Amyloid Accelerator Polyphosphate Implicated as the Mystery Density in α-Synuclein Fibrils.

Aberrant aggregation of α-Synuclein is the pathological hallmark of a set of neurodegenerative diseases termed synucleinopathies. Recent advances in cryo-electron microscopy have led to the structural determination of the first synucleinopathy-derived α-Synuclein fibrils, which contain a non-proteinaceous, "mystery density" at the core of the protofilaments, hypothesized to be highly negatively charged. Guided by previous studies that demonstrated that polyphosphate (polyP), a universally conserved polyanion, significantly accelerates α-Synuclein fibril formation, we conducted blind docking and molecular dynamics simulation experiments to model the polyP binding site in α-Synuclein fibrils. Here we demonstrate that our models uniformly place polyP into the lysine-rich pocket, which coordinates the mystery density in patient-derived fibrils. Subsequent in vitro studies and experiments in cells revealed that substitution of the two critical lysine residues K43 and K45 leads to a loss of all previously reported effects of polyP binding on α-Synuclein, including stimulation of fibril formation, change in filament conformation and stability as well as alleviation of cytotoxicity. In summary, our study demonstrates that polyP fits the unknown electron density present in in vivo α-Synuclein fibrils and suggests that polyP exerts its functions by neutralizing charge repulsion between neighboring lysine residues.

Cryo-EM Structures Reveal Tau Filaments from Down Syndrome Adopt Alzheimer's Disease Fold.

Down Syndrome (DS) is a common genetic condition caused by trisomy of chromosome 21. Among the complex clinical features including musculoskeletal, neurological and cardiovascular disabilities, individuals with DS develop progressive dementia and early onset Alzheimer's Disease (AD). This is attributed to the increased gene dosage of amyloid precursor protein (APP), the formation of self-propagating Aß and tau prion conformers, and the deposition of neurotoxic Aß plaques and tau neurofibrillary tangles. Tau amyloid fibrils have previously been established to adopt many distinct conformations across different neurodegenerative conditions. Here we characterized 4 DS cases spanning 36 to 63 years in age by spectral confocal imaging with conformation-specific dyes and cryo-electron microscopy (cryo-EM) to determine structures of isolated tau fibrils. High-resolution structures reveal paired helical (PHF) and straight filament (SF) conformations of tau that are identical to those determined from AD. The PHFs and SFs are made of two C-shaped protofilaments with a cross-ß/ß-helix motif. Similar to AD, most filaments adopt the PHF form, while a minority (~20%) form SFs. For the youngest individual with no documented dementia samples exhibited sparse tau deposits. To isolate tau for cryo-EM from this challenging sample we employed a novel "affinity grid" method involving a graphene-oxide surface derivatized with anti-tau antibodies. This improved isolation and revealed primarily tau PHFs and a minor population of SSPE type II-like filaments are present at this early age. These findings expand the similarities between AD and DS to the molecular level providing insight into their related pathologies and the potential for targeting common tau filament folds by small molecule therapeutics and diagnostics.

Prognostic factors in 448 newly diagnosed multiple myeloma receiving bortezomib-based induction: impact of ASCT, transplant refusal and high-risk MM.

In Hong Kong, newly diagnosed multiple myeloma (NDMM) receives bortezomib-based triplet induction. Upfront autologous stem cell transplant (ASCT) is offered to transplant eligible (TE) patients (NDMM ≤ 65 years of age), unless medically unfit (TE-unfit) or refused (TE-refused). Data was retrieved for 448 patients to assess outcomes. For the entire cohort, multivariate analysis showed that male gender (p = 0.006), international staging system (ISS) 3 (p = 0.003), high lactate dehydrogenase (LDH) (p = 7.6 × 10-7) were adverse predictors for overall survival (OS), while complete response/ near complete response (CR/nCR) post-induction (p = 2.7 × 10-5) and ASCT (p = 4.8 × 10-4) were favorable factors for OS. In TE group, upfront ASCT was conducted in 252 (76.1%). Failure to undergo ASCT in TE patients rendered an inferior OS (TE-unfit p = 1.06 × 10-8, TE-refused p = 0.002) and event free survival (EFS) (TE-unfit p = 0.00013, TE-refused p = 0.002). Among TE patients with ASCT, multivariate analysis showed that age ≥ 60 (p = 8.9 × 10-4), ISS 3 (p = 0.019) and high LDH (p = 2.6 × 10-4) were adverse factors for OS. In those with high-risk features (HR cytogenetics, ISS 3, R-ISS 3), ASCT appeared to mitigate their adverse impact. Our data reaffirmed the importance of ASCT. The poor survival inherent with refusal of ASCT should be recognized by clinicians. Finally, improved outcome with ASCT in those with high-risk features warrant further studies.

