Precision Diagnostics in Myeloid Malignancies: Development and Validation of a National Capture-Based Gene Panel.

Gene panel sequencing has become a common diagnostic tool for detecting somatically acquired mutations in myeloid neoplasms. However, many panels have restricted content, provide insufficient sensitivity levels, or lack clinically validated workflows. We here describe the development and validation of the Genomic Medicine Sweden myeloid gene panel (GMS-MGP), a capture-based 191 gene panel including mandatory genes in contemporary guidelines as well as emerging candidates. The GMS-MGP displayed uniform coverage across all targets, including recognized difficult GC-rich areas. The validation of 117 previously described somatic variants showed a 100% concordance with a limit-of-detection of a 0.5% variant allele frequency (VAF), achieved by utilizing error correction and filtering against a panel-of-normals. A national interlaboratory comparison investigating 56 somatic variants demonstrated highly concordant results in both detection rate and reported VAFs. In addition, prospective analysis of 323 patients analyzed with the GMS-MGP as part of standard-of-care identified clinically significant genes as well as recurrent mutations in less well-studied genes. In conclusion, the GMS-MGP workflow supports sensitive detection of all clinically relevant genes, facilitates novel findings, and is, based on the capture-based design, easy to update once new guidelines become available. The GMS-MGP provides an important step toward nationally harmonized precision diagnostics of myeloid malignancies.

T-RHEX-RNAseq - a tagmentation-based, rRNA blocked, random hexamer primed RNAseq method for generating stranded RNAseq libraries directly from very low numbers of lysed cells.

BACKGROUND: RNA sequencing has become the mainstay for studies of gene expression. Still, analysis of rare cells with random hexamer priming - to allow analysis of a broader range of transcripts - remains challenging. RESULTS: We here describe a tagmentation-based, rRNA blocked, random hexamer primed RNAseq approach (T-RHEX-RNAseq) for generating stranded RNAseq libraries from very low numbers of FACS sorted cells without RNA purification steps. CONCLUSION: T-RHEX-RNAseq provides an easy-to-use, time efficient and automation compatible method for generating stranded RNAseq libraries from rare cells.

Coumarin-Palladium(II) Complex Acts as a Potent and Non-Toxic Anticancer Agent against Pancreatic Carcinoma Cells.

Pancreatic carcinoma still represents one of the most lethal malignant diseases in the world although some progress has been made in treating the disease in the past decades. Current multi-agent treatment options have improved the overall survival of patients, however, more effective treatment strategies are still needed. In this paper we have characterized the anticancer potential of coumarin-palladium(II) complex against pancreatic carcinoma cells. Cells viability, colony formation and migratory potential of pancreatic carcinoma cells were assessed in vitro, followed by evaluation of apoptosis induction and in vivo testing on zebrafish. Presented results showed remarkable reduction in pancreatic carcinoma cells growth both in vitro and in vivo, being effective at micromolar concentrations (0.5 µM). Treatments induced apoptosis, increased BAX/BCL-2 ratio and suppressed the expression of SOX9 and SOX18, genes shown to be significantly up-regulated in pancreatic ductal adenocarcinoma. Importantly, treatments of the zebrafish-pancreatic adenocarcinoma xenografts resulted in significant reduction in tumor mass, without provoking any adverse toxic effects including hepatotoxicity. Presented results indicate the great potential of the tested compound and the perspective of its further development towards pancreatic cancer therapy.

Active enhancer and chromatin accessibility landscapes chart the regulatory network of primary multiple myeloma.

Multiple myeloma (MM) is an aggressive cancer that originates from antibody-secreting plasma cells. Although genetically and transcriptionally well characterized, the aberrant gene regulatory networks that underpin this disease remain poorly understood. Here, we mapped regulatory elements, open chromatin, and transcription factor (TF) footprints in primary MM cells. In comparison with normal antibody-secreting cells, MM cells displayed consistent changes in enhancer activity that are connected to superenhancer (SE)-mediated deregulation of TF genes. MM cells also displayed widespread decompaction of heterochromatin that was associated with activation of regulatory elements and in a major subset of patients' deregulation of the cyclic adenosine monophosphate pathway. Finally, building SE-associated TF-based regulatory networks allowed identification of several novel TFs that are central to MM biology. Taken together, these findings significantly add to our understanding of the aberrant gene regulatory network that underpins MM.

Ibrutinib induces rapid down-regulation of inflammatory markers and altered transcription of chronic lymphocytic leukaemia-related genes in blood and lymph nodes.

