Health-Related Quality of Life for Parents of Infants with Bronchopulmonary Dysplasia.

OBJECTIVE: To determine how bronchopulmonary dysplasia (BPD) affects health-related quality of life (HRQL) among infants from NICU hospitalization through 1-year postdischarge. STUDY DESIGN: This was a prospective cohort study of infants with BPD and their parents. Parent HRQL was measured with the PedsQL Family Impact Module before NICU discharge and 3- and 12-months post-discharge. At 12 months, parent-reported child health outcomes included questions from the Test of Respiratory and Asthma Control in Kids, Warner Initial Developmental Evaluation of Adaptive and Functional Skills, and National Survey of Children with Special Health Care Needs. HRQL change over time was assessed by multivariable linear regression. RESULTS: Of 145 dyads, 129 (89%) completed 3-month follow-up, and 113 (78%) completed 12-month follow-up. In the NICU, lower HRQL was associated with earlier gestational age, postnatal corticosteroids, outborn status, and gastrostomy tubes. At 3 months, lower HRQL was associated with readmissions and home oxygen use. At 12 months, lower HRQL was associated with parent-reported difficulty breathing, lower developmental scores, and not playing with other children. At 3 and 12 months, 81% of parents reported similar or improved HRQL compared with the NICU period. Parents reporting infant respiratory symptoms experienced less improvement. CONCLUSIONS: BPD affects parent HRQL over the first year. Most parents report similar or better HRQL after discharge compared with the NICU stay. Less improvement is reported by parents of infants experiencing respiratory symptoms at 12 months. Efforts to improve parent HRQL should target respiratory symptoms and social isolation.

Outcomes of infants and children with bronchopulmonary dysplasia-associated pulmonary hypertension who required home ventilation.

BACKGROUND: To characterize a cohort of ventilator-dependent infants and children with bronchopulmonary dysplasia-associated pulmonary hypertension (BPD-PH) and to describe their cardiorespiratory outcomes. METHODS: Subjects with BPD on chronic home ventilation were recruited from outpatient clinics. PH was defined by its presence on ≥1 cardiac catheterization or echocardiogram on or after 36 weeks post-menstrual age. Kaplan-Meier analysis was used to compare the timing of key events. RESULTS: Of the 154 subjects, 93 (60.4%) had PH and of those, 52 (55.9%) required PH-specific medications. The ages at tracheostomy, transition to home ventilator, and hospital discharge were older in those with PH. Most subjects were weaned off oxygen and liberated from the ventilator by 5 years of age, which did not occur later in subjects with PH. The mortality rate after initial discharge was 2.6%. CONCLUSIONS: The majority of infants with BPD-PH receiving chronic invasive ventilation at home survived after initial discharge. Subjects with BPD-PH improved over time as evidenced by weaning off oxygen and PH medications, ventilator liberation, and tracheostomy decannulation. While the presence of PH was not associated with later ventilator liberation or decannulation, the use of PH medications may be a marker of a more protracted disease trajectory. IMPACT STATEMENT: There is limited data on long-term outcomes of children with bronchopulmonary dysplasia (BPD) who receive chronic invasive ventilation at home, and no data on those with the comorbidity of pulmonary hypertension (PH). Almost all subjects with BPD-PH who were on chronic invasive ventilation at home survived after their initial hospital discharge. Subjects with BPD-PH improved over time as evidenced by weaning off oxygen, PH medications, liberation from the ventilator, and tracheostomy decannulation. The presence of PH did not result in later ventilator liberation or decannulation; however, the use of outpatient PH medications was associated with later ventilation liberation and decannulation.

Prospective Risk Stratification Identifies Healthcare Utilization Associated with Home Oxygen Therapy for Infants with Bronchopulmonary Dysplasia.