Incidence and predictors of post-thrombotic syndrome in patients with proximal DVT in a real-world setting: findings from the GARFIELD-VTE registry.

Although substantial progress has been made in the pathophysiology and management of the post-thrombotic syndrome (PTS), several aspects still need clarification. Among them, the incidence and severity of PTS in the real world, the risk factors for its development, the value of patient's self-evaluation, and the ability to identify patients at risk for severe PTS. Eligible participants (n = 1107) with proximal deep-vein thrombosis (DVT) from the global GARFIELD-VTE registry underwent conventional physician's evaluation for PTS 36 months after diagnosis of their DVT using the Villalta score. In addition, 856 patients completed a Villalta questionnaire at 24 months. Variable selection was performed using stepwise algorithm, and predictors of severe PTS were incorporated into a multivariable risk model. The optimistic adjusted c-index was calculated using bootstrapping techniques. Over 36-months, 27.8% of patients developed incident PTS (mild in 18.7%, moderate in 5.7%, severe in 3.4%). Patients with incident PTS were older, had a lower prevalence of transient risk factors of DVT and a higher prevalence of persistent risk factors of DVT. Self-assessment of overall PTS at 24 months showed an agreement of 63.4% with respect to physician's evaluations at 36 months. The severe PTS multivariable model provided an optimistic adjusted c-index of 0.68 (95% CI 0.59-0.77). Approximately a quarter of DVT patients experienced PTS over 36 months after VTE diagnosis. Patient's self-assessment after 24 months provided added value for estimating incident PTS over 36 months. Multivariable risk analysis allowed good discrimination for severe PTS.

The p97/VCP adaptor UBXD1 drives AAA+ remodeling and ring opening through multi-domain tethered interactions.

p97, also known as valosin-containing protein, is an essential cytosolic AAA+ (ATPases associated with diverse cellular activities) hexamer that unfolds substrate polypeptides to support protein homeostasis and macromolecular disassembly. Distinct sets of p97 adaptors guide cellular functions but their roles in direct control of the hexamer are unclear. The UBXD1 adaptor localizes with p97 in critical mitochondria and lysosome clearance pathways and contains multiple p97-interacting domains. Here we identify UBXD1 as a potent p97 ATPase inhibitor and report structures of intact human p97-UBXD1 complexes that reveal extensive UBXD1 contacts across p97 and an asymmetric remodeling of the hexamer. Conserved VIM, UBX and PUB domains tether adjacent protomers while a connecting strand forms an N-terminal domain lariat with a helix wedged at the interprotomer interface. An additional VIM-connecting helix binds along the second (D2) AAA+ domain. Together, these contacts split the hexamer into a ring-open conformation. Structures, mutagenesis and comparisons to other adaptors further reveal how adaptors containing conserved p97-remodeling motifs regulate p97 ATPase activity and structure.

Chinese expert consensus on Bruton tyrosine kinase inhibitors in the treatment of B-cell malignancies.

