How Immunocompromised Hosts Were Left Behind in the Quest to Control the Covid-19 Pandemic.

The immunocompromised population was disproportionately affected by the SARS-CoV-2 pandemic. However, these individuals were largely excluded from clinical trials of vaccines, monoclonal antibodies, and small molecule antivirals. While the community of scientists, clinical researchers, and funding agencies have proven that these therapeutics can be made and tested in record time, extending this progress to vulnerable and medically complex individuals from the start has been a missed opportunity. Here we advocate that it is paramount to plan for future pandemics by investing in specific clinical trial infrastructure for the immunocompromised population to be prepared when the need arises.

CMV Reactivation during Pre-Transplantation Evaluation: A Novel Risk Factor for Post-Transplantation CMV Reactivation.

Cytomegalovirus (CMV) disease occurs occasionally before allogeneic hematopoietic cell transplantation (HCT) and is associated with poor post-HCT outcomes; however, the impact of pre-HCT CMV reactivation is unknown. Pre-HCT CMV reactivation was assessed in HCT candidates from the preemptive antiviral therapy (2007-17) and letermovir prophylaxis (2018-21) eras. CMV DNA PCR surveillance was routinely performed during the pre-HCT work-up period, and antiviral therapy was recommended according to risk for progression to CMV disease. Risk factors for pre-HCT CMV reactivation were characterized and the associations of pre-HCT CMV reactivation with post-HCT outcomes were examined using logistic regression and Cox proportional hazard models, respectively. A total of 1694 patients were identified and 11% had pre-HCT CMV reactivation 14 days (median; IQR 6-23 days) before HCT. Lymphopenia (≤300 cells/uL) was the strongest risk factor for pre-HCT CMV reactivation at multiple PCR levels. In the preemptive therapy era, patients with pre-HCT CMV reactivation had a significantly increased risk of CMV reactivation by day 100 as well as CMV disease and death by 1 year post-HCT. Clearance of pre-HCT CMV reactivation was associated with a lower risk of post-HCT CMV reactivation. Similar associations with post-HCT CMV endpoints were observed in a cohort of patients receiving letermovir prophylaxis. Pre-HCT CMV reactivation can be routinely detected in high-risk HCT candidates and is a significant risk factor for post-HCT CMV reactivation and disease. Pre-HCT CMV DNA PCR surveillance is recommended in high-risk HCT candidates and antiviral therapy may be indicated to prevent post-HCT CMV reactivation.

The effect of gastrointestinal graft-versus-host disease and diarrhea on the pharmacokinetic profile of sotrovimab in hematopoietic stem cell transplant recipients.

BACKGROUND: Monoclonal antibodies (mAbs) are utilized broadly to treat cancer and infectious diseases, and mAb exposure (serum concentration over time) is one predictor of overall treatment efficacy. Herein, we present findings from a clinical trial evaluating the pharmacokinetics (PK) of the long-acting mAb sotrovimab targeting SARS-CoV-2 in hematopoietic cell transplant (HCT) recipients. METHODS: All participants received an intravenous infusion of sotrovimab within one week prior to initiating the pre-transplant preparative regimen. The serum concentration of sotrovimab was measured longitudinally for up to 24 weeks post-transplant. RESULTS: Compared to non-HCT participants, we found that mAb clearance was 10% and 26% higher in autologous and allogeneic HCT recipients, respectively. Overall sotrovimab exposure was approximately 15% lower in HCT recipients compared to non-HCT recipients. Exposure was significantly reduced in HCT recipients who developed diarrhea and lower gastrointestinal (GI) graft-versus-host disease (GVHD) post-transplant. CONCLUSIONS: These data show that sotrovimab exposure may be reduced in HCT recipients, possibly related to increased GI clearance in patients with GVHD. This phenomenon has implications for dose selection and duration of efficacy with sotrovimab and potentially other mAbs in this vulnerable patient population. Thus, mAb dose regimens developed in non-HCT populations may have to be optimized when applied to HCT populations.