OBJECTIVE: To test whether prospective classification of infants with bronchopulmonary dysplasia identifies lower-risk infants for discharge with home oxygen who have fewer rehospitalizations by 1 year after neonatal intensive care unit discharge. STUDY DESIGN: This is a prospective single-center cohort that included infants from 2016 to 2019 with bronchopulmonary dysplasia, defined as receiving respiratory support at 36 weeks of postmenstrual age. "Lower-risk" infants were receiving ≤2 L/min nasal cannula flow, did not have pulmonary hypertension or airway comorbidities, and had blood gas partial pressure of carbon dioxide <70 mm Hg. We compared 3 groups by discharge status: lower-risk room air, lower-risk home oxygen, and higher-risk home oxygen. The primary outcome was rehospitalization at 1 year postdischarge, and the secondary outcomes were determined by the chart review and parent questionnaire. RESULTS: Among 145 infants, 32 (22%) were lower-risk discharged in room air, 49 (32%) were lower-risk using home oxygen, and 64 (44%) were higher-risk. Lower-risk infants using home oxygen had rehospitalization rates similar to those of lower-risk infants on room air (18% vs 16%, P = .75) and lower rates than higher-risk infants (39%, P = .018). Lower-risk infants using home oxygen had more specialty visits (median 10, IQR 7-14 vs median 6, IQR 3-11, P = .028) than those on room air. Classification tree analysis identified risk status as significantly associated with rehospitalization, along with distance from home to hospital, inborn, parent-reported race, and siblings in the home. CONCLUSIONS: Prospectively identified lower-risk infants discharged with home oxygen had fewer rehospitalizations than higher-risk infants and used more specialty care than lower-risk infants discharged in room air.

Identifying barriers and facilitators to care for infants with bronchopulmonary dysplasia after NICU discharge: a prospective study of parents and clinical stakeholders.

OBJECTIVE: Understand barriers and facilitators to follow-up care for infants with bronchopulmonary dysplasia (BPD). METHODS: Qualitative study of parents and clinical stakeholders caring for infants with BPD. The interview guide was developed by a mother of a former 23-week preterm infant, neonatologist, pulmonologist, nurse, and qualitative researcher. Purposive sampling obtained a heterogenous sociodemographic and professional cohort. Subjects discussed their experience with BPD, barriers to care, caregiver quality of life and health education. Interviews were audio-recorded, transcribed and coded. Thematic analysis was used. RESULTS: Eighteen parents and 20 stakeholders completed interviews. Family-level themes included pragmatic barriers like transportation being multi-faceted; and caregiving demands straining mental health. System-level themes included caregiver education needing to balance immediate caregiving activities with future health outcomes; and integrating primary care, specialty, and community supports. CONCLUSIONS: Individual and system barriers impact follow-up for infants with BPD. This conceptual framework can be used to measure and improve care.

Inpatient education reduces length of outpatient oxygen therapy in bronchopulmonary dysplasia: A quality improvement project.

BACKGROUND: Patients discharged on home oxygen therapy (HOT) for bronchopulmonary dysplasia (BPD) often receive months of this therapy. A previous trial comparing two methods of HOT weaning showed that increased parent involvement in HOT weaning decreased HOT duration. Our outpatient team uses a standard protocol for outpatient HOT weaning, starting at the first clinic visit 4-6 weeks after discharge. AIM: To shorten HOT duration by teaching parents the outpatient HOT weaning process before neonatal intensive care unit (NICU) discharge. METHODS: We launched a quality improvement program in April 2021 for preterm infants with BPD without significant comorbidities who were stable on ≤0.5 L nasal cannula. Eligible infants started the outpatient HOT weaning protocol while inpatient, with education for parents and nurses. The outcome measure was the duration of HOT after discharge. Process measures focused on protocol adherence. Balancing measures included NICU length of stay and appropriateness of parent-directed HOT weaning. RESULTS: During the study period, there were a total of 133 eligible patients discharged on home oxygen, with 75 in the baseline group and 58 in the intervention group. Forty-five (78%) participated in the HOT weaning protocol while inpatient. HOT was reduced from an average of 27 to 12 weeks after May 2021. We observed no change in NICU length of stay or inappropriate HOT weaning. CONCLUSION: Early introduction of HOT weaning with a focus on caregiver education is associated with a decreased duration of HOT.

Factors associated with liberation from home mechanical ventilation and tracheostomy decannulation in infants and children with severe bronchopulmonary dysplasia.

