Evaluating omadacycline dosing regimens against drug-resistant pathogens including Staphylococcus aureus, Streptococcus pneumoniae and Haemophilus influenzae in adults: a pharmacokinetic/pharmacodynamic analysis using Monte Carlo simulation.

The objective of this study was to evaluate the efficacy of various dosing regimens of omadacycline against main drug-resistant pathogens in the treatment of acute bacterial skin and skin structure infections (ABSSSI) and community-acquired bacterial pneumonia (CABP). Monte Carlo simulations were conducted using pharmacokinetic parameters and pharmacodynamic data to calculate cumulative fractions of response (CFRs) in terms of drug area under the concentration curve/minimum inhibition concentration targets.CFR ≥ 90% was considered optimal for a dosage regimen. CFR of any approved oral/intravenous regimen with loading-dose was ≥ 90% against methicillin-resistant Staphylococcus aureus (MRSA) for ABSSSI and penicillin-resistant Streptococcus pneumonia, tetracycline-resistant Streptococcus pneumonia, MRSA and ß-lactamase positive Haemophilus influenzae for CABP. In conclusion, approved oral/intravenous loading and maintenance doses of omadacycline showed enough efficacy in the treatment of ABSSI and CABP caused by the main drug-resistant pathogens.

The novel HLA-C*12:02:52 allele, identified by Sanger dideoxy nucleotide sequencing in a Chinese individual.

HLA-C*12:02:52 differs from HLA-C*12:02:02:01 by one nucleotide in exon 1.

Supratherapeutic posaconazole concentrations associated with hyperlipidemia in a patient with HSCT.

Posaconazole is a potent, extended-spectrum triazole antifungal used for the treatment and prophylaxis of serious fungal infections. Previous reports have demonstrated hyperlipidemia resulted in significant changes in posaconazole pharmacokinetics and tissue distribution in rats. However, the effect of hyperlipidemia on the pharmacokinetics of posaconazole in patients has not yet been reported. We report a case of a 34-year-old woman who experienced a supratherapeutic posaconazole trough concentration (PTC) associated with hyperlipidemia after haploidentical hematopoietic stem cell transplantation (HSCT). The patient was admitted 13 months after HSCT for recurrent cough and sputum. She was treated with caspofungin due to developing invasive fungal infection of Candida tropicalis. After 10 days, caspofungin was discontinued due to the poor therapeutic efficacy and replaced with amphotericin B. Afterwards, the condition of the patient improved significantly and she was switched to daily oral posaconazole tablet. Therapeutic drug monitoring (TDM) of posaconazole showed a PTC was 3.2 mg/L. After discharge, she continued to receive posaconazole tablet as antifungal treatment. Two months later, laboratory tests at outpatient showed her blood lipid levels were significantly elevated and PTC was increased to 9.38 mg/L. Therefore, the posaconazole tablet was discontinued and she received lipid-lowering therapy. A few days later, the PTC was down to 5.22 mg/L. No medication errors and significant drug interactions were found. Hence, supratherapeutic PTC for this patient may be caused by hyperlipidemia which altered pharmacokinetics of posaconazole. Our findings highlight the need for close TDM in order to avoid supratherapeutic PTC if hyperlipidimia occurs during posaconazole use.

Developing Strategies to Improve the Efficacy of CAR-T Therapy for Acute Myeloid Leukemia.

OPINION STATEMENT: Acute myeloid leukemia (AML) is a fatal blood malignancy. With the development of immunotherapy, particularly chimeric antigen receptor T cells (CAR-T), the treatment of AML has undergone a significant change. Despite its advantages, CAR-T still faces a number of limitations and challenges while treating AML. Finding novel targets, altering the structure of CAR to increase efficacy while lowering side effects, and using double-target CAR and logic circuits are typical examples of key to answer these problems. With the advancement of gene editing technology, gene editing of tumor cells or normal cells to create therapeutic effects has grown in popularity. Additionally, the combination of multiple drugs is routinely used to address some of the obstacles and difficulties associated with CAR-T therapy. The review's primary goal was to summarize recent strategies and developments of CAR-T therapy for AML.

