Case report: Irinotecan-induced interstitial lung disease in an advanced colorectal cancer patient resurfacing decades after allogeneic bone marrow transplantation for aplastic anemia; a case report and narrative review of literature.

Two mechanisms of drug-induced interstitial lung disease (DILD) have been reported: 1) direct injury of lung epithelial cells and/or endothelial cells in lung capillaries by the drug and/or its metabolites and 2) hypersensitivity reactions. In both mechanisms, immune reactions such as cytokine and T cell activation are involved in DILD. While past and present lung diseases and accumulative lung damage due to smoking and radiation are risk factors for DILD, the association between the immune status of the host and DILD is not well known. Herein, we report a case of advanced colorectal cancer with a history of allogeneic bone marrow transplantation for aplastic anemia more than 30 years prior, in which DILD occurred early after irinotecan-containing chemotherapy. Bone marrow transplantation might be a potential risk factor for DILD.

A Fatal Case of Neuroblastoma Complicated by Posterior Reversible Encephalopathy with Rapidly Evolving Transplantation-Associated Thrombotic Microangiopathy.

BACKGROUND: Transplantation-associated thrombotic microangiopathy (TA-TMA) is a severe complication of hematopoietic stem cell transplantation and is sometimes fatal. OBSERVATIONS: A 4-year-old, male patient with stage M neuroblastoma (NBL) who had received an allogeneic bone marrow transplantation (BMT) from his sibling five months previously presented with rapidly progressive posterior reversible encephalopathy (PRES) complicated with TA-TMA. Although the patient was transferred to the pediatric intensive care unit, he died within one week after the onset of the latest symptoms. CONCLUSIONS: This is the first description of a fatal case of NBL complicated by PRES with rapidly evolving TA-TMA after an allogenic BMT.

Pathological features of inflammatory myopathy as a manifestation of chronic graft-versus-host disease after allogeneic bone marrow transplantation.

Chronic graft-versus-host disease (cGVHD) is the most important complication resulting in the death of bone marrow transplantation (BMT) survivors. It is also a relatively rare cause of inflammatory myopathy (IM). We report the case of a 46-year-old woman who developed severe cGVHD-related IM after BMT for myelodysplastic syndrome. She presented with severe muscle pain and weakness with cGVHD-related symptoms in other organs. Myopathological analysis showed moderate cell infiltration with remarkable necrotic and regenerative fibers. Sarcoplasm and capillaries expressed C5b9 and myxovirus resistance protein 1. Non-necrotic fibers in perifascicular regions expressed MHC-II. Steroid therapy did not sufficiently control cGVHD-related IM, and the patient was concurrently treated with an immunosuppressant. Our findings show that IM is a key manifestation of cGVHD and that the expression of interferon-inducible proteins in muscle pathology is useful for identifying cGVHD-related IM.

Modeling acute graft-versus-host disease (aGVHD) in murine bone marrow transplantation (BMT) models with MHC disparity.

For more than 50years, hematopoietic stem cell transplantation (HSCT) has been the major curative therapy for hematological malignancies and genetic disorders, but its success is limited by the development of graft-versus-host disease (GVHD). GVHD represents a post-transplantation disorder representing the immune-mediated attack of transplant-derived T cells against recipient tissue finally leading to increased morbidity and mortality of the recipient. GVHD develops if donor and recipient are disparate in major or minor histocompatibility antigens (MHC, miHA). Most of the initial knowledge about the biology of GVHD is derived from murine bone marrow transplantation (BMT) models. Of course, GVHD mouse models do not reflect one to one the human situation, but they contribute significantly to our understanding how conditioning and danger signals activate the immune system, enlighten the role of individual molecules, e.g., cytokines, chemokines, death-inducing ligands, define the function of lymphocytes subpopulations for GVHD development and have significant impact on establishing new treatment and prevention strategies used in clinical HSCT. This chapter describes in detail the procedure of allogeneic BMT and the development of GVHD in two commonly used allogeneic murine BMT models (B6→B6.bm1, B6→B6D2F1) with different MHC disparities, which can be used as a basis for advanced studies of GVHD pathology or the development of new treatment strategies.

Update on ocular graft-versus-host disease.

