Tracking of activated cTfh cells following sequential influenza vaccinations reveals transcriptional profile of clonotypes driving a vaccine-induced immune response.

Introduction: A vaccine against influenza is available seasonally but is not 100% effective. A predictor of successful seroconversion in adults is an increase in activated circulating T follicular helper (cTfh) cells after vaccination. However, the impact of repeated annual vaccinations on long-term protection and seasonal vaccine efficacy remains unclear. Methods: In this study, we examined the T cell receptor (TCR) repertoire and transcriptional profile of vaccine-induced expanded cTfh cells in individuals who received sequential seasonal influenza vaccines. We measured the magnitude of cTfh and plasmablast cell activation from day 0 (d0) to d7 post-vaccination as an indicator of a vaccine response. To assess TCR diversity and T cell expansion we sorted activated and resting cTfh cells at d0 and d7 post-vaccination and performed TCR sequencing. We also single cell sorted activated and resting cTfh cells for TCR analysis and transcriptome sequencing. Results and discussion: The percent of activated cTfh cells significantly increased from d0 to d7 in each of the 2016-17 (p < 0.0001) and 2017-18 (p = 0.015) vaccine seasons with the magnitude of cTfh activation increase positively correlated with the frequency of circulating plasmablast cells in the 2016-17 (p = 0.0001) and 2017-18 (p = 0.003) seasons. At d7 post-vaccination, higher magnitudes of cTfh activation were associated with increased clonality of cTfh TCR repertoire. The TCRs from vaccine-expanded clonotypes were identified and tracked longitudinally with several TCRs found to be present in both years. The transcriptomic profile of these expanded cTfh cells at the single cell level demonstrated overrepresentation of transcripts of genes involved in the type-I interferon pathway, pathways involved in gene expression, and antigen presentation and recognition. These results identify the expansion and transcriptomic profile of vaccine-induced cTfh cells important for B cell help.

Long-Term Impact of Hospitalization for Kawasaki Disease on Health-Related Quality of Life.

OBJECTIVE: To prospectively evaluate the long-term impact of Kawasaki disease (KD) hospitalization on health-related quality of life (HRQoL). METHODS: We merged the Outcomes Assessment Program and KD databases and queried for KD admissions between 1 month and 18 years of age. Patients with a diagnosis of community-acquired pneumonia were included as a comparison group. HRQoL was evaluated with the parent proxy Pediatric Quality of Life Inventory (PedsQL). Long-term follow-up PedsQL surveys were performed at least 1 year after initial diagnosis and hospitalization. Results for the entire cohort adjusted for significant differences were calculated. Propensity score-matched cohorts were constructed from the unmatched cohorts of patients with long-term survey responses. Subgroup analysis for the KD group was performed. RESULTS: Patients with KD (n = 61) versus pneumonia (n = 80) had a lower PedsQL total score on admission and experienced a significantly greater HRQoL decline from baseline to admission. At long-term follow-up, no difference occurred in HRQoL between patients with KD and pneumonia, and 89% of patients with KD reached their baseline PedsQL scores. KD diagnostic subtype, coronary artery dilatation, and need for longer follow-up were not associated with HRQoL outcomes at any time point. Intravenous immunoglobulin nonresponders demonstrated lower HRQoL at admission, which did not persist at follow-up. CONCLUSIONS: Children with KD experience acute and significant HRQoL impairment exceeding that of children with newly diagnosed pneumonia, but the scores return to baseline at long-term follow-up. The recoveries at short- and long-term intervals are similar to patients with pneumonia.

Associations Between Health Care Professional Communication Practices and Influenza Vaccination of Hospitalized Children.