OBJECTIVE: To identify factors associated with the timing of ventilator liberation and tracheostomy decannulation among infants with severe bronchopulmonary dysplasia (sBPD) who required chronic outpatient invasive ventilation. STUDY DESIGN: Multicenter retrospective study of 154 infants with sBPD on outpatient ventilators. Factors associated with ventilator liberation and decannulation were identified using Cox regression models and multilevel survival models. RESULTS: Ventilation liberation and decannulation occurred at median ages of 27 and 49 months, respectively. Older age at transition to a portable ventilator and at discharge, higher positive end expiratory pressure, and multiple respiratory readmissions were associated with delayed ventilator liberation. Surgical management of gastroesophageal reflux was associated with later decannulation. CONCLUSIONS: Ventilator liberation timing was impacted by longer initial admissions and higher ventilator pressure support needs, whereas decannulation timing was associated with more aggressive reflux management. Variation in the timing of events was primarily due to individual-level factors, rather than center-level factors.

DNA repair is limiting for haematopoietic stem cells during ageing.

Accumulation of DNA damage leading to adult stem cell exhaustion has been proposed to be a principal mechanism of ageing. Here we address this question by taking advantage of the highly specific role of DNA ligase IV in the repair of DNA double-strand breaks by non-homologous end-joining, and by the discovery of a unique mouse strain with a hypomorphic Lig4(Y288C) mutation. The Lig4(Y288C) mouse, identified by means of a mutagenesis screening programme, is a mouse model for human LIG4 syndrome, showing immunodeficiency and growth retardation. Diminished DNA double-strand break repair in the Lig4(Y288C) strain causes a progressive loss of haematopoietic stem cells and bone marrow cellularity during ageing, and severely impairs stem cell function in tissue culture and transplantation. The sensitivity of haematopoietic stem cells to non-homologous end-joining deficiency is therefore a key determinant of their ability to maintain themselves against physiological stress over time and to withstand culture and transplantation.

Management of diuretics in infants with bronchopulmonary dysplasia discharged on home oxygen.

BACKGROUND: Infants with bronchopulmonary dysplasia (BPD) are often prescribed diuretics before the neonatal intensive care unit (NICU) discharge. It is unknown whether outpatient medication weaning strategies affect the duration of home oxygen therapy. METHODS: This was a secondary cohort analysis of infants born <32 weeks gestational age with BPD from 2015 to 2018 discharged from our NICU or regional NICUs, referred to our pulmonary clinic for home oxygen management. We compared three groups: those discharged with no diuretics, diuretics actively weaned (dose decreased), and diuretics passively weaned (dose not adjusted). RESULTS: Out of 125 infants, 116 were included in the analysis. Forty-five infants were discharged without diuretics, 52 infants were discharged with diuretics that were actively weaned, and 19 infants were discharged with diuretics that were passively weaned. Infants who were passively weaned spent the most time on home oxygen (median 28 weeks, interquartile range [IQR] 16-52; p = 0.011); there were no differences in home oxygen duration in infants actively weaned (median 13 weeks, IQR 10-26) versus not on diuretics (median 22 weeks, IQR 12-30, p = 0.285). Multivariable adjustment for other illness characteristics associated with the duration of home oxygen did not change this finding. CONCLUSIONS: Active weaning of diuretics did not prolong the duration of home oxygen, in the setting of a standardized clinical guideline for weaning home oxygen in infants with BPD. These data can serve as baseline information to implement and test standardized strategies for outpatient medication management.

Identifying Barriers and Facilitators to Care for Infants with Bronchopulmonary Dysplasia After NICU Discharge: A Prospective Study of Parents and Clinical Stakeholders.

Objective: Understand barriers and facilitators to follow-up care for infants with bronchopulmonary dysplasia (BPD). Methods: Qualitative study of parents and clinical stakeholders caring for infants with BPD. The interview guide was developed by a mother of a former 23-week preterm infant, neonatologist, pulmonologist, nurse, and qualitative researcher. Purposive sampling obtained a heterogenous sociodemographic and professional cohort. Subjects discussed their experience with BPD, barriers to care, caregiver quality of life and health education. Interviews were audio-recorded, transcribed and coded. Thematic analysis was used. Results: Eighteen parents and 20 stakeholders completed interviews. Family-level themes included pragmatic barriers like transportation being multi-faceted; and caregiving demands straining mental health. System-level themes included caregiver education needing to balance process needs with future trajectories; and integration of primary care, specialty care, and community supports. Conclusions: Individual and system barriers impact follow-up for infants with BPD. This conceptual framework can be used to measure and improve care.

