Community-acquired infections and their association with myeloid malignancies

Quantitative interpretation of bone marrow biopsies in MPN-What's the point in a molecular age?

The diagnosis of myeloproliferative neoplasms (MPN) requires the integration of clinical, morphological, genetic and immunophenotypic findings. Recently, there has been a transformation in our understanding of the cellular and molecular mechanisms underlying disease initiation and progression in MPN. This has been accompanied by the widespread application of high-resolution quantitative molecular techniques. By contrast, microscopic interpretation of bone marrow biopsies by haematologists/haematopathologists remains subjective and qualitative. However, advances in tissue image analysis and artificial intelligence (AI) promise to transform haematopathology. Pioneering studies in bone marrow image analysis offer to refine our understanding of the boundaries between reactive samples and MPN subtypes and better capture the morphological correlates of high-risk disease. They also demonstrate potential to improve the evaluation of current and novel therapeutics for MPN and other blood cancers. With increased therapeutic targeting of diverse molecular, cellular and extra-cellular components of the marrow, these approaches can address the unmet need for improved objective and quantitative measures of disease modification in the context of clinical trials. This review focuses on the state-of-the-art in image analysis/AI of bone marrow tissue, with an emphasis on its potential to complement and inform future clinical studies and research in MPN.

Bloodstream Infection and Colorectal Cancer Risk in Queensland Australia, 2000-2019

BACKGROUND

Bloodstream infections may occur as a complication of colorectal cancer or be a marker for its occult presence. The objectives of this study were to quantify the overall and etiology-specific risks for incident colorectal cancer-associated bloodstream infection.

METHODS

Population-based surveillance for community-onset bloodstream infection was conducted among adults aged 20 years and older in Queensland, Australia between 2000 and 2019. Statewide databases were used to identify patients with incident colorectal cancer and collect clinical and outcome information.

RESULTS

After exclusion of 1794 patients with prior colorectal cancer, a cohort of 84,754 patients was assembled, of which 1030 had colorectal cancer-associated bloodstream infection and 83,724 had no colorectal cancer. Bloodstream infection was associated with a 16-fold annualized increased risk for diagnosis of colorectal cancer (incidence rate ratio 16.1; 95% confidence interval [CI], 15.1-17.1) in the adult population. Patients who had colorectal cancer-associated bloodstream infection were more likely to be older and male, have hospital-onset and polymicrobial infections, and have fewer non-cancer-related comorbidities. The organisms associated with highest risk for colorectal cancer included Clostridium species (relative risk [RR] 6.1; 95% CI, 4.7-7.9); especially C. septicum (RR 25.0; 95% CI, 16.9-35.7), Bacteroides species (RR 4.7; 95% CI, 3.8-5.8); especially B. ovatus (RR 11.8; 95% CI, 2.4-34.5), Gemella species (RR 6.5; 95% CI, 3.0-12.5), Streptococcus bovis group (RR 4.4; 95% CI, 2.7-6.8); especially S. infantarius subsp. coli (RR 10.6; 95% CI, 2.9-27.3), Streptococcus anginosus group (RR 1.9; 95% CI, 1.3-2.7), and Enterococcus species (RR 1.4; 95% CI, 1.1-1.8).

CONCLUSION

Although much attention has been afforded to S. bovis group over the past decades, there are many other isolates associated with higher risk for colorectal cancer-associated bloodstream infections.

Myeloproliferative neoplasms - blurring the lines between cancer and chronic inflammatory disorder

Myeloproliferative Neoplasm (MPN) is a group of chronic blood cancers that arise from a hematopoietic stem cell (HSC) clone with somatic mutations causing constitutive activation of myeloid cytokine receptor signaling. In addition to elevated blood cell counts, MPN typically presents with increased inflammatory signaling and inflammation symptoms. Therefore, while being a clonally derived neoplasm, MPN has much in common with chronic non-cancerous inflammatory conditions, such as rheumatoid arthritis, lupus, and many more. MPN and chronic inflammatory disease (CID) share similar chronicity, symptoms, dependency on the immune system, environmental triggers, and treatments. Overall, we will highlight the similarities between an MPN and CID. We highlight that while MPN is classified as a cancer, its behavior is more aligned to that of a chronic inflammatory disease. We propose that MPN should inhabit a fluid/spectrum between auto-inflammatory disease and cancer.