Ileus induced by the combination of vinca alkaloids and posaconazole in a patient with acute lymphoblastic leukemia: a case report and literature review.

Vinca alkaloid (VA)-induced ileus, a rare but severe autonomic neuropathy, can be enhanced by concomitant use of antifungal triazole agents. We herein present a case of VA-induced ileus in a 17-year-old girl who was diagnosed with B-cell acute lymphoblastic leukemia. On day 1, the patient received cyclophosphamide, vincristine, and methylprednisolone. On day 2, she began treatment with posaconazole oral suspension at 200 mg three times daily for prophylaxis against invasive fungal infection. On day 5, she began induction therapy consisting of vindesine, methylprednisolone, daunorubicin, and cyclophosphamide. The patient developed severe abdominal pain with marked constipation on day 11 and was diagnosed with incomplete ileus. After switching the antifungal agent to micafungin, performing gastrointestinal decompression, administering parenteral nutrition, and omitting the fourth dose of vindesine, the ileus symptoms were relieved. This case emphasizes the potential interaction between VAs and posaconazole. We also herein present a review of the literature on ileus caused by the combination of VAs and antifungal triazole agents. In clinical practice, physicians and pharmacists should be aware of the possibility of ileus caused by the use of VAs in combination with posaconazole. It is important to reduce complications during chemotherapy to improve patients' prognosis.

Assessment of micafungin dosage regimens against Candida spp. in pediatric patients undergoing hematopoietic stem cell transplantation: a pharmacokinetic/pharmacodynamic analysis using Monte Carlo simulation.

The objective of this study was to evaluate the efficacy of various micafungin dosing regimens against Candida spp. in pediatric patients undergoing hematopoietic stem cell transplantation (HSCT). Monte Carlo simulations were conducted using pharmacokinetic (PK) parameters and pharmacodynamic (PD) data to determine the probabilities of target attainment and cumulative fractions of response in terms of area under the concentration curve/minimum inhibition concentration targets of micafungin. Current standard clinical micafungin dosing regimens of 1 and 2 mg/kg/day were appropriate for the prevention and treatment of Candida glabrata infection in pediatric patients undergoing HSCT, respectively. Moreover, the high-dose prophylactic dosage (2 mg/kg/day) and therapeutic dosage (4 mg/kg/day) should be the preferred option to optimize efficacy against Candida albicans. However, none of the simulated regimens was effective against Candida parapsilosis in pediatric HSCT patients. These PK/PD-based simulations rationalize and optimize the micafungin dosing regimens against Candida spp. in pediatric patients undergoing HSCT.

[Effect and Involved Mechanism of RSL3-induced Ferroptosis in Acute Leukemia Cells MOLM13 and Drug-resistant Cell Lines].

