SARS-CoV-2 mRNA vaccination elicits a robust and persistent T follicular helper cell response in humans.

SARS-CoV-2 mRNA vaccines induce robust anti-spike (S) antibody and CD4+ T cell responses. It is not yet clear whether vaccine-induced follicular helper CD4+ T (TFH) cell responses contribute to this outstanding immunogenicity. Using fine-needle aspiration of draining axillary lymph nodes from individuals who received the BNT162b2 mRNA vaccine, we evaluated the T cell receptor sequences and phenotype of lymph node TFH. Mining of the responding TFH T cell receptor repertoire revealed a strikingly immunodominant HLA-DPB1∗04-restricted response to S167-180 in individuals with this allele, which is among the most common HLA alleles in humans. Paired blood and lymph node specimens show that while circulating S-specific TFH cells peak one week after the second immunization, S-specific TFH persist at nearly constant frequencies for at least six months. Collectively, our results underscore the key role that robust TFH cell responses play in establishing long-term immunity by this efficacious human vaccine.

SARS-CoV-2 antigen exposure history shapes phenotypes and specificity of memory CD8+ T cells.

Although mRNA vaccine efficacy against severe coronavirus disease 2019 remains high, variant emergence has prompted booster immunizations. However, the effects of repeated exposures to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antigens on memory T cells are poorly understood. Here, we utilize major histocompatibility complex multimers with single-cell RNA sequencing to profile SARS-CoV-2-responsive T cells ex vivo from humans with one, two or three antigen exposures, including vaccination, primary infection and breakthrough infection. Exposure order determined the distribution between spike-specific and non-spike-specific responses, with vaccination after infection leading to expansion of spike-specific T cells and differentiation to CCR7-CD45RA+ effectors. In contrast, individuals after breakthrough infection mount vigorous non-spike-specific responses. Analysis of over 4,000 epitope-specific T cell antigen receptor (TCR) sequences demonstrates that all exposures elicit diverse repertoires characterized by shared TCR motifs, confirmed by monoclonal TCR characterization, with no evidence for repertoire narrowing from repeated exposure. Our findings suggest that breakthrough infections diversify the T cell memory repertoire and current vaccination protocols continue to expand and differentiate spike-specific memory.

Association of Vitamin A and D Deficiencies with Infectious Outcomes in Children Undergoing Intensive Induction Therapy for Acute Lymphoblastic Leukemia.

OBJECTIVE: To evaluate the association between deficiency of vitamin A or D at diagnosis of pediatric acute lymphoblastic leukemia (ALL) and subsequent infectious complications during induction therapy. STUDY DESIGN: We conducted an institutional review board-approved, retrospective cohort study of children with newly diagnosed ALL from 2007 to 2017 at St. Jude Children's Research Hospital. We measured vitamin D, vitamin D binding protein, retinol binding protein as a surrogate for vitamin A, and immunoglobulin isotypes in serum obtained at ALL diagnosis, and we assessed the association between vitamin deficiencies or levels and infection-related complications during the 6-week induction phase using Cox regression models. RESULTS: Among 378 evaluable participants, vitamin A and D deficiencies were common (43% and 17%, respectively). Vitamin D deficiency was associated with higher risks of febrile neutropenia (adjusted hazard ratio [aHR], 1.7; P = .0072), clinically documented infection (aHR, 1.73; P = .025), and likely bacterial infection (aHR, 1.86; P = .008). Conversely, vitamin A deficiency was associated solely with a lower risk of sepsis (aHR, 0.19; P = .027). CONCLUSIONS: In this retrospective study, vitamin D deficiency was associated with an increased risk of common infection-related complications during induction therapy for ALL. Additional studies are warranted to evaluate whether vitamin D supplementation could mitigate this effect.

Comparison of Post-hemorrhoid Surgery Pain Profiles in Older and Younger Adults.