Targeted therapy with Bruton tyrosine kinase (BTK) inhibitors have revolutionized the treatment of patients with various B-cell malignancies. BTK inhibitors such as ibrutinib, zanubrutinib, orelabrutinib, and acalabrutinib have shown good clinical efficacy and better safety profiles than those of traditional chemotherapy and chemoimmunotherapy regimens. Multiple studies on new BTK inhibitors are ongoing, which may provide more therapeutic options for the treatment of B-cell malignancies. Considering the unmet need of evidence on BTK inhibitors in all clinical settings and to standardize the use of BTK inhibitors available in mainland China, Taiwan, Hong Kong, and Macau regions, this consensus has been formulated for the treatment of various B-cell malignancies based on the clinical practice and available evidences on the use of BTK inhibitors. The recommendations of this consensus will provide guidance to physicians and clinical researchers on the effective treatment of B-cell malignancies with BTK inhibitors.

The p97/VCP adapter UBXD1 drives AAA+ remodeling and ring opening through multi-domain tethered interactions.

p97/VCP is an essential cytosolic AAA+ ATPase hexamer that extracts and unfolds substrate polypeptides during protein homeostasis and degradation. Distinct sets of p97 adapters guide cellular functions but their roles in direct control of the hexamer are unclear. The UBXD1 adapter localizes with p97 in critical mitochondria and lysosome clearance pathways and contains multiple p97-interacting domains. We identify UBXD1 as a potent p97 ATPase inhibitor and report structures of intact p97:UBXD1 complexes that reveal extensive UBXD1 contacts across p97 and an asymmetric remodeling of the hexamer. Conserved VIM, UBX, and PUB domains tether adjacent protomers while a connecting strand forms an N-terminal domain lariat with a helix wedged at the interprotomer interface. An additional VIM-connecting helix binds along the second AAA+ domain. Together these contacts split the hexamer into a ring-open conformation. Structures, mutagenesis, and comparisons to other adapters further reveal how adapters containing conserved p97-remodeling motifs regulate p97 ATPase activity and structure.

Asymmetric apical domain states of mitochondrial Hsp60 coordinate substrate engagement and chaperonin assembly.

The mitochondrial chaperonin, mtHsp60, promotes the folding of newly imported and transiently misfolded proteins in the mitochondrial matrix, assisted by its co-chaperone mtHsp10. Despite its essential role in mitochondrial proteostasis, structural insights into how this chaperonin binds to clients and progresses through its ATP-dependent reaction cycle are not clear. Here, we determined cryo-electron microscopy (cryo-EM) structures of a hyperstable disease-associated mtHsp60 mutant, V72I, at three stages in this cycle. Unexpectedly, client density is identified in all states, revealing interactions with mtHsp60's apical domains and C-termini that coordinate client positioning in the folding chamber. We further identify a striking asymmetric arrangement of the apical domains in the ATP state, in which an alternating up/down configuration positions interaction surfaces for simultaneous recruitment of mtHsp10 and client retention. Client is then fully encapsulated in mtHsp60/mtHsp10, revealing prominent contacts at two discrete sites that potentially support maturation. These results identify a new role for the apical domains in coordinating client capture and progression through the cycle, and suggest a conserved mechanism of group I chaperonin function.

Asia-Pacific Leukemia Consortium: An innovative and collaborative initiative to improve care of leukemia and related diseases in the Asia-Pacific region.

The burden of leukemia and related diseases is rapidly growing in Asia. Currently, there is a paucity of regional collaborative groups/initiatives that focus exclusively on the management of leukemia in the Asia-Pacific (APAC) region. The Asia-Pacific Leukemia Consortium (APLC) was established on the 8 September 2021 to understand the status quo, unmet needs, and ways to improve the management of leukemia and related diseases in the APAC region. The APLC working group set up a group of experts from various countries (Singapore, Malaysia, Thailand, Hong Kong, Japan, South Korea, Taiwan, China, and Australia) to discuss on the status of: (i) clinical trials; (ii) disease registry database; (iii) genetic and tissue repository; (iv) patient advocacy and care; and (v) disease prevention and education in the APAC region. Low levels of awareness about leukemia amongst the public, lack of financial support, and limited access to newly approved therapies were identified as barriers to the implementation of effective leukemia management in low- or mid-income Asian countries. Patients often enroll in clinical trials to gain access to novel/approved therapies. The APLC group aims to address the growing threat of leukemia through a collaborative approach to advance disease prevention, research, clinical trials, and education.

