Relevance of lymphocyte proliferation to PHA in severe combined immunodeficiency (SCID) and T cell lymphopenia

Severe combined immunodeficiency (SCID) is characterized by a severe deficiency in T cell numbers. We analyzed data collected (n = 307) for PHA-based T cell proliferation from the PIDTC SCID protocol 6901, using either a radioactive or flow cytometry method. In comparing the two groups, a smaller number of the patients tested by flow cytometry had <10% of the lower limit of normal proliferation as compared to the radioactive method (p = 0.02). Further, in patients with CD3+ T cell counts between 51 and 300 cells/μL, there was a higher proliferative response with the PHA flow assay compared to the 3H-T assay (p < 0.0001), suggesting that the method of analysis influences the resolution and interpretation of PHA results. Importantly, we observed many SCID patients with profound T cell lymphopenia having normal T cell proliferation when assessed by flow cytometry. We recommend this test be considered only as supportive in the diagnosis of typical SCID.

Posttransplantation late complications increase over time for patients with SCID: A Primary Immune Deficiency Treatment Consortium (PIDTC) landmark study

BACKGROUND

The Primary Immune Deficiency Treatment Consortium (PIDTC) enrolled children in the United States and Canada onto a retrospective multicenter natural history study of hematopoietic cell transplantation (HCT).

OBJECTIVE

We investigated outcomes of HCT for severe combined immunodeficiency (SCID).

METHODS

We evaluated the chronic and late effects (CLE) after HCT for SCID in 399 patients transplanted from 1982 to 2012 at 32 PIDTC centers. Eligibility criteria included survival to at least 2 years after HCT without need for subsequent cellular therapy. CLE were defined as either conditions present at any time before 2 years from HCT that remained unresolved (chronic), or new conditions that developed beyond 2 years after HCT (late).

RESULTS

The cumulative incidence of CLE was 25% in those alive at 2 years, increasing to 41% at 15 years after HCT. CLE were most prevalent in the neurologic (9%), neurodevelopmental (8%), and dental (8%) categories. Chemotherapy-based conditioning was associated with decreased-height z score at 2 to 5 years after HCT (P < .001), and with endocrine (P < .001) and dental (P = .05) CLE. CD4 count of ≤500 cells/μL and/or continued need for immunoglobulin replacement therapy >2 years after transplantation were associated with lower-height z scores. Continued survival from 2 to 15 years after HCT was 90%. The presence of any CLE was associated with increased risk of late death (hazard ratio, 7.21; 95% confidence interval, 2.71-19.18; P < .001).

CONCLUSION

Late morbidity after HCT for SCID was substantial, with an adverse impact on overall survival. This study provides evidence for development of survivorship guidelines based on disease characteristics and treatment exposure for patients after HCT for SCID.

Genotype, oxidase status, and preceding infection or autoinflammation do not affect allogeneic HCT outcomes for CGD

Chronic granulomatous disease (CGD) is a primary immunodeficiency characterized by life-threatening infections and inflammatory conditions. Hematopoietic cell transplantation (HCT) is the definitive treatment for CGD, but questions remain regarding patient selection and impact of active disease on transplant outcomes. We performed a multi-institutional retrospective and prospective study of 391 patients with CGD treated either conventionally (non-HCT) enrolled from 2004 to 2018 or with HCT from 1996 to 2018. Median follow-up after HCT was 3.7 years with a 3-year overall survival of 82% and event-free survival of 69%. In a multivariate analysis, a Lansky/Karnofsky score <90 and use of HLA-mismatched donors negatively affected survival. Age, genotype, and oxidase status did not affect outcomes. Before HCT, patients had higher infection density, higher frequency of noninfectious lung and liver diseases, and more steroid use than conventionally treated patients; however, these issues did not adversely affect HCT survival. Presence of pre-HCT inflammatory conditions was associated with chronic graft-versus-host disease. Graft failure or receipt of a second HCT occurred in 17.6% of the patients and was associated with melphalan-based conditioning and/or early mixed chimerism. At 3 to 5 years after HCT, patients had improved growth and nutrition, resolved infections and inflammatory disease, and lower rates of antimicrobial prophylaxis or corticosteroid use compared with both their baseline and those of conventionally treated patients. HCT leads to durable resolution of CGD symptoms and lowers the burden of the disease. Patients with active infection or inflammation are candidates for transplants; HCT should be considered before the development of comorbidities that could affect performance status. This trial was registered at www.clinicaltrials.gov as #NCT02082353.

Retrospective Observational Assessment of the Impact of Cefepime Prophylaxis in Neutropenic Pediatric Patients With Acute Myelogenous Leukemia

BACKGROUND

The potential for cefepime prophylaxis to reduce bloodstream infections (BSIs) in pediatric patients with acute myelogenous leukemia (AML) has been incompletely characterized.

