Changing Trends of Candida Species and Antifungal Susceptibility Profile of Candida Bloodstream Isolates: A 5-Year Retrospective Survey

Background: Candida species have emerged as one of the most common causes of bloodstream infections (BSIs). There are limited data on the distribution of Candida spp. and susceptibility by year. Objectives: In this study, we analyzed changes in the distribution of Candida spp. and their antifungal susceptibility profiles from blood cultures. Methods: Records from January 2016 to December 2020 were obtained from the microbiology laboratory in Istanbul. Antifungal susceptibility tests were performed using the VITEK 2 compact system and evaluated according to EUCAST breakpoints. A total of 241 unique candidemia episodes were included in this study. Results: Candida albicans was the predominant pathogen (n = 95, 39.42%), followed by C. parapsilosis (n = 82, 34.02%), C. glabrata (n = 18, 7.47%), C. tropicalis (n = 17, 7.05%), C. krusei (n = 15, 6.22%), and other Candida spp. (n = 14, 5.79%). There was no statistically significant difference in the percentage of episodes of Candida spp. After data analysis, a tendency to shift from C. albicans to C. parapsilosis was observed in the period analyzed in this study. Candida albicans was the most common species in intensive care units (ICUs), hematology and hemopoietic stem cell transplantation units, and surgical clinics, with C. parapsilosis predominant in medical clinics. In general, micafungin susceptibility was the highest, and fluconazole was the lowest. There was reduced sensitivity to fluconazole and voriconazole for C. albicans and C. parapsilosis over 5 years. Conclusions: Detecting changes in the distribution of Candida spp. and antifungal susceptibility over time will lead to the selection of appropriate empirical therapy and monitor phenomena of antifungal resistance. Empirical treatment with antifungal agents is associated with high costs, toxicities, and risk of antifungal resistance. Therefore, it is mandatory to determine and monitor Candida spp. and antifungal susceptibility testing to select appropriate antifungal agents.

Immune Dysregulation Resulting From Impaired Interleukin-10 And The Interleukin-10 Receptor Signaling: A Systematic Review of 284 Monogenic Patients

Purpose: Interleukin-10 (IL-10) and IL-10 receptor (IL-10R) deficiency are monogenic inborn errors of immunity (IEI) causing early-onset inflammatory bowel diseases (IBD). Methods: We systematically reviewed articles that included related keywords using PubMed, Web of Science, and Scopus databases. The articles were screened for eligibility criteria before data extraction. Results: We assessed 284 patients (44.1% female) with IL-10 and/or IL-10R deficiencies who were predominantly from China (41.0%), Italy (14.1%), and South Korea (8.6%). The median age of onset was 1.0 (0.3-4.0) months with a median age of genetic diagnosis at 16.0 (7.4-81.0) months. Consanguinity was reported in all evaluable patients with IL-10 deficiency and in 38.8% of patients with IL-10R deficiency (23.4% of patients with IL-10RA, and 79.4% of patients with IL-10RB deficiency). The most prevalent mutations in IL-10RA were c.301C>T (p.R101W) and c.537G>A (p.T179T), those in IL-10RB were c.139A>G (p.K47E) and c.611G>A (p.W204X). Autoimmunity and enteropathy were present in all cases. The first presentation of both groups was protracted diarrhea (45.7%), bloody diarrhea (18.1%), and colitis (15.7%). Patients with IL-10R deficiency had a high frequency of dermatologic manifestations (50.5%) and failure to thrive (60%), while IL-10 deficient patients lacked those complications. In the majority of patients, the basic immunologic parameters were in normal ranges. Of the entire publications, 30% underwent hemopoietic stem cell transplantation, 61.5% surgery, and 87% immunosuppressive treatment. The ten-year survival rate was higher in patients with IL-10 deficiency than in patients with IL-10R deficiency.Conclusion: IL-10/IL-10R deficiency predominantly presents with treatment-resistant, early-onset IBD within the first months of life. No clear genotype-phenotype correlation was present among these patients. The high prevalence of distinct clinical manifestations reported in IL-10RA- and IL-10RB-deficient patients might be attributable to the interaction between the target tissue and cytokines other than IL- 10 capable of binding to IL-10RB. These results gain translational significance by contributing to earlier diagnosis, adequate therapy, and avoiding delay in the diagnosis and unfavorable outcome.