Ocular graft-versus-host disease (oGVHD) occurs as a complication following hematopoietic stem cell transplantation and is associated with significant ocular morbidity resulting in a marked reduction in the quality of life. With no current consensus on treatment protocols, management becomes challenging as recurrent oGVHD often refractory to conventional treatment. Most authors now diagnose and grade the disease based on criteria provided by the National Institutes of Health Consensus Conference (NIH CC) or the International Chronic oGVHD (ICCGVHD) consensus group. This article will provide an insight into the diagnostic criteria of oGVHD, its classification, and clinical severity grading scales. The inflammatory process in oGVHD can involve the entire ocular surface including the eyelids, meibomian gland, corneal, conjunctiva, and lacrimal system. The varied clinical presentations and treatment strategies employed to manage them have been discussed in the present study. The recent advances in ocular surface imaging in oGVHD patients such as the use of meibography and in vivo confocal microscopy may help in early diagnosis and prognostication of the disease. Researching tear proteomics and identification of novel potential tear biomarkers in oGVHD patients is an exciting field as they may help in objectively diagnosing the disease and monitoring the response to treatment.

Is it time to reconsider prophylactic antimicrobial use for hematopoietic stem cell transplantation? a narrative review of antimicrobials in stem cell transplantation.

INTRODUCTION: Hematopoietic Stem Cell Transplantation (HSCT) is a life-saving procedure for multiple types of hematological cancer, autoimmune diseases, and genetic-linked metabolic diseases in humans. Recipients of HSCT transplant are at high risk of microbial infections that significantly correlate with the presence of graft-versus-host disease (GVHD) and the degree of immunosuppression. Infection in HSCT patients is a leading cause of life-threatening complications and mortality. AREAS COVERED: This review covers issues pertinent to infection in the HSCT patient, including bacterial and viral infection; strategies to reduce GVHD; infection patterns; resistance and treatment options; adverse drug reactions to antimicrobials, problems of antimicrobial resistance; perturbation of the microbiome; the role of prebiotics, probiotics, and antimicrobial peptides. We highlight potential strategies to minimize the use of antimicrobials. EXPERT OPINION: Measures to control infection and its transmission remain significant HSCT management policy and planning issues. Transplant centers need to consider carefully prophylactic use of antimicrobials for neutropenic patients. The judicious use of appropriate antimicrobials remains a crucial part of the treatment protocol. However, antimicrobials' adverse effects cause microbiome diversity and dysbiosis and have been shown to increase morbidity and mortality.

Bone marrow deficiency of mRNA decaying protein Tristetraprolin increases inflammation and mitochondrial ROS but reduces hepatic lipoprotein production in LDLR knockout mice.

Tristetraprolin (TTP), an mRNA binding and decaying protein, plays a significant role in controlling inflammation by decaying mRNAs encoding inflammatory cytokines such as TNFalpha. We aimed to test a hypothesis that TTP in bone marrow (BM) cells regulates atherogenesis by modulating inflammation and lipid metabolism through the modulation of oxidative stress pathways by TTP target genes. In a BM transplantation study, lethally irradiated atherogenic LDLR-/- mice were reconstituted with BM cells from either wild type (TTP+/+) or TTP knockout (TTP-/-) mice, and fed a Western diet for 12 weeks. We made the following observations: (1) TTP-/- BM recipients display a significantly higher systemic and multi-organ inflammation than TTP+/+ BM recipients; (2) BM TTP deficiency modulates hepatic expression of genes, detected by microarray, involved in lipid metabolism, inflammatory responses, and oxidative stress; (3) TTP-/- BM derived macrophages increase production of mitochondrial reactive oxygen species (mtROS); (4) BM-TTP-/- mice display a significant reduction in serum VLDL/LDL levels, and attenuated hepatic steatosis compared to controls; and (5) Reduction of serum VLDL/LDL levels offsets the increased inflammation, resulting in no changes in atherosclerosis. These findings provide a novel mechanistic insight into the roles of TTP-mediated mRNA decay in bone marrow-derived cells in regulating systemic inflammation, oxidative stress, and liver VLDL/LDL biogenesis.

Self-endorsed cognitive problems versus objectively assessed cognitive impairment in blood or bone marrow transplantation recipients: A longitudinal study.

