Comprehensive Analysis of Hypermutation in Human Cancer.

We present an extensive assessment of mutation burden through sequencing analysis of >81,000 tumors from pediatric and adult patients, including tumors with hypermutation caused by chemotherapy, carcinogens, or germline alterations. Hypermutation was detected in tumor types not previously associated with high mutation burden. Replication repair deficiency was a major contributing factor. We uncovered new driver mutations in the replication-repair-associated DNA polymerases and a distinct impact of microsatellite instability and replication repair deficiency on the scale of mutation load. Unbiased clustering, based on mutational context, revealed clinically relevant subgroups regardless of the tumors' tissue of origin, highlighting similarities in evolutionary dynamics leading to hypermutation. Mutagens, such as UV light, were implicated in unexpected cancers, including sarcomas and lung tumors. The order of mutational signatures identified previous treatment and germline replication repair deficiency, which improved management of patients and families. These data will inform tumor classification, genetic testing, and clinical trial design.

Childhood Cancer Survivors' Reported Late Effects, Motivations for Seeking Survivorship Care, and Patterns of Attendance.

BACKGROUND: Childhood cancer survivors are vulnerable to long-term treatment-related health conditions, which can lead to poor quality of life. Little data exist on the overall health of long-term Australian and New Zealand childhood cancer survivors or on survivors' motivations for attending survivorship clinics. METHODS: This study administers a cross-sectional questionnaire to long-term survivors ≥5 years from their primary diagnosis. We compared participant-reported number of late effects by a cancer diagnosis, and identified clinical (eg, treatment) and demographic (eg, age) factors that were associated with late effects burden and engagement in cancer survivorship care. RESULTS: A total of 634 participants completed questionnaires (48% male, mean age = 21.7 years). Most participants (79%) reported at least one cancer-related late effect, most commonly fatigue (40%) and memory/learning difficulties (34%). Brain tumor survivors reported a higher total number of late effects than survivors with other diagnoses (mean = 5.7 vs. 3.2, P < .001). Participants' most commonly reported motivators for engaging in care were to understand problems that may occur later in life because of their cancer and/or treatment (98.5%) and to get reassurance about one's health (97.4%). The proportion of survivors endorsing each motivating factor was similar across cancer diagnoses, with the exception of learning more about insurance and pensions (highest in brain tumor survivors = 80%). In multivariable analyses, survivors were more likely to report being engaged in survivorship care if they were younger (P < .001), less time had elapsed since their diagnosis (P < .001), or they reported a higher number of motivating factors (P = .016). CONCLUSION: Survivors report a range of health problems decades after treatment completion. Understanding the burden of late effects, and motivators for seeking survivorship care to manage these health problems, is important for ensuring that tailored interventions or services are available to meet the needs of this growing population and to design effective models of survivorship care.

Multisystem screening reveals SARS-CoV-2 in neurons of the myenteric plexus and in megakaryocytes.

SARS-CoV-2, the causative agent of COVID-19, typically manifests as a respiratory illness, although extrapulmonary involvement, such as in the gastrointestinal tract and nervous system, as well as frequent thrombotic events, are increasingly recognised. How this maps onto SARS-CoV-2 organ tropism at the histological level, however, remains unclear. Here, we perform a comprehensive validation of a monoclonal antibody against the SARS-CoV-2 nucleocapsid protein (NP) followed by systematic multisystem organ immunohistochemistry analysis of the viral cellular tropism in tissue from 36 patients, 16 postmortem cases and 16 biopsies with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 status from the peaks of the pandemic in 2020 and four pre-COVID postmortem controls. SARS-CoV-2 anti-NP staining in the postmortem cases revealed broad multiorgan involvement of the respiratory, digestive, haematopoietic, genitourinary and nervous systems, with a typical pattern of staining characterised by punctate paranuclear and apical cytoplasmic labelling. The average time from symptom onset to time of death was shorter in positively versus negatively stained postmortem cases (mean = 10.3 days versus mean = 20.3 days, p = 0.0416, with no cases showing definitive staining if the interval exceeded 15 days). One striking finding was the widespread presence of SARS-CoV-2 NP in neurons of the myenteric plexus, a site of high ACE2 expression, the entry receptor for SARS-CoV-2, and one of the earliest affected cells in Parkinson's disease. In the bone marrow, we observed viral SARS-CoV-2 NP within megakaryocytes, key cells in platelet production and thrombus formation. In 15 tracheal biopsies performed in patients requiring ventilation, there was a near complete concordance between immunohistochemistry and PCR swab results. Going forward, our findings have relevance to correlating clinical symptoms with the organ tropism of SARS-CoV-2 in contemporary cases as well as providing insights into potential long-term complications of COVID-19. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Australian and New Zealand consensus guideline for paediatric newly diagnosed immune thrombocytopaenia endorsed by Australian New Zealand Children's Haematology and Oncology Group.