Allogeneic haematopoietic stem cell transplantation for myelofibrosis: prognostic indicators and the role of JAK2V617F measurable-residual disease monitoring by droplet-digital polymerase chain reaction.

Relapse after allogeneic haematopoietic stem cell transplantation (HSCT) is one of the key determinants of outcome in myelofibrosis (MF) and remains an important unmet need. In this retrospective single-centre study, we evaluated 35 consecutive patients with MF receiving allogeneic HSCT. At 30 days post-HSCT, full donor chimerism was achieved in 31 patients (88.6%). The median time to neutrophil engraftment was 16.8 (10-42) days and the median time to platelet engraftment was 26 (12-245) days. Four patients (11.4%) experienced primary graft failure. With a median duration of follow-up of 33 (1-223) months, with the 5-year overall survival (OS) and progression-free survival (PFS) were 51.6% and 46.3%, respectively. Relapse after HSCT (P < 0.001), leucocyte count ≥ 18 × 109/L at HSCT (P = 0.003) and accelerated/blast phase disease at HSCT (P < 0.001) were significantly associated with worse OS. Age at HSCT ≥ 54 years (P = 0.01), mutated ETV6 (P = 0.03), leucocyte count ≥ 18 × 109/L (P = 0.02), accelerated/blast phase MF (P = 0.001), and grade 2-3 bone marrow reticulin fibrosis at 12 months post-HSCT (P = 0.002) were significantly associated with worse PFS. JAK2V617F MRD ≥ 0.047 [sensitivity 85.7%; positive predictive value (PPV) 100%; AUC 0.984; P = 0.001] at 6 months and JAK2V617F MRD ≥ 0.009 (sensitivity 100%; PPV 100%; AUC 1.0; P = 0.001) at 12 months were highly predictive of post-HSCT relapse. Inferior OS and PFS were significantly associated with detectable JAK2V617F MRD at 12 months (P = 0.003 and P = 0.0001, respectively).

Stacked binding of a PET ligand to Alzheimer's tau paired helical filaments.

Accumulation of filamentous aggregates of tau protein in the brain is a pathological hallmark of Alzheimer's disease (AD) and many other neurodegenerative tauopathies. The filaments adopt disease-specific cross-ß amyloid conformations that self-propagate and are implicated in neuronal loss. Development of molecular diagnostics and therapeutics is of critical importance. However, mechanisms of small molecule binding to the amyloid core is poorly understood. We used cryo-electron microscopy to determine a 2.7 Å structure of AD patient-derived tau paired-helical filaments bound to the PET ligand GTP-1. The compound is bound stoichiometrically at a single site along an exposed cleft of each protofilament in a stacked arrangement matching the fibril symmetry. Multiscale modeling reveals pi-pi aromatic interactions that pair favorably with the small molecule-protein contacts, supporting high specificity and affinity for the AD tau conformation. This binding mode offers critical insight into designing compounds to target different amyloid folds found across neurodegenerative diseases.

Expert consensus on the management of chronic lymphocytic leukaemia in Asia.

In recent years, considerable progress has been made in the standard treatment for chronic lymphocytic leukaemia (CLL) due to the availability of new potent drugs. However, the majority of data on CLL were derived from Western populations, with limited studies and guidelines on the management of CLL from an Asian population perspective. This consensus guideline aims to understand treatment challenges and suggest appropriate management approaches for CLL in the Asian population and other countries with a similar socio-economic profile. The following recommendations are based on a consensus by experts and an extensive literature review and contribute towards uniform patient care in Asia.

36-month clinical outcomes of patients with venous thromboembolism: GARFIELD-VTE.

