The Bacterial Microbiota Promotes Normal Hematopoiesis Via Interferon Alpha and NOD1 Signaling Pathways

Long-term antibiotic therapy is associated with hematological side effects such as neutropenia and anemia. Our lab and others have shown that long-term antibiotic treatment in mice leads to bone marrow suppression and agranulocytosis in mice through depletion of the commensal bacteria. Our work further showed that Stat1-deficient mice phenocopy the bone marrow suppression phenotype of antibiotic-treated mice, suggesting that commensal microbiota mediate hematopoiesis via Stat1 signaling. However, the upstream actors of this pathway and the bacterial mediators required for commensal microbiota regulation of normal hematopoiesis still remain poorly understood. Such knowledge will be essential for understanding how to treat antibiotic-associated cytopenias. We hypothesize that microbial products detected by host cells trigger STAT1 signaling to potentiate normal hematopoiesis. To identify the host cells that require Stat1 for microbiota-promoted hematopoiesis, we treated conditional Stat1 knock-out mice with two weeks of antibiotic therapy. Of the four conditional knock-out mice we evaluated (LepR-Cre, Villin-Cre, Vav-iCre, LysM-Cre), only the mice deficient in STAT1 in hematopoietic cells (Vav-iCre Stat1 fl/fl) phenocopied the bone marrow suppression of antibiotic-treated mice. Our data suggest that STAT1 signaling is necessary in non-myeloid hematopoietic cells, but not intestinal epithelial cells or mesenchymal stromal cells for microbiota-promoted hematopoiesis. Non-competitive transplantation of Stat1 -/- bone marrow into wild type mice validated these findings; mice lacking STAT1 only in hematopoietic tissues phenocopied the Vav-iCre mice, consistent with a specific role for microbiota-mediated STAT1 signaling in the hematopoietic compartment. To assess the upstream mediator of STAT1 signaling in this biological context, we treated interferon (IFN) receptor knock out mice with two weeks of antibiotics. Of the three types of IFN receptor knock-outs evaluated, only mice deficient in type I IFN signaling phenocopied the bone marrow suppression of antibiotic-treated mice. These findings suggest that type I IFN signaling, and not type II or III, was required for microbiota-dependent hematopoiesis. These results were validated by showing that the administration of pegylated-IFNα was sufficient to rescue the depletion of type I IFN-STAT1 signaling in antibiotic-treated mice. To determine the microbial signals that may potentiate hematopoiesis, we evaluated two microbial products that were previously shown to alter hematopoiesis and to activate type I IFN signaling (Iwamura et al. Blood 2017 & Steed et al. Science 2017). We discovered that oral administration of these commensal-derived products, the metabolite desaminotyrosine (DAT) or NOD1 ligand (NOD1L), a motif of peptidoglycan, were each sufficient to rescue the hematopoietic defects induced by antibiotics in mice. To test whether these products rescue hematopoiesis by activating STAT1 signaling, we attempted to rescue the hematopoietic defects in Stat1 -/- mice. These studies showed that NOD1L rescues granulocyte but not progenitor counts in Stat1 -/- mice, suggesting that NOD1 and type I IFN signaling work together at the progenitor level, but independently at the downstream myeloid progenitor level to promote granulopoiesis. Overall, our studies expand our understanding of the signaling pathways by which the microbiota promotes normal hematopoiesis and identify novel therapeutic agents that can be used to ameliorate antibiotic-induced BM suppression. Disclosures No relevant conflicts of interest to declare.

Observation on the stability of rat myelosuppression model established by different doses of cyclophosphamide solution

Objective to investigate the stability of different doses of cyclophosphamide solution in establishing rat myelosuppression model. Methods In this study, 30 SD rats were randomly divided into control group (Group C) and model group (M1, M2, M3, M4). The rats in the model groups were injected with cyclophosphamide solution by intraperitoneal injection at doses of 30、40、(30+15) and (40+20) mg/kg respectively to establish a bone marrow suppression rat model. The changes of WBC, lym, Mon, GRA, RBC, Hb and PLT in peripheral blood were observed on the 1st, 5th and 13th day after modeling. Results （1）After modeling, the weight of rats in the model group was lower than that in the control group (P < 0.05). （2）On the 5th day, the levels of WBC, lym, mon and gra in the serum of each model group were lower than those before modeling(P < 0.05). The content of RBC in M1 and M2 groups was lower than that before modeling (P < 0.05), the content of Hb in M1, M2 and M3 groups was lower than that before modeling (P < 0.05), and the content of PLT in M1, M2, m3 and M4 groups was lower than that before modeling (P < 0.05). （3）On the 13th day, the levels of WBC, lym, mon and gra in M1 and M2 groups were higher than those on the 5th day, except for the GRA in M2 group.The levels of WBC and lym in m3 and M4 were lower than those in M1 and M2 (P < 0.05); The contents of RBC and Hb in M1 and M2 groups were lower than those before modeling (P < 0.05); Compared with M1 and M2, the content of Hb in m3 and M4 groups was higher (P < 0.05); The PLT content in the peripheral blood of M3 and M4 rats was higher than that of the 5th day, but lower than that of M1 and M2 groups (P < 0.05). Conclusion The improved method can maintain the stability of rat myelosuppression model.