The impact of pre-transplant respiratory virus detection on post-transplant outcomes in children undergoing hematopoietic cell transplantation.

BACKGROUND: Pre-transplant respiratory virus (RV) infections have been associated with negative transplant outcomes in adult hematopoietic cell transplantation (HCT) recipients. In the era of HCT delay due to high-risk RVs, we examined the impact of pre-transplant RV detection on transplant outcomes in a pediatric HCT recipients. METHODS: This retrospective cohort study included myeloablative allogeneic HCT recipients from 2010 to 2019. All patients were screened for RV at least once within 90 days before HCT using RT-PCR, regardless of symptoms. Post-transplant outcomes included days alive and out of hospital (DAOH) and progression to lower respiratory tract infection (LRTI). RESULTS: Among 310 patients, 134 had a RV detected in the 90 days prior to HCT. In univariable analysis, transplant factors including younger age, total body irradiation, umbilical cord blood transplantation, lymphocyte count less than 100/mm3, and HCT comorbidity index score ≥3, and viral factors including symptomatic infection, human rhinovirus (HRV) as a virus type, and symptomatic pre-transplant upper respiratory tract infection (URTI) were associated with fewer DAOH. In multivariable analysis, transplant factors remained significant, but not viral factors. There was a higher incidence of progression to post-transplant LRTI with the same pre-transplant RV if the last positive PCR before HCT was ≤30 days compared to >30 days (p=0.007). CONCLUSION: In the setting of recommending HCT delay for high-risk RVs, symptomatic URTI, including HRV infections, may lead to increased duration of hospitalization and early progression to LRTI when transplantation is performed within 30 days of the last positive PCR test.

Human Herpesvirus-6 Reactivation and Disease Are Infrequent in Chimeric Antigen Receptor T-cell Therapy Recipients.

Human herpesvirus-6B (HHV-6B) reactivation and disease are increasingly reported after CAR-T-cell therapy (CARTx). HHV-6 reactivation in the CAR-T-cell product was recently reported, raising questions about product and patient management. Due to overlapping manifestations with immune effector cell-associated neurotoxicity syndrome, diagnosing HHV-6B encephalitis is challenging. We provide two lines of evidence assessing the incidence and outcomes of HHV-6B after CARTx. First, in a prospective study with weekly HHV-6B testing for up to 12 weeks post-infusion, HHV-6B reactivation occurred in eight of 89 participants; three had chromosomally integrated HHV-6 and were excluded, resulting in a cumulative incidence of HHV-6B reactivation of 6% (95% confidence interval (CI), 2.2-12.5%). HHV-6B detection was low level (median peak, 435 copies/mL; IQR, 164-979) and did not require therapy. Second, we retrospectively analyzed HHV-6B detection in blood and/or cerebrospinal fluid (CSF) within 12 weeks post-infusion in CARTx recipients. Of 626 patients, 24 had symptom-driven plasma testing with detection in one. Among 34 patients with CSF HHV-6 testing, one patient had possible HHV-6 encephalitis for a cumulative incidence of 0.17% (95% CI, 0.02-0.94%), although symptoms improved without treatment. Our data demonstrate that HHV-6B reactivation and disease are infrequent after CARTx. Routine HHV-6 monitoring is not warranted.

Outcomes in Hematopoietic Cell Transplant and Chimeric Antigen Receptor T Cell Therapy Recipients with Pre-Cellular Therapy SARS-CoV-2 Infection.