Novel Mechanisms of Thrombopoietin Generation: The Essential Role of Kupffer Cells

Thrombopoietin (TPO) is the physiological regulator of hemopoietic stem cell niche and megakaryocyte differentiation, and therefore platelet production. Prevailing theory posits that TPO is constitutively expressed by hepatocytes, and levels are fine-tuned through platelet and megakaryocyte internalization/clearance via the c-Mpl receptor. Our lab has previously shown that platelet glycoprotein (GP) Ibα is indispensable for platelet-mediated TPO generation (Blood 2018), and recent reports have demonstrated that Kupffer cells, the tissue resident macrophages of the liver, contribute to the clearance of desialylated platelets. However, whether Kupffer cells may contribute to TPO generation has never been explored. To determine the possible role of Kupffer cells in TPO production, clodronate liposome was intravenously administered to deplete Kupffer cells in wild-type mice. Wild-type, Kupffer cell depleted mice showed a TPO decrease of 43.6% (±16%) 2 days post depletion, with only a gradual insignificant increase in TPO levels to day 6. Interestingly, TPO levels could not be significantly increased in wild-type Kupffer cell depleted mice even when transfused 2x10 8 wild-type or desialylated platelets, or 50mU neuraminidase. Kupffer cell depletion in IL4Rα/GPIbα-transgenic mice, which lack platelet-mediated TPO generation, showed a TPO decrease of 22.5% (±5%) from baseline 2 days post depletion, with only a gradual increase in levels to day 6, suggesting that Kupffer cells are required for constitutive in addition to platelet-mediated TPO production. As our lab has previously shown that platelet GPIbα drives platelet-mediated TPO generation, and that Kupffer cells now required, WT and GPIbα -/- platelets were co-cultured with Kupffer cells to assess interaction. Desialylated WT platelets interacted significantly more with Kupffer cells as analyzed by flow cytometry than GPIbα -/- platelets. Interestingly, desialylation of GPIbα -/- platelets did not increase binding to Kupffer cells, consolidating that desialylated GPIbα is required for Kupffer cell interaction, and subsequent TPO generation. This data demonstrates the novel and unexpected finding that Kupffer cells are required for both platelet-mediated and baseline hepatocellular TPO generation. Elucidation of the role of Kupffer cells in this crucial mechanism will provide a better understanding of why thrombocytopenias may occur in pathological states, as well as contribute to the development of TPO mimetic therapies. Disclosures No relevant conflicts of interest to declare.