BACKGROUND: Health care professionals (HCPs) (eg, nurses, doctors) play a key role in vaccine uptake. Few studies describe HCP influenza vaccine communication with parents of hospitalized children. METHODS: This study included English- and Spanish-speaking parents of influenza vaccine-eligible children hospitalized at a tertiary care pediatric hospital between October 2018 and May 2019. A survey was completed online or via telephone 2 to 15 weeks (median 4 weeks) after discharge. It examined parental intent to vaccinate their child during hospitalization and parent-reported inpatient HCP communication practices (eg, vaccine recommendation strength, format for initiating the recommendation). Multivariable logistic regression examined the associations between HCP communication practices and influenza vaccination during hospitalization, adjusting for demographic, clinical, and visit characteristics. RESULTS: Parents (n = 194; 63.0% response rate) were mostly white (66.8%) and English-speaking (97.4%). Their children were primarily 5 through 17 years (67.0%) with chronic disease (68.6%); 24.7% were vaccinated before discharge. Most parents initially had no plan (55.6%) or planned to decline (31.1%) influenza vaccine for their child during hospitalization. Of these parents, 22.2% decided to accept the vaccine, 66.7% citing a HCP conversation as the main reason for changing their mind. Overall, 75.3% recalled a HCP conversation about influenza vaccination. Of these parents, 61.0% reported a HCP recommendation (53.8% described it as "very strong"; 11.1% noted a presumptive initiation format). A parent-reported HCP conversation (adjusted odds ratio [AOR] 5.23, 95% confidence interval [CI] 1.64-16.68) and recommendation (AOR 5.59, 95% CI 2.01-15.51) were associated with influenza vaccination during hospitalization. CONCLUSION: This study highlights the importance of discussing and recommending influenza vaccination with parents of hospitalized children.

Influenza-Related Knowledge, Beliefs, and Experiences Among Caregivers of Hospitalized Children.

OBJECTIVE: Caregivers frequently decline influenza vaccine for their hospitalized child. In this study, we aimed to examine factors impacting their influenza vaccine decision-making. METHODS: We conducted a cross-sectional survey study of English- and Spanish-speaking caregivers of children hospitalized at a tertiary care pediatric hospital between November 2017 and April 2018. The survey assessed influenza-related knowledge, beliefs, experiences, and vaccine hesitancy. Multivariable logistic regression examined associations between survey responses and child influenza vaccination status at admission (already vaccinated versus not yet vaccinated this season) and, among caregivers with vaccine-eligible children, influenza vaccine acceptance (versus declination) for their child during hospitalization. RESULTS: Caregivers (N =522; 88.9% response rate) were mostly non-Hispanic white (66.9%) and English-speaking (97.7%). At admission, 63.2% of children were already vaccinated this season. The caregiver view that influenza vaccination is important for their child's health was the strongest positive predictor of having an already vaccinated child (adjusted odds ratio [aOR]: 3.16; 95% confidence interval [CI]: 2.46-4.05); vaccine hesitancy was the strongest negative predictor (aOR: 0.61; 95% CI: 0.50-0.75). Among caregivers with vaccine-eligible children, 30.3% accepted influenza vaccine for their hospitalized child. Their belief regarding the child health benefits of influenza vaccination was associated with vaccine acceptance during hospitalization (aOR: 6.87; 95% CI: 3.38-13.96). Caregiver vaccine hesitancy and agreement that children with mild illness should delay vaccination negatively impacted vaccine acceptance (aOR: 0.39; 95% CI: 0.25-0.62; aOR: 0.33; 95% CI: 0.20-0.56, respectively). CONCLUSIONS: We identified key factors impacting influenza vaccine decision-making among caregivers of hospitalized children, a critical step to improving uptake in this population.

Increased Frequency of Memory CD4+ T-Cell Responses in Individuals With Previously Treated Extrapulmonary Tuberculosis.

Extrapulmonary TB (EPTB) occurs with increased frequency in persons with underlying immunodeficiency. Even after recovery from acute illness, differences in immune phenotype and activation persist. Studies defining characteristics of immune responses after recovery from extrapulmonary TB may provide insights into factors that increase TB risk. We performed two case-control studies (in the United States and Brazil) among HIV-seronegative adults with previous EPTB (n = 9; 25), previous pulmonary TB (n = 7; 25), latent M. tuberculosis (Mtb) infection (n = 11; 25), and uninfected TB contacts (n = 10; 25). We assessed the frequency of dual CD4+ interferon-γ and tumor necrosis factor-α responses after stimulation with overlapping Mtb peptides from ESAT-6 or CFP-10, or gamma-irradiated Mtb H37Rv, proliferative responses to Mtb antigens, T-regulatory cell (Treg) frequency and phenotype. In both study populations, individuals with prior EPTB had the highest frequency of intracellular cytokine-producing cells in response to Mtb antigens (p < 0.05; p <.0001). Persons with prior EPTB in Brazil had the highest levels of CD4 proliferation to Mtb antigens (p < 0.0001), and the highest expression of CD39 on Tregs (p < 0.0001). Individuals with treated EPTB maintained high frequencies of Mtb-specific memory responses and active Treg cells, suggesting that susceptibility to EPTB occurs despite the ability to develop and maintain enhanced adaptive immune responses.