OBJECTIVE: To investigate the effect and involved mechanism of RSL3 on ferroptosis action in acute leukemia cells MOLM13 and its drug-resistant cells. METHODS: After MOLM13 treated with RSL3, CCK-8 assay was performed to detect cell viability, flow cytometry was used to detect the reactive oxygen species (ROS) level of the cells, RT-qPCR and Western blot were used to detect the expression of glutathione peroxidase 4 (GPX4). After MOLM13/IDA and MOLM13/Ara-C, the drug-resistant cell lines were constructed, the ferroptosis induced by RSL3 was observed. Bone marrow samples were collected from patients with acute monocytic leukemia. RT-qPCR and Western blot were performed to detect the expression of related genes and proteins involved in ferroptosis pathway. RESULTS: RSL3 significantly inhibited the cell viability of MOLM13 and increased the intracellular ROS level, which were partially reversed by ferrostatin-1. The mRNA and protein expression of GPX4 decreased in MOLM13 treated with RSL3. RSL3 inhibited the viability of MOLM13/IDA and MOLM13/Ara-C cells more strongly than that of non-drug resistant cells, also increased the intracellular ROS level . The cytotoxic effects were partially reversed by ferrostatin-1. The mRNA and protein expressions of GPX4 in MOLM13/IDA and MOLM13/Ara-C cells were higher than those in non-drug resistant cells. The mRNA and protein levels of GPX4 in bone marrow of relapsed/refractory acute mononuclear leukemia patients were higher than those of ordinary acute mononuclear leukemia patients. CONCLUSION: RSL3 can induce non-drug resistant cells MOLM13 ferroptosis by inhibiting GPX4 activity. MOLM13/IDA and MOLM13/Ara-C are more sensitive to RSL3 compared with non-drug resistant cells MOLM13, which may be caused by the differences in GPX4 expression. The expressions of GPX4 mRNA and protein in relapsed/refractory acute mononuclear leukemia are higher than those in ordinary acute mononuclear leukemia.

Noninvasive tools based on immune biomarkers for the diagnosis of central nervous system graft-vs-host disease: Two case reports and a review of the literature.

BACKGROUND: Central nervous system graft-vs-host disease (CNS-GVHD) is a rare cause of CNS disorders after allogeneic hematopoietic stem cell transplantation. Currently, establishing a diagnosis of CNS-GVHD is challenging because the diagnostic criteria and diagnostic methods are not well defined and many confounding factors need to be ruled out. CASE SUMMARY: Here, we present two patients with CNS-GVHD. Both patients with a history of acute GVHD or chronic GVHD developed neurological symptoms that could not be explained by other causes, and had abnormal cerebrospinal fluid (CSF) studies as determined by CSF and blood immune biomarker examinations, suggestive of suspected CNS-GVHD. Due to the lack of specific magnetic resonance imaging abnormalities and the rapid clinical deterioration of the patients, we did not attempt to perform a brain biopsy, but prompted the initiation of empirical immunosuppressive therapy. In view of the rapid and favorable response to local and systematic immunosuppressive treatment and the aforementioned neurologic manifestations together with CSF abnormalities and other negative findings, a final diagnosis of CNS-GVHD was made. CONCLUSION: CSF and blood immune biomarker examinations facilitated the diagnosis of CNS-GVHD, which are particularly suitable for patients who are critically ill and require urgent treatment and for those who are unsuitable for invasive diagnostic procedures.

[Clinical Effectiveness of Decitabine Combined with Reduced FLAG Regimen in the Treatment of Senile Patients with High-Risk Acute Myeloid Leukemia].

OBJECTIVE: To explore the efficacy and adverse reactions of decitabine combined with reduction FLAG regimen on the senile patients with high-risk AML. METHODS: 12 senile patients with high-risk AML received decitabine combined with reduced FLAG regimen (decitabine 20 mg/m2, intravenous drip, qd, d 1-5; fludarabine 30 mg/m2, intravenous drip lasts 30 min, qd, d 3-6; Ara-C 1 g/m2, intravenous drip, qd, d 3-6; and G-CSF 300 µg/d, subcu- taneous injection, d 2 to neutrophils reached the lowest return to＞1.0×109/L) in our study. The efficacy and adverse reactions of this regimen were analyzed. RESULTS: 9 patients achieved complete remission(CR) after one course of decitabine combined with reduced FLAG regimen, 2 patients achieved partial remission (PR) and 1 patient reached a stable disease (SD). The overall response rate was 92%. The median follow-up period was 7.4 months ranged from 3 to 12 months. The median survival time for all patients was 6.4 months. The main treatment-related toxicities were myelosuppression and infection due to neutropenia. Severe non-hematologic toxicities were not observed in these patients, and there was no treatment-related mortality. CONCLUSION: Decitabine combined with reduced FLAG regimen has a definite clinical efficacy in the treatment of senile patients with high-risk AML. This regimen, as induction remission regimen, can effectively improve the CR rate and reduce the adverse reactions. Therefore, it may be used as one of the preferred induction remission regimen to treat the senile patients with high-risk AML.