BACKGROUND: Venous thromboembolism (VTE), encompassing both deep vein thrombosis (DVT) and pulmonary embolism (PE), is a leading cause of morbidity and mortality worldwide. METHODS: GARFIELD-VTE is a prospective, non-interventional observational study of real-world treatment practices. We aimed to capture the 36-month clinical outcomes of 10,679 patients with objectively confirmed VTE enrolled between May 2014 and January 2017 from 415 sites in 28 countries. FINDINGS: A total of 6582 (61.6 %) patients had DVT alone, 4097 (38.4 %) had PE ± DVT. At baseline, 98.1 % of patients received anticoagulation (AC) with or without other modalities of therapy. The proportion of patients on AC therapy decreased over time: 87.6 % at 3 months, 73.0 % at 6 months, 54.2 % at 12 months and 42.0 % at 36 months. At 12-months follow-up, the incidences (95 % confidence interval [CI]) of all-cause mortality, recurrent VTE and major bleeding were 6.5 (7.0-8.1), 5.4 (4.9-5.9) and 2.7 (2.4-3.0) per 100 person-years, respectively. At 36-months, these decreased to 4.4 (4.2-4.7), 3.5 (3.2-2.7) and 1.4 (1.3-1.6) per 100 person-years, respectively. Over 36-months, the rate of all-cause mortality and major bleeds were highest in patients treated with parenteral therapy (PAR) versus oral anti-coagulants (OAC) and no OAC, and the rate of recurrent VTE was highest in patients on no OAC versus those on PAR and OAC. The most frequent cause of death after 36-month follow-up was cancer (n = 565, 48.6 %), followed by cardiac (n = 94, 8.1 %), and VTE (n = 38, 3.2 %). Most recurrent VTE events were DVT alone (n = 564, 63.3 %), with the remainder PE, (n = 236, 27.3 %), or PE in combination with DVT (n = 63, 7.3 %). INTERPRETATION: GARFIELD-VTE provides a global perspective of anticoagulation patterns and highlights the accumulation of events within the first 12 months after diagnosis. These findings may help identify treatment gaps for subsequent interventions to improve patient outcomes in this patient population.

Unique structural features govern the activity of a human mitochondrial AAA+ disaggregase, Skd3.

The AAA+ protein, Skd3 (human CLPB), solubilizes proteins in the mitochondrial intermembrane space, which is critical for human health. Skd3 variants with defective protein-disaggregase activity cause severe congenital neutropenia (SCN) and 3-methylglutaconic aciduria type 7 (MGCA7). How Skd3 disaggregates proteins remains poorly understood. Here, we report a high-resolution structure of a Skd3-substrate complex. Skd3 adopts a spiral hexameric arrangement that engages substrate via pore-loop interactions in the nucleotide-binding domain (NBD). Substrate-bound Skd3 hexamers stack head-to-head via unique, adaptable ankyrin-repeat domain (ANK)-mediated interactions to form dodecamers. Deleting the ANK linker region reduces dodecamerization and disaggregase activity. We elucidate apomorphic features of the Skd3 NBD and C-terminal domain that regulate disaggregase activity. We also define how Skd3 subunits collaborate to disaggregate proteins. Importantly, SCN-linked subunits sharply inhibit disaggregase activity, whereas MGCA7-linked subunits do not. These advances illuminate Skd3 structure and mechanism, explain SCN and MGCA7 inheritance patterns, and suggest therapeutic strategies.

Inhibition of C3 with pegcetacoplan results in normalization of hemolysis markers in paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematologic disorder characterized by complement-mediated hemolysis. C5 inhibitors (eculizumab/ravulizumab) control intravascular hemolysis but do not prevent residual extravascular hemolysis. The newly approved complement inhibitor, pegcetacoplan, inhibits C3, upstream of C5, and has the potential to improve control of complement-mediated hemolysis. The PADDOCK and PALOMINO clinical trials assessed the safety and efficacy of pegcetacoplan in complement inhibitor-naïve adults (≥ 18 years) diagnosed with PNH. Patients in PADDOCK (phase 1b open-label, pilot trial) received daily subcutaneous pegcetacoplan (cohort 1: 180 mg up to day 28 [n = 3]; cohort 2: 270-360 mg up to day 365 [n = 20]). PALOMINO (phase 2a, open-label trial) used the same dosing protocol as PADDOCK cohort 2 (n = 4). Primary endpoints in both trials were mean change from baseline in hemoglobin, lactate dehydrogenase, haptoglobin, and the number and severity of treatment-emergent adverse events. Mean baseline hemoglobin levels were below the lower limit of normal in both trials (PADDOCK: 8.38 g/dL; PALOMINO: 7.73 g/dL; normal range: 11.90-18.00 g/dL), increased to within normal range by day 85, and were sustained through day 365 (PADDOCK: 12.14 g/dL; PALOMINO: 13.00 g/dL). In PADDOCK, 3 serious adverse events (SAE) led to study drug discontinuation, 1 of which was deemed likely related to pegcetacoplan and 1 SAE, not deemed related to study drug, led to death. No SAE led to discontinuation/death in PALOMINO. Pegcetacoplan was generally well tolerated and improved hematological parameters by controlling hemolysis, while also improving other clinical PNH indicators in both trials. These trials were registered at www.clinicaltrials.gov (NCT02588833 and NCT03593200).