Mutations, inflammation and phenotype of myeloproliferative neoplasms

Knowledge on the myeloproliferative neoplasms (MPNs) - polycythemia vera (PV), essential thrombocythemia (ET), primary myelofibrosis (PMF) - has accumulated since the discovery of the JAK/STAT-activating mutations associated with MPNs: JAK2V617F, observed in PV, ET and PMF; and the MPL and CALR mutations, found in ET and PMF. The intriguing lack of disease specificity of these mutations, and of the chronic inflammation associated with MPNs, triggered a quest for finding what precisely determines that MPN patients develop a PV, ET or PMF phenoptype. The mechanisms of action of MPN-driving mutations, and concomitant mutations (ASXL1, DNMT3A, TET2, others), have been extensively studied, as well as the role played by these mutations in inflammation, and several pathogenic models have been proposed. In parallel, different types of drugs have been tested in MPNs (JAK inhibitors, interferons, hydroxyurea, anagrelide, azacytidine, combinations of those), some acting on both JAK2 and inflammation. Yet MPNs remain incurable diseases. This review aims to present current, detailed knowledge on the pathogenic mechanisms specifically associated with PV, ET or PMF that may pave the way for the development of novel, curative therapies.

Supportive Care for Patients With Myelodysplastic Syndromes

ABSTRACT

Myelodysplastic syndromes are a heterogeneous group of bone marrow disorders characterized by ineffective hematopoiesis, progressive cytopenias, and an innate capability of progressing to acute myeloid leukemia. The most common causes of morbidity and mortality are complications related to myelodysplastic syndromes rather than progression to acute myeloid leukemia. Although supportive care measures are applicable to all patients with myelodysplastic syndromes, they are especially essential in patients with lower-risk disease who have a better prognosis compared with their higher-risk counterparts and require longer-term monitoring of disease and treatment-related complications. In this review, we will address the most frequent complications and supportive care interventions used in patients with myelodysplastic syndromes, including transfusion support, management of iron overload, antimicrobial prophylaxis, important considerations in the era of COVID-19 (coronavirus infectious disease 2019), role of routine immunizations, and palliative care in the myelodysplastic syndrome population.

Inflammation and cancer: paradoxical roles in tumorigenesis and implications in immunotherapies

Chronic inflammation caused by persistent infections and metabolic disorders is thought to contribute to the increased cancer risk and the accelerated cancer progression. Oppositely, acute inflammation induced by bacteria-based vaccines or that is occurring after cancer selectively inhibits cancer progression and metastasis. However, the interaction between inflammation and cancer may be more complex than the current explanations for the relationship between chronic and acute inflammation and cancer. In this review, we described the impact of inflammation on cancer on the basis of three perspectives, including inflammation with different durations (chronic and acute inflammation), different scopes (systemic and local inflammation) and different occurrence sequences (inflammation occurring after and before cancer). In addition, we also introduced bacteria/virus-based cancer immunotherapies. We perceive that inflammation may be a double-edged sword with cancer-promoting and cancer-suppressing functions in certain cases. We expect to further improve the understanding of the relationship between inflammation and cancer and provide a theoretical basis for further research on their complex interaction.

Inflammation in Myeloid Malignancies: From Bench to Bedside

Myeloid malignancies, stemming from a somatically mutated hematopoietic clone, can cause a wide variety of clinical consequences, including pancytopenia in myelodysplastic syndrome, overproduction of three myeloid lineages in myeloproliferative neoplasm, and the rapid growth of immature hematopoietic cells in acute myeloid leukemia (AML). It is becoming clear that inflammation is a hallmark feature of clonal myeloid conditions, ranging from clonal hematopoiesis of indeterminate potential to AML. Fundamental findings from laboratory research on inflammation in myeloid malignancies has potential implications for diagnosis, prognostication, and treatment in these diseases. In this review, we highlighted some pertinent basic science findings regarding the role of inflammation in myeloid malignancies and speculated how these findings could impact the clinical care of patients.