INTRODUCTION: Older and younger adults are offered similar analgesic options after hemorrhoid surgery (HS), but the differences in pain between the two populations are unknown. This study aims to compare postoperative pain outcomes after HS in older and younger individuals. METHODS: This is a retrospective analysis of electronic medical records of patients who underwent HS between 2018 and 2023. Patients were excluded if additional anorectal procedures were performed at the time of HS. Data related to pain-related outcomes were compiled: (1) need for narcotic prescription refills; (2) documentation of a pain-related phone call within 30 d; (3) urgent postoperative office visit before regular scheduled follow-up; and (4) pain-related postoperative emergency department visits. Associations between age and pain-related outcomes were tested using Fisher's exact test, chi-square test, and covariate adjusted logistic regression modeling. RESULTS: There were a total of 249 patients, 60 older adults, and 189 younger adults. Compared to younger patients, older adults demonstrated a reduced frequency of pain-related phone calls (10.3 versus 32.1%, P < 0.01) and opioid refills (0 versus 14.4%, P < 0.01). After adjusting for confounders, older age remained inversely associated with pain-related postoperative phone calls (odds ratio = 0.25, 95% confidence interval = [0.1-0.6], P = 0.003). CONCLUSIONS: Older adults had better pain outcomes after HS in comparison to younger patients. These findings suggest that the postoperative analgesic needs of older patients after HS are lower than those of younger patients. Decisions regarding opioid prescription in older adults recovering from HS should be tailored to avoid narcotic-related complications.

Fluoroquinolone prophylaxis in patients with neutropenia at high risk of serious infections: Exploring pros and cons.

BACKGROUND: The use of fluoroquinolones to prevent infections in neutropenic patients with cancer or undergoing hematopoietic stem cell transplantation (HSCT) is a controversial issue, with international guidelines providing conflicting recommendations. Although potential benefits are clear, concerns revolve around efficacy, potential harms, and antimicrobial resistance (AMR) implications. DISCUSSION: Fluoroquinolone prophylaxis reduces neutropenic fever (NF) bloodstream infections and other serious bacterial infections, based on evidence from systematic reviews, randomized controlled trials, and observational studies in adults and children. Fluoroquinolone prophylaxis may also reduce infection-related morbidity and healthcare costs; however, evidence is conflicting. Adverse effects of fluoroquinolones are well recognized in the general population; however, studies in the cancer cohort where it is used for a defined period of neutropenia have not reflected this. The largest concern for routine use of fluoroquinolone prophylaxis remains AMR, as many, but not all, observational studies have found that fluoroquinolone prophylaxis might increase the risk of AMR, and some studies have suggested negative impacts on patient outcomes as a result. CONCLUSIONS: The debate surrounding fluoroquinolone prophylaxis calls for individualized risk assessment based on patient characteristics and local AMR patterns, and prophylaxis should be restricted to patients at the highest risk of serious infection during the highest risk periods to ensure that the risk-benefit analysis is in favor of individual and community benefit. More research is needed to address important unanswered questions about fluoroquinolone prophylaxis in neutropenic patients with cancer or receiving HSCT.

Evolution of vancomycin-resistant Enterococcus faecium during colonization and infection in immunocompromised pediatric patients.

Patients with hematological malignancies or undergoing hematopoietic stem cell transplantation are vulnerable to colonization and infection with multidrug-resistant organisms, including vancomycin-resistant Enterococcus faecium (VREfm). Over a 10-y period, we collected and sequenced the genomes of 110 VREfm isolates from gastrointestinal and blood cultures of 24 pediatric patients undergoing chemotherapy or hematopoietic stem cell transplantation for hematological malignancy at St. Jude Children's Research Hospital. We used patient-specific reference genomes to identify variants that arose over time in subsequent gastrointestinal and blood isolates from each patient and analyzed these variants for insight into how VREfm adapted during colonization and bloodstream infection within each patient. Variants were enriched in genes involved in carbohydrate metabolism, and phenotypic analysis identified associated differences in carbohydrate utilization among isolates. In particular, a Y585C mutation in the sorbitol operon transcriptional regulator gutR was associated with increased bacterial growth in the presence of sorbitol. We also found differences in biofilm-formation capability between isolates and observed that increased biofilm formation correlated with mutations in the putative E. faecium capsular polysaccharide (cps) biosynthetic locus, with different mutations arising independently in distinct genetic backgrounds. Isolates with cps mutations showed improved survival following exposure to lysozyme, suggesting a possible reason for the selection of capsule-lacking bacteria. Finally, we observed mutations conferring increased tolerance of linezolid and daptomycin in patients who were treated with these antibiotics. Overall, this study documents known and previously undescribed ways that VREfm evolve during intestinal colonization and subsequent bloodstream infection in immunocompromised pediatric patients.