METHODS

A retrospective quasi-experimental study of patients under 21 years of age admitted with AML from 2010 through 2018 at two affiliated pediatric tertiary-care hospitals before and after the adoption of routine cefepime prophylaxis for afebrile AML patients during profound neutropenia.

RESULTS

The rate of BSIs per 1000 neutropenia days was significantly lower in the prophylaxis group than the baseline group (2.6 vs 15.5, incidence rate ratio [IRR] 0.17, 95% CI 0.09-0.32). Interrupted time-series analysis showed that a sharp reduction in BSIs coincided with the implementation of prophylaxis. Bacteremia with viridans group streptococci was frequent in the baseline group but not observed after adopting prophylaxis. Despite the increased use of cefepime, the rate of cefepime-nonsusceptible BSIs per 1000 neutropenia days decreased (1.6 vs 4.1, IRR 0.40, 95% CI 0.16-0.99). The median number of febrile neutropenia episodes per patient also decreased in the prophylaxis group, as did the proportion of patients admitted to the intensive care unit (ICU) (22/51 (43.1%) vs 26/38 (68.4%); risk difference -25.3%, 95% CI -44.4 to -2.8). A trend was observed toward an increased proportion of patients with Clostridioides difficile infection in the prophylaxis group (10/51 (19.6%) vs 3/38 (7.9%); risk difference 11.7%, 95% CI -3.4 to 29.0).

CONCLUSIONS

Cefepime prophylaxis was associated with a significant reduction in BSIs, febrile neutropenia, and ICU admission among pediatric AML patients.

Autologous hematopoietic stem cell transplantation in a pediatric patient with aquaporin-4 neuromyelitis optica spectrum disorder

We report on a child with an early and severe manifestation of an Aquaporin-4 (AQP-4) positive Neuromyelitis Optica Spectrum Disorder (NMOSD) who had a refractory disease course despite aggressive immunotherapy and underwent autologous hematopoietic stem cell transplant (AHSCT).

Therapeutic Delivery of Ang(1-7) via Genetically Modified Probiotic: A Dosing Study

In recent years a number of beneficial health effects have been ascribed to the renin-angiotensin system (RAS) that extend beyond lowering blood pressure, primarily mediated via the angiotensin-converting enzyme-2 (ACE2)/angiotensin (1–7) or Ang(1–7)/MAS receptor axis. Moreover, once thought as merely a systemic effector, RAS components exist within tissues. The highest tissue concentrations of ACE2 mRNA are located in the gut making it an important target for altering RAS function. Indeed, genetically engineered recombinant probiotics are promising treatment strategies offering delivery of therapeutic proteins with precision. An Ang(1–7) secreting Lactobacillus paracasei (LP) or LP-A has been described for regulation of diabetes and hypertension; however, we are the first to the best of our knowledge to propose this paradigm as it relates to aging. In this Research Practice manuscript, we provide proof of concept for using this technology in a well-characterized rodent model of aging: the Fisher344 x Brown Norway Rat (F344BN). Our primary findings suggest that LP-A increases circulating levels of Ang(1–7) both acutely and chronically (after 8 or 28 treatment days) when administered 3× or 7×/week over 4 weeks. Our future preclinical studies will explore the impact of this treatment on gut and other age-sensitive distal tissues such as brain and muscle.

SARS-CoV-2 infection associated with hepatitis in an infant with X-linked severe combined immunodeficiency

X-linked severe combined immunodeficiency (X-SCID) is a disorder of adaptive immunity caused by mutations in the IL-2 receptor common gamma chain gene resulting in deficiencies of T and natural killer cells, coupled with severe dysfunction in B cells. X-SCID is lethal without allogeneic stem cell transplant or gene therapy due to opportunistic infections. An infant with X-SCID became infected with SARS-CoV-2 while awaiting transplant. The patient developed severe hepatitis without the respiratory symptoms typical of COVID-19. He was treated with convalescent plasma, and thereafter was confirmed to have SARS-CoV-2 specific antibodies, as detected with a microfluidic antigen array. After resolution of the hepatitis, he received a haploidentical CD34 selected stem cell transplant, without conditioning, from his father who had recovered from COVID-19. SARS CoV-2 was detected via RT-PCR on nasopharyngeal swabs until 61 days post transplantation. He successfully engrafted donor T and NK cells, and continues to do well clinically.

Infections in Infants with SCID: Isolation, Infection Screening, and Prophylaxis in PIDTC Centers

PURPOSE

The Primary Immune Deficiency Treatment Consortium (PIDTC) enrolled children with severe combined immunodeficiency (SCID) in a prospective natural history study of hematopoietic stem cell transplant (HSCT) outcomes over the last decade. Despite newborn screening (NBS) for SCID, infections occurred prior to HSCT. This study's objectives were to define the types and timing of infection prior to HSCT in patients diagnosed via NBS or by family history (FH) and to understand the breadth of strategies employed at PIDTC centers for infection prevention.