The shape of low-concentration dose-response functions for benzene: implications for human health risk assessment

Are dose-response relationships for benzene and health effects such as myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) supra-linear, with disproportionately high risks at low concentrations, e.g. below 1 ppm? To investigate this hypothesis, we apply recent mode of action (MoA) and mechanistic information and modern data science techniques to quantify air benzene-urinary metabolite relationships in a previously studied data set for Tianjin, China factory workers. We find that physiologically based pharmacokinetics (PBPK) models and data for Tianjin workers show approximately linear production of benzene metabolites for air benzene (AB) concentrations below about 15 ppm, with modest sublinearity at low concentrations (e.g. below 5 ppm). Analysis of the Tianjin worker data using partial dependence plots reveals that production of metabolites increases disproportionately with increases in air benzene (AB) concentrations above 10 ppm, exhibiting steep sublinearity (J shape) before becoming saturated. As a consequence, estimated cumulative exposure is not an adequate basis for predicting risk. Risk assessments must consider the variability of exposure concentrations around estimated exposure concentrations to avoid over-estimating risks at low concentrations. The same average concentration for a specified duration is disproportionately risky if it has higher variance. Conversely, if chronic inflammation via activation of inflammasomes is a critical event for induction of MDS and other health effects, then sufficiently low concentrations of benzene are predicted not to cause increased risks of inflammasome-mediated diseases, no matter how long the duration of exposure. Thus, we find no evidence that the dose-response relationship is supra-linear at low doses; instead sublinear or zero excess risk at low concentrations is more consistent with the data. A combination of physiologically based pharmacokinetic (PBPK) modeling, Bayesian network (BN) analysis and inference, and partial dependence plots appears a promising and practical approach for applying current data science methods to advance benzene risk assessment.

Sepsis and Cancer: An Interplay of Friends and Foes

Sepsis and cancer share a number of pathophysiological features, and both result from the inability of the host's immune system to cope with the initial insult (tissue invasion by pathogens and malignant cell transformation, respectively). The common coexistence of both disorders and the profound related alterations in immune homeostasis raise the question of their mutual impact on each other's course. This translational review aims to discuss the interactions between cancer and sepsis supported by clinical data and the translation to experimental models. The dramatic improvement in cancer has come at a cost of increased risks of life-threatening infectious complications. Investigating the long-term outcomes of sepsis survivors has revealed an unexpected susceptibility to cancer long after discharge from the ICU. Nonetheless, it is noteworthy that an acute septic episode may harbor antitumoral properties under particular circumstances. Relevant double-hit animal models have provided clues to whether and how bacterial sepsis may impact malignant tumor growth. In sequential sepsis-then-cancer models, postseptic mice exhibited accelerated tumor growth. When using reverse cancer-then-sepsis models, bacterial sepsis applied to mice with cancer conversely resulted in inhibition or even regression of tumor growth. Experimental models thus highlight dual effects of sepsis on tumor growth, mostly depending on the sequence of insults, and allow deciphering the immune mechanisms and their relation with microorganisms.

The Microenvironment in Myeloproliferative Neoplasms

Chronic inflammation is a hallmark of myeloproliferative neoplasms (MPNs), with elevated levels of proinflammatory cytokines being commonly found in all 3 subtypes. Systemic inflammation is responsible for the constitutional symptoms, thrombosis risk, premature atherosclerosis, and disease evolution in MPN. Although the neoplastic clone and their differentiated progeny drive the inflammatory process, they also induce ancillary cytokine secretion from nonmalignant cells. Here, the authors describe the inflammatory milieu in MPN based on soluble factors and cellular mediators. They also discuss the prognostic value of cytokine measurements in patients with MPN and potential therapeutic strategies that target the cellular players in inflammation.

Casting a wider protective net: Anti-infective vaccine strategies for patients with hematologic malignancy and blood and marrow transplantation

Patients who have hematologic malignancies are at high risk for infections but vaccinations may be effective prophylaxis. The increased infection risk derives from immune defects secondary to malignancy, the classic example being CLL, and chemotherapies and immunotherapy used to treat the malignancies. Therapy of hematologic malignancies is being revolutionized by introduction of novel targeted agents and immunomodulatory medications, improving the survival of patients. At the same time those agents uniquely change the infection risk and response to immunizations. This review will summarize current vaccine recommendations for patients with hematologic malignancies including patients who undergo hematopoietic cell transplant.