BACKGROUND: Hematopoietic cell transplant (HCT) or chimeric antigen receptor T cell (CAR-T) therapy recipients have high morbidity from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. There are limited data on outcomes from SARS-CoV-2 infection shortly before cellular therapy and uncertainty whether to delay therapy. METHODS: We conducted a retrospective cohort study of patients with SARS-CoV-2 infection within 90 days prior to HCT or CAR-T therapy between January 2020 and November 2022. We characterized the kinetics of SARS-CoV-2 detection, clinical outcomes following cellular therapy, and impact on delays in cellular therapy. RESULTS: We identified 37 patients (n=15 allogeneic HCT, n=11 autologous HCT, n=11 CAR-T therapy) with SARS-CoV-2 infections within 90 days of cellular therapy. Most infections (73%) occurred between March and November 2022, when Omicron strains were prevalent. Most patients had asymptomatic (27%) or mild (68%) coronavirus disease 2019 (COVID-19). SARS-CoV-2 positivity lasted a median of 20.0 days [IQR, 12.5-26.25]. The median time from first positive SARS-CoV-2 test to cellular therapy was 45 days [IQR, 37.75-70]; one patient tested positive on the day of infusion. After cellular therapy, no patients had recrudescent SARS-CoV-2 infection or COVID-19-related complications. Cellular therapy delays related to SARS-CoV-2 infection occurred in 70% of patients for a median of 37 days. Delays were more common after allogeneic (73%) and autologous (91%) HCT compared to CAR-T cell therapy (45%). CONCLUSIONS: Patients with asymptomatic or mild COVID-19 may not require prolonged delays in cellular therapy in the context of contemporary circulating variants and availability of antiviral therapies.

Late cytomegalovirus disease after hematopoietic cell transplantation: significance of novel transplantation techniques.

ABSTRACT: Preemptive therapy (PET) and letermovir prophylaxis are effective in preventing cytomegalovirus (CMV) disease within the first 100 days after allogeneic hematopoietic cell transplantation (HCT) but are associated with late-onset CMV disease. We retrospectively examined the clinical manifestations, risk factors, prevention algorithm, and outcome of late CMV disease in CMV seropositive day 100 survivors transplanted between 2001-2017 (PET cohort) and 2018-2021 (letermovir cohort). There were 203 episodes of late CMV disease among 2469 day 100 survivors, and the estimated cumulative incidence of first late CMV disease was 7.2% (95% confidence interval [CI], 6.2-8.3) with no difference between the PET (7.4%; 95% CI, 6.4-8.6) and the letermovir group (5.4%; 95% CI, 3.2-8.3). Thirty-seven patients (1.5%) had a second episode of CMV disease. In multivariable Cox regression models, posttransplant cyclophosphamide was associated with an increased risk of gastrointestinal CMV disease. CMV viremia or disease detected before day 100, corticosteroid treatment after day 100 at dose ≥1 mg/kg, acute and chronic graft-versus-host disease, lymphopenia, HLA-mismatched related donor status, were also associated with late CMV disease. HLA-mismatched donor status and late use of corticosteroids (≥1 mg/kg) were risk factors for late CMV disease recurrence. Late CMV disease occurred most frequently in a setting of prolonged low-level untreated viremia and was independently associated with death by 2 years after HCT. In summary, late CMV disease continues to occur in the present era. Improved prevention strategies for late CMV disease are needed.

Comparative diagnostic utility of SARS-CoV-2 rapid antigen and molecular testing in a community setting.