Satisfaction With Care Coordination for Families of Children With Disabilities.

INTRODUCTION: Children with disabilities have significant health care needs, and receipt of care coordinator services may reduce caregiver burdens. The present study assessed caregivers' experience and satisfaction with care coordination. METHOD: Caregivers of Medicaid-enrolled children with disabilities (n = 2,061) completed a survey (online or by telephone) collecting information on the caregivers' experiences and satisfaction with care coordination using the Family Experiences with Coordination of Care questionnaire. RESULTS: Eighty percent of caregivers with a care coordinator reported receiving help making specialist appointments, and 71% reported help obtaining community services. Caregivers who reported that the care coordinator helped with specialist appointments or was knowledgeable, supportive, and advocating for children had increased odds of satisfaction (odds ratio = 3.46, 95% confidence interval = [1.01, 11.77] and odds ratio = 1.07, 95% confidence interval = [1.03, 1.11], respectively). DISCUSSION: Findings show opportunities for improving care coordination in Medicaid-enrolled children with disabilities and that some specific elements of care coordination may enhance caregiver satisfaction with care.

Kawasaki Disease Substantially Impacts Health-Related Quality of Life.

OBJECTIVE: To prospectively evaluate the acute impact of Kawasaki disease (KD) on health-related quality of life (HRQoL) and to assess deterioration in the HRQoL experienced by children with KD compared with other childhood diseases. STUDY DESIGN: We merged the Outcomes Assessment Program database obtained prospectively with the existing KD database and queried for KD admissions between 1 month and 13 years of age. HRQoL was evaluated with the parent-proxy Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core and Infant Scales. We compared the KD HRQoL results with those obtained from newly diagnosed patients with cancer and pneumonia, matched for age, sex and race. PedsQL total scores over time were assessed with ANCOVA models, adjusted for matching variables and PedsQL score prior to admission. RESULTS: We identified 89 patients with KD and compared 65 subjects with an equal number with pneumonia and with 67 subjects with newly diagnosed cancer. Patients with demonstrated lower PedsQL total score on admission and suffered a significantly greater HRQoL decline from baseline to admission than the other groups. KD diagnostic subtype (complete or incomplete) and coronary artery dilatation were not associated with HRQoL outcomes. However, non-intravenous immunoglobulin responders showed greater HRQoL decline than responders (P = .03). CONCLUSIONS: Children with KD suffer acute and significant HRQoL impairment exceeding that of children newly diagnosed with cancer. Lack of immediate treatment response may exert an additional HRQoL burden, whereas KD subtype and coronary artery dilatation do not.

Families' Priorities Regarding Hospital-to-Home Transitions for Children With Medical Complexity.

BACKGROUND: National health care policy recommends that patients and families be actively involved in discharge planning. Although children with medical complexity (CMC) account for more than half of pediatric readmissions, scalable, family-centered methods to effectively engage families of CMC in discharge planning are lacking. We aimed to systematically examine the scope of preferences, priorities, and goals of parents of CMC regarding planning for hospital-to-home transitions and to ascertain health care providers' perceptions of families' transitional care goals and needs. METHODS: We conducted semistructured interviews with parents and health care providers at a tertiary care hospital. Interviews were continued until thematic saturation was reached. Interviews were audio recorded, transcribed verbatim, and analyzed to identify emergent themes via a general inductive approach. RESULTS: Thirty-nine in-depth interviews were conducted, including 23 with family caregivers of CMC and 16 with health care providers. Families' priorities, preferences, and goals for hospital-to-home transitions aligned with 7 domains: effective engagement with health care providers, respect for families' discharge readiness, care coordination, timely and efficient discharge processes, pain and symptom control, self-efficacy to support recovery and ongoing child development, and normalization and routine. These domains also emerged in interviews with health care providers, although there were minor differences in themes discussed. CONCLUSIONS: Although CMC have diverse transitional care needs, their families' priorities, preferences, and goals aligned with 7 domains that bridged their hospital admission with reestablishment of a home routine. This research provides essential foundational data to engage families in discharge planning, guiding the operationalization of national health policy recommendations.

Greater activation of peripheral T follicular helper cells following high dose influenza vaccine in older adults forecasts seroconversion.