Evaluating posaconazole dosing regimens of the different formulations against Aspergillus spp. in adults: a pharmacokinetic/pharmacodynamic analysis using Monte Carlo simulation.

The objective of this study was to evaluate the efficacy of various posaconazole dosing regimens of the different formulations against Aspergillus spp. in adults. Monte Carlo simulations were conducted using pharmacokinetic (PK) parameters and pharmacodynamic (PD) data to determine the probability of target attainment (PTA) and cumulative fraction of response (CFR) in terms of area under the concentration-time curve/minimum inhibition concentration (AUC/MIC) targets of posaconazole. According to the results of the PTA analysis, currently recommended clinical dosing regimens of the delayed-release tablet and intravenous (i.v.) solution were appropriate in prophylaxis against Aspergillus spp. with MICs ≤ 0.125 µg/mL. However, only high-dose regimens of the delayed-release tablet could achieve the target PTA in the treatment against Aspergillus spp. at an MIC of 0.125 µg/mL. Furthermore, the CFR was calculated for each dosing regimen. For the oral suspension, none of the simulated dosing regimens was effective against Aspergillus spp. For the delayed-release tablet and i.v. solution, the recommended dosing regimens were effective for prophylaxis of invasive fungal infections by four Aspergillus spp. (Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans and Aspergillus terreus). However, these recommended dosing regimens were only effective for the treatment of A. terreus infection. Therefore, the high-dose regimen (200 mg oral every 12 h) of the delayed-release tablet should be recommended to achieve optimal therapeutic efficacy against four Aspergillus spp. (A. flavus, A. fumigatus, A. nidulans and A. terreus). These PK/PD-based simulations rationalise and optimise the dosing regimens of the different posaconazole formulations against Aspergillus spp. in adults.

Pharmacokinetic/Pharmacodynamic Analysis of Daptomycin Against Staphylococcus aureus and Enterococcus faecium in Pediatric Patients by Monte Carlo Simulation.

The objective of this study was to evaluate the efficacy of various daptomycin dosing regimens against Staphylococcus aureus and Enterococcus faecium in pediatric patients with proven/suspected gram-positive infection. Monte Carlo simulations (MCSs) were conducted using pharmacokinetic (PK) parameters and pharmacodynamic (PD) data to determine the probabilities of target attainment and cumulative fractions of response in terms of area under the concentration curve/minimum inhibition concentration (MIC) targets of daptomycin. According to the results of the MCSs, currently approved pediatric dosage regimens were sufficient against Staphylococcus aureus with MIC ≤ 0.5 µg/mL for all pediatric patients, but poor when MIC ≥ 1 µg/mL except for adolescents (12-17 years) who need a dosage of ≥10 mg/kg/day at MIC = 1 µg/mL. For Enterococcus faecium with MIC ≤ 4 µg/mL, the recommended dosage of 8-12 mg/kg/day in adults was enough for adolescents, but not subjected to younger pediatric patients. Furthermore, based on MIC distributions obtained from the European Committee on Antimicrobial Susceptibility Testing, the approved high-dose regimen should be recommended for infants aged 3-12 months, children (2-11 years), and adolescents to achieve better clinical efficacy against methicillin-resistant Staphylococcus aureus. In addition, the dosage of 8-12 mg/kg/day was powerful against Enterococcus faecium for adolescents; however, only the highest dosage of 12 mg/kg/day was effective for infants aged 3-12 months and children. All the simulated regimens were not optimal for infants aged 13-24 months. These PK/PD-based simulations rationalize and optimize the dosage regimens of daptomycin against Staphylococcus aureus and Enterococcus faecium in pediatric patients.

Effect and changes in PD­1 expression of CD19 CAR­T cells from T cells highly expressing PD­1 combined with reduced­dose PD­1 inhibitor.