In children, the majority of cases are self-limiting and thus many paediatric patients can be managed conservatively with minimal complications. This varies considerably compared to adult newly diagnosed immune thrombocytopaenia (NDITP) where, in most cases, thrombocytopaenia persists with higher risk of moderate to severe bleeding complications. In the past decade, local and international guidelines have emerged to support approaches to the investigation and management of NDITP, with a focus primarily on adult immune thrombocytopaenia (ITP). International consensus guidelines on paediatric NDITP have been developed, however gaps remain, and approaches vary between North American, Asia, Europe and the UK. There are no current Australian or New Zealand paediatric ITP guidelines readily available, rather differing guidelines for each state, territory or island. These inconsistencies cause uncertainty for patients, families and physicians managing cases. Subsequently, physicians, including paediatric haematologists and general paediatricians, have come together to provide a consensus approach guideline specific to paediatric NDITP for Australian or New Zealand. Persistent or chronic paediatric ITP remains a complex and separate entity and are not discussed here.

B-cell acute lymphoblastic leukaemia: recent discoveries in molecular pathology, their prognostic significance, and a review of the current classification.

Acute lymphoblastic leukaemia (ALL) remains a leading cause of non-traumatic death in children, and the majority of adults diagnosed will succumb to the disease. Recent advances in molecular biology and bioinformatics have enabled more detailed genomic analysis and a better understanding of the molecular biology of ALL. A number of recurrent genomic drivers have recently been described, which not only aid in diagnosis and prognostication, but also may offer opportunities for specific therapeutic targeting. The present review summarises B-ALL genomic pathology at diagnosis, including lesions detectable using traditional cytogenetic methods as well as those detected only through advanced molecular techniques.

Prospective longitudinal evaluation of treatment-related toxicity and health-related quality of life during the first year of treatment for pediatric acute lymphoblastic leukemia.

BACKGROUND: Pediatric acute lymphoblastic leukemia (ALL) therapy is accompanied by treatment-related toxicities (TRTs) and impaired quality of life. In Australia and New Zealand, children with ALL are treated with either Children's Oncology Group (COG) or international Berlin-Frankfurt-Munster (iBFM) Study Group-based therapy. We conducted a prospective registry study to document symptomatic TRTs (venous thrombosis, neurotoxicity, pancreatitis and bone toxicity), compare TRT outcomes to retrospective TRT data, and measure the impact of TRTs on children's general and cancer-related health-related quality of life (HRQoL) and parents' emotional well-being. METHODS: Parents of children with newly diagnosed ALL were invited to participate in the ASSET (Acute Lymphoblastic Leukaemia Subtypes and Side Effects from Treatment) study and a prospective, longitudinal HRQoL study. TRTs were reported prospectively and families completed questionnaires for general (Healthy Utility Index Mark 3) and cancer specific (Pediatric Quality of Life Inventory (PedsQL)-Cancer Module) health related quality of life as well the Emotion Thermometer to assess emotional well-being. RESULTS: Beginning in 2016, 260 pediatric patients with ALL were enrolled on the TRT registry with a median age at diagnosis of 59 months (range 1-213 months), 144 males (55.4%), majority with Pre-B cell immunophenotype, n = 226 (86.9%), 173 patients (66.5%) treated according to COG platform with relatively equal distribution across risk classification sub-groups. From 2018, 79 families participated in the HRQoL study through the first year of treatment. There were 74 TRT recorded, reflecting a 28.5% risk of developing a TRT. Individual TRT incidence was consistent with previous studies, being 7.7% for symptomatic VTE, 11.9% neurotoxicity, 5.4% bone toxicity and 5.0% pancreatitis. Children's HRQoL was significantly lower than population norms throughout the first year of treatment. An improvement in general HRQoL, measured by the HUI3, contrasted with the lack of improvement in cancer-related HRQoL measured by the PedsQL Cancer Module over the first 12 months. There were no persisting differences in the HRQoL impact of COG compared to iBFM therapy. CONCLUSIONS: It is feasible to prospectively monitor TRT incidence and longitudinal HRQoL impacts during ALL therapy. Early phases of ALL therapy, regardless of treatment platform, result in prolonged reductions in cancer-related HRQoL.

