with FLAG regimen. The results show that the rate of complete remission was 48.2% (13/27), the rate of partial remission was 14.8% (4/27), and the overall response rate was 63.0%. Main toxicities were gastrointestinal side effectes, myelosupression and neutropenia. It is concluded that FLAG regimen can be employed in treatment of the refractory or relapsed patients who were not respond to other regimen, and the regiment was safe.

To study the clinical significance of the detection of inv(16) (p13 q22) by FISH in the diagnosis and prognosis for M(4), the metaphase bone marrow cells of 6 cases M(4) which had already diagnosed by morphology were detected for CBFbeta-MYH(11) fusion gene by MYH 11 probe including dual labelled sequences and the results were compared with that of conventional cytogenetic analysis. The results showed that 4 cases inv(16) (two M(4) EO and two M(4)) were found by G banding kanyotyping test. One case M(4) had trisomy (+22) in addition to inv(16); one case M(4) had hypodiploid in addition to inv(16), which relapsed after CR 8 months. All 6 cases had inv(16) abnormal fluorescence signal. Among them case No 2 had the deletion of 16p13 showed by red fluorescence signal in addition to inv(16). It is concluded that the detection of inv(16) by FISH is of sensitivity and specificity. It is the important supplement to the conventional cytogenetic analysis. It possesses the important clinical significance in the diagnosis and prognosis of M(4) patients.

To compare the clinical outcome of autologous peripheral blood stem cell transplantation (APBSCT) and autologous bone marrow transplantation (ABMT) in treatment of patients with acute leukemia in first remission, 41 patients received APBSCT, 17 patients received unpurged ABMT and 30 patients received purged ABMT. The results showed that hematopoietic recovery was significantly earlier after APBSCT than that after purged or unpurged ABMT. The 3-year disease-free survival (DFS), relapse rate (RR) and transplant-related mortality (TRM) for all patients of 3 groups were 51.7%, 41.7% and 6.8%, respectively. DFS and RR were significantly influenced by disease types (ALL or AML) and intervals between diagnosis and CR(1) or CR(1) and transplant. The main causes of transplant-related death were infection and hemorrhage. After APBSCT, DFS, RR and TRM were 48.4%, 43.9% and 4.9%, respectively, and did not differ significantly from those found in unpurged ABMT (47.1%, 45.6% and 11.8%) or purged ABMT (66.5%, 29.6% and 6.7%). It is concluded that the clinical outcome of APBSCT is similar to unpurged or purged ABMT but APBSCT allows faster recovery of hematopoiesis and needs less transfusion support.

Objective: To evaluate fluorescence in situ hybridization (FISH) in the detection of inv (16) (p13; q22)., Methods: Spectrum red labeled yeast artificial chromosome (YAC) clone 854E2 which spans the breakpoint cluster region in MYH11 in band 16p13 and single color interphase FISH were used to detect inv (16) in 26 cases of acute myelomonocytic leukemias (AML-M(4)), and the results were compared with that of conventional cytogenetic analysis., Results: R banding karyotyping test revealed no inv (16) in 25 cases, one AML M(4Eo) case showed inv (16) by G banding. Nine cases including all three M(4Eo) had inv (16) by FISH analysis, among whom the characteristic fluorescence signal pattern of the inv (16) was seen in 13.3% to 32.1% (median, 21.3%) of the tested cells., Conclusion: YAC 854E2 and interphase FISH provide a powerful technique in the detection of inv (16) (p13q22).