CD19 chimeric antigen receptor (CAR) T cell therapy has changed the outcomes of relapsed/refractory B­cell leukemia and lymphoma. However, its efficacy in patients with relapsed/refractory non­Hodgkin lymphoma (NHL) has been less impressive compared with that in patients with acute lymphoid leukemia. Furthermore, immune checkpoints have a critical role in the immune system. Several clinical trials have confirmed the dramatic effects of programmed death­1/programmed death­ligand 1 (PD­1/PD­L1) inhibitors in numerous malignancies, but the immune­associated adverse events of PD­1/PD­L1 inhibitors may occur in a number of systems. The aim of the present study was to investigate the combination of CD19 CAR­T cells with a reduced dose of PD­1 inhibitor. This method is expected to overcome the side-effects of PD­1 inhibitors, while maintaining therapeutic efficacy. The findings demonstrated that a reduced dose of PD­1 inhibitor did not affect the transfection rate, proliferation rate or cytokine secretion of CD19 CAR­T cells. An interesting finding of the present study was that the number of PD­1­positive cells CAR­T cells, measured by flow cytometry, declined when they were cultured in vitro, but returned to high levels with gradual prolongation of the co­culture time of CD19 CAR­T cells with lymphoma cells; however, there was no change in the mRNA expression of T cells and CAR­T cells during this process. This phenomenon may be one of the reasons why the curative effect of CAR­T cells on B­cell lymphoma is unsatisfactory compared with B­cell leukemia. The synergistic effect of a reduced­dose PD­1 inhibitor combined with CD19 CAR­T cells from T cells highly expressing PD­1 was confirmed in a mouse trial. Mice in the combined treatment group achieved the longest survival time. In this group, the proportion of CAR­T cells and the level of interleukin­6 were higher compared with those in the CAR­T cell group. In conclusion, a reduced dose of a PD­1 inhibitor combined with CD19 CAR­T cells appears to be a promising treatment option for relapsed/refractory B­NHL exhibiting high PD­1 expression by T cells. This method may achieve good clinical efficacy while reducing the side-effects of PD­1 inhibitors.

[Establishment and Identification of MDS Mouse Model with Irom Overload].

OBJECTIVE: To establish a MDS mouse model with iron overload and to study the effect of iron overload on MDS. METHODS: The exogenous mutant gene RUNX1-S291fs was inserted into the mice bone marrow mononuclear cell's genome in mice by retrovirus and transplanted into C57BL/6 mice irradiated by 60 Co γ-ray. After 8 weeks,intraperitoneal injection of iron was performed to establish an MDS mouse model with iron overload. After 24 weeks of transplantation, the peripheral blood, bone marrow, femur, liver and spleen of mice were taken, then the morphological characteristics of peripheral blood and bone marrow cells were observed by Wright's staining; the liver, spleen and bone marrow were stained with Prussian blue to observe the iron deposition. The surface antigens of bone marrow cells were detected by flow cytometry. Bone marrow mononuclear cells and spleen tissue proteins were detected by Western blot to confirm the transfection of RUNX1-S291fs gene and expression of protein. The blood routine and transplanted cell chimeric rate of mice were monitored periodically. RESULTS: Compared with the empty plasmid control mice, levels of leukocyte and hemoglobin as well as platelet were decreased in RUNX1-S291fs mutant mice; the peripheral blood cells and bone marrow cells showed pathological hematopoiesis; the liver and spleen enlarged significantly; the tissue structure of femur, liver and spleen was abnormal; the expression of bone marrow cell surface antigens was abnormal. Bone marrow cells and spleen tissue expressed the RUNX1-S291fs protein. Compared with the controlled mice injected with normal saline, iron deposition occurred in the bone marrow, liver and spleen stained with Prussian blue in the mice injected with iron agent. CONCLUSION: Mice engineered to carry exogenous mutant gene RUNX1-S291fs and injected with iron showed pathologic features of MDS and iron overload, resulting in establishing MDS iron overloaded mouse model successfully, which lays a foundation for studying the effect of iron overload on MDS.