BACKGROUND: Influenza related morbidity and mortality disproportionately impacts older adults. The serologic response to vaccine is diminished in older adults; however, high dose inactivated influenza vaccine (HD IIV) has shown improved rates of seroconversion compared to standard dose (SD IIV). We hypothesize this may be due to the superior ability of high dose vaccine to activate T follicular helper (Tfh) cells and provide B cell dependent T cell help. METHODS: We measured peripheral Tfh (pTfh) activation in 50 community dwelling adults 65years or older who were randomly assigned to receive either the HD IIV or SD IIV. RESULTS: The HD vaccination elicited significantly higher levels of ICOS expression on pTfh cells, at day 7 compared to SD vaccination (p=0.02). The magnitude of the increase in ICOS+ pTfh cells from baseline to day 7 was predictive of seroconversion for both influenza A and B vaccination. CONCLUSION: Strong Tfh activation in response to influenza vaccination forecasts successful seroconversion in older adults, and HD IIV elicits greater Tfh activation than SD IIV. Future vaccine studies should focus on ways to further optimize the Tfh response.

Chronic HIV-1 Infection Impairs Superantigen-Induced Activation of Peripheral CD4+CXCR5+PD-1+ Cells, With Relative Preservation of Recall Antigen-Specific Responses.

Peripheral CD4+CXCR5+PD-1+ T cells are a putative circulating counterpart to germinal center T follicular helper (TFH) cells. They show both phenotypic and functional similarities to TFH cells, which provide necessary help for the differentiation of B cells to antibody-secreting plasmablasts. In this study, we evaluated the frequency, phenotypes, and responses of peripheral TFH-like (pTFH) cells to superantigen and recall antigen stimulation in 10 healthy and 34 chronically infected treatment-naive HIV-1+ individuals. There was no difference in the frequency of pTFH cells between HIV+ and HIV- individuals. Surface expression of ICOS, but not CD40L, was higher on pTFH cells at baseline in HIV+ individuals. Compared with HIV- individuals, pTFH cells from HIV+ individuals had decreased maximal expression of ICOS and CD40L in response to in vitro superantigen stimulation. This decreased response did not correlate with viral control, CD4 T-cell count, duration of infection, or the degree of neutralizing antibody breadth. Despite a decreased maximal response, pTFH responses to HIV Gag and tetanus toxoid recall antigens were preserved.

Neither vaginal nor buccal administration of 800 µg misoprostol alters mucosal and systemic immune activation or the cervicovaginal microbiome: a pilot study.

OBJECTIVES: The aim of the study was to assess the extent to which misoprostol alters mucosal or systemic immune responses following either buccal or vaginal administration. METHODS: This was a prospective, crossover pilot study of 15 healthy, reproductive-age women. Women first received 800 µg misoprostol either via buccal or vaginal administration and were crossed over 1 month later to receive the drug via the other route. Cervicovaginal lavage samples, cervical Cytobrush samples, cervicovaginal swabs, urine and blood were obtained immediately prior to drug administration and the following day. Parameters assessed included urine and cervicovaginal misoprostol levels, whole blood cytokine responses (by ELISA) to immune stimulation with lipopolysaccharide, peripheral blood and cervical lymphocyte phenotyping by flow cytometry, cervicovaginal antimicrobial peptide measurement by ELISA and vaginal microbial ecology assessment by 16S rRNA sequencing. RESULTS: Neither buccal nor vaginal misoprostol significantly altered local or systemic immune and microbiological parameters. CONCLUSION: In this pilot study, we did not observe significant alteration of mucosal or systemic immunology or vaginal microbial ecology 1 day after drug administration following either the buccal or vaginal route.

Multiparameter analysis of stimulated human peripheral blood mononuclear cells: A comparison of mass and fluorescence cytometry.

Mass and fluorescence cytometry are quantitative single cell flow cytometry approaches that are powerful tools for characterizing diverse tissues and cellular systems. Here mass cytometry was directly compared with fluorescence cytometry by studying phenotypes of healthy human peripheral blood mononuclear cells (PBMC) in the context of superantigen stimulation. One mass cytometry panel and five fluorescence cytometry panels were used to measure 20 well-established lymphocyte markers of memory and activation. Comparable frequencies of both common and rare cell subpopulations were observed with fluorescence and mass cytometry using biaxial gating. The unsupervised high-dimensional analysis tool viSNE was then used to analyze data sets generated from both mass and fluorescence cytometry. viSNE analysis effectively characterized PBMC using eight features per cell and identified similar frequencies of activated CD4+ T cells with both technologies. These results suggest combinations of unsupervised analysis programs and extended multiparameter cytometry will be indispensable tools for detecting perturbations in protein expression in both health and disease.