In chronic lymphocytic leukaemia (CLL) patients, treatment with the Bruton tyrosine kinase inhibitor ibrutinib induces a rapid shift of tumour cells from lymph nodes (LN) to peripheral blood (PB). Here, we characterized in depth the dynamics of ibrutinib-induced inflammatory, transcriptional and cellular changes in different compartments immediately after treatment initiation in seven relapsed/refractory CLL patients. Serial PB and LN samples were taken before start and during the first 29 days of treatment. Changes in plasma inflammation-related biomarkers, CLL cell RNA expression, B-cell activation and migration markers expression, and PB mononuclear cell populations were assessed. A significant reduction of 10 plasma inflammation markers, the majority of which were chemokines and not CLL-derived, was observed within hours, and was paralleled by very early increase of CD19+ circulating cells. At the RNA level, significant and continuous changes in transcription factors and signalling molecules linked to B-cell receptor signalling and CLL biology was observed in both PB and LN CLL cells already after 2 days of treatment. In conclusion, ibrutinib seems to instantly shut off an ongoing inflammatory response and interfere with diverse sensitive pathways in the LN.

The chromatin-remodeling factor CHD4 is required for maintenance of childhood acute myeloid leukemia.

Epigenetic alterations contribute to leukemogenesis in childhood acute myeloid leukemia and therefore are of interest for potential therapeutic strategies. Herein, we performed large-scale ribonucleic acid interference screens using small hairpin ribonucleic acids in acute myeloid leukemia cells and non-transformed bone marrow cells to identify leukemia-specific dependencies. One of the target genes displaying the strongest effects on acute myeloid leukemia cell growth and less pronounced effects on nontransformed bone marrow cells, was the chromatin remodeling factor CHD4 Using ribonucleic acid interference and CRISPR-Cas9 approaches, we showed that CHD4 was essential for cell growth of leukemic cells in vitro and in vivo Loss of function of CHD4 in acute myeloid leukemia cells caused an arrest in the G0 phase of the cell cycle as well as downregulation of MYC and its target genes involved in cell cycle progression. Importantly, we found that inhibition of CHD4 conferred anti-leukemic effects on primary childhood acute myeloid leukemia cells and prevented disease progression in a patient-derived xenograft model. Conversely, CHD4 was not required for growth of normal hematopoietic cells. Taken together, our results identified CHD4 as a potential therapeutic target in childhood acute myeloid leukemia.

Interleukin 17 inhibits myogenic and promotes osteogenic differentiation of C2C12 myoblasts by activating ERK1,2.

The present study evaluated the role of interleukin (IL) 17 in multilineage commitment of C2C12 myoblastic cells and investigated associated signaling pathways. The results concerning the effects on cell function showed that IL-17 inhibits the migration of C2C12 cells, while not affecting their proliferation. The data regarding the influence on differentiation demonstrated that IL-17 inhibits myogenic differentiation of C2C12 cells by down-regulating the myogenin mRNA level, myosin heavy chain expression and myotube formation, but promotes their osteogenic differentiation by up-regulating the Runt-related transcription factor 2 mRNA level, cyclooxygenase-2 expression and alkaline phosphatase activity. IL-17 exerted these effects by activating ERK1,2 mitogen activated protein kinase signaling pathway, which in turn regulated the expression of relevant genes and proteins to inhibit myogenic differentiation and induce osteogenic differentiation. Additional analysis showed that the induction of osteogenic differentiation by IL-17 is independent of BMP signaling. The results obtained demonstrate the potential of IL-17 not only to inhibit the myogenic differentiation of C2C12 myoblasts but also to convert their differentiation pathway into that of osteoblast lineage providing new insight into the capacities of IL-17 to modulate the differentiation commitment.

Whole-genome informed circulating tumor DNA analysis by multiplex digital PCR for disease monitoring in B-cell lymphomas: a proof-of-concept study.