Objective: To evaluate the effect of a novel aminosteroid(KH) on WEHI-3B cells., Methods: The effects and mechanism of KH on proliferation, differentiation and apoptosis of WEHI-3B cells in vitro were studied by semi-solid colony culture, MTT assay, morphologic examination, NBT reduction test, NSE assay, DNA fragmentation in gel electrophoresis and RT-PCR of c-myc oncogene., Results: The growth of leukemic colony was inhibited by KH(10(-8)-10(-4) mol.L-1) after treatment of KH for 7 days. The percentages of NBT and NSE positive cells were increased from 40.38% to 71.17% and 48.25% to 79.25%, respectively as well as the typical ladders of DNA fragments in gel electrophoresis were also observed after WEHI-3B cells were treated with KH(10(-8)-10(-4) mol.L-1) for 5 days. The c-myc mRNA expression of WEHI-3B cells was decreased by 58.7% after WEHI-3B cells were treated with KH(10(-8) mol.L-1) for 5 days., Conclusion: KH might suppress the proliferation of WEHI-3B cells, induce the differentiation of WEHI-3B cells into macrophage-like cells and facilitate the cell apoptosis. There is relationship between the above effects and c-myc mRNA expression of WEHI-3B cells.

Objective: To evaluate the effect of curcumin on the proliferation of hematopoietic progenitor cells or leukemic stem cells., Methods: Mouse bone marrow cells (colony forming unit-granulocyte and macrophage, CFU-GM) and WEHI-3B cells were observed using the colony assays., Results: The curcumin significantly inhibited the proliferation of both CFU-GM and WEHI-3B cells in a dose-dependent manner ranging from 10(-8) to 10(-4) mol.L-1; their IC50S were 1.036 x 10(-5) mol.L-1 and 1.220 x 10(-6) mol.L-1 of curcumin respectively., Conclusion: The proliferation of murine CFU-GM and WEHI-3B cells can be suppressed by curcumin. The inhibitory effect of curcumin on the proliferation of WEHI-3B cells is stronger than that of CFU-GM.

Objective: To explore the expression and effects of isoforms of macrophage colony-stimulating factor (M-CSF) in human leukemic cell lines., Methods: Three normal human peripheral blood mononuclear cells (PBMCs) and 4 human myelomonocytic leukemic cell lines including J6-1, J6-2, K562 and HL-60 were studied using ABC immunoperoxidase assay, indirect immunofluorescence staining, flow cytometry, Western blot and reverse enzyme-linked DNA-protein interaction assay (reverse ELDIA)., Results: M-CSF was noticed to be localized in the cytoplasm, nucleus and at the cell membrane in 4 human leukemic cell lines; expression of M-CSF was not detected in normal human PBMCs without PHA stimulation. Human PBMCs stimulated by PHA expressed a low level of M-CSF. Frequencies of membrane bound M-CSF expression in J6-1, J6-2, K562 and HL-60 were 71.6%, 69.7%, 42.7% and 57.4% respectively. Frequencies of cytoplasm and nucleus associated M-CSF were 65.7%, 45.4%, 36.5% and 72.5% respectively. The cytosolic bound M-CSF was expressed in J6-1 cell as four isoforms with a molecular weight of 14,000, 16,000, 20,000 and 44,000. While nucleus associated M-CSF expressed as two isoforms with a molecular weight of 16,000 and 20,000. Anti-M-CSF monoclonal antibody could dramatically inhibit proliferation of leukemic cells and its inhibitory effect was related to the levels of membrane bound M-CSF expression in leukemic cells. Reverse ELDIA showed that M-CSF could bind with DNA in vitro., Conclusions: Expression of M-CSF isoforms is heterogeneous and polymorphous in leukemic cells. Membrane bound M-CSF is crucial for the proliferation of leukemic cells, which might be a DNA-bound protein and could be involved in the transformation and tumorigenesis of hematopoietic cells.

To evaluate the effect of a novel aminosteroid on murine myelomonocytic leukemia, BALB/c mice were treated by the novel aminosteroid for 7 days after receiving 1 x 10(6) WEHI-3B(myelomonocytic leukemia) cells intraperitoneally. The counts and classification of white blood cells obtained from tail blood were determined on the day before transplanting WEHI-3B cells and 7, 14, 21, 28 days after transplantation. Undifferentiated cell percentage of bone marrow and spleen weight were checked 30 days after transplantation. The results demonstrated that the above indexes of mice treated with the novel aminosteroid were decreased compared with those treated with normal saline(NS). Decrease of the indexes showed a dose-dependent relationship ranging from 5-20 mg.kg-1.d-1. It is suggested that leukemia mice could be effectively treated by the novel aminosteroid and the efficacy maybe paralleled with the dosage of the novel aminosteroid.