BACKGROUND: Cognitive impairment in survivors of blood or bone marrow transplantation (BMT) is well documented. However, to the authors' knowledge, the clinical relevance of self-endorsed cognitive problems and their relation to objectively assessed cognitive impairment is not known. METHODS: The authors assessed cognitive impairment in 378 BMT recipients (median age, 52.2 years, 40% of whom were female and 68% of whom were non-Hispanic white) and 98 healthy controls at 5 predetermined time points: at baseline (before BMT) and at 6 months, 1 year, 2 years, and 3 years after BMT. Self-endorsed cognitive problems were evaluated using the Neuropsychological Impairment Scale (NIS) and correlated with a standardized 2-hour battery of objective cognitive testing at each time point. The authors examined the magnitude of difference in self-endorsed cognitive problems between BMT recipients and healthy controls, and the rate of change in scores over time. Multivariable analyses were used to identify clinical and/or demographic variables associated with self-endorsed cognitive problems. The authors also examined the association between cognitive impairment and returning to work after BMT. RESULTS: Compared with healthy controls, BMT recipients endorsed more cognitive problems (P < .001) at all time points, and the rate of change in NIS scores was found to be significantly greater in BMT recipients. Fatigue was associated with greater endorsement of cognitive problems at 1 year after BMT (odds ratio, 4.23; 95% CI, 2.1-8.3 [P < .001]). Overall, there was a statistically significant, modest correlation noted between self-endorsed cognitive problems and objective cognitive impairment (range, 0.401-0.445 [P ≤ .01]). Higher self-endorsed cognitive problems were associated with a 3.7-fold (P = .02) higher odds of not returning to work at 3 years after BMT. CONCLUSIONS: The results of the current study demonstrated that self-endorsed cognitive problems can help to identify vulnerable patient subpopulations for detailed cognitive assessment and possible cognitive remediation.

Oral feeding with polyunsaturated fatty acids fosters hematopoiesis and thrombopoiesis in healthy and bone marrow-transplanted mice.

Hematopoietic stem cells play the vital role of maintaining appropriate levels of cells in blood. Therefore, regulation of their fate is essential for their effective therapeutic use. Here we report the role of polyunsaturated fatty acids (PUFAs) in regulating hematopoiesis which has not been explored well so far. Mice were fed daily for 10 days with n-6/n-3 PUFAs, viz. linoleic acid (LA), arachidonic acid (AA), alpha-linolenic acid and docosahexanoic acid (DHA) in four separate test groups with phosphate-buffered saline fed mice as control set. The bone marrow cells of PUFA-fed mice showed a significantly higher hematopoiesis as assessed using side population, Lin-Sca-1+ckit+, colony-forming unit (CFU), long-term culture, CFU-spleen assay and engraftment potential as compared to the control set. Thrombopoiesis was also stimulated in PUFA-fed mice. A combination of DHA and AA was found to be more effective than when either was fed individually. Higher incorporation of PUFAs as well as products of their metabolism was observed in the bone marrow cells of PUFA-fed mice. A stimulation of the Wnt, CXCR4 and Notch1 pathways was observed in PUFA-fed mice. The clinical relevance of this study was evident when bone marrow-transplanted recipient mice, which were fed with PUFAs, showed higher engraftment of donor cells, suggesting that the bone marrow microenvironment may also be stimulated by feeding with PUFAs. These data indicate that oral administration of PUFAs in mice stimulates hematopoiesis and thrombopoiesis and could serve as a valuable supplemental therapy in situations of hematopoietic failure.

Comparison of Blood Transfusion Plus Chelation Therapy and Bone Marrow Transplantation in Patients with ß-Thalassemia: Application of SF-36, EQ-5D, and Visual Analogue Scale Measures.

BACKGROUND: ß-Thalassemia is a prevalent genetic disease in Mediterranean countries. The most common treatments for this disease are blood transfusion plus iron chelation (BTIC) therapy and bone marrow transplantation (BMT). Patients using these procedures experience different health-related quality of life (HRQoL). The purpose of the present study was to measure HRQoL in these patients using 2 different multiattribute quality of life (QoL) scales. METHODS: In this cross-sectional study, data were gathered using 3 instruments: a socio-demographic questionnaire, EQ-5D, and SF-36. A total of 196 patients with ß-thalassemia were randomly selected from 2 hospitals in Shiraz (Southern Iran). Data were analyzed using logistic regression and multiple regression models to identify factors that affect the patients' HRQoL. RESULTS: The average EQ-5D index and EQ visual analog scale (VAS) scores were 0.86 (95% CI: 0.83-0.89) and 71.85 (95% CI: 69.13-74.58), respectively. Patients with BMT reported significantly higher EQ VAS scores (83.27 vs 68.55, respectively). The results showed that patients who lived in rural area and patients with BMT reported higher EQ VAS scores (rural; ß= 10.25, P = .006 and BMT; ß= 11.88, P = .000). As well, SF-36 between 2 groups of patients were statistically significant in physical component scale (PCS). CONCLUSION: Patients in the BMT group experienced higher HRQoL in both physical and mental aspects compared to those in the BTIC group. More studies are needed to assess the relative cost-effectiveness of these methods in developing countries.