Tobacco Use Predicts Unique Mutagenesis Signature in Acute Myelogenous Leukemia

Background: Endogenous and exogenous processes are active in leukemia initiation. Single-base substitution (SBS) data permits aggregation into mutational signatures [MS] with potential for clinical application. Acetaldehyde and Benzo [a] pyrene (BaP) are tobacco mutagens that "drive" signature SBS4 [Catalog of Somatic Mutations in Cancer (COSMIC) https://cancer.sanger.ac.uk/signatures/sbs/] in lung cancer characterized by C>A transversion. This specific MS is associated with favorable response to immune-checkpoint therapy (ICT). Previous epidemiologic data correlate smoking with cancer including leukemia. Tobacco mutagens are ubiquitously distributed in organs once inhaled. However, how mutagenicity develops in hemopoietic stem cell/progenitor is unknown. In this study, our primary objective was to investigate the incidence of MS among patients (pt) diagnosed with Acute Myelogenous Leukemia (AML) with smoking exposure. Methods: After IRB approval, we performed retrospective analysis using the BCM AML database. Data from 58 AML pt was available. For all analysis, current and past smoking were aggregated into "positive exposure". SBSs (C>A, C>G, C>T, T>C, T>G, G>C, G>A, GT and AG) in smokers and never smoker were annotated from ELN 2017 predefined subgroups [i.e. CEBPA, NPM1, P53, ASLX1, RUNX1 and FLT3ITD] and all additional mutations in individual pt. We used descriptive statistics to detect differential clinical predictors for smoking induced MS. Chi-square was used to determine association between SBSs and smoking history. Stepwise logistic regression allowed identification of independent MS that correlated with smoking. Results: Median age for 58 AML pt was 65.5 years [y] (range, 22-89) and 58.3% were male. Smokers were 26/58 (44.8%). Whites, African Americans, Hispanics and Asians comprised 35/60 (58.3%), 7/60 (7.1%), 16/60 (26.6%) and 2/60 (2.3%), respectively. 112 myeloid mutations [91 SBSs, 16 duplications, 16 deletions, and 3 insertions] were recorded. 32/58 (55.1%) had positive smoking exposure. Previous reports suggest that C>A [COSMIC=SBS4], G>C [COSMIC= SBS2 and SBS13] and T>C [COSMIC=SBS5] retain strong smoking association with cancer. However, in addition to C>A [HR=0.10 (0.01-0.6), p=0.02], our logistic model identified G>A, HR=0.12 (0.02-0.4), p=0.002, as predictors of exposure. C>A+G>A MS was observed in 19/25 (76%) of AML pt with smoking exposure, OR=6.56 (1.8-23.9), p=0.002. By ELN-2017 defined subgroups, P53, ASXL1, RUNX1, FLT3 and NPM1 mut were detected in 11/58 (18.9%), 5/58 (8.6%), 4/58 (6.8%), 13/58 (22.4%) and 5/58 (8.6%). RAS was seen in 12/58 (20.6%), IDH 12/58 (20.6%), DNMT3A 10/58 (17.2%) and TET2 7/58 (12%). Interestingly, among smokers exhibiting or not C>A+G>A SBP substitution, P53 was identified in 3/3 (100%) v 0/3 (0%), p=0.05 and RAS in 75% v 25%, p=0.08. Conclusions: Our data suggest that C>A and G>A SBS substitutions are frequently observed in AML pt with smoking exposure. Hemopoietic stem cell/progenitors exposed to smoking products may initiate similar SBSs substitutions as those observed in tobacco induced solid tumors. Previously, lung cancer studies demonstrated that TP53 and KRAS mutations tumors exhibited high rate of C>A transversion associated with tumor-infiltrating lymphocytes (TIL) and high program-death 1 ligand (PD-L1) expression. Further similar studies are needed in adult diagnosed with P53 AML. Figure 1 Figure 1. Disclosures Mims: IDEC: Current holder of individual stocks in a privately-held company; Biogen: Current holder of individual stocks in a privately-held company; Incyte: Research Funding; Pfizer: Research Funding; AVEO: Research Funding; Celgene: Research Funding.

A Cas Report of Diamond-Blackfan Anaemia with RPS19 Mutation

Diamond Blackfan Anaemia (DBA) is a rare disorder which presents with anaemia in early childhood. This heterogenous disorder is mainly autosomal dominantly inherited. Significantproportions of the cases are associated with craniofacial anomalies and some cases may end up developing malignancy. The diagnosis is established by blood investigations, and bone marrow studies in which red cell precursors are reduced or absent. Screening for the mutations including those encoding for ribosomal proteins in the patient and the family members is confirmatory for diagnosis. Human Leukocyte Antigen (HLA) matched hemopoietic stem cell transplantation is the definitive treatment of choice. In other cases, corticosteroids have been tried. The haemoglobin level is maintained with packed red cell transfusion. We are presenting here a male baby who had anaemia soon after birth and was brought to us at the age of 1 year 3 months. The diagnosis of DBA was made since the patient presented with anaemia and supportive biochemical and histological evidence. Genetic screening revealed mutation in ribosomal protein S19 (RPS19) gene in the baby.