Validation of an outpatient questionnaire for bronchopulmonary dysplasia control.

INTRODUCTION: Despite bronchopulmonary dysplasia (BPD) being a common morbidity of preterm birth, there is no validated objective tool to assess outpatient respiratory symptom control for clinical and research purposes. METHODS: Data were obtained from 1049 preterm infants and children seen in outpatient BPD clinics of 13 US tertiary care centers from 2018 to 2022. A new standardized instrument was modified from an asthma control test questionnaire and administered at the time of clinic visits. External measures of acute care use were also collected. The questionnaire for BPD control was validated in the entire population and selected subgroups using standard methodology for internal reliability, construct validity, and discriminative properties. RESULTS: Based on the scores from BPD control questionnaire, the majority of caregivers (86.2%) felt their child's symptoms were under control, which did not differ by BPD severity (p = 0.30) or a history of pulmonary hypertension (p = 0.42). Across the entire population and selected subgroups, the BPD control questionnaire was internally reliable, suggestive of construct validity (albeit correlation coefficients were -0.2 to -0.4.), and discriminated control well. Control categories (controlled, partially controlled, and uncontrolled) were also predictive of sick visits, emergency department visits, and hospital readmissions. CONCLUSION: Our study provides a tool for assessing respiratory control in children with BPD for clinical care and research studies. Further work is needed to identify modifiable predictors of disease control and link scores from the BPD control questionnaire to other measures of respiratory health such as lung function testing.

Respiratory Outcomes for Ventilator-Dependent Children With Bronchopulmonary Dysplasia.

OBJECTIVES: To describe outpatient respiratory outcomes and center-level variability among children with severe bronchopulmonary dysplasia (BPD) who require tracheostomy and long-term mechanical ventilation. METHODS: Retrospective cohort of subjects with severe BPD, born between 2016 and 2021, who received tracheostomy and were discharged on home ventilator support from 12 tertiary care centers participating in the BPD Collaborative Outpatient Registry. Timing of key respiratory events including time to tracheostomy placement, initial hospital discharge, first outpatient clinic visit, liberation from the ventilator, and decannulation were assessed using Kaplan-Meier analysis. Differences between centers for the timing of events were assessed via log-rank tests. RESULTS: There were 155 patients who met inclusion criteria. Median age at the time of the study was 32 months. The median age of tracheostomy placement was 5 months (48 weeks' postmenstrual age). The median ages of hospital discharge and first respiratory clinic visit were 10 months and 11 months of age, respectively. During the study period, 64% of the subjects were liberated from the ventilator at a median age of 27 months and 32% were decannulated at a median age of 49 months. The median ages for all key events differed significantly by center (P ≤ .001 for all events). CONCLUSIONS: There is wide variability in the outpatient respiratory outcomes of ventilator-dependent infants and children with severe BPD. Further studies are needed to identify the factors that contribute to variability in practice among the different BPD outpatient centers, which may include inpatient practices.

Identification of a Steap3 endosomal targeting motif essential for normal iron metabolism.

Hereditary forms of iron-deficiency anemia, including animal models, have taught us much about the normal physiologic control of iron metabolism. However, the discovery of new informative mutants is limited by the natural mutation frequency. To address this limitation, we have developed a screen for heritable abnormalities of red blood cell morphology in mice with single-nucleotide changes induced by the chemical mutagen ethylnitrosourea (ENU). We now describe the first strain, fragile-red, with hypochromic microcytic anemia resulting from a Y228H substitution in the ferrireductase Steap3 (Steap3(Y288H)). Analysis of the Steap3(Y288H) mutant identifies a conserved motif required for targeting Steap3 to internal compartments and highlights how phenotypic screens linked to mutagenesis can identify new functional variants in erythropoiesis and ascribe function to previously unidentified motifs.