Fludarabine, cytarabine, granulocyte colony-stimulating factor and melphalan (FALG with L-PAM) as a reduced toxicity conditioning regimen in children with acute leukemia.

BACKGROUND: The conventional conditioning regimen for patients with leukemia prior to allogeneic stem cell transplantation is myeloablation to eradicate residual leukemic cells and host immunocompetent cells. This helps prevent leukemic relapse as well as rejection after transplantation. A myeloablative conditioning regimen with busulfan (BU) or total body irradiation (TBI) is effective for eradication of leukemic cells but is also associated with significant toxicities in the acute or late phase in pediatric patients. In an effort to minimize these adverse effects, we conducted bone marrow transplantation (BMT) from unrelated volunteer donors using a conditioning regimen without BU or TBI. PROCEDURE: Ten patients with acute leukemia in first or second remission were given a "non-BU, non-TBI conditioning regimen," which consisted of fludarabine (FLU), cytarabine (CA), and melphalan (L-PAM) after FLAG combined with L-PAM. RESULTS: Engraftment was obtained in all patients, and two patients died of relapse. Eight of 10 patients have been disease-free for a median of 126 months (116-142) after transplantation. The overall survival, event-free survival, relapse rate, and treatment-related mortality were 80.0%, 80.0%, 20.0% and 0.0%, respectively. In female patients, spontaneous menstruation with normal luteinizing hormone (LH), follicle stimulating hormone (FSH), and estradiol (E2) levels was observed in all four patients at post-pubertal age. CONCLUSIONS: This conditioning regimen of FLAG combined with L-PAM (which did not contain BU and TBI) was associated with good outcomes and minimal late adverse effects in children with acute leukemia who have undergone allogeneic BMT from unrelated volunteer donors.

HLA-haploidentical donor lymphocyte infusions for patients with relapsed hematologic malignancies after related HLA-haploidentical bone marrow transplantation.

Treatment of relapse after related HLA-haploidentical T cell-replete bone marrow transplantation (haploBMT) with post-transplantation cyclophosphamide (PTCy) using haploidentical donor lymphocyte infusion (haploDLI) is not documented. All patients who received haploDLI after haploBMT with PTCy between June 2003 and October 2012 were identified and assessed for graft-versus-host disease (GVHD) and outcomes. Forty patients received 52 haploDLI doses. Sixteen patients had acute myeloid leukemia, 11 had lymphomas, and 34 had nonmyeloablative conditioning before haploBMT. The median time from haploBMT to relapse was 183 (range, 0 to 1399) days. The median age at haploDLI was 48 (range, 3 to 70) years. The first haploDLI doses were 1 × 10(5) CD3(+) cells/kg with subsequent escalation. The most commonly used first haploDLI dose was 1 × 10(6) CD3(+) cells/kg. The median follow-up after haploDLI was 7 (mean, 15.4; range, .5 to 96) months for the entire cohort, and 17.5 (mean, 28; range, 2.4 to 96) months for the responders. Acute GVHD developed in 10 patients (25%), 6 patients had grade 3 to 4, and 3 developed chronic GVHD. Twelve (30%) patients achieved a complete response (CR) with a median duration of 11.8 (mean, 22.5; range, .4 to 94) months. At last follow-up, 8 responders were alive in CR; 6 for over a year. HaploDLI for relapse after haploBMT is associated with acceptable toxicities and can result in durable responses.

The identification and characteristics of IL-22-producing T cells in acute graft-versus-host disease following allogeneic bone marrow transplantation.

Graft-versus-host disease (GVHD) remains the major obstacle for allogeneic bone marrow transplantation, in which many proinflammatory cytokines secreted by alloreactive donor T cells are involved. Role of IL-22 as a member of IL-10 family in GVHD is still disputed and the properties of IL-22-producing cells are unclear. We demonstrated here that CD4⁺ T cells but not CD8⁺ T cells involved in GVHD were the main cellular source of donor-derived IL-22. Th1 and Th17 cells were detected not only express classical cytokine IFN-γ or IL-17, but also contributed to IL-22 secretion in GVHD. Th22 cells characterized by the independent secretion of IL-22 were identified and occupied almost half percentage of IL-22-producing CD4⁺ T cells. The frequency of IL-22-producing CD4⁺ T cells showed dynamic changes with the development of GVHD. Finally, we observed that IL-22-producing CD4⁺ T cells in GVHD mouse carried CD62L⁻CD44(high/low) surface markers. In conclusion, we illuminate the characteristics of donor-derived IL-22-producing CD4⁺ T cells, which may have potent implication for further study of pathogenesis of GVHD.