Impact of Host, Lifestyle and Environmental Factors in the Pathogenesis of MPN

Philadelphia-negative myeloproliferative neoplasms (MPNs) occur when there is over-production of myeloid cells stemming from hematopoietic stem cells with constitutive activation of JAK/STAT signaling, with JAK2V617F being the most commonly occurring somatic driver mutation. Chronic inflammation is a hallmark feature of MPNs and it is now evident that inflammation is not only a symptom of MPN but can also provoke development and precipitate progression of disease. Herein we have considered major MPN driver mutation independent host, lifestyle, and environmental factors in the pathogenesis of MPN based upon epidemiological and experimental data. In addition to the traditional risk factors such as advanced age, there is evidence to indicate that inflammatory stimuli such as smoking can promote and drive MPN clone emergence and expansion. Diet induced inflammation could also play a role in MPN clonal expansion. Recognition of factors associated with MPN development support lifestyle modifications as an emerging therapeutic tool to restrain inflammation and diminish MPN progression.

Sepsis inhibits tumor growth in mice with cancer through Toll-like receptor 4-associated enhanced Natural Killer cell activity

Sepsis-induced immune dysfunctions are likely to impact on malignant tumor growth. Sequential sepsis-then-cancer models of tumor transplantation in mice recovering from sepsis have shown that the post-septic immunosuppressive environment was able to promote tumor growth. We herein addressed the impact of sepsis on pre-established malignancy in a reverse cancer-then sepsis experimental model. Mice previously inoculated with MCA205 fibrosarcoma cells were subjected to septic challenges by polymicrobial peritonitis induced by cecal ligation and puncture or endotoxinic shock. The anti-tumoral immune response was assessed through the distribution of tumor-infiltrating immune cells, as well as the functions of cytotoxic cells. As compared to sham surgery, polymicrobial sepsis dampened malignant tumor growth in wild-type (WT) mice, but neither in Toll-like receptor 4 (Tlr4)^-/- nor in Myd88^-/- mice. Similar tumor growth inhibition was observed following a LPS challenge in WT mice, suggesting a regulatory role of Tlr4 in this setting. The low expression of MHC class 1 onto MCA205 cells suggested the involvement of Natural Killer (NK) cells in sepsis-induced tumor inhibition. Septic insults applied to mice with cancer promoted the main anti-tumoral NK functions of IFNγ production and degranulation. The anti-tumoral properties of NK cells obtained from septic mice were exacerbated when cultured with MHC1^low MCA205 or YAC-1 cells. These results suggest that sepsis may harbor dual effects on tumor growth depending on the sequential experimental model. When applied in mice with cancer, sepsis prevents tumor growth in a Tlr4-dependent manner by enhancing the anti-tumoral functions of NK cells.

Serum Vitamin D Levels in Patients with Myelodysplastic Syndromes: A Retrospective Single-Center Analysis

BACKGROUND/AIMS

There is growing evidence supporting the role of innate immune deregulation and inflammation in the pathogenesis of myelodysplastic syndromes (MDS). Vitamin D (VD) is known to be involved in various immune and epigenetic processes. This analysis aimed to evaluate serum VD levels in patients with MDS and to analyze associations between serum VD levels and disease characteristics.

METHODS

Serum levels of 25-hydroxyvitamin D3 (25(OH)-D3), the major form of VD in human serum, were measured by chemiluminescence immunoassay in 62 unselected patients with MDS. Associations between serum 25(OH)-D3 levels and disease characteristics were analyzed using Kendall's tau and two-sided p values.

RESULTS

The median serum 25(OH)-D3 level was markedly reduced (17.5 ng/mL). Patients with lower-risk disease features had lower serum 25(OH)-D3 levels than patients with higher-risk disease features with regard to medullary blast counts (16 vs. 31 ng/mL, p < 0.001), the revised international prognostic scoring system (13 vs. 30.5 ng/mL, p = 0.001), and blood counts.

CONCLUSIONS

We show that patients with lower-risk disease characteristics exhibit lower serum VD levels than patients with higher-risk disease characteristics. Whether these findings might reflect innate immune deregulation has to be investigated in further studies.

Vaccination of patients with haematological malignancies who did not have transplantations: guidelines from the 2017 European Conference on Infections in Leukaemia (ECIL 7)

Patients with haematological malignancies are at high risk of infection because of various mechanisms of humoral and cell-mediated immune deficiencies, which mainly depend on underlying disease and specific therapies. Some of these infections are vaccine preventable. However, these malignancies are different from each other, and the treatment approaches are diverse and rapidly evolving, so it is difficult to have a common programme for vaccination in a haematology ward. Additionally, because of insufficient training about the topic, vaccination is an area often neglected by haematologists, and influenced by cultural differences, even among health-care workers, in compliance to vaccines. Several issues are encountered when addressing vaccination in haematology: the small size of the cohorts that makes it difficult to show the clinical benefits of vaccination, the subsequent need to rely on biological parameters, their clinical pertinence not being established in immunocompromised patients, scarcity of clarity on the optimal timing of vaccination in complex treatment schedules, and the scarcity of data on long-term protection in patients receiving treatments. Moreover, the risk of vaccine-induced disease with live-attenuated vaccines strongly limits their use. Here we summarise guidelines for patients without transplantations, and address the issue by the haematological group-myeloid and lymphoid-of diseases, with a special consideration for children with acute leukaemia.