The effectiveness of family-centered transition processes from hospital settings to home: a review of the literature.

BACKGROUND AND OBJECTIVES: The quality of care transitions is of growing concern because of a high incidence of postdischarge adverse events, poor communication with patients, and inadequate information transfer between providers. The objective of this study was to conduct a targeted literature review of studies examining the effectiveness of family-centered transition processes from hospital- and emergency department (ED)-to-home for improving patient health outcomes and health care utilization. METHODS: We conducted an electronic search (2001-2012) of PubMed, CINAHL, Cochrane, PsycInfo, Embase, and Web of Science databases. Included were experimental studies of hospital and ED-to-home transition interventions in pediatric and adult populations meeting the following inclusion criteria: studies evaluating hospital or ED-to-home transition interventions, study interventions involving patients/families, studies measuring outcomes≤30 days after discharge, and US studies. Transition processes, principal outcome measures (patient health outcomes and health care utilization), and assessment time-frames were extracted for each study. RESULTS: The search yielded 3458 articles, and 16 clinical trials met final inclusion criteria. Four studies evaluated pediatric ED-to-home transitions and indicated family-tailored discharge education was associated with better patient health outcomes. Remaining trials evaluating adult hospital-to-home transitions indicated a transition needs assessment or provision of an individualized transition record was associated with better patient health outcomes and reductions in health care utilization. The effectiveness of postdischarge telephone follow-up and/or home visits on health care utilization showed mixed results. CONCLUSIONS: Patient-tailored discharge education is associated with improved patient health outcomes in pediatric ED patients. Effective transition processes identified in the adult literature may inform future quality improvement research regarding pediatric hospital-to-home transitions.

Validity and responsiveness of the pediatric quality of life inventory (PedsQL) 4.0 generic core scales in the pediatric inpatient setting.

IMPORTANCE: Validated patient-reported outcomes responsive to clinical change are needed to evaluate the effectiveness of quality improvement interventions. OBJECTIVES: To evaluate responsiveness, construct validity, and predictive validity of the Pediatric Quality of Life Inventory (PedsQL) 4.0 Generic Core Scales in the pediatric inpatient setting. DESIGN, SETTING, AND PARTICIPANTS: Prospective, cohort study of parents and caregivers of patients 1 month to 18 years old (n = 4637) and patients 13 to 18 years old (n = 359) admitted to Seattle Children's Hospital between October 1, 2011, and December 31, 2013. Of 7184 eligible participants invited to complete the survey, 4637 (64.5%) completed the PedsQL on admission, and of these 2694 (58.1%) completed the follow-up survey 2 to 8 weeks after discharge. MAIN OUTCOMES AND MEASURES: Responsiveness was assessed by calculating improvement scores (difference between follow-up and admission scores). Construct validity was examined by comparing the mean improvement scores for known groups differing by medical complexity. Predictive validity was assessed using Poisson regression to examine associations among admission scores, prolonged length of stay (≥3 days), and 30-day readmissions or emergency department (ED) return visits. Similar models examined the association between improvement scores and risk for 30-day readmissions or ED return visits. RESULTS: The mean (SD) PedsQL improvement scores (scale, 0-100) were 22.1 (22.7) for total, 29.4 (32.4) for physical, and 17.1 (21.0) for psychosocial. The mean PedsQL total improvement scores were lower for patients with medically complex conditions compared with patients without chronic conditions (13.7 [95% CI, 11.6-15.8] vs. 24.1 [95% CI, 22.4-25.7], P < .001). A 10-point decrement in the PedsQL total admission score below the established community-based mean was associated with an increase in risk for prolonged length of stay (15% [95% CI, 13%-17%]), 30-day readmissions (8% [95% CI, 3%-14%]), and ED return visits (13% [95% CI, 6%-20%]). A 5-point decrement in the PedsQL total improvement score below the study sample mean improvement score was associated with an increase in risk for 30-day readmissions or ED return visits (9% [95% CI, -1% to 19%]). CONCLUSIONS AND RELEVANCE: The PedsQL demonstrated responsiveness, construct validity, and predictive validity in hospitalized pediatric patients. The PedsQL may be a useful patient-reported outcome for hospital-based clinical effectiveness research.