Prevalence and risk factors of antibodies to human leukocyte antigens in haploidentical stem cell transplantation candidates: A multi-center study.

We investigated the prevalence of and risk factors for antibodies to HLA in 1663 haploidentical transplant candidates. Among these cases, 349 (21.0%) showed positive panel-reactive antibody (PRA) either for class I or class II HLA. Multivariate analysis showed the following: i) risk factors associated with the prevalence of PRA either for class I or class II HLA were female gender (P = 0.018), prior transfusions (P < 0.001) or pregnancy (P < 0.001), and cases with MDS (P = 0.018); compared to other patients, subjects with ALL had a lower prevalence of class I antibodies (P = 0.017); and ii) risk factors associated with the prevalence of PRA both for class I and class II HLA were female gender (P = 0.014), prior transfusions (P = 0.003), previous pregnancy (P < 0.001), and diagnosis with MDS (P = 0.035). The percentages of antibodies against different antigens coded by the different HLA loci, including HLA-A, -B, -C, -DP, -DQ, and -DR, among all cases were 15.6%, 17.3%, 10.5%, 5.6%, 8.5%, and 9.7%, respectively. Risk factors associated with specific antibodies against HLA-A, -B, -C, -DP, -DQ, and -DR were female gender, prior transfusion, previous pregnancy, and underlying disease. Our findings suggest that gender, prior pregnancy, transfusion and underlying diseases are risk factors for HLA sensitization, which could guide HLA antibody monitor and donor selection.

Empirical antifungal treatment for diagnosed and undiagnosed invasive fungal disease in patients with hematologic malignancies.

BACKGROUND: Empirical antifungal therapy is effective in some patients with risk factors for invasive fungal disease (IFD) who do not qualify for the EORTC/MSG criteria for IFD, but who fail to respond to anti-bacterial and anti-viral therapy. OBJECTIVE: This retrospective single-center study investigated the epidemiology of IFD and empirical antifungal therapy in patients with hematological malignancies. METHODS: This study recruited 893 patients with hematologic malignancies who had failed to respond to anti-bacterial and anti-viral treatment and received antifungal therapy, but not for antifungal prophylaxis. Antifungal therapy regimens included amphotericin B, voriconazole, itraconazole and caspofungin. A total of 689 patients were diagnosed with proven, probable, or possible IFD, while 159 patients did not meet the EORTC/MSG criteria for IFD diagnosis but recovered with antifungal treatment, and 45 were excluded from having IFD. Effective treatment was defined as the disappearance or resolution of clinical symptoms of IFD. RESULTS: Patients diagnosed with IFD underwent chemotherapy at a higher proportion, and had significantly higher neutrophil counts compared to those who did not qualify for the EORTC/MSG criteria for IFD but responded to antifungals. The mortality due to all causes within 3 months was significantly higher for patients diagnosed with proven IFD, compared with those who did not qualify for the EORTC/MSG criteria for IFD. There was no discontinuation reported due to adverse events of caspofungin. CONCLUSION: Empirical antifungal treatment could help save the lives of some patients with severe infections who are strongly suspected of having IFD.

[Expression and Significance of HIF-1α in Erythropoiesis of Secondary Iron Overload Disease after Irradiation Damage].