Nocardiosis Causing Hypocellular Bone Marrow after Allogeneic Peripheral Blood Stem Cell Transplantation.

Nocardia infection is rare in bone marrow transplant (BMT) recipients with less than 30 cases reported in the literature [1-4]. The majority of the cases occurred late in the post-transplant period. Common clinical presentations included formation of widespread and multiple abscesses. Bone marrow hypoplasia is an uncommon finding. We describe the first case of nocardiosis, diagnosed at day 100 after non-myeloablative allogeneic peripheral blood stem cell transplantation, presenting as pancytopenia and hypocellular marrow. Eradication of the infection with antibiotics resulted in complete hematological recovery.

A Case of Eosinophilic Folliculitis after Allogenic Bone Marrow Transplantatino in Acute Myelogenous Leukemia

Eosinophilic folliculitis (EF) is regarded as a variant of eosinophilic pustular folliculitis (EPF), because it has a few distinctive clinical features different from those of EPF. EF is generally associated with systemic disorders, such as acquired immunodeficiency syndrome (AIDS) and hematologic malignancies. We have recently experienced a case of EF occurring in a 40 year-old male patient treated with allogenic bone marrow transplantation (BMT) for acute myelogenous leukemia(AML) and achieved a good clinical outcome after a short course of systemic corticosteroid therapy. The immunologic aberration resulting from systemic diseases may play a role in the development of EF.

Serial Assessment of Cardiac Function and Morhology Using Transthoracic Echocardiography after Bone Marrow Transplatiation

PURPOSE: Bone Marrow Transplantation (BMT) is very stressful treatment to the patients' hearts. The aim of this study was to evaluate the serial change of cardiac function and morphology on echocardiography and to propose the guidelines of echocardiographic monitoring in BMT patients. METHOD: We divided the 64 patients (M:F=42:22, mean age 33+/-9, 25 AML, 8 ALL, 19 CML, 12 others) with hematologic diseases into early group (M:F=22:7, mean age=33+/-9) whose follow up echocardiograms were taken within 90 days, and late group (M:F=20:15, mean age=33+/-8) whose follow up echocardiograms were taken beyond 90 days after BMT. In both groups, changes of left ventricular dimensions, ejection fraction, wall thickness, E/A ratio and deceleration time (DT) were measured before and after BMT. RESULTS: Cardiac complications were observed in 18 pateints after BMT. The pericardial effusion in 6, benign arrhythmias in 6, including sinus arrhythmia, premature ventricular contraction, premature atrial contraction developed in the early group, but 5 of 6 patients who had ejection fraction less than 40% were in the late group. After BMT, the thickness of interventricular septum and left ventricular posterior wall was significantly increased (p<0.05) and ejection fraction and E/A ratio was significantly decreased (p<0.05, respectively) in the early group. In the late group the thickness of interventricular septum returned to normal range, but ejection fraction was significantly decreased (p<0.05) and deceleration time significantly (p<0.05) shortened. CONCLUSION: This study shows that the early cardiac change after BMT is mainly decrease of LV systolic function with hypertrophy and the late change is not only decrease of systolic function but also change of diastolic parameters. Therefore the serial assessment of cardiac function and morphology using transthoracic echocardiography is essential for the early diagnosis of cardiac toxicity, especially early after BMT.

THE STRATEGIES FOR PREVENTING AND TREATING INFECTION OF CYTOMEGALOVIRUS IN BONE MARROW TRANSPLANTATION / 药物分析学报

In bone marrow transplantation (BMT), cytomegalovirus (CMV) interstitial pneumonitis (IP) is one of the most dangerous complications, which has been the first important cause to lead the failure of BMT. At present, there is no effective and specific therapy for CMV-IP, therefore how to prevent CMV infection effectively is a top task. From 1991 to 1996, we used comprehensive steps to prevent CMV-IP in BMT, and none of 14 patients developed CMV-IP. The preventing results that we achieved by using the steps were quite satisfied.