Cocaine enhances HIV-1-induced CD4(+) T-cell apoptosis: implications in disease progression in cocaine-abusing HIV-1 patients.

Substance abuse is a major barrier in eradication of the HIV epidemic because it serves as a powerful cofactor for viral transmission, disease progression, and AIDS-related mortality. Cocaine, one of the commonly abused drugs among HIV-1 patients, has been suggested to accelerate HIV disease progression. However, the underlying mechanism remains largely unknown. Therefore, we tested whether cocaine augments HIV-1-associated CD4(+) T-cell decline, a predictor of HIV disease progression. We examined apoptosis of resting CD4(+) T cells from HIV-1-negative and HIV-1-positive donors in our study, because decline of uninfected cells plays a major role in HIV-1 disease progression. Treatment of resting CD4(+) T cells with cocaine (up to 100 µmol/L concentrations) did not induce apoptosis, but 200 to 1000 µmol/L cocaine induced apoptosis in a dose-dependent manner. Notably, treatment of CD4(+) T cells isolated from healthy donors with both HIV-1 virions and cocaine significantly increased apoptosis compared with the apoptosis induced by cocaine or virions alone. Most important, our biochemical data suggest that cocaine induces CD4(+) T-cell apoptosis by increasing intracellular reactive oxygen species levels and inducing mitochondrial depolarization. Collectively, our results provide evidence of a synergy between cocaine and HIV-1 on CD4(+) T-cell apoptosis that may, in part, explain the accelerated disease observed in HIV-1-infected drug abusers.

B cell responses to HIV antigen are a potent correlate of viremia in HIV-1 infection and improve with PD-1 blockade.

Infection with Human Immunodeficiency Virus Type 1 (HIV-1) induces defects of both cellular and humoral immune responses. Impaired CD4+ T cell help and B cell dysfunction may partially explain the low frequency of broadly neutralizing antibodies in HIV-infected individuals. To understand the extent of B cell dysfunction during HIV infection, we assessed the level of B cell activation at baseline and after stimulation with a variety of antigens. Increased levels of viremia were associated with higher baseline expression of the activation marker CD86 on B cells and with decreased ability of B cells to increase expression of CD86 after in vitro stimulation with inactivated HIV-1. In a series of cell isolation experiments B cell responses to antigen were enhanced in the presence of autologous CD4+ T cells. HIV infected individuals had a higher frequency of PD-1 expression on B cells compared to HIV- subjects and PD-1 blockade improved B cell responsiveness to HIV antigen, suggesting that inhibitory molecule expression during HIV-1 infection may contribute to some of the observed B cell defects. Our findings demonstrate that during chronic HIV infection, B cells are activated and lose full capacity to respond to antigen, but suppression of inhibitory pressures as well as a robust CD4+ T cell response may help preserve B cell function.

Antiretroviral therapy reduces the magnitude and T cell receptor repertoire diversity of HIV-specific T cell responses without changing T cell clonotype dominance.

After initiation of antiretroviral therapy (ART), HIV loads and frequencies of HIV epitope-specific immune responses decrease. A diverse virus-specific T cell receptor (TCR) repertoire allows the host to respond to viral epitope diversity, but the effect of antigen reduction as a result of ART on the TCR repertoire of epitope-specific CD8(+) T cell populations has not been well defined. We determined the TCR repertoires of 14 HIV-specific CD8(+) T cell responses from 8 HIV-positive individuals before and after initiation of ART. We used multiparameter flow cytometry to measure the distribution of memory T cell subsets and the surface expression of PD-1 on T cell populations and T cell clonotypes within epitope-specific responses from these individuals. Post-ART, we noted decreases in the frequency of circulating epitope-specific T cells (P = 0.02), decreases in the number of T-cell clonotypes found within epitope-specific T cell receptor repertoires (P = 0.024), and an overall reduction in the amino acid diversity within these responses (P < 0.0001). Despite this narrowing of the T cell response to HIV, the overall hierarchy of dominant T cell receptor clonotypes remained stable compared to that pre-ART. CD8(+) T cells underwent redistributions in memory phenotypes and a reduction in CD38 and PD-1 expression post-ART. Despite extensive remodeling at the structural and phenotypic levels, PD-1 was expressed at higher levels on dominant clonotypes within epitope-specific responses before and after initiation of ART. These data suggest that the antigen burden may maintain TCR diversity and that dominant clonotypes are sensitive to antigen even after dramatic reductions after initiation of ART.