OBJECTIVE: To study the expression of hypoxia inducible factor 1α(HIF-1α) of iron-overloaded in irradiated mice and its effect on erythropoiesis. METHODS: Twenty mice were randomly divided into 4 groups: Ctrl (control group), IR (irradiation group), IO (irradiation + iron overload group), and RAPA (rapamycin treatment group). The iron overload model was verified. The CFU-E (colony forming unit-erythroid) and BFU-E(burst colony forming unit-erythroid) were cultured; flow cytometry was used to detect the ratios of early stage (Ter119+CD71-) to late stage (Ter119+CD71+) of primitive erythroblasts; RT-PCR was used to detect the mRNA expression of HIF-1α and its related signal molecules in bone marrow cells. RESULTS: The expression of HIF-1α in IR and IO group was significantly higher than that in Ctrl group, and that in IO group was significantly higher than IR group (P<0.05). The ratio of late stage primitive erythroblasts, the number of CFU-E and BFU-E in both IR and IO group were lower than those in Ctrl group, and those in IO group were significantly lower than those in IR group (P<0.05). Compared with Ctrl group, the expression of HIF-1α related signal pathway molecules in both IR and IO group was significantly decreased (P<0.05). Compared with IO group, the expression of HIF-1α and its related signal molecules in RAPA(mTOR inhibitor) group was decreased significantly (P<0.05), the number of BFU-E was increased significantly(P<0.05). CONCLUSION: Irradiation induces the increase of HIF-1α and the decrease of the ability of hematopoietic colony formation and the ratio of late stage primitive erythroblasts. Iron overload can aggravate the injury. mTOR inhibitor rapamycin can partially alleviate the injury, suggesting that iron overload can lead to injury of erythropoiesis through HIF-1α.

Reactive oxygen species mediated T lymphocyte abnormalities in an iron-overloaded mouse model and iron-overloaded patients with myelodysplastic syndromes.

The adverse effects of iron overload have raised more concerns as a growing number of studies reported its association with immune disorders. This study aimed to investigate alterations in the immune system by iron overload in patients with myelodysplastic syndrome (MDS) and an iron-overloaded mouse model. The peripheral blood from patients was harvested to test the effect of iron overload on the subsets of T lymphocytes, and the level of reactive oxygen species (ROS) was also evaluated. The data showed that iron-overloaded patients had a lower percentage of CD3+ T cells and disrupted T cell subsets, concomitant with higher ROS level in lymphocytes. In order to explore the mechanism, male C57Bl/6 mice were intraperitoneally injected with iron dextran at a dose of 250 mg/kg every 3 days for 4 weeks to establish an iron-overloaded mouse model and the blood of each mouse was collected for the analysis of the T lymphocyte subsets and T cell apoptosis. The results showed that iron overload could reduce the percentage of CD3+ T cells and the ratio of Th1/Th2 and Tc1/Tc2 but increase the percentage of regulatory T (Treg) cells and the ratio of CD4/CD8. We also found that iron overload induced the apoptosis of T lymphocytes and increased its ROS level. Furthermore, these effects could be partially recovered after treating with antioxidant N-acetyl-L-cysteine (NAC) or iron chelator deferasirox (DFX). Taken together, these observations indicated that iron overload could selectively affect peripheral T lymphocytes and induce an impaired cellular immunity by increasing ROS level.

[Effects of Iron Overload on the Apoptosis and Function of Splenic CD8+ T Cells in Mice].