The Baseline Serum Uric Acid as an Indicator of Chemotherapy-Related Adverse Reaction and Mortality in Aged Males with Stage IIIB or IV Non-Small Cell Lung Cancer

Objective: To evaluate the accuracy of baselineserum uric acid(BSUA) in estimating adverse effects (AE) and all-cause mortality (ACM) in older males with stage IIIB or IV non-small cell lung cancer (NSCLC) diagnosis.Study design:This is a single-center retrospective examination, conducted at the West China Hospital, Sichuan University in Chengdu, Sichuan Province, China, between the duration of January 2010 and December 2017.Primary outcome and measures:: All patients data was obtained based on medical reports and mortality information was gathered via telephone interviews. BUSA was assessed prior to chemotherapy. Additionally, the end points of this study included chemotherapy-mediated AE and ACM. Binarylogistic regression analysis was used to explore the correlation between BSUA and AE. Lastly, Cox regression analysis was utilized to examine theimpactof BSUA on ACM.Results: 317 male patients with NSCLC were eligible for this study. Within this population, 18.3% had stage IIIB and 81.7% had stage IV NSCLC. Moreover, 81.39% suffered from adenocarcinoma lung cancer (ACLC), whereas 18.61% suffered from squamous cell carcinoma lung cancer (SCCLC). As of March 1, 2019, 257 (81.07%) patients expired. Following the initial chemotherapeutic course, short-term AE like bone marrow suppression, all infection, liver dysfunction, and digestive reactions, wereobserved in 13.25%, 7.26%, 5.36%, and 4.1% of cases, respectively. Upon normalizing with confounding factors, the adjustedlogistic regression model demonstrated thatthe moderate BSUA was independently linked to a lower risk of bone marrow suppression (OR=0.407,95% CI:0.178-0.931; p=0.033).Moreover, based on the Cox regression analysis, moderate BSUAwas also independently correlated with a low mortality risk (HR=0.705,95% CI:0.518-0.959; p=0.026).Conclusion：In males patients withstage IIIB or IV NSCLC, BSUA is intimately linked to chemotherapy-driven AE and ACM.

The Baseline Serum Uric Acid as an Indicator of Chemotherapy-related Adverse Reaction and Mortality in Aged Males with Stage IIIB or IV Non-small Cell Lung Cancer

Objective: To evaluate the accuracy of baseline serum uric acid (BSUA) in estimating adverse effects (AE) and all-cause mortality (ACM) in older males with stage IIIB or IV non-small cell lung cancer (NSCLC) diagnosis.Methods: All patients data was obtained based on medical reports and mortality information was gathered via telephone interviews. BUSA was assessed prior to chemotherapy. Additionally, the end points of this study included chemotherapy-mediated AE and ACM. Binary logistic regression analysis was used to explore the correlation between BSUA and AE. Lastly, Cox regression analysis was utilized to examine the impact of BSUA on ACM.Results: 317 male patients with NSCLC were eligible for this study. Within this population, 18.3% had stage IIIB and 81.7% had stage IV NSCLC. Moreover, 81.39% suffered from adenocarcinoma lung cancer (ACLC), whereas 18.61% suffered from squamous cell carcinoma lung cancer (SCCLC). As of March 1, 2019, 257 (81.07%) patients expired. Following the initial chemotherapeutic course, short-term AE like bone marrow suppression, all infection, liver dysfunction, and digestive reactions, were observed in 13.25%, 7.26%, 5.36%, and 4.1% of cases, respectively. Upon normalizing with confounding factors, the adjusted logistic regression model demonstrated that the moderate BSUA was independently linked to a lower risk of bone marrow suppression (OR=0.407,95% CI:0.178-0.931; p=0.033). Moreover, based on the Cox regression analysis, moderate BSUA was also independently correlated with a low mortality risk (HR=0.705, 95% CI:0.518-0.959; p=0.026).Conclusion：In males patients with stage IIIB or IV NSCLC, BSUA is intimately linked to chemotherapy-driven AE and ACM.

Pneumocystis Pneumonia and Acute Myeloid Leukemia: A Systematic Review

Background: Pneumocystis pneumonia (PCP) incidence in acute myeloid leukemia (AML) patients have not been well described and some studies have shown the risk of this infection in these groups of patients. In this systematic review, we reviewed the published studies about PCP in AML to evaluate the PCP incidence and outcomes in these patients and then focuses on its immunological mechanism. Method: All articles reviewed in this collection are from recruited sites: PubMed and Embase databases. No time limit was considered for article searching. The following keywords were used: (“Pneumonia, Pneumocystis” OR Pneumocystis Pneumonia” OR “Pneumocystis jirovecii”), AND (“leukemia, myeloid, acute OR acute myeloid leukemia”). Our search strategy yielded 356 articles. After implementing the exclusion and inclusion criteria, the final papers were selected and reviewed. Result: By our search, 356 articles were found (316 in PubMed and 40 in Embase). After the implementation of inclusion and exclusion criteria, seven papers remained. A total of seven articles with a total number of 41 patients were included. Conclusion: Affected patients appear to have a clear resistance to PCP infection despite chemotherapy and bone marrow suppression due to the preservation of a specific immunological milieu in the lung. In fact, may be due to immunological stability of the lungs that remains intact. Further studies are needed.