METHODS

We analyzed retrospective data on infections and pre-transplant management in patients with SCID diagnosed by NBS and/or FH and treated with HSCT between 2010 and 2014. PIDTC centers were surveyed in 2018 to understand their practices and protocols for pre-HSCT management.

RESULTS

Infections were more common in patients diagnosed via NBS (55%) versus those diagnosed via FH (19%) (p = 0.012). Outpatient versus inpatient management did not impact infections (47% vs 35%, respectively; p = 0.423). There was no consensus among PIDTC survey respondents as to the best setting (inpatient vs outpatient) for pre-HSCT management. While isolation practices varied, immunoglobulin replacement and antimicrobial prophylaxis were more uniformly implemented.

CONCLUSION

Infants with SCID diagnosed due to FH had lower rates of infection and proceeded to HSCT more quickly than did those diagnosed via NBS. Pre-HSCT management practices were highly variable between centers, although uses of prophylaxis and immunoglobulin support were more consistent. This study demonstrates a critical need for development of evidence-based guidelines for the pre-HSCT management of infants with SCID following an abnormal NBS.

TRIAL REGISTRATION

NCT01186913.

Transition From Hospital to Home Following Hematopoietic Stem Cell Transplantation: A Feasibility Study for "Rooming in"

Background: The experience of hematopoietic stem cell transplant (HSCT) on both the patients and their caregivers is complex and challenging during hospitalization and post discharge. Complex patient populations require heightened attention on discharge practices to ensure that they are prepared for home regimens. "Rooming in" is a standardized intervention implemented prior to discharge that allows patients and caregivers to assume post discharge care with the support of staff. Other complex patient populations have reported positive outcomes related to "rooming in." Aims: The purpose of this study was to assess the feasibility of a standardized "rooming in" intervention for discharge of pediatric HSCT patients. An additional aim was to describe the quality of discharge teaching, readiness for hospital discharge, and postdischarge coping difficulty in a cohort of HSCT patients using validated questionnaires. Method: Data were collected via medical chart review. A prospective cohort completed validated study questionnaires at discharge and 30 days postdischarge. Results: All caregivers of post-HSCT patients were able to complete the "rooming in" intervention. There was no statistically significant difference for length of stay between the retrospective and prospective cohorts. Caregivers enrolled on the study rated the Quality of Discharge Teaching Scale-Parent Form high (Mdn = 165). Conclusion: We conclude that "rooming in" is a feasible discharge intervention for caregivers of pediatric HSCT patients.

A phase I study of panobinostat in children with relapsed and refractory hematologic malignancies

Background: Panobinostat demonstrates activity against pediatric cancers in vitro. A phase I trial in children with refractory hematologic malignancies was conducted. Study design: The trial evaluated two schedules of oral panobinostat using 3 + 3 dose escalations in 28-day cycles. For children with leukemia, panobinostat was given once daily three days a week each week at 24, 30 and 34 mg/m2/day. For children with lymphoma, panobinostat was given once daily three days a week every other week at 16, 20 and 24 mg/m2/day. Cerebrospinal fluid (CSF) from Day 29 of the first cycle, when available, was evaluated for PK. The study was registered on clinicaltrials.gov (NCT01321346) Results: Twenty-two subjects enrolled with leukemia. Five enrolled at dose level 1, 6 at dose level 2, and 11 at dose level 3. There was one dose limiting toxicity (DLT) in the leukemia arm at dose level 3 (Grade 4 hypertriglyceridemia), but no maximum tolerated dose (MTD) was identified. No subjects required removal from protocol therapy for QTc prolongation. PK studies were available in 11 subjects with similar exposure in children as in adults. Four Day 29 CSF specimens were found to have panobinostat levels below the lower limit of quantification. Five subjects with lymphoma were enrolled and received study drug, and 4 were evaluable for DLT. A DLT was reported (Grade 3 enteritis) on the lymphoma arm. Conclusions: Panobinostat was tolerated in heavily pretreated pediatric subjects. Gastrointestinal effects were observed on this study. There were no cardiac findings. There were no responses.