OBJECTIVE: To investigate the effects of iron overload on apoptosis and function of splenic CD8+ T cells in mice. METHODS: Forty C57BL/6 mice were randomly divided into control groups, Iron overload (IO), IO+NAC and IO+DFX groups. The iron overload model was established by intraperitoneal injection of iron dextran, and saline was injected as the control. The levels of intracellular reactive oxygen species (ROS) and labile iron pool (LIP) were analyzed by measuring the mean fluorescence intensity (MFI) of 2-7 dichlorofluorescein (DCF) or calcein. The ratio of CD8+ T cells and the levels of IFN-γ, TNF-α, Granzyme-B, and perforin in CD8+ T cells were detected by flow cytometry. The CD8+ T cell apoptosis was determined by flow cytometry with Annexin V/PI double staining. Real-time PCR was used to detect the expression of IFN-γ, TNF-α, Granzyme-B, perforin, BCL-2, and bax at mRNA level in CD8+ T cells. RESULTS: Iron overload was found by spleen iron staining and flow cytometry. The level of intracellular ROS in iron overload (IO) groups was higher than that of the control groups (P<0.01). The percentage of CD8+ T cells in spleen from mice with IO was lower than that in control groups (P<0.05). The expression of IFN-γ and Granzyme-B in CD8+ T cells in IO group were lower than that in control group, the expression of IFN-γ and Granzyme-B at mRNA level in CD8+ T cells was lower than that of control group (P<0.05). CD8+ T cell apoptosis in iron overload group was significantly higher than that in control groups (P<0.01); the expression of BCL-2 at mRNA level was lower than that in control group, but the expression of BAX at mRNA level was higher than that in control group (P<0.05). These effects could be reversed after treating iron-overloaded mice with DFX or NAC. CONCLUSION: Iron overload can inhibit the ratio of CD8+ T cells of splenic cells in mice, decrease the expression of IFN-γ, Granzyme-B, increase the apoptosis of CD3+ CD8+/CD8-. These effects may be regulated through increasing the intracellular ROS level, and can be partially reversed after treating iron-overloaded mice with DFX or NAC.

Colony Stimulating Factor 3 Mutations and Myeloid Malignancies.

Granulocyte colony stimulating factor (G-CSF) plays a major role in the proliferation, differentiation, and activation of neutrophil cell line hematopoietic cells. G-CSF exert the function depending on its binding to colony-stimulating factor 3 receptor (CSF3R), a homo-dimer receptor located on the surface of effector cells. Some recent studies have demonstrated that CSF3R mutations play a significant role in many diseases. Some of the hematopoietic diseases, especially myeloid malignancies (e.g. chronic neutrophilic leukemia) are related to the presence of various CSF3R mutations, which leads to abnormal G-CSF signal pathways. Also, the downstream kinases can be the treatment targets for these diseases. This review summarizes CSF3R mutations, mechanisms of mutations, and their contributions to the myeloid malignancies, with an attempt to further reveal the pathogenesis of myeloid malignancies, inform the diagnosis and clinical treatment of the myeloid malignancies, and provide clues for the research and development of new molecular target drugs.

Anti-CD20 antibody induces the improvement of cytokine-induced killer cell activity via the STAT and MAPK/ERK signaling pathways.

There is a current requirement for novel therapeutic strategies for the treatment of hematopoietic tumors. Residual tumor cells are the main origin of tumor relapse. The aim of this study was to eliminate the residual tumor cells of hematopoietic tumors. Cytokine-induced killer (CIK) cells are used in immunotherapy to deplete the residual cells. However, it is necessary to increase the antitumor activity and clinical applicability of CIK cells. The present study investigated the antitumor activity of CIK cells to the SU-DHL2 human B-cell lymphoma and K562 human chronic myelogenous leukemia cell lines. CD3+CD56+ cells from healthy donors were expanded in culture with cytokines and anti-CD20 monoclonal antibody (mAb; rituximab) to generate CIK cells. A preliminary investigation of their mechanism was then performed. The increase in the cytotoxicity of the CIK cells induced by the anti-CD20 mAb was associated with an increase in the expression of cytotoxic factors. The expression of components of the signal transducer and activator of transcription (STAT) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathways was found to increase. Upregulation of the expression of STAT1, STAT3 and STAT5 is important as these co-stimulatory molecules enhance T-cell proliferation. Activation of the MAPK signaling pathway is a possible mechanism for the anti-apoptosis effect on the proliferation of CIK cells. In conclusion, anti-CD20 mAb may play an important role in the improvement of CIK-mediated cytotoxicity to tumor cells. These observations may aid in the improvement of the effects of immunotherapy in depleting the residual cells of hematopoietic tumors. Thus, the use of CIK cells cultured with anti-CD20 mAb could be a novel therapeutic strategy for the depletion of chemotherapy-resistant or residual cells in anaplastic large and B-cell lymphoma.