Host Predictors of Broadly Cross-Reactive Antibodies Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Variants of Concern Differ Between Infection and Vaccination.

BACKGROUND: Following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or vaccination there is significant variability between individuals in protective antibody levels against SARS-CoV-2, and within individuals against different virus variants. However, host demographic or clinical characteristics that predict variability in cross-reactive antibody levels are not well-described. These data could inform clinicians, researchers, and policymakers on the populations most likely to require vaccine booster shots. METHODS: In an institutional review board-approved prospective observational cohort study of staff at St. Jude Children's Research Hospital, we identified participants with plasma samples collected after SARS-CoV-2 infection, after mRNA vaccination, and after vaccination following infection, and quantitated immunoglobulin G (IgG) levels by enzyme-linked immunosorbent assay to the spike receptor binding domain (RBD) from 5 important SARS-CoV-2 variants (Wuhan Hu-1, B.1.1.7, B.1.351, P.1, and B.1.617.2). We used regression models to identify factors that contributed to cross-reactive IgG against 1 or multiple viral variants. RESULTS: Following infection, a minority of the cohort generated cross-reactive antibodies, IgG antibodies that bound all tested variants. Those who did had increased disease severity, poor metabolic health, and were of a particular ancestry. Vaccination increased the levels of cross-reactive IgG levels in all populations, including immunocompromised, elderly, and persons with poor metabolic health. Younger people with a healthy weight mounted the highest responses. CONCLUSIONS: Our findings provide important new information on individual antibody responses to infection/vaccination that could inform clinicians on populations that may require follow-on immunization.

Telemedicine services for living kidney donation: A US survey of multidisciplinary providers.

Individuals considering living kidney donation face geographic, financial, and logistical challenges. Telemedicine can facilitate healthcare access/care coordination. Yet difficulties exist in telemedicine implementation and sustainability. We sought to examine centers' practices and providers' attitudes toward telemedicine to improve services for donors. We surveyed multidisciplinary providers from 194 active adult US living donor kidney transplant centers; 293 providers from 128 unique centers responded to the survey (center representation rate = 66.0%), reflecting 83.9% of practice by donor volume and 91.5% of US states/territories. Most centers (70.3%) plan to continue using telemedicine beyond the pandemic for donor evaluation/follow-up. Video was mostly used by nephrologists, surgeons, and psychiatrists/psychologists. Telephone and video were mostly used by social workers, while video or telephone was equally used by coordinators. Half of respondent nephrologists and surgeons were willing to accept a remote completion of physical exam; 68.3% of respondent psychiatrists/psychologists and social workers were willing to accept a remote completion of mental status exam. Providers strongly agreed that telemedicine was convenient for donors and would improve the likelihood of completing donor evaluation. However, providers (65.5%) perceived out-of-state licensing as a key policy/regulatory barrier. These findings help inform practice and underscore the instigation of policies to remove barriers using telemedicine to increase living kidney donation.

Referral and Evaluation for Kidney Transplantation Following Implementation of the 2014 National Kidney Allocation System.