Introduction: Analyzing liquid biopsies for tumor-specific aberrations can facilitate detection of measurable residual disease (MRD) during treatment and at follow-up. In this study, we assessed the clinical potential of using whole-genome sequencing (WGS) of lymphomas at diagnosis to identify patient-specific structural (SVs) and single nucleotide variants (SNVs) to enable longitudinal, multi-targeted droplet digital PCR analysis (ddPCR) of cell-free DNA (cfDNA). Methods: In 9 patients with B-cell lymphoma (diffuse large B-cell lymphoma and follicular lymphoma), comprehensive genomic profiling at diagnosis was performed by 30X WGS of paired tumor and normal specimens. Patient-specific multiplex ddPCR (m-ddPCR) assays were designed for simultaneous detection of multiple SNVs, indels and/or SVs, with a detection sensitivity of 0.0025% for SV assays and 0.02% for SNVs/indel assays. M-ddPCR was applied to analyze cfDNA isolated from serially collected plasma at clinically critical timepoints during primary and/or relapse treatment and at follow-up. Results: A total of 164 SNVs/indels were identified by WGS including 30 variants known to be functionally relevant in lymphoma pathogenesis. The most frequently mutated genes included KMT2D, PIM1, SOCS1 and BCL2. WGS analysis further identified recurrent SVs including t(14;18)(q32;q21) (IGH::BCL2), and t(6;14)(p25;q32) (IGH::IRF4). Plasma analysis at diagnosis showed positive circulating tumor DNA (ctDNA) levels in 88% of patients and the ctDNA burden correlated with baseline clinical parameters (LDH and sedimentation rate, p-value <0.01). While clearance of ctDNA levels after primary treatment cycle 1 was observed in 3/6 patients, all patients analyzed at final evaluation of primary treatment showed negative ctDNA, hence correlating with PET-CT imaging. One patient with positive ctDNA at interim also displayed detectable ctDNA (average variant allele frequency (VAF) 6.9%) in the follow-up plasma sample collected 2 years after final evaluation of primary treatment and 25 weeks before clinical manifestation of relapse. Conclusion: In summary, we demonstrate that multi-targeted cfDNA analysis, using a combination of SNVs/indels and SVs candidates identified by WGS analysis, provides a sensitive tool for MRD monitoring and can detect lymphoma relapse earlier than clinical manifestation.

Monitoring of pediatric patients with malignant hematological diseases after allogeneic HSCT: Serbian experience.

We describe the implementation of short tandem repeats-polymerase chain reaction (STR-PCR) chimerism analyses coupled with reverse transcription PCR detection of recurrent translocations characteristic for childhood leukemia in monitoring of patients after allogeneic hematopoietic stem cell transplantation in Serbia and the first clinical results thereof. Chimerism and minimal residual disease were regularly analyzed from blood and marrow samples of 26 pediatric patients taken after stem cell transplantation with a median follow-up of 17.6 months. Our results demonstrate that STR-based chimerism monitoring is sufficient in establishing the origin of engrafted cells after transplantation and in detecting graft rejection, but more specific and more sensitive method is necessary for identifying patients with threatening leukemia relapse.

Case Report: Whole genome sequencing identifies CCDC88C as a novel JAK2 fusion partner in pediatric T-cell acute lymphoblastic leukemia.

In the present report, we applied whole genome sequencing (WGS) to genetically characterize a case of pediatric T-cell acute lymphoblastic leukemia (ALL) refractory to standard therapy. WGS identified a novel JAK2 fusion, with CCDC88C as a partner. CCDC88C encodes a protein part of the Wnt signaling pathway and has previously been described in hematological malignancies as fusion partner to FLT3 and PDGFRB. The novel CCDC88C::JAK2 fusion gene results in a fusion transcript, predicted to produce a hybrid protein, which retains the kinase domain of JAK2 and is expected to respond to JAK2 inhibitors. This report illustrates the potential of WGS in the diagnostic setting of ALL.

Data-driven support to decision-making in molecular tumour boards for lymphoma: A design science approach.

Background: The increasing amount of molecular data and knowledge about genomic alterations from next-generation sequencing processes together allow for a greater understanding of individual patients, thereby advancing precision medicine. Molecular tumour boards feature multidisciplinary teams of clinical experts who meet to discuss complex individual cancer cases. Preparing the meetings is a manual and time-consuming process. Purpose: To design a clinical decision support system to improve the multimodal data interpretation in molecular tumour board meetings for lymphoma patients at Karolinska University Hospital, Stockholm, Sweden. We investigated user needs and system requirements, explored the employment of artificial intelligence, and evaluated the proposed design with primary stakeholders. Methods: Design science methodology was used to form and evaluate the proposed artefact. Requirements elicitation was done through a scoping review followed by five semi-structured interviews. We used UML Use Case diagrams to model user interaction and UML Activity diagrams to inform the proposed flow of control in the system. Additionally, we modelled the current and future workflow for MTB meetings and its proposed machine learning pipeline. Interactive sessions with end-users validated the initial requirements based on a fictive patient scenario which helped further refine the system. Results: The analysis showed that an interactive secure Web-based information system supporting the preparation of the meeting, multidisciplinary discussions, and clinical decision-making could address the identified requirements. Integrating artificial intelligence via continual learning and multimodal data fusion were identified as crucial elements that could provide accurate diagnosis and treatment recommendations. Impact: Our work is of methodological importance in that using artificial intelligence for molecular tumour boards is novel. We provide a consolidated proof-of-concept system that could support the end-to-end clinical decision-making process and positively and immediately impact patients. Conclusion: Augmenting a digital decision support system for molecular tumour boards with retrospective patient material is promising. This generates realistic and constructive material for human learning, and also digital data for continual learning by data-driven artificial intelligence approaches. The latter makes the future system adaptable to human bias, improving adequacy and decision quality over time and over tasks, while building and maintaining a digital log.