BACKGROUND: SARS-CoV-2 antigen-detection rapid diagnostic tests (Ag-RDTs) have become widely utilized but longitudinal characterization of their community-based performance remains incompletely understood. METHODS: This prospective longitudinal study at a large public university in Seattle, WA utilized remote enrollment, online surveys, and self-collected nasal swab specimens to evaluate Ag-RDT performance against real-time reverse transcription polymerase chain reaction (rRT-PCR) in the context of SARS-CoV-2 Omicron. Ag-RDT sensitivity and specificity within 1 day of rRT-PCR were evaluated by symptom status throughout the illness episode and Orf1b cycle threshold (Ct). RESULTS: From February to December 2022, 5,757 participants reported 17,572 Ag-RDT results and completed 12,674 rRT-PCR tests, of which 995 (7.9%) were rRT-PCR-positive. Overall sensitivity and specificity were 53.0% (95% CI: 49.6-56.4%) and 98.8% (98.5-99.0%), respectively. Sensitivity was comparatively higher for Ag-RDTs used 1 day after rRT-PCR (69.0%), 4 to 7 days post-symptom onset (70.1%), and Orf1b Ct ≤20 (82.7%). Serial Ag-RDT sensitivity increased with repeat testing ≥2 (68.5%) and ≥4 (75.8%) days after an initial Ag-RDT-negative result. CONCLUSION: Ag-RDT performance varied by clinical characteristics and temporal testing patterns. Our findings support recommendations for serial testing following an initial Ag-RDT-negative result, especially among recently symptomatic persons or those at high-risk for SARS-CoV-2 infection.

Evaluation of Three Cytomegalovirus IgG Lateral Flow Assays for Rapid Determination of CMV Serostatus.

Background: Cytomegalovirus (CMV) serostatus is a major determinant of CMV infection, disease risk, and transplant outcomes. Current clinical serology assays are limited by relatively slow turnaround time, design for batched testing, need for trained personnel, and/or specialized equipment. Rapid diagnostic assays in development have a role in emerging settings, such as critically ill patients, but have not been systematically evaluated. Methods: We assessed the performance of 3 rapid lateral flow assays (LFAs) for the detection of CMV immunoglobulin (Ig)G antibodies compared with a reference commercially available CMV IgG enzyme-linked immunosorbent assay in residual serum samples from 200 consecutive adults who underwent clinical CMV serology testing. Samples with discrepant results between the LFA and reference assay were tested by a second reference assay. A subset of serum samples was assessed for interoperator variability. Operating characteristics of the QooLabs LFA were separately assessed in plasma samples. Results: The sensitivity and specificity of the individual LFA assays using serum varied significantly: 86%/83%, 99/93%, and 57/97%, for Healgen, QNow automated reader, and nanoComposix, respectively, compared with the reference assay. Results for the QNow assay were comparable between automated and manual reads. Among a subset of 10 serum samples assessed by 5 individual operators, 44 of 50 (88%) results were concordant. Among 50 plasma samples assessed by the QooLabs LFA, the sensitivity and specificity were 72% and 96%. Conclusions: The ease of performance, rapid turnaround time, and good operating characteristics provide the rationale for further evaluation of the Qoolabs QNow LFA in specialized settings where rapid assessment of CMV serostatus would be advantageous.

HHV-6B detection and host gene expression implicate HHV-6B as pulmonary pathogen after hematopoietic cell transplant.

Limited understanding of the immunopathogenesis of human herpesvirus 6B (HHV-6B) has prevented its acceptance as a pulmonary pathogen after hematopoietic cell transplant (HCT). In this prospective multicenter study of patients undergoing bronchoalveolar lavage (BAL) for pneumonia after allogeneic HCT, we test blood and BAL fluid (BALF) for HHV-6B DNA and mRNA transcripts associated with lytic infection and perform RNA-seq on paired blood. Among 116 participants, HHV-6B DNA is detected in 37% of BALs, 49% of which also have HHV-6B mRNA detection. We establish HHV-6B DNA viral load thresholds in BALF that are highly predictive of HHV-6B mRNA detection and associated with increased risk for overall mortality and death from respiratory failure. Participants with HHV-6B DNA in BALF exhibit distinct host gene expression signatures, notable for enriched interferon signaling pathways in participants clinically diagnosed with idiopathic pneumonia. These data implicate HHV-6B as a pulmonary pathogen after allogeneic HCT.

Differential Association between Blood Glucose Levels and Nonrelapse Mortality after Allogeneic Hematopoietic Cell Transplantation Based on Presence or Absence of Preexisting Diabetes.