RATIONALE & OBJECTIVE: The national kidney allocation system (KAS) implemented in December 2014 in the United States redefined the start of waiting time from the time of waitlisting to the time of kidney failure. Waitlisting has declined post-KAS, but it is unknown if this is due to transplant center practices or changes in dialysis facility referral and evaluation. The purpose of this study was to assess the impact of the 2014 KAS policy change on referral and evaluation for transplantation among a population of incident and prevalent patients with kidney failure. STUDY DESIGN: Cohort study. SETTING & PARTICIPANTS: 37,676 incident (2012-2016) patients in Georgia, North Carolina, and South Carolina identified within the US Renal Data System at 9 transplant centers and followed through December 2017. A prevalent population of 6,079 patients from the same centers receiving maintenance dialysis in 2012 but not referred for transplantation in 2012. EXPOSURE: KAS era (pre-KAS vs post-KAS). OUTCOME: Referral for transplantation, start of transplant evaluation, and waitlisting. ANALYTICAL APPROACH: Multivariable time-dependent Cox models for the incident and prevalent population. RESULTS: Among incident patients, KAS was associated with increased referrals (adjusted HR, 1.16 [95% CI, 1.12-1.20]) and evaluation starts among those referred (adjusted HR, 1.16 [95% CI, 1.10-1.21]), decreased overall waitlisting (adjusted HR, 0.70 [95% CI, 0.65-0.76]), and lower rates of active waitlisting among those evaluated compared to the pre-KAS era (adjusted HR, 0.81 [95% CI, 0.74-0.90]). Among the prevalent population, KAS was associated with increases in overall waitlisting (adjusted HR, 1.74 [95% CI, 1.15-2.63]) and active waitlisting among those evaluated (adjusted HR, 2.01 [95% CI, 1.16-3.49]), but had no significant impact on referral or evaluation starts among those referred. LIMITATIONS: Limited to 3 states, residual confounding. CONCLUSIONS: In the southeastern United States, the impact of KAS on steps to transplantation was different among incident and prevalent patients with kidney failure. Dialysis facilities referred more incident patients and transplant centers evaluated more incident patients after implementation of KAS, but fewer evaluated patients were placed onto the waitlist. Changes in dialysis facility and transplant center behaviors after KAS implementation may have influenced the observed changes in access to transplantation.

Accuracy of National Surgical Quality Improvement Program Risk Calculator Among Elderly Patients Undergoing Pancreas Resection.

INTRODUCTION: A preoperative goals-of-care discussion is essential in maintaining the autonomy of older adults who require surgery. The purpose of this study was to determine the accuracy of the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) risk calculator and its association with age for patients who underwent pancreatectomy. METHODS: Using the American College of Surgeons NSQIP database, patients who underwent pancreatectomy between 2012 and 2015 were identified. Age was categorized into three groups: 18-64, 65-79, and 80-89 y. Analysis of variance and Pearson correlation coefficients were employed to assess differences between age categories in predicted and actual mortality and morbidity. Covariate-adjusted logistic regression models were employed to evaluate associations while accounting for potential confounders. RESULTS: A total of 17,906 patients were included. The correlation between actual and predicted mortality was low (r = 0.14, P < 0.001). This correlation was weakest for the age category 80-89 y (r = 0.04, P = 0.07) and strongest for 65-79 y category (r = 0.14, P > 0.001). The correlation was weakest among patients who underwent pancreatoduodenectomy (r = 0.06, P = 0.08) and in this group mortality was overestimated for older adults in the age group 80-89 (actual mortality: 3.2% versus predicted mortality: 5.6%, P = 0.08). After adjusting for covariates, the interaction term between age and predicted mortality (P = 0.0021) indicated that the relationship between predicted and actual mortality is significantly influenced by patient age. CONCLUSIONS: The NSQIP risk calculator appears to overestimate mortality and morbidity risk for elderly patients undergoing pancreatoduodenectomy. These predictions should be used with caution in preoperative goals-of-care discussions with patients aged 80 y and older.

Short-Term Outcomes for Restorative and Non-Restorative Proctocolectomy in Older Adults.