Histological findings of tracheal samples from COVID-19 positive critically ill mechanically ventilated patients.

OBJECTIVES: This study examines the histological findings of tracheal tissue samples obtained from COVID-19 positive mechanically ventilated patients, to assess the degree of tracheal inflammation/ulceration present. DESIGN AND PARTICIPANTS: Retrospective single-centre observational cohort study. All patients admitted to Adult Intensive Care Unit (AICU) with COVID-19 infection, requiring mechanical ventilation and surgical tracheostomy between 1 April and 1 May 2020, were included (Group 1). Tracheal windows excised at tracheostomy underwent histological analysis. Comparison was made with: tracheal windows from COVID-19 positive AICU ventilated patients admitted between 1 January and 1 March 2021 (Group 2); tracheal windows from COVID-19 negative AICU ventilated patients (Group 3); and, tracheal autopsy samples from COVID-19 positive patients that died without undergoing prolonged mechanical ventilation (Group 4). RESULTS: Group 1 demonstrated mild/moderate inflammation (tracheitis) in nearly all samples (15/16, 93.8%), with infrequent micro-ulceration (2/16, 12.5%). Group 2 demonstrated similar mild/moderate inflammation in all samples (17/17, 100%), with no ulceration. Histological findings of Groups 1 and 2 COVID-19 positive patients were similar to Group 3 COVID-19 negative patients, which demonstrated mild/moderate inflammation (5/5, 100%), with uncommon superficial erosion (1/5, 20%). Group 4 demonstrated mild chronic inflammation or no significant inflammation, with uncommon micro-ulceration (1/4, 25%). CONCLUSIONS: Severe tracheal inflammation was not demonstrated in mechanically ventilated COVID-19 positive patients at the level of the second/third tracheal rings, at the stage of disease patients underwent tracheostomy. Histological findings were similar between mechanically ventilated COVID-19 positive and negative patients. Tracheal ulceration may be a feature of early or severe COVID-19 disease.

A randomized controlled trial of a structured exercise intervention after the completion of acute cancer treatment in adolescents and young adults.