Burden of community-acquired pneumonia, predisposing factors and health-care related costs in patients with cancer

BACKGROUND

Data on the burden of community-acquired pneumonia (CAP) and health-care related costs in patients with cancer is scarce. We aimed to estimate the CAP incidence rate, mortality, and healthcare-related costs of CAP patients with different cancer subtypes in Germany.

METHODS

We used German health claims data of a representative sample of 4 million subjects to conduct cohort studies in patients with a new diagnosis of lung, hematological, breast, gastro-intestinal tract and renal/urinary-tract cancer and a comparator cohort without cancer between 2011 and 2015. CAP cases were identified in both the hospital and ambulatory care setting. Crude and age- and sex-standardized incidence rates (sIR) of CAP and mortality after CAP were calculated. To compare the health care-related costs of cancer patients with and without a diagnosis of CAP, a propensity-score (PS) matched control group was created.

RESULTS

The study population comprised of 89,007 patients with cancer. In lung cancer patients, the sIR was increased 21-fold compared to the control cohort. For the other cancer subtypes, the sIR was increased 4.3-fold (hematological malignancies) to 1.7-fold (breast cancer) compared to the control cohort. The 30-day mortality in CAP cases was highest in lung cancer patients with 20.0% and ranged from 7.2 to 18.5% in CAP cases with other cancer subtypes. The highest costs were observed in CAP cases with hematological malignancies with 28,969 € (SD 37,142 €) and the lowest in patients with renal/urinary tract cancer with 17,432 € (SD 19,579 €). The absolute difference in the mean overall costs between CAP cases and controls without CAP ranged from 4,111€ to 9,826€, depending on the cancer type. CAP-related costs were predominantly triggered by substantially elevated hospital costs in CAP cases.

CONCLUSIONS

The incidence rate of CAP and related mortality is high in patients with cancer with strong variations by cancer subtype. Furthermore, CAP in cancer patients is associated with substantial direct excess costs.

Increased Risk of Infectious Complications in Older Patients With Indolent Non-Hodgkin Lymphoma Exposed to Bendamustine

Background

Bendamustine is a potent chemotherapy agent increasingly used to treat indolent non-Hodgkin lymphoma (iNHL). While effective, it causes significant T-cell lymphopenia, which may increase risk of infection. We examined infectious complications associated with bendamustine-containing regimens among older patients with iNHL.

Methods

For this Surveillance, Epidemiology, and End Results (SEER)-Medicare cohort study, we identified 9395 patients with iNHL (follicular, marginal zone, Waldenström macroglobulinemia) treated with chemotherapy from 2006 to 2013. Thirteen percent received bendamustine-containing regimens. We compared baseline characteristics and infection incidence rates between patients treated with and without bendamustine. We conducted multivariate Cox proportional hazards regression (adjusting for demographics, comorbidities, disease and treatment characteristics, risk factors for infection, and antimicrobial prophylaxis) to determine infectious risks associated with bendamustine.

Results

Bendamustine was associated with an increased risk of both common infections such as bacterial pneumonia (hazard ratio [HR], 1.50 [95% confidence interval {CI}, 1.21-4.85]) and opportunistic infections such as cytomegalovirus (HR, 3.98 [95% CI, 1.40-11.26]), varicella zoster virus (HR, 1.49 [95% CI, 1.18-1.89]), histoplasmosis (HR, 3.55 [95% CI, 1.10-11.42]), and Pneumocystis jirovecii pneumonia (when administered as third-line therapy: HR, 3.32 [95% CI, 1.00-11.11]). Risk of infections was more prominent in patients receiving bendamustine as part of later (third-line and above) regimens, and independently associated with well-established factors such as neutropenia and corticosteroid exposure.