BACKGROUND: Curative surgery for ulcerative colitis can be subdivided into restorative (with pouch and anastomosis) and non-restorative operations. Restorative surgery in older adults is controversial, due to concerns about surgical risk and long-term functional outcome. The goal of this study is to compare 30-day outcomes for restorative and non-restorative surgery in older adults with ulcerative colitis. METHODS: Data were obtained from the American College of Surgeons National Surgical Quality Initiative Program from 2012-2018. Patients were included if they were >65 years old and had ulcerative colitis. Restorative and non-restorative surgeries were defined with procedure codes. Patient characteristics and adverse surgical outcomes were compared between restorative and non-restorative surgeries utilizing chi-square tests and Fisher's exact tests. Multivariate logistic regression models were constructed to evaluate the association of restorative versus non-restorative surgery with adverse surgical outcomes while adjusting for potential confounders. RESULTS: Of 392 total patients, 95 had restorative and 297 had non-restorative surgery. Patients undergoing restorative surgery, compared to non-restorative surgery, were significantly younger (P<0.01), had lower incidences of steroid usage (P<0.001) and higher rates of readmission (P = 0.02). There were no differences in post-operative complications between the groups in both unadjusted analyses and covariate-adjusted regression analysis (P > 0.05). CONCLUSION: In carefully selected older patients with ulcerative colitis, restorative surgery is associated with increased readmission, but otherwise similar rates of morbidity or mortality compared to non-restorative surgery. Data regarding postoperative functional outcome and quality of life are also needed to help select the most appropriate curative option for older adults.

Insensitivity of machine log files to MLC leaf backlash and effect of MLC backlash on clinical dynamic MLC motion: An experimental investigation.

PURPOSE: Multi-leaf-collimator (MLC) leaf position accuracy is important for accurate dynamic radiotherapy treatment plan delivery. Machine log files have become widely utilized for quality assurance (QA) of such dynamic treatments. The primary aim is to test the sensitivity of machine log files in comparison to electronic portal imaging device (EPID)-based measurements to MLC position errors caused by leaf backlash. The secondary aim is to investigate the effect of MLC leaf backlash on MLC leaf motion during clinical dynamic plan delivery. METHODS: The sensitivity of machine log files and two EPID-based measurements were assessed via a controlled experiment, whereby the length of the "T" section of a series of 12 MLC leaf T-nuts in a Varian Millennium MLC for a Trilogy C-series type linac was reduced by sandpapering the top of the "T" to introduce backlash. The built-in machine MLC leaf backlash test as well as measurements for two EPID-based dynamic MLC positional tests along with log files were recorded pre- and post-T-nut modification. All methods were investigated for sensitivity to the T-nut change by assessing the effect on measured MLC leaf positions. A reduced version of the experiment was repeated on a TrueBeam type linac with Millennium MLC. RESULTS: No significant differences before and after T-nut modification were detected in any of the log file data. Both EPID methods demonstrated sensitivity to the introduced change at approximately the expected magnitude with a strong dependence observed with gantry angle. EPID-based data showed MLC positional error in agreement with the micrometer measured T-nut length change to 0.07 ± 0.05 mm (1 SD) using the departmental routine QA test. Backlash results were consistent between linac types. CONCLUSION: Machine log files appear insensitive to MLC position errors caused by MLC leaf backlash introduced via the T-nut. The effect of backlash on clinical MLC motions is heavily gantry angle dependent.

Fire in the Operating Room: Surgical Case Report From a Forced-Air Warming Device Equipment Fire.

Surgical fires are critical life-threatening events that can result in patient morbidity and mortality. This case report describes an equipment fire originating from a forced-air warming device occurring during a shoulder arthroscopy operation and discusses how the surgical team responded to mitigate risks to the patient and staff. Rapid response by the anesthesia professional and the surgical team helped prevent the fire from negatively impacting patient and staff safety. The patient was discharged from the hospital without any complications. We recommend that surgical teams engage in a coordinated and continual cycle of fire prevention, including enhanced education and interprofessional team training.

Metformin use and the risk of anal intraepithelial neoplasia in type II diabetic patients.