Objective: To investigate whether apoptosis occurs in vivo in patients with acute leukemia during induction chemotherapy and its significance., Methods: Apoptotic effect on peripheral blood of 20 patients with different types of acute leukemia prior to and during routine chemotherapy was studied by cell morphology, DNA electrophoresis and FCM-DNA analysis., Results: After chemotherapy, with falls in WBC and blast count, no apoptotic cell appeared on smears of peripheral blood, nor did ladder pattern of DNA on electrophoresis and subdiploid peak on FCM., Conclusion: Although anticancer drugs have been shown to induce apoptosis in vitro, circulating apoptotic cells are hardly detected probably due to their rapid clearance from the circulation. It is more difficult to study apoptosis in vivo than in vitro.

Objects: To study the clonal growth on single layer, agar of high proliferative potential colony-forming cells (HPP-CFC) of bone marrow obtained from both normal mice (NBM) and mice treated 2 days earlier with 5-fluorouracil (FU,BM) using conditioned media., Material and Methods: Using liquid cell culture to harvert WEHI2-CM and L929-CM as the substitutes for IL-3 and M-CSF respectively; using semi-solid culture to assay HP-CFCin vitro., Results: (1) the combination of WEHI3-CM and L929-CM produced HPP-CFC in vitro, and the addition of rhIL-1 alpha, rhIL-6 and rmGM-CSF further enhanced HPP-CFC was enriched in the FU2 BM. Morphological investigation showed that the HPP-CFC colony was large and compact, great than 0.5mm in diameter and contained more than 50,000 cells, most of which were macrophage like cells. The hydroxyurea suicide rate for HPP-CFC was less than 10%., Conclusion: The results suggested that (1) WEHI3-CM and L929-CM can be used as the substitutes of IL-3 and M-CSF to stimulate the formation of HPP-CFC; (2) FU can enrich HPP-CFC of the mice.

The effects of LiCl on the proliferation of high proliferative potential colony-forming cells (HPP-CFC) and granulocyte macrophage colony-forming unit (CFU-GM) from bone marrow of BALB/c mice were observed. The colonies of HPP-CFC were supported by IL-1, IL-6, WEHI-3 conditioned medium (WEHI-3 CM, which contained IL-3) and L929 conditioned medium (L929-CM, which contained M-CSF); the colonies of CFU-GM were supported by WEHI-3 CM. It was shown that LiCl at concentrations ranging from 0.4 mmol/L to 2 mmol/L significantly inhibited the proliferation of HPP-CFC (P < 0.01), but concentrations ranging from 0.4 mmol/L to 1 mmol/L significantly increased the production of CFU-GM (P < 0.05), both effects displayed in dose-dependent manners. The different effects of LiCl on the proliferation of HPP-CFC and CFU-GM suggest that LiCl may induce HPP-CFC differentiation into more mature cells.

Using serum-free culture system and liquid/semi-solid dual culture technique, we examined the effect of rhSCF on self-renewal of the stem/progenitor cells of human acute myelogenous leukemia (AML-CFU). The results revealed that the rhSCF as a hematopoietic growth factor (HGF) exerted its effect hierarchically earlier than interleukin-3 and granulocyte/macrophage colony-stimulating factor on AML-CFU. rhSCF, whether used alone or in combination with other HGFs, showed potential maintenance of self-renewal of AML-CFU in most AML patients studied. However, considerable discrepancy existed in maintenance among various FAB types of patients or even in patients with the same FAB type. It is suggested that SCF may play an important role in the pathological development of AML.