Linezolid-induced black hairy tongue in a patient with multidrug-resistant tuberculosis: A case report

The revised World Health Organization guidelines on multidrug-resistant tuberculosis include linezolid in the core drugs group. Consequently, the use of linezolid for patients with multidrug-resistant tuberculosis is increasing. Common adverse events of long-term linezolid use include bone marrow suppression and neuropathies. However, there is limited information on a rare adverse event, black hairy tongue. Here, we report a case of linezolid-induced black hairy tongue in a patient with multidrug-resistant tuberculosis. The etiology, pathogenesis, diagnosis, and treatment of black hairy tongue are also discussed.

Comparison of non-myeloablative lymphodepleting preconditioning regimens in patients undergoing adoptive T cell therapy

BackgroundAdoptive cell therapy with T cells genetically engineered to express a chimeric antigen receptor (CAR-T) or tumor-infiltrating T lymphocytes (TIL) demonstrates impressive clinical results in patients with cancer. Lymphodepleting preconditioning prior to cell infusion is an integral part of all adoptive T cell therapies. However, to date, there is no standardization and no data comparing different non-myeloablative (NMA) regimens.MethodsIn this study, we compared NMA therapies with different doses of cyclophosphamide or total body irradiation (TBI) in combination with fludarabine and evaluated bone marrow suppression and recovery, cytokine serum levels, clinical response and adverse events.ResultsWe demonstrate that a cumulative dose of 120 mg/kg cyclophosphamide and 125 mg/m2 fludarabine (120Cy/125Flu) and 60Cy/125Flu preconditioning were equally efficient in achieving deep lymphopenia and neutropenia in patients with metastatic melanoma, whereas absolute lymphocyte counts (ALCs) and absolute neutrophil counts were significantly higher following 200 cGyTBI/75Flu-induced NMA. Thrombocytopenia was most profound in 120Cy/125Flu patients. 30Cy/75Flu-induced preconditioning in patients with acute lymphoblastic leukemia resulted in a minor ALC decrease, had no impact on platelet counts and did not yield deep neutropenia. Following cell infusion, 120Cy/125Flu patients with objective tumor response had significantly higher ALC and significant lower inflammatory indexes, such as neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR). Receiver-operating characteristics curve analysis 7 days after cell infusion was performed to determine the cut-offs, which distinguish between responding and non-responding patients in the 120Cy/125Flu cohort. NLR≤1.79 and PLR≤32.7 were associated with clinical response and overall survival. Cytokine serum levels did not associate with clinical response in patients with TIL. Patients in the 120Cy/125Flu cohort developed significantly more acute NMA-related adverse events, including thrombocytopenia, febrile neutropenia and cardiotoxicity, and stayed significantly longer in hospital compared with the 60Cy/125Flu and TBI/75Flu cohorts.ConclusionsBone marrow depletion and recovery were equally affected by 120Cy/125Flu and 60Cy/125Flu preconditioning; however, toxicity and consequently duration of hospitalization were significantly lower in the 60Cy/125Flu cohort. Patients in the 30Cy/75Flu and TBI/75Flu groups rarely developed NMA-induced adverse events; however, both regimens were not efficient in achieving deep bone marrow suppression. Among the regimens, 60Cy/125Flu preconditioning seems to achieve maximum effect with minimum toxicity.

Transient leukopenia after radioactive iodine treatment in patients with Graves’ disease: A retrospective cohort study

Context Radioactive 131I (RAI) for the treatment of differentiated thyroid cancer is known to induce bone marrow suppression, which occurs approximately 1 month post treatment. However, it is unknown whether RAI therapy for Graves’ disease causes bone marrow suppression. Objective This study aimed to evaluate the short- and long-term effects of RAI therapy on bone marrow function in patients with Graves’ disease. Methods In this retrospective cohort study, we included patients with Graves’ disease who received RAI therapy only once between 2003 and 2019 at Tokyo Women’s Medical University. Blood cell counts at baseline were compared with counts at 1, 2, 4, 12, 24, 48, 144, and 240 weeks after RAI therapy. Moreover, changes in white blood cell (WBC) count and leukopenia at 1 week after RAI treatment were compared by baseline patient characteristics. Results We enrolled 48 patients. Leukopenia was observed in 6 patients at 1 week after RAI treatment, and the overall WBC count significantly decreased (p&lt;0.001) 1 week after the therapy; however, the values were not significantly lower after 2 weeks. Neither red blood cell nor platelet count were significantly altered. Moreover, independent of other factors, the neutrophil count at the baseline was significantly negatively associated with changes in WBC count or the occurrence of leukopenia 1 week after the RAI treatment. Conclusions These data showed that RAI treatment induced transient reduction in the WBC count 1 week after treatment, although WBC levels were subsequently restored.