Room air challenge predicts duration of supplemental respiratory support for infants with bronchopulmonary dysplasia.

OBJECTIVE: To determine whether a room air challenge (RAC) correlates with duration of respiratory support for infants with bronchopulmonary dysplasia (BPD). STUDY DESIGN: Prospective study of preterm infants with BPD from 2015 to 2018. Infants receiving ≤2 l flow at 36 weeks postmenstrual age (PMA) underwent RAC. Cox regression was used to adjust the duration of respiratory support after 36 weeks PMA for significant covariates. RESULTS: Of 161 infants with BPD, 91 were eligible for RAC; 51 passed and 40 failed. Infants who failed RAC had longer respiratory support after 36 weeks PMA than infants who passed (median 19 weeks (IQR 15-33) versus 2 weeks (IQR 1-8, p < 0.001)), which persisted after multivariable adjustment (hazard ratio -1.42, 95% CI -1.94 to -0.91, p < 0.001). Infants failing RAC also had more frequent and longer duration of home oxygen use. CONCLUSION: RAC may help provide anticipatory guidance regarding duration of respiratory support for infants with BPD.

Using a home oxygen weaning protocol and pCO2 to evaluate outcomes for infants with bronchopulmonary dysplasia discharged on home oxygen.

BACKGROUND: Predischarge capillary blood gas partial pressure of carbon dioxide (pCO2 ) has been associated with increased adverse events including readmission. This study aimed to determine if predischarge pCO2 or 36-week pCO2 was associated with increased respiratory readmissions or other pulmonary healthcare utilization in the year after neonatal intensive care unit (NICU) discharge for infants with bronchopulmonary dysplasia (BPD) discharged with home oxygen, using a standardized outpatient oxygen weaning protocol. METHODS: This was a secondary cohort analysis of infants born <32 weeks gestational age with BPD, referred to our clinic for home oxygen therapy from either from our level IV NICU or local level III NICUs between 2015 and 2017. Infants with major nonrespiratory comorbidities were excluded. Subject information was obtained from electronic health records. RESULTS: Of 125 infants, 120 had complete 1-year follow-up. Twenty-three percent of infants experienced a respiratory readmission after NICU discharge. There was no significant association between predischarge or 36-week pCO2 and respiratory readmissions, emergency room visits, new or increased bronchodilators, or diuretics. Higher 36-week pCO2 was associated with a later corrected age when oxygen was discontinued (<6 months; median, 54 mmHg; interquartile range [IQR], 51-61; 6-11 months; median, 62 mmHg; IQR, 57-65; ≥12 months, median, 66 mmHg; IQR, 58-73; p = .006). CONCLUSIONS: Neither predischarge pCO2 nor 36-week pCO2 was associated with 1-year respiratory readmissions. However higher pCO2 at 36 weeks was associated with a longer duration of home oxygen. Neonatal illness measures like 36-week pCO2 may be useful in communicating expectations for home oxygen therapy to families.

A prospective trial of structured treatment interruptions in human immunodeficiency virus infection.