Ginsenosides are the main active component of Panax ginseng. It has been shown that ginsenosides have antineoplastic, antiaging, immunologic function enhancing and other pharmacological actions. In this article, result of experimental studies showed ginsenosides extracted from stem and leaf of Panax ginseng (GSL) has inductive differentiation effect on all types of acute nonlymphocytic leukemia cells in primary culture. The effect on M5, M4 was most potent, followed by M1, M2 and the least, on M3. Through analysis, it was considered that the inductive differentiation effect of ginsenosides might be due to the comprehensive effect of increasing intracellular cAMP and inducing interferon. Since GSL have some other important actions, therefore, if it could be used as a differentiation inducer in clinical practice or combined with other antineoplastic drugs, it would show co-antineoplastic actions in many aspect.

In vitro proliferative response of the blast cells from 21 AML patients to hematopoietic growth factors (IL-3, GM-CSF, G-CSF and MCSF) was investigated. Proliferation of AML cells in the majority of cases was induced or promoted by one or more CSFs, among which the stimulation of IL-3 was the most effective. Spontaneous proliferation of the blast cells was also observed in half of the cases and could be inhibited as well as promoted by some CSFs. It is suggested that in vitro proliferation of AML cells varies from patient to patient and that CSF plays important roles in leukemogenesis.

Histopathological changes of pretreatment bone marrow biopsy from 42 cases with acute myeloid leukemia (AML) were described. A considerable difference was shown between the results of aspirate smears and the findings of plastic embedded biopsy sections, particularly in bone marrow cellularity such as infiltration of inflammatory cells and presence of residual hemopoietic cells, qualitative and quantitative abnormalities of megakaryocytes suggestive of myelodysplastic features were more accurately assessed in the sections of marrow biopsy than in the aspirate smears. In three cases there was considerable infiltration of maturing but dysplastic granulocytic cells and erythroid precursors in the sections, but not in the aspirate smears. Our study shows that plastic embedded biopsy sections provide more information than aspiration smears for the diagnosis of AML.

In the light of high sensitivity of fresh bone marrow blast progenitor of human myeloid leukemia (L-CFU) towards the action of low molecular tumor suppressor isolated from human fetal liver, massive bone marrow was aspirated from the patients suffering from acute myeloid leukemia at the stage of first complete remission and cocultured in a long-term bone marrow culture system for 9 days. The purged marrow cells were then re-infused into the patients after preconditioning with large doses of cytotoxin and acute ionizing irradiation. Hematopoiesis was reconstituted due to the autologous transplantation in vivo. After the autologous bone marrow transplantation without chemical treatment, two cases are still survival with the time of more than 17 and 15 months respectively.

We analysed the effects of recombinant human G-CSF (rhG-CSF) and retinoic acid (RA) on proliferation and differentiation of HL-60 cells and human acute myeloid leukemic (AML) cells. A synergistic effect on granulocyte differentiation was observed when HL-60 cells and primary cultured acute promyelocyte leukemic cells were cocultured with 10(-8)mol/L RA plus 1:2000 or 1:1000 rhG-CSF. The rhG-CSF plus RA treated cells demonstrated significant increase in the percentage of mature cells. Morphological changes and nitroblue tetrazolium (NBT) reduction activity evidenced more increase than RA treatment alone (P less than 0.001). The results suggest that RA not only inhibits the proliferative action of G-CSF, but also retains and enhances the action of G-CSF to induce differentiation. Therefore, we believe that the combined use of G-CSF with RA may improve the treatment of leukemia.

Thirty four cases of isolated extramedullary relapse after complete remission of acute leukemia were reported. The relapse took place in central nervous system (CNS), genito-urinary system, skin, serous cavity, tonsils, lymph nodes, liver, spleen, gastro-intestinal tract, pancreas and ocular fundus. These 34 cases of isolated extramedullary relapse of leukemia was found in 206 cases with complete remission, constituting 16.5% of the total. In order to discover CNS relapse with no symptoms and signs, the author strongly suggest that cerebrospinal fluid examination be carried out periodically. If some symptoms signs in the patient can not explained by infection, congestion or other causes, extramedullary relapse should be considered and further examination and appropriate treatment are needed.