Conclusions

Bendamustine is associated with an increased risk of common and opportunistic infections in patients with iNHL. Further prospective investigation into the potential role of antimicrobial prophylaxis is needed in these patients.

NSAID consumption and risk of acute myeloid leukemia: a national population-based case-control study

Background

Most cases of acute leukemia arise without identifiable risk factors. Studies investigating the impact of autoimmune diseases and infections on leukemogenesis have revealed conflicting results. If inflammation increases the risk of acute myeloid leukemia (AML), nonsteroidal anti-inflammatory drug (NSAID) use may decrease the risk of leukemia.

Methods

We conducted a case-control study of 3,053 patients with AML diagnosed between 2000 and 2013, who were registered in the Danish National Acute Leukemia Registry, and 30,530 population controls matched on sex and age. We identified prescriptions through the Danish National Health Service Prescription Database. We used conditional logistic regression analysis to compute ORs associating AML with NSAID use overall, in patients with inflammatory diseases, and for specific AML subtypes (de novo AML, AML related to previous hematological disease, ie, secondary AML [sAML], or therapy-related AML [tAML; exposed to previous cytotoxic therapy]).

Results

Overall, NSAID use was not associated with a lower risk of AML (OR 1.1, 95% CI=1.0-1.2), de novo AML (OR 1.0, 95% CI=0.9-1.1), and sAML/tAML (OR 1.3, 95% CI=1.1-1.5). In addition, in patients with known inflammatory diseases, NSAIDs did not affect AML risk (OR 0.9, 95% CI=0.5-1.6). Number of prescriptions, type of NSAID, age, or sex did not influence the results.

Conclusion

In line with our recent findings that showed no association between autoimmune diseases and infections and de novo AML, NSAID use was not found to reduce the risk of AML.

Autoimmune diseases, infections, use of antibiotics and the risk of acute myeloid leukaemia: a national population-based case-control study

Previous studies reported increased risk of acute myeloid leukaemia (AML) in individuals with inflammatory conditions. However, it is unclear whether this association is explained by preceding cytotoxic therapy or haematological diseases. We conducted a nationwide case-control study that included 3053 AML patients, diagnosed in Denmark between 2000 and 2013, and 30 530 sex- and age-matched population controls. We retrieved information on autoimmune disease, infections, and use of antibiotics and computed odds ratios for AML (conditional logistic regression). Results were stratified by AML type, sex, and age. Autoimmune diseases were associated with an overall increased risk of AML {odds ratio [OR] 1·3 [95% confidence interval (CI) = 1·1-1·5]}. However, the risk was confined to patients with previous haematological disease or cytotoxic therapy exposure [secondary/therapy-related AML (sAML/tAML0) OR 2·0 (95% CI = 1·6-2·6)] and not de novo AML [OR 1·1 (95% CI = 0·9-1·3)]. Similarly, any prior infection requiring hospitalization was associated with a higher risk of AML [OR 1·3 (95% CI = 1·1-1·4)]. Again, this association was evident for sAML/tAML [OR 1·8 (95% CI = 1·5-2·2)], and not de novo AML [OR 1·1 (95% CI = 1·0-1·2)]. In conclusion, autoimmune diseases and infections were associated with an increased AML risk only in subjects with prior haematological disease and/or cytotoxic treatment. These observations suggest, that inflammation plays - if any - a minor role for the development of de novo AML.

Mathematical modelling as a proof of concept for MPNs as a human inflammation model for cancer development

The chronic Philadelphia-negative myeloproliferative neoplasms (MPNs) are acquired stem cell neoplasms which ultimately may transform to acute myelogenous leukemia. Most recently, chronic inflammation has been described as an important factor for the development and progression of MPNs in the biological continuum from early cancer stage to the advanced myelofibrosis stage, the MPNs being described as "A Human Inflammation Model for Cancer Development". This novel concept has been built upon clinical, experimental, genomic, immunological and not least epidemiological studies. Only a few studies have described the development of MPNs by mathematical models, and none have addressed the role of inflammation for clonal evolution and disease progression. Herein, we aim at using mathematical modelling to substantiate the concept of chronic inflammation as an important trigger and driver of MPNs.The basics of the model describe the proliferation from stem cells to mature cells including mutations of healthy stem cells to become malignant stem cells. We include a simple inflammatory coupling coping with cell death and affecting the basic model beneath. First, we describe the system without feedbacks or regulatory interactions. Next, we introduce inflammatory feedback into the system. Finally, we include other feedbacks and regulatory interactions forming the inflammatory-MPN model. Using mathematical modeling, we add further proof to the concept that chronic inflammation may be both a trigger of clonal evolution and an important driving force for MPN disease progression. Our findings support intervention at the earliest stage of cancer development to target the malignant clone and dampen concomitant inflammation.