Linked-read whole-genome sequencing resolves common and private structural variants in multiple myeloma.

Multiple myeloma (MM) is an incurable and aggressive plasma cell malignancy characterized by a complex karyotype with multiple structural variants (SVs) and copy-number variations (CNVs). Linked-read whole-genome sequencing (lrWGS) allows for refined detection and reconstruction of SVs by providing long-range genetic information from standard short-read sequencing. This makes lrWGS an attractive solution for capturing the full genomic complexity of MM. Here we show that high-quality lrWGS data can be generated from low numbers of cells subjected to fluorescence-activated cell sorting (FACS) without DNA purification. Using this protocol, we analyzed MM cells after FACS from 37 patients with MM using lrWGS. We found high concordance between lrWGS and fluorescence in situ hybridization (FISH) for the detection of recurrent translocations and CNVs. Outside of the regions investigated by FISH, we identified >150 additional SVs and CNVs across the cohort. Analysis of the lrWGS data allowed for resolution of the structure of diverse SVs affecting the MYC and t(11;14) loci, causing the duplication of genes and gene regulatory elements. In addition, we identified private SVs causing the dysregulation of genes recurrently involved in translocations with the IGH locus and show that these can alter the molecular classification of MM. Overall, we conclude that lrWGS allows for the detection of aberrations critical for MM prognostics and provides a feasible route for providing comprehensive genetics. Implementing lrWGS could provide more accurate clinical prognostics, facilitate genomic medicine initiatives, and greatly improve the stratification of patients included in clinical trials.

FOXO Dictates Initiation of B Cell Development and Myeloid Restriction in Common Lymphoid Progenitors.

The development of B cells relies on an intricate network of transcription factors critical for developmental progression and lineage commitment. In the B cell developmental trajectory, a temporal switch from predominant Foxo3 to Foxo1 expression occurs at the CLP stage. Utilizing VAV-iCre mediated conditional deletion, we found that the loss of FOXO3 impaired B cell development from LMPP down to B cell precursors, while the loss of FOXO1 impaired B cell commitment and resulted in a complete developmental block at the CD25 negative proB cell stage. Strikingly, the combined loss of FOXO1 and FOXO3 resulted in the failure to restrict the myeloid potential of CLPs and the complete loss of the B cell lineage. This is underpinned by the failure to enforce the early B-lineage gene regulatory circuitry upon a predominantly pre-established open chromatin landscape. Altogether, this demonstrates that FOXO3 and FOXO1 cooperatively govern early lineage restriction and initiation of B-lineage commitment in CLPs.

FOXO1 and FOXO3 Cooperatively Regulate Innate Lymphoid Cell Development.

Natural killer (NK) cells play roles in viral clearance and early surveillance against malignant transformation, yet our knowledge of the underlying mechanisms controlling their development and functions remain incomplete. To reveal cell fate-determining pathways in NK cell progenitors (NKP), we utilized an unbiased approach and generated comprehensive gene expression profiles of NK cell progenitors. We found that the NK cell program was gradually established in the CLP to preNKP and preNKP to rNKP transitions. In line with FOXO1 and FOXO3 being co-expressed through the NK developmental trajectory, the loss of both perturbed the establishment of the NK cell program and caused stalling in both NK cell development and maturation. In addition, we found that the combined loss of FOXO1 and FOXO3 caused specific changes to the composition of the non-cytotoxic innate lymphoid cell (ILC) subsets in bone marrow, spleen, and thymus. By combining transcriptome and chromatin profiling, we revealed that FOXO TFs ensure proper NK cell development at various lineage-commitment stages through orchestrating distinct molecular mechanisms. Combined FOXO1 and FOXO3 deficiency in common and innate lymphoid cell progenitors resulted in reduced expression of genes associated with NK cell development including ETS-1 and their downstream target genes. Lastly, we found that FOXO1 and FOXO3 controlled the survival of committed NK cells via gene regulation of IL-15Rß (CD122) on rNKPs and bone marrow NK cells. Overall, we revealed that FOXO1 and FOXO3 function in a coordinated manner to regulate essential developmental genes at multiple stages during murine NK cell and ILC lineage commitment.