Influence of race and socioeconomic status on engagement in pediatric primary care.

OBJECTIVE: To understand the association of race/ethnicity with engagement in pediatric primary care and examine how any racial/ethnic disparities are influenced by socioeconomic status. METHODS: Visit videos and parent surveys were obtained for 405 children who visited for respiratory infections. Family and physician engagement in key visit tasks (relationship building, information exchange, and decision making) were coded. Two parallel regression models adjusting for covariates and clustering by physician were constructed: (1) race/ethnicity only and (2) race/ethnicity with SES (education and income). RESULTS: With and without adjustment for SES, physicians seeing Asian families spoke 24% fewer relationship building utterances, compared to physicians seeing White, non-Latino families (p<0.05). Latino families gathered 24% less information than White, non-Latino families (p<0.05), but accounting for SES mitigates this association. Similarly, African American families were significantly less likely to be actively engaged in decision making (OR=0.32; p<0.05), compared to White, non-Latino families, but adjusting for SES mitigated this association. CONCLUSION: While engagement during pediatric visits differed by the family's race/ethnicity, many of these differences were eliminated by accounting for socioeconomic status. PRACTICE IMPLICATIONS: Effective targeting and evaluation of interventions to reduce health disparities through improving engagement must extend beyond race/ethnicity to consider socioeconomic status more broadly.

Dominant clonotypes within HIV-specific T cell responses are programmed death-1high and CD127low and display reduced variant cross-reactivity.

HIV epitope-specific T cell responses are often comprised of clonotypic expansions with distinct functional properties. In HIV(+) individuals, we measured programmed death-1 (PD-1) and IL-7Rα expression, MHC class I tetramer binding, cytokine production, and proliferation profiles of dominant and subdominant TCR clonotypes to evaluate the relationship between the composition of the HIV-specific T cell repertoire and clonotypic phenotype and function. Dominant clonotypes are characterized by higher PD-1 expression and lower C127 expression compared with subdominant clonotypes, and TCR avidity positively correlates with PD-1 expression. At low peptide concentrations, dominant clonotypes fail to survive in culture. In response to stimulation with peptides representing variant epitopes, subdominant clonotypes produce higher relative levels of cytokines and display greater capacity for cross-recognition compared with dominant clonotypes. These data indicate that dominant clonotypes within HIV-specific T cell responses display a phenotype consistent with ongoing exposure to cognate viral epitopes and suggest that cross-reactive, subdominant clonotypes may retain greater capacity to suppress replication of viral variants as well as to survive in the absence of strong antigenic signaling.

Clonal expansion and TCR-independent differentiation shape the HIV-specific CD8+ effector-memory T-cell repertoire in vivo.

Flexibility of the HIV-specific T-cell receptor repertoire is a hallmark of HIV-1 infection. Altered differentiation of HIV-specific CD45RO(+)/CCR7(-) (TemRO) CD8(+) effector-memory T cells into CD45RA(+)/CCR7(-) (TemRA) CD8(+) effector-memory T cells as well as increased expression of the senescence marker CD57 has been frequently observed HIV-1 infection, but the structural relationship between clonal expansion and T-cell differentiation has not been defined. In this study, we demonstrate that HIV-specific clonotypes have differing degrees of TemRA differentiation but always maintain a significant proportion of TemRO-phenotype cells. These data indicate that structural constraints of the TCR/peptide major histocompatibility complex interaction play a central role in the TemRA differentiation of HIV-specific CD8(+) T cells in chronic HIV-1 infection. Clonotypes with a predominantly TemRA phenotype had a substantial fraction of cells without expression of CD57; and in contrast to the high clonotypic variability of TemRA differentiation, expression of CD57 was highly correlated among T-cell clonotypes within epitope-specific responses, indicating TCR-independent expression of CD57 in vivo. Our data highlight the importance of the structural composition of the TCR repertoire for the effector-memory differentiation of the immune response in chronic viral infections and suggest that TCR-dependent and -independent homeostasis shapes the pathogen-specific effector-memory repertoire in vivo.