Malglycemia, defined as hyperglycemia, hypoglycemia, or increased glycemic variability, has been associated with increased mortality after allogeneic hematopoietic cell transplantation (HCT). Among critically ill non-HCT recipients with diabetes and poor glycemic control, compared to those without diabetes, stringent blood glucose control has been associated with increased mortality. This study investigated whether a pre-HCT diagnosis of diabetes and the type of pre-HCT diabetes treatment modulate the previously reported negative impact of malglycemia on post-HCT nonrelapse mortality (NRM). We performed a single-institution retrospective analysis of mortality outcomes after allogeneic HCT as a function of post-HCT blood glucose levels, pre-HCT diagnosis of diabetes, and type of pre-HCT diabetes treatment (insulin, no insulin). A total of 1062 patients who underwent allogeneic HCT between 2015 and 2020 were included in this study. Among these patients, 84 (8%) had a pre-HCT diagnosis of diabetes, of whom 38 (4%) used insulin and 46 (4%) used a noninsulin antiglycemic agent. Post-HCT blood glucose values measured within 100 days from HCT, modeled as a continuous nonlinear time-varying covariate, were associated with day-200 NRM, with both lower and higher glycemic values associated with higher NRM compared to normoglycemic values (adjusted P < .0001). The association between post-HCT blood glucose and NRM varied, however, depending on the presence or absence of a pre-HCT diagnosis of diabetes; that is, there was evidence of a statistical interaction between blood glucose levels and diabetes (adjusted P = .008). In particular, the detrimental impact of hyperglycemic values was more pronounced in patients without a pre-HCT diagnosis of diabetes compared to those with a pre-HCT diagnosis of diabetes. As reported previously, higher and lower blood glucose levels measured within 100 days after allogeneic HCT were associated with an increased risk of NRM; however, this association was more pronounced among patients without a pre-HCT diagnosis of diabetes compared to those with a pre-HCT diagnosis of diabetes, suggesting that patients with diabetes are relatively protected from the downstream effects of hyperglycemia. These data support the notion that patients with pre-HCT diabetes may need a different approach to blood glucose management after transplantation compared to those without diabetes. © 2024 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.

Within-Host Rhinovirus Evolution in Upper and Lower Respiratory Tract Highlights Capsid Variability and Mutation-Independent Compartmentalization.

BACKGROUND: Rhinovirus (RV) infections can progress from the upper (URT) to lower (LRT) respiratory tract in immunocompromised individuals, causing high rates of fatal pneumonia. Little is known about how RV evolves within hosts during infection. METHODS: We sequenced RV complete genomes from 12 hematopoietic cell transplant patients with infection for up to 190 days from both URT (nasal wash, NW) and LRT (bronchoalveolar lavage, BAL). Metagenomic and amplicon next-generation sequencing were used to track the emergence and evolution of intrahost single nucleotide variants (iSNVs). RESULTS: Identical RV intrahost populations in matched NW and BAL specimens indicated no genetic adaptation is required for RV to progress from URT to LRT. Coding iSNVs were 2.3-fold more prevalent in capsid over nonstructural genes. iSNVs modeled were significantly more likely to be found in capsid surface residues, but were not preferentially located in known RV-neutralizing antibody epitopes. Newly emergent, genotype-matched iSNV haplotypes from immunocompromised individuals in 2008-2010 could be detected in Seattle-area community RV sequences in 2020-2021. CONCLUSIONS: RV infections in immunocompromised hosts can progress from URT to LRT with no specific evolutionary requirement. Capsid proteins carry the highest variability and emergent mutations can be detected in other, including future, RV sequences.

Serial Quantitation of Plasma Microbial Cell-Free DNA Before and After Diagnosis of Pulmonary Invasive Mold Infections After Hematopoietic Cell Transplant.