Pulmonary arterial hypertension-associated changes in gut pathology and microbiota

Emerging evidence implicates an interplay among multiple organs such as brain, vasculature, gut and lung in the development of established pulmonary arterial hypertension (PAH). This has led us to propose that activated microglia mediated-enhanced sympathetic activation contributes to PAH pathophysiology. Since enhanced sympathetic activity is observed in human PAH and the gut is highly innervated by sympathetic nerves that regulate its physiological functions, we hypothesized that PAH would be associated with gut pathophysiology. A monocrotaline rat model of PAH was utilized to investigate the link between gut pathology and PAH. Haemodynamics, histology, immunocytochemistry and 16S RNA gene sequencing were used to assess cardiopulmonary functions, gut pathology and gut microbial communities respectively. Monocrotaline treatment caused increased right ventricular systolic pressure, haemodynamics and pathological changes associated with PAH. PAH animals also showed profound gut pathology that included increased intestinal permeability, increased muscularis layer, decreased villi length and goblet cells. These changes in gut pathology were associated with alterations in microbial communities, some unique to PAH animals. Furthermore, enhanced gut-neural communication involving the paraventricular nucleus of the hypothalamus and increased sympathetic drive were observed. In conclusion, our data show the presence of gut pathology and distinct changes in gut microbiota and increased sympathetic activity in PAH. They suggest that dysfunctional gut-brain crosstalk could be critical in PAH and considered a future therapeutic target for PAH.

Microglial Cells Impact Gut Microbiota and Gut Pathology in Angiotensin II-Induced Hypertension

RATIONALE

Increased microglial activation and neuroinflammation within autonomic brain regions have been implicated in sustained hypertension, and their inhibition by minocycline-an anti-inflammatory antibiotic-produces beneficial effects. These observations led us to propose a dysfunctional brain-gut communication hypothesis for hypertension. However, it has been difficult to reconcile whether an anti-inflammatory or antimicrobial action is the primary beneficial effect of minocycline in hypertension. Accordingly, we utilized chemically modified tetracycline-3 (CMT-3)-a derivative of tetracycline that has potent anti-inflammatory activity-to address this question.

OBJECTIVE

Test the hypothesis that central administration of CMT-3 would inhibit microglial activation, attenuate neuroinflammation, alter selective gut microbial communities, protect the gut wall from developing hypertension-associated pathology, and attenuate hypertension.

METHODS AND RESULTS

Rats were implanted with radiotelemetry devices for recording mean arterial pressure. Ang II (angiotensin II) was infused subcutaneously using osmotic mini-pumps to induce hypertension. Another osmotic mini-pump was surgically implanted to infuse CMT-3 intracerebroventricularly. Intracerebroventricular CMT- 3 infusion was also investigated in SHR (spontaneously hypertensive rats). Physiological, pathological, immunohistological parameters, and fecal microbiota were analyzed. Intracerebroventricular CMT-3 significantly inhibited Ang II-induced increases in number of microglia, their activation, and proinflammatory cytokines in the paraventricular nucleus of hypothalamus. Further, intracerebroventricular CMT-3 attenuated increased mean arterial pressure, normalized sympathetic activity, and left ventricular hypertrophy in Ang II rats, as well as in the SHR. Finally, CMT-3 beneficially restored certain gut microbial communities altered by Ang II and attenuated pathological alterations in gut wall.

CONCLUSIONS

These observations demonstrate that inhibition of microglial activation alone was sufficient to induce significant antihypertensive effects. This was associated with unique changes in gut microbial communities and profound attenuation of gut pathology. They suggest, for the first time, a link between microglia and certain microbial communities that may have implications for treatment of hypertension.

Outcomes after bloodstream infection in hospitalized pediatric hematology/oncology and stem cell transplant patients

BACKGROUND

Pediatric hematology/oncology (PHO) patients receiving therapy or undergoing hematopoietic stem cell transplantation (HSCT) often require a central line and are at risk for bloodstream infections (BSI). There are limited data describing outcomes of BSI in PHO and HSCT patients.

METHODS

This is a multicenter (n = 17) retrospective analysis of outcomes of patients who developed a BSI. Centers involved participated in a quality improvement collaborative referred to as the Childhood Cancer and Blood Disorder Network within the Children's Hospital Association. The main outcome measures were all-cause mortality at 3, 10, and 30 days after positive culture date; transfer to the intensive care unit (ICU) within 48 hours of positive culture; and central line removal within seven days of the positive blood culture.

RESULTS

Nine hundred fifty-seven BSI were included in the analysis. Three hundred fifty-four BSI (37%) were associated with at least one adverse outcome. All-cause mortality was 1% (n = 9), 3% (n = 26), and 6% (n = 57) at 3, 10, and 30 days after BSI, respectively. In the 165 BSI (17%) associated with admission to the ICU, the median ICU stay was four days (IQR 2-10). Twenty-one percent of all infections (n = 203) were associated with central line removal within seven days of positive blood culture.

CONCLUSIONS

BSI in PHO and HSCT patients are associated with adverse outcomes. These data will assist in defining the impact of BSI in this population and demonstrate the need for quality improvement and research efforts to decrease them.