Comparative Study of FISH, PCR and Cytogenetics on 25 Patients Submitted to Bone Marrow Transplantation (BMT) for Chronic Myelogenous Leukemia (CML); Which Tests can we Use in Routine Analysis Post BMT?

Chronic Myeloid Leukaemia (CML) shows an excellent response to allogeneic bone marrow transplantation (BMT) with a 60-80% long term disease free survival in recipients of unmanipulate marrow. The most frequent cause of treatment failure is leukaemic relapse, due to the re-emergence of malignant recipient clones. Clinical and haematological relapse is usually preceded by molecular evidence of relapse. Early detection of molecular relapse may allow intervention with immunotherapy such as donor lymphocyte infusions (DLI). This study was undertaken to compare results from two centres who employ either Fluorescent In Situ Hybridisation (FISH) or polymerase chain reaction (PCR) analysis of DNA polymorphisms as their routine method of detecting residual host cells following BMT for CML in order to establish (1) if these methods are equivalent for routine laboratory use in reporting of chimaerism results to the referring clinician, and (2) if these methods are beneficial for indicating new and early therapeutic strategies. FISH analyses for the X and Y chromosomes (in sex mismatched patients) and/or FISH for BCR and ABL loci were compared with short tandem repeat PCR (STR-PCR) and conventional karyotyping in serial analyses in 25 patients submitted to BMT for Philadelphia positive (Ph) CML. Comparison of all results on samples assessed between 1 and 13 years post BMT indicated that FISH and PCR, performed on the same bone marrow samples displayed similar results in more than 90% of patients in first 3 years after BMT which increased to a concordance rate of 100% in long term survivors. In contrast, comparison of FISH or PCR versus cytogenetic analysis indicated a low concordance rate, with less than 50% of samples showing similar results during all the follow-up period. Eighty percent of recipients (22 patients) had evidence of mixed chimaerism following BMT (initial level of positivity 1-6% recipient cells) during the follow-up period. This low percentage of recipient cells remained stable in 7 patients, while 9 patients reverted to a donor profile. All 16 patients are in haematological remission. In addition the 3 patients with complete donor chimaerism remain in remission. In the remaining 6 patients, a progressive increase in recipient cells occurred (progressive mixed chimaerism, PMC), and was followed by haematological relapse. We conclude that FISH and PCR can be used to monitor CML patients post BMT and transient or stable low level mixed chimaerism is not associated with leukaemia relapse, but PMC is predictive of imminent relapse and its detection may help to illucidate the timing of early intervention with donor lymphocyte infusion.

High-Efficiency Retroviral Vector Containing Human Mutated Dihydrofolate Reductase cDNA and Its Expression in Murine Hematopoietic Progenitor Cells / 中国肿瘤生物治疗杂志

A double-copy Moloney leukemia virus-based retroviral vector containing both the Neo~(R) gene and a mutant human dihydrofolate re-ductase(S31 mutation) cDNA was packaged into the Amphotropic packaging cell hne GP-EAM12( AM12), and a Amphotropic producer cell hne (named AM12-S31)was obtained. In this study, we investigated its drug resistant characteristics, viral titer and for murine hematopoietic progenitor cells transduction as well. MTT assay verified that the AM12-S31 cells were resistant to G418 and methotrexate(MTX), the IC50 were more than 800 ?g/ml and 100 ?M respectively while the control cell line AM12 was sensitive to both drugs, the IC50 were 180 ?g/ml and 10 ?M, respectively. The viral titer for this cell line was approximately 7.8? 104~4.2? 105 G418-resistant colony forming units/ml. The replication-competent virus can not be detected in this producer cell line. We also use the AM12-S31 cells to transfect murine hematopoietic cells (By coculture) . The positive colonies were found in all the G418 concentrations using CFU-GM assay. No G418-resistant colony was found using AM12 transfection. The infected murine marrow cells were returned to lethally irradiated(900rad)recipients. The murine transplanted with AM12-S31 infected marrow cells showed protection from lethal MTX toxicity as compared with AM12 infected animals. Evidence for integration and the proviral DNA was obtained by PCR amplification of proviral DNA. These results indicated this producer cell hne could produce high titer, high-efficiency and non-replcational competent virus. The murine marrow cells could be transfected successfully using this system, and express the foreign gene. The lethal irradiated murine marrow function could be reinstitution by infusing the hematopoietic progenitor cells tranducted with human mutant dihydrofolate reductase. In my opinion, this system would play an important role in research the long-term protection of murine marrow hematopoietic function and drug resistant gene therapy.