BACKGROUND: Plasma microbial cell-free DNA sequencing (mcfDNA-Seq) is a noninvasive test for microbial diagnosis of invasive mold infection (IMI). The utility of mcfDNA-Seq for predicting IMI onset and the clinical implications of mcfDNA concentrations are unknown. METHODS: We retrospectively tested plasma from hematopoietic cell transplant (HCT) recipients with pulmonary IMI and ≥1 mold identified by mcfDNA-Seq in plasma collected within 14 days of clinical diagnosis. Samples collected from up to 4 weeks before and 4 weeks after IMI diagnosis were evaluated using mcfDNA-Seq. RESULTS: Thirty-five HCT recipients with 39 IMIs (16 Aspergillus and 23 non-Aspergillus infections) were included. Pathogenic molds were detected in 38%, 26%, 11%, and 0% of samples collected during the first, second, third, and fourth week before clinical diagnosis, respectively. In non-Aspergillus infections, median mcfDNA concentrations in samples collected within 3 days of clinical diagnosis were higher in infections with versus without extrapulmonary spread (4.3 vs 3.3 log10 molecules per microliter [mpm], P = .02), and all patients (8/8) with mcfDNA concentrations >4.0 log10 mpm died within 42 days after clinical diagnosis. CONCLUSIONS: Plasma mcfDNA-Seq can identify pathogenic molds up to 3 weeks before clinical diagnosis of pulmonary IMI. Plasma mcfDNA concentrations may correlate with extrapulmonary spread and mortality in non-Aspergillus IMI.

Cytomegalovirus (CMV) Reactivation and CMV-Specific Cell-Mediated Immunity After Chimeric Antigen Receptor T-Cell Therapy.

BACKGROUND: The epidemiology of cytomegalovirus (CMV) after chimeric antigen receptor-modified T-cell immunotherapy (CARTx) is poorly understood owing to a lack of routine surveillance. METHODS: We prospectively enrolled 72 adult CMV-seropositive CD19-, CD20-, or BCMA-targeted CARTx recipients and tested plasma samples for CMV before and weekly up to 12 weeks after CARTx. We assessed CMV-specific cell-mediated immunity (CMV-CMI) before and 2 and 4 weeks after CARTx, using an interferon γ release assay to quantify T-cell responses to IE-1 and pp65. We tested pre-CARTx samples to calculate a risk score for cytopenias and infection (CAR-HEMATOTOX). We used Cox regression to evaluate CMV risk factors and evaluated the predictive performance of CMV-CMI for CMV reactivation in receiver operator characteristic curves. RESULTS: CMV was detected in 1 patient (1.4%) before and in 18 (25%) after CARTx, for a cumulative incidence of 27% (95% confidence interval, 16.8-38.2). The median CMV viral load (interquartile range) was 127 (interquartile range, 61-276) IU/mL, with no end-organ disease observed; 5 patients received preemptive therapy based on clinical results. CMV-CMI values reached a nadir 2 weeks after infusion and recovered to baseline levels by week 4. In adjusted models, BCMA-CARTx (vs CD19/CD20) and corticosteroid use for >3 days were significantly associated with CMV reactivation, and possible associations were detected for lower week 2 CMV-CMI and more prior antitumor regimens. The cumulative incidence of CMV reactivation almost doubled when stratified by BCMA-CARTx target and use of corticosteroids for >3 days (46% and 49%, respectively). CONCLUSIONS: CMV testing could be considered between 2 and 6 weeks in high-risk CARTx recipients.

homeRNA self-blood collection enables high-frequency temporal profiling of pre-symptomatic host immune kinetics to respiratory viral infection: a prospective cohort study.