Sustained Captopril-Induced Reduction in Blood Pressure Is Associated With Alterations in Gut-Brain Axis in the Spontaneously Hypertensive Rat

Background We have demonstrated that the antihypertensive effect of the angiotensin-converting enzyme inhibitor, captopril ( CAP ), is associated with beneficial effects on gut pathology. Coupled with the evidence that CAP exerts prolonged reduction in blood pressure ( BP ) after discontinuation of treatment, we investigate whether persistent beneficial actions of CAP are linked to alterations of gut microbiota and improvement of hypertension-induced gut pathology. Methods and Results Spontaneously hypertensive rats ( SHR ) and Wistar Kyoto rats were treated with CAP (250 mg/kg/day) for 4 weeks followed by withdrawal for 16 weeks. Gut microbiota, gut pathology, BP, and brain neuronal activity were assessed. CAP resulted in a ≈60 mm Hg decrease in systolic BP after 3 weeks of treatment in SHR , and the decrease remained significant at least 5 weeks after CAP withdrawal. In contrast, CAP caused modest decrease in systolic BP in Wistar Kyoto. 16S rRNA gene-sequencing-based gut microbial analyses in SHR showed sustained alteration of gut microbiota and increase in Allobaculum after CAP withdrawal. Phylogenetic investigation of communities by reconstruction of unobserved states analysis revealed significant increase in bacterial sporulation upon CAP treatment in SHR . These were associated with persistent improvement in gut pathology and permeability. Furthermore, manganese-enhanced magnetic resonance imaging showed significantly decreased neuronal activity in the posterior pituitary of SHR 4 weeks after withdrawal. Conclusions Decreased BP , altered gut microbiota, improved gut pathology and permeability, and dampened posterior pituitary neuronal activity were maintained after CAP withdrawal in the SHR . They suggest that CAP influences the brain-gut axis to maintain the sustained antihypertensive effect of CAP after withdrawal.

SCID genotype and 6-month posttransplant CD4 count predict survival and immune recovery

The Primary Immune Deficiency Treatment Consortium (PIDTC) performed a retrospective analysis of 662 patients with severe combined immunodeficiency (SCID) who received a hematopoietic cell transplantation (HCT) as first-line treatment between 1982 and 2012 in 33 North American institutions. Overall survival was higher after HCT from matched-sibling donors (MSDs). Among recipients of non-MSD HCT, multivariate analysis showed that the SCID genotype strongly influenced survival and immune reconstitution. Overall survival was similar for patients with RAG, IL2RG, or JAK3 defects and was significantly better compared with patients with ADA or DCLRE1C mutations. Patients with RAG or DCLRE1C mutations had poorer immune reconstitution than other genotypes. Although survival did not correlate with the type of conditioning regimen, recipients of reduced-intensity or myeloablative conditioning had a lower incidence of treatment failure and better T- and B-cell reconstitution, but a higher risk for graft-versus-host disease, compared with those receiving no conditioning or immunosuppression only. Infection-free status and younger age at HCT were associated with improved survival. Typical SCID, leaky SCID, and Omenn syndrome had similar outcomes. Landmark analysis identified CD4+ and CD4+CD45RA+ cell counts at 6 and 12 months post-HCT as biomarkers predictive of overall survival and long-term T-cell reconstitution. Our data emphasize the need for patient-tailored treatment strategies depending upon the underlying SCID genotype. The prognostic significance of CD4+ cell counts as early as 6 months after HCT emphasizes the importance of close follow-up of immune reconstitution to identify patients who may need additional intervention to prevent poor long-term outcome.

Abstract 037: Global ACE2 Over-Expression is Protective Against a Dysfunctional Brain-Gut-Lung Axis in Hypoxia-Induced Pulmonary Hypertension

Background and Objectives: Angiotensin converting enzyme 2 (ACE2), key enzyme of the vasoprotective axis of the renin angiotensin system, has been implicated in many pulmonary diseases including pulmonary hypertension (PH). Plasma levels of ACE2 in group-1 pulmonary hypertensive patients are decreased and activation of this enzyme by small molecule activators, overexpression or administration of recombinant ACE2, all have beneficial outcomes on PH. Furthermore, involvement of neuroinflammation and impaired brain-gut-lung axis have been proposed in PH. These observations have led us to propose that beneficial effect of ACE2 are, at least in part, due to attenuation of neuroinflammation and rebalancing of gut microbiota and improvement in pathology.

Methods: ACE2 knock-in (ACE2KI) and wild-type mice (WT; C57BL/6) were subjected to hypoxia (10% FIO2) or room air for 4 weeks (n=8-10/group). Right ventricular systolic pressure (RVSP), and electrocardiography were performed, tissues examined by standard histological techniques, and stool collected for 16S rRNA analysis at 4 weeks.