The Promise and the Hope of Gene Therapy

It has been over 30 years since visionary scientists came up with the term “Gene Therapy,” suggesting that for certain indications, mostly monogenic diseases, substitution of the missing or mutated gene with the normal allele via gene addition could provide long-lasting therapeutic effect to the affected patients and consequently improve their quality of life. This notion has recently become a reality for certain diseases such as hemoglobinopathies and immunodeficiencies and other monogenic diseases. However, the therapeutic wave of gene therapies was not only applied in this context but was more broadly employed to treat cancer with the advent of CAR-T cell therapies. This review will summarize the gradual advent of gene therapies from bench to bedside with a main focus on hemopoietic stem cell gene therapy and genome editing and will provide some useful insights into the future of genetic therapies and their gradual integration in the everyday clinical practice.

The “Vesicular Intelligence” Strategy of Blood Cancers

Blood cancers are a heterogeneous group of disorders including leukemia, multiple myeloma, and lymphoma. They may derive from the clonal evolution of the hemopoietic stem cell compartment or from the transformation of progenitors with immune potential. Extracellular vesicles (EVs) are membrane-bound nanovesicles which are released by cells into body fluids with a role in intercellular communication in physiology and pathology, including cancer. EV cargos are enriched in nucleic acids, proteins, and lipids, and these molecules can be delivered to target cells to influence their biological properties and modify surrounding or distant targets. In this review, we will describe the “smart strategy” on how blood cancer-derived EVs modulate tumor cell development and maintenance. Moreover, we will also depict the function of microenvironment-derived EVs in blood cancers and discuss how the interplay between tumor and microenvironment affects blood cancer cell growth and spreading, immune response, angiogenesis, thrombogenicity, and drug resistance. The potential of EVs as non-invasive biomarkers will be also discussed. Lastly, we discuss the clinical application viewpoint of EVs in blood cancers. Overall, blood cancers apply a ‘vesicular intelligence’ strategy to spread signals over their microenvironment, promoting the development and/or maintenance of the malignant clone.

Single-dose MGTA-145/plerixafor leads to efficient mobilization and in vivo transduction of HSCs with thalassemia correction in mice

We have developed an in vivo hemopoietic stem cell (HSC) gene therapy approach without the need for myelosuppressive conditioning and autologous HSC transplantation. It involves HSC mobilization and IV injection of a helper-dependent adenovirus HDAd5/35++ vector system. The current mobilization regimen consists of granulocyte colony-stimulating factor (G-CSF) injections over a 4-day period, followed by the administration of plerixafor/AMD3100. We tested a simpler, 2-hour, G-CSF–free mobilization regimen using truncated GRO-β (MGTA-145; a CXCR2 agonist) and plerixafor in the context of in vivo HSC transduction in mice. The MGTA-145+plerixafor combination resulted in robust mobilization of HSCs. Importantly, compared with G-CSF+plerixafor, MGTA-145+plerixafor led to significantly less leukocytosis and no elevation of serum interleukin-6 levels and was thus likely to be less toxic. With both mobilization regimens, after in vivo selection with O6-benzylguanine (O6BG)/BCNU, stable GFP marking was achieved in >90% of peripheral blood mononuclear cells. Genome-wide analysis showed random, multiclonal vector integration. In vivo HSC transduction after mobilization with MGTA-145+plerixafor in a mouse model for thalassemia resulted in >95% human γ-globin+ erythrocytes at a level of 36% of mouse β-globin. Phenotypic analyses showed a complete correction of thalassemia. The γ-globin marking percentage and level were maintained in secondary recipients, further demonstrating that MGTA145+plerixafor mobilizes long-term repopulating HSCs. Our study indicates that brief exposure to MGTA-145+plerixafor may be advantageous as a mobilization regimen for in vivo HSC gene therapy applications across diseases, including thalassemia and sickle cell disease.