IL-17 and FGF signaling involved in mouse mesenchymal stem cell proliferation.

The mouse is a suitable experimental model to study the biology of mesenchymal stem cells (MSCs), as well as to be used in biocompatibility studies and tissue engineering models. However, the isolation and purification of murine MSCs is far more challenging than their counterparts from other species. In this study, we isolated, expanded and characterized mouse MSCs from bone marrow (BM-MSCs). Additionally, we analyzed the effects of two regulatory molecules, interleukin 17 (IL-17) and basic fibroblast growth factor (bFGF), on BM-MSCs growth and elucidated the signaling pathways involved. The results revealed that IL-17 increased the frequency of colony-forming units fibroblast (CFU-F) as well as the BM-MSCs proliferation in a dose-dependent manner, while bFGF supplementation had no significant effect on CFU-F frequency but induced an increase in cell proliferation. Their combined usage did not produce additive effects on BM-MSCs proliferation and even induced reduction in the number of CFU-F. Also, the involvement of both p38 and extracellular signal-regulated kinase (ERK) mitogen-activated protein kinases (MAPKs) signaling in proliferative activity of IL-17 and bFGF on murine BM-MSCs and, moreover, the increased co-activation of a common signaling molecule, p38 MAPK, were demonstrated. Together, the data presented highlighted the role of IL-17 and bFGF in murine BM-MSCs proliferation and pointed to the complexity and specificity of the signaling networks leading to MSCs proliferation in response to different regulatory molecules.

p38 MAPK signaling mediates IL-17-induced nitric oxide synthase expression in bone marrow cells.

The effects of interleukin (IL)-17 on nitric oxide (NO) synthase (NOS) expression, as well as the participation of mitogen-activated protein kinases (MAPKs) in IL-17-mediated effects were examined in murine bone marrow cells. The results demonstrated the ability of IL-17 to upregulate the expression of mRNA for both inducible NOS and constitutive, endothelial NOS isoforms, as well as to enhance the phosphorylation of p38 MAPK. Moreover, both the NOS-inducing effect of IL-17 and the in vitro IL-17-mediated inhibition colony forming unit-erythroid (CFU-E) growth were dependent on p38 MAPK activity. The data demonstrating that the in vivo reducing effect of IL-17 on bone marrow CFU-E was prevented by co-treatment with the NOS inhibitor Nw-nitro-l-arginine methyl ester hydrochloride (L-NAME), implied that this effect is mediated through NOS activation. Besides revealing a link between the IL-17, NO, and haematopoiesis, data presented gave an insight into the mechanisms by which IL-17 exerts its modulatory effects on bone marrow cells.

The Concerted Action of E2-2 and HEB Is Critical for Early Lymphoid Specification.

The apparition of adaptive immunity in Gnathostomata correlates with the expansion of the E-protein family to encompass E2-2, HEB, and E2A. Within the family, E2-2 and HEB are more closely evolutionarily related but their concerted action in hematopoiesis remains to be explored. Here we show that the combined disruption of E2-2 and HEB results in failure to express the early lymphoid program in Common lymphoid precursors (CLPs) and a near complete block in B-cell development. In the thymus, Early T-cell progenitors (ETPs) were reduced and T-cell development perturbed, resulting in reduced CD4 T- and increased γδ T-cell numbers. In contrast, hematopoietic stem cells (HSCs), erythro-myeloid progenitors, and innate immune cells were unaffected showing that E2-2 and HEB are dispensable for the ancestral hematopoietic lineages. Taken together, this E-protein dependence suggests that the appearance of the full Gnathostomata E-protein repertoire was critical to reinforce the gene regulatory circuits that drove the emergence and expansion of the lineages constituting humoral immunity.

The histone chaperone NAP1L3 is required for haematopoietic stem cell maintenance and differentiation.