Results: Hypoxia-induced significantly increased RVSP in WT but not ACE2KI mice (20±1.6 vs 32±1.9, p<0.001 and 24.3±1.5 vs 21±1.3mmHg, respectively). This was accompanied in WT, but not ACEKI, by ~5-fold increase in sympathetic activation (LF/HF; p<0.001) and ~2-fold increase (p<0.01) in microglia activation in the paraventricular nucleus (PVN) of the hypothalamus. There was increased fibrotic area (p<0.01) and muscularis layer thickening (p<0.001) and decreased villi length (p<0.01) and goblet cells (p<0.001) in the small intestine of WT but not ACE2KI mice following hypoxia. Finally, beta diversity of gut microbiome of WT, but not ACE2KI, mice was significantly altered by hypoxia (ANOSIM P=0.001).

Conclusions: Microglial activation in PVN, sympathetic activation, gut pathology and altered gut microbiome are associated with hypoxia-induced PH. Global overexpression of ACE2 prevents all of these parameters. The involvement of organs other than lungs, and ACE2, present novel therapeutic potentials for PH.

Abstract P235: Altered Brain-Gut-Lung Axis in Hypoxia-Induced Pulmonary Hypertension

Background: Recent evidence indicate that gut microbiota plays important role in pathogenesis and progression of chronic lung diseases such as asthma, respiratory infections and COPD. However, implications of this gut-lung communication and involvement of peripheral and neural immune system in pulmonary hypertension (PH) remains unknown.

Objective: Investigate the hypothesis that increased activation of microglial cells, autonomic nervous system, altered gut pathology and gut microbiota are associated with PH suggesting a dysfunctional brain-gut-lung axis in PH pathology.

Methods: C57BL/6 (WT) male mice were exposed to chronic hypoxia (10%O2) or Normoxia for 4 weeks in a ventilated chamber (n=5-8/group). Millar pressure catheter was used to measure pulmonary hemodynamics, Iba1 specific antibody for immunohistochemical analysis of microglial cells and fecal 16S rDNA for gut microbiota analysis.

Results: Hypoxia induced a 77% increase in right ventricular (RV) systolic pressure (RVSP: N:19.5 ± 2 mmHg Vs H:33.7 ± 2, p<0.001) and RV hypertrophy (RVH: N: 0.139 ± 0.09 Vs H: 0.192± 0.008). This was associated with substantial enhancement in sympathetic activity (LF/HF: N:0.23 ± 0.8 mmHg Vs H: 1.19 ± 0.08, p<0.001) and increase in number of microglial cells in autonomic brain regions, predominantly the paraventricular nucleus of hypothalamus. Characteristics of gut pathology such as ~50% increase in fibrotic area and muscularis layer thickness and significantly decreased villi length and number of goblet cells in small intestine were also observed. Also, principal coordinate analysis of the bacterial composition profile showed a clear separation and clustering of bacterial genera of hypoxic and normoxic mice (ANOSIM p<0.001).

Conclusions: (I) Hypoxia-induced pulmonary and cardiac pathophysiology is associated with increased microglia in cardiorespiratory-relevant areas and enhanced sympathetic activity. (II) Fibrotic area and muscularis layer thickness increased while villi length and number of goblet cells decreased in gut (III) gut microbiota are altered. Together, these observations indicated an altered brain-gut-lung axis in PH.

Involvement of Neuroinflammation in the Pathogenesis of Monocrotaline-Induced Pulmonary Hypertension

Pulmonary hypertension (PH) is a devastating disease and its successful treatment remains to be accomplished despite recent advances in pharmacotherapy. It has been proposed that PH be considered as a systemic disease, rather than primarily a disease of the pulmonary vasculature. Consequently, an investigation of the intricate interplay between multiple organs such as brain, vasculature, and lung in PH could lead to the identification of new targets for its therapy. However, little is known about this interplay. This study was undertaken to examine the concept that altered autonomic-pulmonary communication is important in PH pathophysiology. Therefore, we hypothesize that activation of microglial cells in the paraventricular nucleus of hypothalamus and neuroinflammation is associated with increased sympathetic drive and pulmonary pathophysiology contributing to PH. We utilized the monocrotaline rat model for PH and intracerebroventricular administration of minocycline for inhibition of microglial cells activation to investigate this hypothesis. Hemodynamic, echocardiographic, histological, immunohistochemical, and confocal microscopic techniques assessed cardiac and pulmonary function and microglial cells. Monocrotaline treatment caused cardiac and pulmonary pathophysiology associated with PH. There were also increased activated microglial cells and mRNA for proinflammatory cytokines (IL [interleukin]-1β, IL-6, and TNF [tumor necrosis factor]-α) in the paraventricular nucleus. Furthermore, increased sympathetic drive and plasma norepinephrine were observed in rats with PH. Intracerebroventricular infusion of minocycline inhibited all these parameters and significantly attenuated PH. These observations implicate a dysfunctional autonomic-lung communication in the development and progression of PH providing new therapeutic targets, such as neuroinflammation, for PH therapy.