BACKGROUND: Cancer treatments are frequently associated with impaired physical fitness, quality of life (QOL), and fatigue, often persisting into survivorship.  Studies in older adults with cancer have demonstrated benefits from exercise; however, this has not been rigorously investigated in adolescents and young adults (AYA). The aim of this study was to determine whether a structured 10-week exercise intervention was associated with improved cardiorespiratory fitness (VO2peak ), fatigue, and QOL in AYA who have recently completed cancer treatment. METHOD: Forty-three AYA (median age 21 ± 6 years) were randomly assigned to an exercise group (n = 22) or a control group (n = 21). The exercise group received a structured 10-week exercise program comprising progressive aerobic and resistance exercise; the control arm received routine care. VO2peak was measured at baseline, 10 weeks, and six months. Fatigue and QOL were assessed by the FACIT fatigue scale and the PEDS QL, respectively. RESULTS: Mean VO2peak at baseline was 26.5 ± 7.2 mL.kg-1 .min-1 , which is substantially lower than population norms. The exercise group demonstrated significant improvement in VO2peak at 10 weeks compared with controls (33.8 ± 8.1 vs 29.6 ± 7.6 mL.kg-1 .min-1 , P = 0.0002), but by six months, the difference was no longer significant (32.9 ± 7.0 vs 30.9 ± 11.0 mL.kg-1 .min-1 , P = 0.21). There were no significant differences in fatigue or total QOL scores between groups. CONCLUSION: Cancer treatment is associated with reduced VO2peak in AYA. Improvement in VO2peak was accelerated by a 10-week exercise program; however, no significant benefit was observed in QOL or fatigue. The plateau in VO2peak at six months suggests that a maintenance exercise program may be beneficial.

Long-term health-related quality of life in young childhood cancer survivors and their parents.

PURPOSE: Few studies have investigated the health-related quality of life (HRQoL) of young childhood cancer survivors and their parents. This study describes parent and child cancer survivor HRQoL compared to population norms and identifies factors influencing child and parent HRQoL. METHODS: We recruited parents of survivors who were currently <16 years, and >5 years postdiagnosis. Parents reported on their child's HRQoL (Kidscreen-10), and their own HRQoL (EQ-5D-5L). Parents rated their resilience and fear of cancer recurrence and listed their child's cancer-related late effects. RESULTS: One hundred eighty-two parents of survivors (mean age = 12.4 years old and 9.7 years postdiagnosis) participated. Parent-reported child HRQoL was significantly lower than population norms (48.4 vs. 50.7, p < .009). Parents most commonly reported that their child experienced sadness and loneliness (18.1%). Experiencing more late effects and receiving treatments other than surgery were associated with worse child HRQoL. Parents' average HRQoL was high (0.90) and no different to population norms. However 38.5% of parents reported HRQoL that was clinically meaningfully different from perfect health, and parents experienced more problems with anxiety/depression (43.4%) than population norms (24.7%, p < .0001). Worse child HRQoL, lower parent resilience, and higher fear of recurrence was associated with worse parent HRQoL. CONCLUSIONS: Parents report that young survivors experience small but significant ongoing reductions in HRQoL. While overall mean levels of HRQoL were no different to population norms, a subset of parents reported HRQoL that was clinically meaningfully different from perfect health. Managing young survivors' late effects and improving parents' resilience through survivorship may improve HRQoL in long-term survivorship.

Risk of Leukemia in Children With Peripheral Facial Palsy.

Most children with peripheral facial palsy will not have a cause identified. Although leukemia can cause facial nerve palsy, the magnitude of the risk is unknown and recommendations for investigations are variable. We are currently conducting a randomized, placebo-controlled trial of prednisolone for the treatment of Bell's palsy in children within the Paediatric Research in Emergency Departments International Collaborative emergency research network. In the course of the assessment for eligibility of the trial, from 644 acute-onset facial palsy presentations we identified 5 children with previously undiagnosed leukemia. We estimate the rate of leukemia in children with acute-onset facial palsy who present to emergency departments to be 0.6% (95% confidence interval 0.2% to 1.6%). In accordance with these cases, we suggest consideration of a screening CBC count for acute-onset peripheral facial palsy presentations in children before initiation of corticosteroid treatment.

Low-pressure multipass Raman spectrometer.