How we treat NK/T-cell lymphomas.

Natural killer (NK)/T-cell lymphomas are aggressive malignancies with a predilection for Asian and South American populations. Epstein-Barr virus (EBV) infection in lymphoma cells is universal. Predominantly extranodal, NK/T-cell lymphomas are divided clinically into nasal (involving the nose and upper aerodigestive tract), non-nasal (involving the skin, gastrointestinal tract, testes, and other organs), and aggressive leukaemia/lymphoma (involving the marrow and multiple organs) subtypes. Initial assessment should include imaging with positron emission tomography computed tomography (PET/CT), quantification of plasma EBV DNA as a surrogate marker of lymphoma load, and bone marrow examination with in situ hybridization for EBV-encoded small RNA. Prognostication can be based on presentation parameters (age, stage, lymph node involvement, clinical subtypes, and EBV DNA), which represent patient factors and lymphoma load; and dynamic parameters during treatment (serial plasma EBV DNA and interim/end-of-treatment PET/CT), which reflect response to therapy. Therapeutic goals are to achieve undetectable plasma EBV DNA and normal PET/CT (Deauville score ≤ 3). NK/T-cell lymphomas express the multidrug resistance phenotype, rendering anthracycline-containing regimens ineffective. Stage I/II nasal cases are treated with non-anthracycline asparaginase-based regimens plus sequential/concurrent radiotherapy. Stage III/IV nasal, and non-nasal and aggressive leukaemia/lymphoma cases are treated with asparaginase-containing regimens and consolidated by allogeneic haematopoietic stem cell transplantation (HSCT) in suitable patients. Autologous HSCT does not improve outcome. In relapsed/refractory cases, novel approaches comprise immune checkpoint blockade of PD1/PD-L1, EBV-specific cytotoxic T-cells, monoclonal antibodies, and histone deacetylase inhibitors. Future strategies may include inhibition of signalling pathways and driver mutations, and immunotherapy targeting the lymphoma and its microenvironment.

Clonal heterogeneity of polymorphic B-cell lymphoproliferative disease, EBV-positive, iatrogenic/immune senescence: implications on pathogenesis and treatment.

BACKGROUND: Epstein Barr virus positive (EBV+) immunodeficiency-associated lymphoproliferative disorders (IA-LPD) are heterogeneous diseases with variable treatment strategies that are not well-defined. CASE PRESENTATION: A 68-year-old woman with systemic lupus erythematosus developed EBV+ B-cell polymorphic lymphoproliferative disease (LPD). Positron emission tomography computed tomography (PET/CT) showed a large nasopharyngeal mass, multiple pulmonary lesions, splenomegaly and disseminated lymphadenopathy. Plasma EBV DNA was grossly elevated to 1.5 × 104 IU/mL. There were three paraproteins. Treatment with O-CHOP (obinutuzumab, cyclophosphamide, adriamycin, vincristine, prednisolone) led to undetectable plasma EBV DNA, suggesting eradiation of the EBV-positive malignant clone. However, radiologic abnormalities were still present on PET/CT, and paraprotein persisted. A nasopharyngeal re-biopsy showed infiltration with EBV-negative plasma cells. On treatment with lenalidomide, she finally achieved complete metabolic response. Molecular analysis showed that the EBV+ B-cell LPD and the EBV- plasma cell lesion exhibited identical immunoglobulin gene rearrangements. Next generation sequencing revealed that the EBV+ B-LPD showed mutation in only one gene (TP53), a profile typical of EBV-driven lymphoid neoplasms. However, the EBV- plasma cell lesion showed mutations in five genes (TP53, SF3B1, STAT5B, CD79B and CRKL), suggesting that these mutations instead of EBV infection were the oncogenic driver. CONCLUSION: The presence of both EBV+ and EBV- lesions, which showed different mutational profiles, indicated clonal heterogeneity that might be of biologic and therapeutic significance.