Long-term outcomes of 176 patients with X-linked hyper-IgM syndrome treated with or without hematopoietic cell transplantation

BACKGROUND

X-linked hyper-IgM syndrome (XHIGM) is a primary immunodeficiency with high morbidity and mortality compared with those seen in healthy subjects. Hematopoietic cell transplantation (HCT) has been considered a curative therapy, but the procedure has inherent complications and might not be available for all patients.

OBJECTIVES

We sought to collect data on the clinical presentation, treatment, and follow-up of a large sample of patients with XHIGM to (1) compare long-term overall survival and general well-being of patients treated with or without HCT along with clinical factors associated with mortality and (2) summarize clinical practice and risk factors in the subgroup of patients treated with HCT.

METHODS

Physicians caring for patients with primary immunodeficiency diseases were identified through the Jeffrey Modell Foundation, United States Immunodeficiency Network, Latin American Society for Immunodeficiency, and Primary Immune Deficiency Treatment Consortium. Data were collected with a Research Electronic Data Capture Web application. Survival from time of diagnosis or transplantation was estimated by using the Kaplan-Meier method compared with log-rank tests and modeled by using proportional hazards regression.

RESULTS

Twenty-eight clinical sites provided data on 189 patients given a diagnosis of XHIGM between 1964 and 2013; 176 had valid follow-up and vital status information. Sixty-seven (38%) patients received HCT. The average follow-up time was 8.5 ± 7.2 years (range, 0.1-36.2 years). No difference in overall survival was observed between patients treated with or without HCT (P = .671). However, risk associated with HCT decreased for diagnosis years 1987-1995; the hazard ratio was significantly less than 1 for diagnosis years 1995-1999. Liver disease was a significant predictor of overall survival (hazard ratio, 4.9; 95% confidence limits, 2.2-10.8; P < .001). Among survivors, those treated with HCT had higher median Karnofsky/Lansky scores than those treated without HCT (P < .001). Among patients receiving HCT, 27 (40%) had graft-versus-host disease, and most deaths occurred within 1 year of transplantation.

CONCLUSION

No difference in survival was observed between patients treated with or without HCT across all diagnosis years (1964-2013). However, survivors treated with HCT experienced somewhat greater well-being, and hazards associated with HCT decreased, reaching levels of significantly less risk in the late 1990s. Among patients treated with HCT, treatment at an early age is associated with improved survival. Optimism remains guarded as additional evidence accumulates.

Abstract 009: Genetically Modified Probiotics for Oral Delivery of Angiotensin-(1-7) Confers Protection Against Pulmonary Hypertension

Background: Previous studies have established that activation of the members of the vasoprotective axis of the renin-angiotensin system [Angiotensin Converting Enzyme 2 (ACE2) or Angiotensin-(1-7) (Ang-(1-7))] prevents and arrests progression of pulmonary hypertension (PH) pathophysiology. Our objective in this present study was to generate a probiotic containing Ang-(1-7) and test the hypothesis that oral administration of such a probiotic would provide cardiopulmonary protection against PH.

Methods: In this study, we genetically modified the commensal bacterium Lactobacillus paracasei (LP), commonly found in the gut and used as a probiotic, to serve as a live vector for the oral delivery of Ang-(1-7) and investigated its therapeutic potential in attenuating PH. The vectors pTRKH3- ldh -SP-GFP or pTRKH3- ldh -SP-Ang-(1-7) were introduced by electroporation into LP. PH was induced by a single injection of monocrotaline (MCT; 50 mg/Kg s.c) in rats. A subset of animals was orally gavaged every other day for four weeks with 1x10 9 CFU of LP, LP secreting GFP (LP-GFP), or LP secreting Ang-(1-7) (LP-A).

Results: Oral feeding of LP-A significantly reduced MCT-induced right ventricular systolic pressure (RVSP) by 43% (Control: 27±1; MCT: 76±8; MCT+LP: 56±6; MCT+LP-GFP: 59±7; MCT+LP-A: 43±3 mmHg) and RV hypertrophy by 33% (Control: 0.25±0.01; MCT: 0.6+0.02; MCT+LP: 0.48±0.04; MCT+LP-GFP: 0.48±0.04; MCT+LP-A: 0.41±0.03). Moreover, LP-A feeding restored cardiac contractility (Control: 2070±95; MCT: 3133±295; LP-A: 2060±119 mmHg/s) and attenuated myocardial fibrosis. These beneficial effects on the cardiopulmonary system were associated with profound changes in gut pathology. MCT-induced PH was associated with an increase in ileum villus length and thickening of proximal colon, and a decrease in goblet cells/villus area, all of which indicate intestinal injury and altered immune status. However, these parameters were significantly attenuated by oral feeding of LP-A.