AIM: Emerging evidence has suggested that metformin may be protective against the development of human-papillomavirus-related cancers. Anal intraepithelial neoplasia (AIN) is highly associated with human papillomavirus infection and a precancerous status of anal cancer. The aim of this study was to investigate the relationship between metformin usage and the development of AIN in a large national sample. METHODOLOGY: The IBM MarketScan dataset was used to design a nested case-control study from 2010 to 2017. Patients aged 18-65 years with type 2 diabetes mellitus (DM) were evaluated, and cases of AIN were identified. Four controls were randomly selected in the risk set of each case by using incidence density sampling. The association between metformin usage and AIN was assessed using multivariate logistic regression modelling. RESULTS: A total of 258 patients with type 2 DM were diagnosed with AIN during the study interval, and these were matched to 1032 control patients without a diagnosis of AIN. Patients who developed AIN had 38% lower odds of prior metformin use compared to those without a history of AIN (P < 0.01) and this finding remained robust after adjusting for age, sex, human immunodeficiency virus infection and DM complications (P = 0.02). Patients with AIN had 56% lower odds of long-term metformin use compared to control patients (P = 0.01). CONCLUSIONS: An AIN diagnosis in patients with DM is associated with 56% lower likelihood of prior metformin use. This relationship suggests that metformin could potentially play a protective role against AIN. Prospective studies in non-diabetic patients are warranted to examine these findings further.

Outcomes and Disposition of Oncology Patients With Non-neutropenic Fever and Positive Blood Cultures.

Children with cancer and non-neutropenic fever (NNF) episodes are often treated as outpatients if they appear well. However, a small subset have bloodstream infections (BSIs) and must return for further evaluation. These patients may be directly admitted to inpatient units, whereas others are first evaluated in outpatient settings before admission. The best practice for securing care for patients discovered to have outpatient bacteremia are unclear. To determine outcomes and compare time to antibiotics between the 2 disposition, we retrospectively reviewed all NNF initially treated as outpatients and later had positive blood cultures from 2012 to 2016. Of 845 NNF cases initially treated in outpatient settings, 48 episodes (n=43 patients) had BSIs. Of those, 77.1% (n=37) were re-evaluated as outpatients and admitted; 14.6% (n=7) were direct admissions. The median time to antibiotic did not significantly differ between outpatient re-evaluations (119 min) and direct admissions (191 min), P=0.11. One patient met sepsis criteria upon return and required intensive care unit admission for vasopressor support. No patient died within 1 week of the febrile episode. Most patients with NNF and BSIs initially discharged are stable upon return. Institutions should evaluate their patient flows to ensure that patients receive timely care.

Longitudinal Trajectories of Neurocognitive Functioning in Childhood Acute Lymphoblastic Leukemia.

OBJECTIVE: Children with acute lymphoblastic leukemia (ALL) are at risk for neurocognitive deficits, and examining individual variability is essential to understand these risks. This study evaluated latent longitudinal trajectories and risk factors of neurocognitive outcomes in childhood ALL. METHODS: There were 233 participants with ALL who were enrolled on a phase 3, risk-stratified chemotherapy-only clinical trial (NCT00137111) and who completed protocol-directed neurocognitive assessments [47.6% female, mean (SD) = 6.6 (3.7) years]. Measures of sustained attention, learning/memory, and parent ratings of attention were completed during and after treatment. Longitudinal latent class analyses were used to classify participants into distinct trajectories. Logistic regression was used to identify predictors of class membership. RESULTS: Within the overall group, attention performance was below age expectations across time (Conners Continuous Performance Test detectability/variability, p < 0.01); memory performance and parent ratings were below expectations at later phases (California Verbal Learning Test learning slope, p < 0.05; Conners Parent Rating Scale, Revised attention/learning, p < 0.05). Most participants (80-89%) had stable neurocognitive profiles; smaller groups showed declining (3-6%) or improving (3-11%) trajectories. Older age (p = 0.020), female sex (p = 0.018), and experiencing sepsis (p = 0.047) were associated with greater attention problems over time. Lower baseline IQ was associated with improved memory (p = 0.035) and fewer ratings of attention problems (p = 0.013) over time. CONCLUSIONS: Most patients with ALL have stable neurocognitive profiles. Smaller groups have significant impairments shortly after diagnosis or have worsening performance over time. A tiered assessment approach, which includes consideration of individual and clinical risk factors, may be useful for monitoring neurocognitive functioning during treatment and survivorship.