Background: Early host immunity to acute respiratory infections (ARIs) is heterogenous, dynamic, and critical to an individual's infection outcome. Due to limitations in sampling frequency/timepoints, kinetics of early immune dynamics in natural human infections remain poorly understood. In this nationwide prospective cohort study, we leveraged a self-blood collection tool (homeRNA) to profile detailed kinetics of the pre-symptomatic to convalescence host immunity to contemporaneous respiratory pathogens. Methods: We enrolled non-symptomatic adults with recent exposure to ARIs who subsequently tested negative (exposed-uninfected) or positive for respiratory pathogens. Participants self-collected blood and nasal swabs daily for seven consecutive days followed by weekly blood collection for up to seven additional weeks. Symptom burden was assessed during each collection. Nasal swabs were tested for SARS-CoV-2 and common respiratory pathogens. 92 longitudinal blood samples spanning the pre-shedding to post-acute phase of eight SARS-CoV-2-infected participants and 40 interval-matched samples from four exposed-uninfected participants were subjected to high-frequency longitudinal profiling of 773 host immune genes. Findings: Between June 2021 - April 2022, 68 participants across 26 U.S. states completed the study and self-collected a total of 691 and 466 longitudinal blood and nasal swab samples along with 688 symptom surveys. SARS-CoV-2 was detected in 17 out of 22 individuals with study-confirmed respiratory infection. With rapid dissemination of home self-collection kits, two and four COVID-19+ participants started collection prior to viral shedding and symptom onset, respectively, enabling us to profile detailed expression kinetics of the earliest blood transcriptional response to contemporaneous variants of concern. In pre-shedding samples, we observed transient but robust expression of T-cell response signatures, transcription factor complexes, prostaglandin biosynthesis genes, pyrogenic cytokines, and cytotoxic granule genes. This is followed by a rapid induction of many interferon-stimulated genes (ISGs), concurrent to onset of viral shedding and increase in nasal viral load. Finally, we observed increased expression of host defense peptides (HDPs) in exposed-uninfected individuals over the 4-week observational window. Interpretation: We demonstrated that unsupervised self-collection and stabilization of capillary blood can be applied to natural infection studies to characterize detailed early host immune kinetics at a temporal resolution comparable to that of human challenge studies. The remote (decentralized) study framework enables conduct of large-scale population-wide longitudinal mechanistic studies. Expression of cytotoxic/T-cell signatures in pre-shedding samples preceding expansion of innate ISGs suggests a potential role for T-cell mediated pathogen control during early infection. Elevated expression of HDPs in exposed-uninfected individuals warrants further validation studies to assess their potential role in protective immunity during pathogen exposure. Funding: This study was funded by R35GM128648 to ABT for in-lab developments of homeRNA, Packard Fellowship from the David and Lucile Packard Foundation to ABT, and R01AI153087 to AW.

American Society of Transplantation and Cellular Therapy Series: #7 - Management of Respiratory Syncytial Virus Infections in Hematopoietic Cell Transplant Recipients.

The Practice Guidelines Committee of the American Society of Transplantation and Cellular Therapy (ASTCT) partnered with its Transplant Infectious Disease Special Interest Group (TID-SIG) to update the 2009 compendium-style infectious disease guidelines for hematopoietic cell transplantation (HCT). A new approach was adopted to better serve clinical providers by publishing each standalone topic in the infectious disease series in a concise format of frequently asked questions (FAQ), tables, and figures. Experts in HCT and infectious diseases identified FAQs and then provided answers based on the strength of the recommendation and the level of supporting evidence. In the seventh guideline in the series, we focus on the respiratory syncytial virus (RSV) with FAQs addressing epidemiology, clinical diagnosis, prophylaxis, and treatment. Special consideration was given to RSV in pediatric, cord blood, haploidentical, and T cell-depleted HCT and chimeric antigen receptor T cell therapy recipients, as well as to identify future research directions.

Cytomegalovirus Viral Load Threshold to Guide Preemptive Therapy in Hematopoietic Cell Transplant Recipients: Correlation with CMV Disease.

A systematic review of recent randomized and observational studies demonstrated that antiviral preemptive therapy started at cytomegalovirus (CMV) viral load thresholds between 2 and 3 log10 IU/mL were associated with similar CMV disease rates. Thus, viral thresholds in this range appear to effectively protect patients not receiving prophylaxis.