Nucleosome assembly proteins (NAPs) are histone chaperones with an important role in chromatin structure and epigenetic regulation of gene expression. We find that high gene expression levels of mouse Nap1l3 are restricted to haematopoietic stem cells (HSCs) in mice. Importantly, with shRNA or CRISPR-Cas9 mediated loss of function of mouse Nap1l3 and with overexpression of the gene, the number of colony-forming cells and myeloid progenitor cells in vitro are reduced. This manifests as a striking decrease in the number of HSCs, which reduces their reconstituting activities in vivo. Downregulation of human NAP1L3 in umbilical cord blood (UCB) HSCs impairs the maintenance and proliferation of HSCs both in vitro and in vivo. NAP1L3 downregulation in UCB HSCs causes an arrest in the G0 phase of cell cycle progression and induces gene expression signatures that significantly correlate with downregulation of gene sets involved in cell cycle regulation, including E2F and MYC target genes. Moreover, we demonstrate that HOXA3 and HOXA5 genes are markedly upregulated when NAP1L3 is suppressed in UCB HSCs. Taken together, our findings establish an important role for NAP1L3 in HSC homeostasis and haematopoietic differentiation.

Signaling pathways implicated in hematopoietic progenitor cell proliferation and differentiation.

The objective of this study was to investigate the signal transduction pathways associated with the clonal development of myeloid and erythroid progenitor cells. The contribution of particular signaling molecules of protein tyrosine kinases (PTKs), mitogen-activated protein (MAP) kinase, and PI-3 kinase signaling to the growth of murine bone marrow colony forming unit-granulocyte-macrophage (CFU-GM) and erythroid (burst forming unit-erythroid [BFU-E] and colony forming unit-erythroid [CFU-E]) progenitors was examined in studies performed in the presence or absence of specific signal transduction inhibitors. The results clearly pointed to different signal transducing intermediates that are involved in cell proliferation and differentiation depending on the cell lineage, as well as on the progenitors' maturity. Lineage-specific differences were obtained when chemical inhibitors specific for receptor- or nonreceptor-PTKs, as well as for the main groups of distinctly regulated MAPK cascades, were used because all of these compounds suppressed the growth of erythroid progenitors, with no major effects on myeloid progenitors. At the same time, differential involvement of MEK/extracellular signal-regulated kinase (ERK) MAPK transduction pathway was observed in the proliferation and/or differentiation of early, BFU-E, and late, CFU-E, erythroid progenitor cells. The results also demonstrated that phosphatydylinositol (PI)-3 kinase and nuclear factor kappaB (NF-kappaB) transcriptional factor were required for maintenance of both myeloid and erythroid progenitor cell function. Overall, the data obtained indicated that committed hematopoietic progenitors express a certain level of constitutive signaling activity that participates in the regulation of normal steady-state hematopoiesis and point to the importance of evaluating the impact of signal transduction inhibitors on normal bone marrow when used as potential therapeutic agents.

Hematopoietic changes and altered reactivity to IL-17 in Syphacia obvelata-infected mice.

Pinworm parasites commonly infect laboratory mice with high prevalence even in well-managed animal colonies. Although often considered as irrelevant, these parasites if undetected may significantly interfere with the experimental settings and alter the interpretation of final results. There are a few reports documenting the effects of pinworms on research and the effects of pinworms on the host hematopoiesis have not yet been investigated. In this study we examined the changes within various hematopoietic cell lineages in the bone marrow, spleen, peripheral blood and peritoneal space during naturally acquired Syphacia obvelata infection in inbred CBA mice. The data obtained showed significant hematopoietic alterations, characterized by increased myelopoiesis and erythropoiesis in S. obvelata-infected animals. In order to additionally evaluate if this pinworm infection modifies hematopoietic cells' reactivity, we examined the effect of murine interleukin-17, T cell-derived cytokine implicated in the regulation of hematopoiesis and inflammation, on the growth of bone marrow progenitor cells and demonstrated that bone marrow myeloid and erythroid progenitors from S. obvelata-infected mice displayed altered sensitivity to IL-17 when compared to non-infected controls. Taken together the alterations presented pointed out that this rodent pinworm is an important environmental agent that might significantly modify the hosts' hematopoietic response, and therefore interfere with the experimental settings and alter the interpretation of the final results. However, the results obtained also contributed new data concerning the activity of IL-17 on bone marrow hematopoietic cells, supporting our previous reports that depending on physiological/pathological status of the organism IL-17 exerts differential effects on the growth of progenitor cells.