Nonintrusive, quantitative measurements of thermodynamic properties of flows associated with propulsion systems are pivotal to advance their design and optimization. Laser-based diagnostics are ideal to provide quantitative results without influencing the flow; however, the environments in which such flows exist are often not conducive for such techniques. Namely, they often lack the optical accessibility required to facilitate the delivery of incident laser radiation and the subsequent collection of induced signals. A particularly challenging, yet crucial, task is to measure thermodynamic properties of plumes issuing from thrusters operating within a vacuum chamber. Large chambers used to simulate the vacuum of space generally lack optical ports that can facilitate complex laser-based measurements. Additionally, the near-vacuum environments within such chambers coupled with the ability of thrusters to efficiently expand the gas flowing through their nozzles lead to plumes with prohibitively low number densities (pressures below 1 Torr). Thus, there is a need to develop a diagnostic system that can offer high throughput without the use of free-space optical ports. Moreover, facilities where propulsion systems are tested typically lack vibrationally isolated space for diagnostic equipment and accurate climate control. As a result, such a high-throughput system must also be compact, versatile, and robust. To this end, the present work describes a fiber-coupled, multipass cell, spontaneous Raman scattering spectroscopy system. This system is intended to provide accurate temperature measurements within low-pressure environments via H2 rotational Raman thermometry. Proof-of-principle measurements are successfully performed at pressures as low as 67 Pa (500 mTorr). Techniques to maintain the signal-to-noise ratio at lower pressures, and the trade-offs associated with them, are discussed and evaluated. Finally, the ability of this system to facilitate additional quantitative measurements is also discussed.

Clinical implications of elective replacement indicator setting changes in patients with dual-chamber pacemaker devices.

OBJECTIVE: This study sought to determine if single-chamber operation and/or loss of rate response (RR) during elective replacement indicator (ERI) in patients with dual-chamber pacemakers lead to increased symptom burden, healthcare utilization, and atrial fibrillation (AF). BACKGROUND: Dual-chamber pacemakers often change from dual- to single-chamber pacing mode and/or lose RR functionality at ERI to preserve battery. Single-chamber pacing increases the incidence of heart failure, AF, and pacemaker syndrome suggesting these changes may be deleterious. METHODS: A retrospective analysis of 700 patients was completed. Three comparisons were analyzed: Comparison 1: mode change and RR loss versus no change; Comparison 2: RR loss only versus no change; Comparison 3: mode change only versus no change (in patients with no RR programmed at baseline). RESULTS: In Comparison 1, 121 (46%) patients with setting changes experienced symptoms (most often dyspnea and fatigue/exercise intolerance) versus 3 (4%) without setting changes (p < .0001). Similar results were noted in Comparisons 2 and 3 (p = .0016 and p = .0001, respectively). In Comparison 1, patients with setting change sought provider contact more than patients without setting changes (p = .0001). A significant difference was not noted in Comparison 2 or 3. Overall 14 (2%) patients were hospitalized, all of whom had setting changes. CONCLUSIONS: Setting changes at ERI including a change from dual- to single-chamber pacing and/or loss of RR results in a significantly increased symptom burden and increased healthcare utilization.

Models of care for adolescent and young adult cancer programs.

This review draws on the experience of adolescent and young adult (AYA) cancer clinicians from Australia, the United States, and the United Kingdom to summarize common aspects of models of care implemented in their countries. The principles underpinning these models include patient- and family-focused care informed by an understanding of normal AYA development, enhancing existing adult or pediatric cancer services to meet the needs of AYA, and promoting collaboration between pediatric and adult oncologists. Common elements of AYA cancer care include establishing an AYA multidisciplinary team that integrates medical and psychosocial care, efforts to centralize complex care, providing access and equity for all AYA, promoting clinical trials, and helping facilitate transition to healthy survivorship. Several organizational approaches are described, noting that local program development depends on resources, infrastructure, and assessment of unmet needs within the region. The development of national networks provides opportunities for shared learning and approaches to evaluation.

Medium-Chain Polyprenols Influence Chloroplast Membrane Dynamics in Solanum lycopersicum.