Venetoclax in combination with cytarabine with or without idarubicin in children with relapsed or refractory acute myeloid leukaemia: a phase 1, dose-escalation study.

BACKGROUND: Outcomes for children with relapsed or refractory acute myeloid leukaemia remain poor. The BCL-2 inhibitor, venetoclax, has shown promising activity in combination with hypomethylating agents and low-dose cytarabine in older adults for whom chemotherapy is not suitable with newly diagnosed acute myeloid leukaemia. We aimed to determine the safety and explore the activity of venetoclax in combination with standard and high-dose chemotherapy in paediatric patients with relapsed or refractory acute myeloid leukaemia. METHODS: We did a phase 1, dose-escalation study at three research hospitals in the USA. Eligible patients were aged 2-22 years with relapsed or refractory acute myeloid leukaemia or acute leukaemia of ambiguous lineage with adequate organ function and performance status. During dose escalation, participants received venetoclax orally once per day in continuous 28-day cycles at either 240 mg/m2 or 360 mg/m2, in combination with cytarabine received intravenously every 12 h at either 100 mg/m2 for 20 doses or 1000 mg/m2 for eight doses, with or without intravenous idarubicin (12 mg/m2) as a single dose, using a rolling-6 accrual strategy. The primary endpoint was the recommended phase 2 dose of venetoclax plus chemotherapy and the secondary endpoint was the proportion of patients treated at the recommended phase 2 dose who achieved complete remission or complete remission with incomplete haematological recovery. Analyses were done on patients who received combination therapy. The study is registered with ClinicalTrials.gov (NCT03194932) and is now enrolling to address secondary and exploratory objectives. FINDINGS: Between July 1, 2017, and July 2, 2019, 38 patients were enrolled (aged 3-22 years; median 10 [IQR 7-13]), 36 of whom received combination therapy with dose escalation, with a median follow-up of 7·1 months (IQR 5·1-11·2). The recommended phase 2 dose of venetoclax was found to be 360 mg/m2 (maximum 600 mg) combined with cytarabine (1000 mg/m2 per dose for eight doses), with or without idarubicin (12 mg/m2 as a single dose). Overall responses were observed in 24 (69%) of the 35 patients who were evaluable after cycle 1. Among the 20 patients treated at the recommended phase 2 dose, 14 (70%, 95% CI 46-88) showed complete response with or without complete haematological recovery, and two (10%) showed partial response. The most common grade 3-4 adverse events were febrile neutropenia (22 [66%]), bloodstream infections (six [16%]), and invasive fungal infections (six [16%]). Treatment-related death occurred in one patient due to colitis and sepsis. INTERPRETATION: The safety and activity of venetoclax plus chemotherapy in paediatric patients with heavily relapsed and refractory acute myeloid leukaemia suggests that this combination should be tested in newly diagnosed paediatric patients with high-risk acute myeloid leukaemia. FUNDING: US National Institutes of Health, American Lebanese Syrian Associated Charities, AbbVie, and Gateway for Cancer Research.

Nasal Wash Cytokines during Respiratory Viral Infection in Pediatric Allogeneic Hematopoietic Cell-Transplant Recipients.

Allogeneic hematopoietic cell-transplant (alloHCT) recipients are at increased risk of complications from viral respiratory-tract infections (vRTIs). We measured cytokine concentrations in nasal washes (NWs) from pediatric alloHCT recipients to better understand their local response to vRTI. Forty-one immunologic analytes were measured in 70 NWs, collected during and after vRTI, from 15 alloHCT recipients (median age, 11 yr) with 19 episodes of vRTI. These were compared with NW cytokine concentrations from an independent group of otherwise healthy patients. AlloHCT recipients are able to produce a local response to vRTI and produce IFN-α2 and IL-12p40 in significant quantities above an uninfected baseline early in infection. Compared with otherwise healthy comparator-group patients, alloHCT recipients have higher NW concentrations of IL-4 when challenged with vRTI. Further study of these immunologic analytes as well as of type 1 versus type 2 balance in the respiratory mucosa in the context of vRTI during immune reconstitution may be of future research interest in this vulnerable patient population.