BACKGROUND: According to the "autovaccination hypothesis," reexposure to human immunodeficiency virus (HIV) during treatment interruptions may stimulate the HIV-specific immune response and lead to low viremia after withdrawal of highly active antiretroviral treatment (HAART). Many patients who started HAART earlier in their disease course than is currently recommended would like to discontinue, but it is unknown whether it is safe to do so. OBJECTIVES: To determine whether repeated treatment interruptions of HAART (1) stimulated the cytotoxic HIV-specific immune response and whether such stimulation correlated with low viremia off treatment, and (2) were safe with respect to clinical complications, development of viral resistance, and decline in CD4 cell counts. DESIGN: Interventional study with before-after comparison. SETTING: Outpatient clinics of university hospitals in Switzerland and Spain. PATIENTS: A total of 133 patients receiving HAART, with a median CD4 cell count of 740/ microL, and whose viral load had been undetectable for a median of 21 months. INTERVENTIONS: HAART was interrupted for 2 weeks, restarted, and continued for 8 weeks. After 4 such cycles, treatment was indefinitely suspended 40 weeks after study entry. MAIN OUTCOME MEASURES: HIV-specific cytotoxic T-cell responses were evaluated by interferon gamma enzyme-linked immunospot analysis. The proportion of "responders" (viral load <5000 copies/mL) was measured at weeks 52 and 96. HIV-related diseases and CD4 cell counts were recorded. RESULTS: Seventeen percent of patients (95% confidence interval, 11%-25%) were responders at week 52, and 8% at week 96. Low pre-HAART viral load and lack of rebound during weeks 0 to 40 predicted response. HIV-specific CD8+ T cells increased between week 0 (median, 343 spot-forming cells per million peripheral blood lymphocytes [SFC/106 PBL]) and week 52 (median, 1930 SFC/106 PBL), but there was an inverse correlation between response and the number of spot-forming cells. Eighty-five (64%) of 133 patients stopped therapy for at least 12 weeks, and 55 (41%) for at least 56 weeks. The median CD4 cell count decreased from 792/ microL to 615/ microL during the first 12 weeks without treatment, but stabilized thereafter. One patient (0.75%) developed drug resistance necessitating salvage treatment. There were no AIDS-related clinical complications. CONCLUSIONS: Results of this study do not favor the autovaccination hypothesis. Treatment interruptions did not provoke clinical complications, and there was little drug resistance. Comparative trials will have to show what benefit, if any, is associated with intermittent, as opposed to continuous treatment.

Residual HIV-specific CD4 and CD8 T cell frequencies after prolonged antiretroviral therapy reflect pretreatment plasma virus load.

BACKGROUND: Virus-specific cellular immune responses mediated by CD4 and CD8 T lymphocytes are thought to be central to the effective control of HIV-1 replication in vivo. However, quantitative correlations between HIV-specific T lymphocyte frequencies and plasma virus load (pVL) have proved difficult to establish in infected human individuals. This most likely reflects the complex interactions between the virus and these immune effector cells in the absence of treatment. OBJECTIVE: To assess frequencies of HIV-specific T lymphocytes after prolonged suppression of viral replication, i.e., under conditions where the effects of virus on the immune response are standardized and minimized, thereby fixing an important variable in a dynamic multivariate system. METHODS: HIV-specific CD4 and CD8 T lymphocyte frequencies were measured in 122 individuals after prolonged periods of successful combination antiretroviral therapy (ART) administered during chronic HIV-1 infection. RESULTS: The residual frequency of both CD4 and CD8 T lymphocytes specific for HIV-1 was inversely related to the pretreatment pVL. This relationship appeared to be non-linear, indicating the presence of a threshold pretreatment pVL level above which HIV-specific CD4 and CD8 T lymphocyte responses could not be maintained when antigenic drive was suppressed. Substantial populations of functional HIV-specific CD4 and CD8 T lymphocytes were generally detectable after prolonged ART only in those individuals with a pretreatment plasma HIV-1 RNA < 100,000 copies/ml. CONCLUSION: These findings identify a quantitative immune associate of host-virus interactions in established HIV-1 infection.

Do people with schizophrenia lack emotional intelligence?

Social cognition is a domain of cognitive function that includes the ability to understand and manage social interactions. Emotional intelligence (EI) has been identified as a component of social cognition and is defined as the ability to identify, use, understand, and manage emotions. Neurocognitive impairments are known to be associated with poorer social function in people with schizophrenia, but less is known about the relationships between EI, neurocognition, and social function. The current study assessed EI using the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT) in 20 people with schizophrenia and 20 controls. The schizophrenia group had significantly lower scores on all measures of EI and demonstrated poorer neurocognition and social functioning than controls. The difference between schizophrenia and control groups was greatest for the Understanding Emotions Branch of the MSCEIT. The neurocognition score and total EI score accounted for 18.3% of the variance in social function in the control group and 9.1% of the variance in social function in the schizophrenia group. Our results suggest that a total EI score is not a useful predictor of overall social function and it may be more clinically useful to develop an individual profile of social cognitive abilities, including EI, to form a remediation program.