Severe atypical herpes zoster as an initial symptom of fatal myelodysplastic syndrome with refractory anemia and blast excess (RAEB II)

Herpes zoster is a common disease caused due to varicella zoster virus (VZV) infection with increasing incidence by age. If the patient has a severe, extended, or treatment-recalcitrant course of herpes zoster, this must be a red flag to search for underlying pathologies. Here, we report about a 64-year-old male patient with diabetes, who came to our emergency department because of general malaise, fever, chills, and a pronounced nuchal and facial swelling on the left side. Based on herpetiform-grouped vesicles and yellowish crusts, an impetiginized facial herpes zoster was diagnosed, and combined antiviral and antibiotic treatment was initiated. He was HIV negative. Despite intensified treatment, his situation worsened. We observed blasts in peripheral blood, but bone marrow biopsy was initially denied. Some days later after deterioration of his disease, he accepted further diagnostics. A myelodysplastic syndrome with blast excess (refractory anemia and blast excess II, RAEB II) could be confirmed. The following translocations were detected: t(2;12)(p13; q13) and t(6;9)(p22;q34). REAB II has an unfortunate prognosis. Cytoreductive treatment was initiated by the hematooncologist. Unfortunately, the patient deceased due to septic shock.

IL-33 signaling contributes to the pathogenesis of myeloproliferative neoplasms

Myeloproliferative neoplasms (MPNs) are characterized by the clonal expansion of one or more myeloid cell lineage. In most cases, proliferation of the malignant clone is ascribed to defined genetic alterations. MPNs are also associated with aberrant expression and activity of multiple cytokines; however, the mechanisms by which these cytokines contribute to disease pathogenesis are poorly understood. Here, we reveal a non-redundant role for steady-state IL-33 in supporting dysregulated myelopoiesis in a murine model of MPN. Genetic ablation of the IL-33 signaling pathway was sufficient and necessary to restore normal hematopoiesis and abrogate MPN-like disease in animals lacking the inositol phosphatase SHIP. Stromal cell-derived IL-33 stimulated the secretion of cytokines and growth factors by myeloid and non-hematopoietic cells of the BM, resulting in myeloproliferation in SHIP-deficient animals. Additionally, in the transgenic JAK2V617F model, the onset of MPN was delayed in animals lacking IL-33 in radio-resistant cells. In human BM, we detected increased numbers of IL-33-expressing cells, specifically in biopsies from MPN patients. Exogenous IL-33 promoted cytokine production and colony formation by primary CD34+ MPN stem/progenitor cells from patients. Moreover, IL-33 improved the survival of JAK2V617F-positive cell lines. Together, these data indicate a central role for IL-33 signaling in the pathogenesis of MPNs.

Deregulation of innate immune and inflammatory signaling in myelodysplastic syndromes

Myelodysplastic syndromes (MDSs) are a group of heterogeneous clonal hematologic malignancies that are characterized by defective bone marrow (BM) hematopoiesis and by the occurrence of intramedullary apoptosis. During the past decade, the identification of key genetic and epigenetic alterations in patients has improved our understanding of the pathophysiology of this disease. However, the specific molecular mechanisms leading to the pathogenesis of MDS have largely remained obscure. Recently, essential evidence supporting the direct role of innate immune abnormalities in MDS has been obtained, including the identification of multiple key regulators that are overexpressed or constitutively activated in BM hematopoietic stem and progenitor cells. Mounting experimental results indicate that the dysregulation of these molecules leads to abnormal hematopoiesis, unbalanced cell death and proliferation in patients' BM, and has an important role in the pathogenesis of MDS. Furthermore, there is compelling evidence that the deregulation of innate immune and inflammatory signaling also affects other cells from the immune system and the BM microenvironment, which establish aberrant associations with hematopoietic precursors and contribute to the MDS phenotype. Therefore, the deregulation of innate immune and inflammatory signaling should be considered as one of the driving forces in the pathogenesis of MDS. In this article, we review and update the advances in this field, summarizing the results from the most recent studies and discussing their clinical implications.