Safety and Efficacy of Fidaxomicin and Vancomycin in Children and Adolescents with Clostridioides (Clostridium) difficile Infection: A Phase 3, Multicenter, Randomized, Single-blind Clinical Trial (SUNSHINE).

BACKGROUND: Fidaxomicin, a narrow-spectrum antibiotic approved for Clostridioides (Clostridium) difficile infection (CDI) in adults, is associated with lower rates of recurrence than vancomycin; however, pediatric data are limited. This multicenter, investigator-blind, phase 3, parallel-group trial assessed the safety and efficacy of fidaxomicin in children. METHODS: Patients aged <18 years with confirmed CDI were randomized 2:1 to 10 days of treatment with fidaxomicin (suspension or tablets, twice daily) or vancomycin (suspension or tablets, 4 times daily). Safety assessments included treatment-emergent adverse events. The primary efficacy end point was confirmed clinical response (CCR), 2 days after the end of treatment (EOT). Secondary end points included global cure (GC; CCR without CDI recurrence) 30 days after EOT (end of study; EOS). Plasma and stool concentrations of fidaxomicin and its active metabolite OP-1118 were measured. RESULTS: Of 148 patients randomized, 142 were treated (30 <2 years old). The proportion of participants with treatment-emergent adverse events was similar with fidaxomicin (73.5%) and vancomycin (75.0%). Of 3 deaths in the fidaxomicin arm during the study, none were CDI or treatment related. The rate of CCR at 2 days after EOT was 77.6% (76 of 98 patients) with fidaxomicin and 70.5% (31 of 44) with vancomycin, whereas the rate of GC at EOS was significantly higher in participants receiving fidaxomicin (68.4% vs 50.0%; adjusted treatment difference, 18.8%; 95% confidence interval, 1.5%-35.3%). Systemic absorption of fidaxomicin and OP-1118 was minimal, and stool concentrations were high. CONCLUSIONS: Compared with vancomycin, fidaxomicin was well tolerated and demonstrated significantly higher rates of GC in children and adolescents with CDI. CLINICAL TRIALS REGISTRATION: NCT02218372.

Guideline for Antibacterial Prophylaxis Administration in Pediatric Cancer and Hematopoietic Stem Cell Transplantation.

BACKGROUND: Bacteremia and other invasive bacterial infections are common among children with cancer receiving intensive chemotherapy and in pediatric recipients of hematopoietic stem cell transplantation (HSCT). Systemic antibacterial prophylaxis is one approach that can be used to reduce the risk of these infections. Our purpose was to develop a clinical practice guideline (CPG) for systemic antibacterial prophylaxis administration in pediatric patients with cancer and those undergoing HSCT. METHODS: An international and multidisciplinary panel was convened with representation from pediatric hematology/oncology and HSCT, pediatric infectious diseases (including antibiotic stewardship), nursing, pharmacy, a patient advocate, and a CPG methodologist. The panel used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to generate recommendations based on the results of a systematic review of the literature. RESULTS: The systematic review identified 114 eligible randomized trials of antibiotic prophylaxis. The panel made a weak recommendation for systemic antibacterial prophylaxis for children receiving intensive chemotherapy for acute myeloid leukemia and relapsed acute lymphoblastic leukemia (ALL). Weak recommendations against the routine use of systemic antibacterial prophylaxis were made for children undergoing induction chemotherapy for ALL, autologous HSCT and allogeneic HSCT. A strong recommendation against its routine use was made for children whose therapy is not expected to result in prolonged severe neutropenia. If used, prophylaxis with levofloxacin was recommended during severe neutropenia. CONCLUSIONS: We present a CPG for systemic antibacterial prophylaxis administration in pediatric cancer and HSCT patients. Future research should evaluate the long-term effectiveness and adverse effects of prophylaxis.