Early differential expression of oncostatin M in obstructive nephropathy.

Interstitial fibrosis plays a major role in progression of renal diseases. Oncostatin M (OSM) is a cytokine that regulates cell survival, differentiation, and proliferation. Renal tissue from patients with chronic obstructive nephropathy was examined for OSM expression. The elevated levels in diseased human kidneys suggested possible correlation between OSM level and kidney tissue fibrosis. Indeed, unilateral ureteral obstruction (UUO), a model of renal fibrosis, increased OSM and OSM receptor (OSM-R) expression in a time-dependent manner within hours following UUO. In vitro, OSM overexpression in tubular epithelial cells (TECs) resulted in epithelial-myofibroblast transdifferentiation. cDNA microarray technology identified up-regulated expression of immune modulators in obstructed compared with sham-operated kidneys. In vitro, OSM treatment up-regulated CC chemokine ligand CCL7, and CXC chemokine ligand (CXCL)-14 mRNA in kidney fibroblasts. In vivo, treatment of UUO mice with neutralizing anti-OSM antibody decreased renal chemokines expression. In conclusion, OSM is up-regulated in kidney tissue early after urinary obstruction. Therefore, OSM might play an important role in initiation of renal fibrogenesis, possibly by inducing myofibroblast transdifferentiation of TECs as well as leukocyte infiltration. This process may, in turn, contribute in part to progression of obstructive nephropathy and makes OSM a promising therapeutic target in renal fibrosis.

Impaired lymphocyte development and antibody class switching and increased malignancy in a murine model of DNA ligase IV syndrome.

Hypomorphic mutations in DNA ligase IV (LIG4) cause a human syndrome of immunodeficiency, radiosensitivity, and growth retardation due to defective DNA repair by the nonhomologous end-joining (NHEJ) pathway. Lig4-null mice are embryonic lethal, and better mouse models are needed to study human LigIV syndrome. We recently identified a viable mouse strain with a Y288C hypomorphic mutation in the Lig4 gene. Lig4Y288C mice exhibit a greater than 10-fold reduction of LigIV activity in vivo and recapitulate the immunodeficiency and growth retardation seen in human patients. Here, we have demonstrated that the Lig4Y288C mutation leads to multiple defects in lymphocyte development and function, including impaired V(D)J recombination, peripheral lymphocyte survival and proliferation, and B cell class switch recombination. We also highlight a high incidence of thymic tumors in the Lig4Y288C mice, suggesting that wild-type LigIV protects against malignant transformation. These findings provide explanations for the complex lymphoid phenotype of human LigIV syndrome.

Functional discrepancies in HIV-specific CD8+ T-lymphocyte populations are related to plasma virus load.

The potent ability of current antiretroviral drug regimens to control human immunodeficiency Virus-1 (HIV-1) replication, in conjunction with the clinical practice of structured therapeutic interruptions, provides a system in which virus levels are manipulated during a persistent infection in humans. Here, we exploit this system to examine the impact of variable plasma virus load (pVL) on the functionality of HIV-specific CD8+ T-lymphocyte populations. Using both ELISpot methodology and intracellular cytokine staining for interferon (IFN)-gamma to assess functional status, together with fluorochrome-labeled peptide-major histocompatibility complex (pMHC) class I tetramer analysis to detect the physical presence of CD8+ T lymphocytes expressing cognate T-cell receptors (TCRs), we observed that the proportion of HIV-specific CD8+ T lymphocytes capable of mounting an effector response to antigen challenge directly ex vivo is related to the kinetics of virus exposure. Specifically, (a) after prolonged suppression of pVL with antiretroviral therapy (ART), physical and functional measures of HIV-specific CD8+ T-lymphocyte frequencies approximated; and (b) the percentage of functionally responsive cells in the HIV-specific CD8+ T lymphocyte populations declined substantially when therapy was discontinued and pVL recrudesced in the same patients. These results corroborate and extend observations in animal models that describe nonresponsive CD8+ T lymphocytes in the presence of high levels of antigen load and have implications for the interpretation of quantitative data generated by methods that rely on functional readouts.