The widespread occurrence of polyprenols throughout the plant kingdom is well documented, yet their functional role is poorly understood. These lipophilic compounds are known to be assembled from isoprenoid precursors by a class of enzymes designated as cis-prenyltransferases (CPTs), which are encoded by small CPT gene families in plants. In this study, we report that RNA interference (RNAi)-mediated knockdown of one member of the tomato CPT family (SlCPT5) reduced polyprenols in leaves by about 70%. Assays with recombinant SlCPT5 produced in Escherichia coli determined that the enzyme synthesizes polyprenols of approximately 50-55 carbons (Pren-10, Pren-11) in length and accommodates a variety of trans-prenyldiphosphate precursors as substrates. Introduction of SlCPT5 into the polyprenol-deficient yeast Δrer2 mutant resulted in the accumulation of Pren-11 in yeast cells, restored proper protein N-glycosylation and rescued the temperature-sensitive growth phenotype that is associated with its polyprenol deficiency. Subcellular fractionation studies together with in vivo localization of SlCPT5 fluorescent protein fusions demonstrated that SlCPT5 resides in the chloroplast stroma and that its enzymatic products accumulate in both thylakoid and envelope membranes. Transmission electron microscopy images of polyprenol-deficient leaves revealed alterations in chloroplast ultrastructure, and anisotropy measurements revealed a more disordered state of their envelope membranes. In polyprenol-deficient leaves, CO2 assimilation was hindered and their thylakoid membranes exhibited lower phase transition temperatures and calorimetric enthalpies, which coincided with a decreased photosynthetic electron transport rate. Taken together, these results uncover a role for polyprenols in governing chloroplast membrane dynamics.

Outcomes of video-assisted thoracoscopic surgery for transvenous lead extraction.

INTRODUCTION: To evaluate the outcomes of video-assisted thoracoscopic surgery (VATS) during transvenous lead extractions (TLEs). METHODS AND RESULTS: Ninety-one high-risk patients who underwent TLE in the operating room from January 1, 2015, to March 31, 2017, were included in the study. Of these, 9 patients underwent VATS during TLE. Their clinical characteristics, indications for lead extraction, and complications associated with TLE in the 9 patients who had VATS were compared with those for the 82 patients who did not have VATS. The mean (SD) age of the study patients was 61 (17) years (64.8% were male). The lead dwell time, number of leads extracted, and clinical comorbidities were similar between the 2 groups. Superior vena cava (SVC) tear occurred in 2 of the 9 patients in VATS group and in 1 of the 82 in the non-VATS group (22.2% vs. 1.2%, P = 0.03). Of the 2 patients in the VATS group who had SVC tears, in 1 the tear was visualized immediately and there was no hemodynamic compromise. In the other patient, the SVC tear was within the pericardium; the blood pressure recovered quickly after sternotomy and repair. Both patients had complete lead extraction and survived hospitalization. The patient in the non-VATS group who had an SVC tear had a successful repair but died of postoperative complications. CONCLUSIONS: Utilization of VATS to facilitate TLE is beneficial for early recognition of SVC tear and timely surgical repair in select high-risk patients.

Do Australian adolescents' and young adults' experiences of cancer care influence their quality of life?

OBJECTIVE: To examine the relationship between the cancer care experiences of adolescents and young adults (AYAs) and their quality of life. METHODS: Two hundred and nine AYAs completed a cross-sectional, self-report survey distributed through the population-based cancer registries in 2 Australian states (New South Wales and Victoria). Eligible AYAs were 15 to 24 years old when diagnosed with any cancer (excluding early-stage melanoma) and were 3 to 24 months post-diagnosis. Questions examined whether particular care experiences occurred for the patient at different points in the cancer care pathway, including diagnosis, treatment, inpatient care, and at the end of treatment. Quality of life was assessed using the Functional Assessment of Cancer Therapy-General scale. RESULTS: Positive experiences of care at diagnosis, during treatment, during inpatient stays, and when finishing treatment were associated with higher functional, emotional, and social well-being. However, these associations generally became nonsignificant when communication and support experiences were included in the model. Inpatient experiences positively influenced emotional well-being over and above the effect of communication and support experiences. CONCLUSIONS: The results suggest that, for most AYAs' quality of life outcomes, positive experiences of age-appropriate communication and emotional support may underpin the effect of positive experiences of care throughout the cancer care pathway. The results support the need for communication and support tailored to an AYA audience, as recognised by recent Australian and international guidelines on the care of AYAs with cancer.