Conclusions: Oral administration of a genetically modified commensal bacterium that can secrete Ang-(1-7) provides cardiopulmonary protection against PH. Thus, delivery of Ang-(1-7) by probiotic means could be considered an innovative therapeutic strategy for PH.

Unrelated donor cord blood transplantation for children with severe sickle cell disease: results of one cohort from the phase II study from the Blood and Marrow Transplant Clinical Trials Network (BMT CTN)

The Sickle Cell Unrelated Donor Transplant Trial (SCURT trial) of the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) is a phase II study of the toxicity and efficacy of unrelated donor hematopoietic cell transplantation in children with severe sickle cell disease (SCD) using a reduced-intensity conditioning regimen. Here we report the results for the cord blood cohort of this trial. Eight children with severe SCD underwent unrelated donor cord blood transplantation (CBT) following alemtuzumab, fludarabine, and melphalan. Cyclosporine or tacrolimus and mycophenolate mofetil were administered for graft-versus-host disease (GVHD) prophylaxis. Donor/recipient HLA match status was 6 of 6 (n = 1) or 5 of 6 (n = 7), based on low/intermediate-resolution molecular typing at HLA -A, -B, and high-resolution typing at -DRB1. Median recipient age was 13.7 years (range: 7.4-16.2 years), and median weight was 35.0 kg (range: 25.2-90.2 kg). The median pre-cryopreservation total nucleated cell dose was 6.4 × 10(7) /kg (range: 3.1-7.6), and the median postthaw infused CD34 cell dose was 1.5 × 10(5) /kg (range: 0.2-2.3). All patients achieved neutrophil recovery (absolute neutrophil count >500/mm(3)) by day 33 (median: 22 days). Three patients who engrafted had 100% donor cells by day 100, which was sustained, and 5 patients had autologous hematopoietic recovery. Six of 8 patients had a platelet recovery to >50,000/mm(3) by day 100. Two patients developed grade II acute GVHD. Of these, 1 developed extensive chronic GVHD and died of respiratory failure 14 months posttransplantation. With a median follow-up of 1.8 years (range: 1-2.6), 7 patients are alive with a 1-year survival of 100%, and 3 of 8 are alive without graft failure or disease recurrence. Based upon the high incidence of graft rejection after unrelated donor CBT, enrollment onto the cord blood arm of the SCURT trial was suspended. However, because this reduced-intensity regimen has demonstrated a favorable safety profile, this trial remains open to enrollment for unrelated marrow donor transplants. Novel approaches aimed at improving engraftment will be needed before unrelated CBT can be widely adopted for transplanting patients with severe SCD.

Severity of coronary artery calcification by electron beam computed tomography predicts silent myocardial ischemia

BACKGROUND

Detection of subclinical coronary artery disease (CAD) before the development of life-threatening cardiac complications has great potential clinical relevance. Electron beam computed tomography (EBCT) is currently the only noninvasive test that can detect CAD in all stages of its development and thus has the potential to be an excellent screening technique for identifying asymptomatic subjects with underlying myocardial ischemia.

METHODS AND RESULTS

Over 2.5 years, we prospectively studied 3895 generally asymptomatic subjects with EBCT, 411 of whom had stress myocardial perfusion tomography (SPECT) within a close (median, 17 days) time period. SPECT and exercise treadmill results were compared with the coronary artery calcium score (CACS) as assessed by EBCT. The total CACS identified a population at high risk for having myocardial ischemia by SPECT although only a minority of subjects (22%) with an abnormal EBCT had an abnormal SPECT. No subject with CACS <10 had an abnormal SPECT compared with 2.6% of those with scores from 11 to 100, 11.3% of those with scores from 101 to 399, and 46% of those with scores >/=400 (P<0.0001). CACS predicted an abnormal SPECT regardless of subject age or sex.

CONCLUSIONS

CACS identifies a high-risk group of asymptomatic subjects who have clinically important silent myocardial ischemia. Our results support the role of EBCT as the initial screening tool for identifying individuals at various stages of CAD development for whom therapeutic decision making may differ considerably.

Uvulitis in three children: etiology and respiratory distress

Uvulitis is an uncommonly reported disorder with the potential for significant morbidity. We describe three cases of uvulitis seen within a six month period in our emergency department. In two cases with respiratory distress, but without epiglottitis, Haemophilus influenzae was isolated from throat or blood cultures. The third case was associated with group A streptococcus tonsillitis and no respiratory compromise. Atypical presentations of upper airway infection with H. influenzae may be increasingly common.