Bendamustine treatment of haematological malignancies: significant risks of opportunistic viral, fungal and bacterial infections.

OBJECTIVES: Bendamustine is a standard treatment for low-grade B-cell lymphomas, and considered safe in clinical trials. Its safety in routine practice might be different. METHODS: We retrospectively analyzed the infection complications in an unselected cohort of patients treated with bendamustine over a nine-year period. Patients were regularly monitored for blood counts and cytomegalovirus (CMV) reactivation by antigen assay and polymerase chain reaction. They received granulocyte colony stimulating factor for neutropenia, and routine anti-pneumocystis and optional anti-fungal prophylaxis. RESULTS: There were 179 men and 127 women at a median age of 61.5 (20-90) years, 52% receiving bendamustine for relapsed/refractory disease. Malignancies included low-grade B-cell lymphomas (54%), myeloma (10%), T-cell lymphomas (11%), Hodgkin lymphoma (2%) and other lymphoid neoplasms (23%). Most patients had good performance status (Eastern Cooperative Oncology Group score: 0-1, 72%). CMV reactivation occurred in 58 patients (19%) at a median age of 68 (39-85) years. Univariate analysis showed CMV reactivation to be significantly associated with elevated lactate dehydrogenase (P = 0.045), decreased albumin (P = 0.003) and older age (reactivation versus no reactivation: 66.3 ± 11.4 versus 59.4 ± 14.5 years, P = 0.0016). Age remained the only significant risk on multivariate analysis. CMV reactivation resulted in retinitis (N = 4), ependymitis/ventriculitis (N = 1) and duodenitis/colitis (N = 1). Invasive fungal disease occurred in five patients (candidemia, N = 2; aspergillosis N = 1; cryptococcemia, N = 1; scedosporiosis, N-1). Nineteen patients had culture positive septicaemia. CONCLUSION: Our observations showed that even with a vigorous anti-infective strategy, bendamustine treatment was still associated with significant risks of bacterial and opportunistic viral and fungal infections.

Epigenetic Silencing of PTEN and Epi-Transcriptional Silencing of MDM2 Underlied Progression to Secondary Acute Myeloid Leukemia in Myelodysplastic Syndrome Treated with Hypomethylating Agents.

In myelodysplastic syndrome (MDS), resistance to hypomethylating agents (HMA) portends a poor prognosis, underscoring the importance of understanding the molecular mechanisms leading to HMA-resistance. In this study, P39 and Kasumi-1 cells and their azacitidine-resistant and decitabine-resistant sublines were evaluated comparatively with transcriptomic and methylomic analyses. Expression profiling and genome-wide methylation microarray showed downregulation of PTEN associated with DNA hypermethylation in P39 cell lines resistant to azacitidine and decitabine. This pattern of PTEN dysregulation was also confirmed in a cohort of patients failing treatment with HMA. DNA hypomethylation of MDM2 was detected with downregulation of MDM2 in HMA resistant cell lines. Long-read sequencing revealed significant RNA hypomethylation of MDM2 resulting in alternative splicing and production of a truncated MDM2 transcript in azacitidine-resistant P39 cells. The expression of this MDM2 truncated transcript was also significantly increased in HMA-resistant patients compared with HMA-responsive patients. In conclusion, epigenetic and epi-transcriptomic dysregulation of PTEN and MDM2 were associated with resistance to hypomethylating agents.