Factors influencing the provision of fertility counseling and impact on quality of life in adolescents and young adults with cancer.

PURPOSE: This study investigated the impact of fertility-related discussions on Adolescent and Young Adult (AYA) cancer patients' quality of life (QoL) and the factors influencing provision of these discussions. METHODS: Recruitment was conducted through population-based state cancer registries. Eligible AYAs were 15-24 years at diagnosis, 3-24 months postdiagnosis, with any cancer (except early stage melanoma). As part of a larger survey, AYAs were asked about their experiences of fertility-related discussions and QoL (FACT-G). RESULTS: Of the 207 AYAs returning surveys (29% response rate) 88% reported a discussion about infertility risks, 75% reported a discussion about preservation options and 59% were offered a referral to a fertility specialist. Patients attending health services with an AYA focus were more likely than those attending other types of centers to report discussions of fertility preservation (FP) options (85% versus 67%) and referrals (75% versus 49%). Social well-being was positively related to discussions about preservation options and being provided fertility risk information in a sensitive, supportive manner. CONCLUSIONS: Providing a sensitive and proactive discussion about fertility-related risks may benefit AYAs' well-being. Services with an AYA focus are fulfilling their mandate of ensuring optimal fertility-related care for AYA cancer patients.

Antigen-specific single B cell sorting and expression-cloning from immunoglobulin humanized rats: a rapid and versatile method for the generation of high affinity and discriminative human monoclonal antibodies.

BACKGROUND: There is an ever-increasing need of monoclonal antibodies (mAbs) for biomedical applications and fully human binders are particularly desirable due to their reduced immunogenicity in patients. We have applied a strategy for the isolation of antigen-specific B cells using tetramerized proteins and single-cell sorting followed by reconstruction of human mAbs by RT-PCR and expression cloning. RESULTS: This strategy, using human peripheral blood B cells, enabled the production of low affinity human mAbs against major histocompatibility complex molecules loaded with peptides (pMHC). We then implemented this technology using human immunoglobulin transgenic rats, which after immunization with an antigen of interest express high affinity-matured antibodies with human idiotypes. Using rapid immunization, followed by tetramer-based B-cell sorting and expression cloning, we generated several fully humanized mAbs with strong affinities, which could discriminate between highly homologous proteins (eg. different pMHC complexes). CONCLUSIONS: Therefore, we describe a versatile and more effective approach as compared to hybridoma generation or phage or yeast display technologies for the generation of highly specific and discriminative fully human mAbs that could be useful both for basic research and immunotherapeutic purposes.

TIDEL-II: first-line use of imatinib in CML with early switch to nilotinib for failure to achieve time-dependent molecular targets.

The Therapeutic Intensification in De Novo Leukaemia (TIDEL)-II study enrolled 210 patients with chronic phase chronic myeloid leukemia (CML) in two equal, sequential cohorts. All started treatment with imatinib 600 mg/day. Imatinib plasma trough level was performed at day 22 and if <1000 ng/mL, imatinib 800 mg/day was given. Patients were then assessed against molecular targets: BCR-ABL1 ≤10%, ≤1%, and ≤0.1% at 3, 6, and 12 months, respectively. Cohort 1 patients failing any target escalated to imatinib 800 mg/day, and subsequently switched to nilotinib 400 mg twice daily for failing the same target 3 months later. Cohort 2 patients failing any target switched to nilotinib directly, as did patients with intolerance or loss of response in either cohort. At 2 years, 55% of patients remained on imatinib, and 30% on nilotinib. Only 12% were >10% BCR-ABL1 at 3 months. Confirmed major molecular response was achieved in 64% at 12 months and 73% at 24 months. MR4.5 (BCR-ABL1 ≤0.0032%) at 24 months was 34%. Overall survival was 96% and transformation-free survival was 95% at 3 years. This trial supports the feasibility and efficacy of an imatinib-based approach with selective, early switching to nilotinib. This trial was registered at www.anzctr.org.au as #12607000325404.