Development and optimization of a diluted whole blood ELISpot assay to test immune function.

Sepsis remains a leading cause of death worldwide with no proven immunomodulatory therapies. Stratifying Patient Immune Endotypes in Sepsis ('SPIES') is a prospective, multicenter observational study testing the utility of ELISpot as a functional bioassay specifically measuring cytokine-producing cells after stimulation to identify the immunosuppressed endotype, predict clinical outcomes in septic patients, and test potential immune stimulants for clinical development. Most ELISpot protocols call for the isolation of PBMC prior to their inclusion in the assay. In contrast, we developed a diluted whole blood (DWB) ELISpot protocol that has been validated across multiple laboratories. Heparinized whole blood was collected from healthy donors and septic patients and tested under different stimulation conditions to evaluate the impact of blood dilution, stimulant concentration, blood storage, and length of stimulation on ex vivo IFNγ and TNFα production as measured by ELISpot. We demonstrate a dynamic range of whole blood dilutions that give a robust ex vivo cytokine response to stimuli. Additionally, a wide range of stimulant concentrations can be utilized to induce cytokine production. Further modifications demonstrate anticoagulated whole blood can be stored up to 24 h at room temperature without losing significant functionality. Finally, we show ex vivo stimulation can be as brief as 4 h allowing for a substantial decrease in processing time. The data demonstrate the feasibility of using ELISpot to measure the functional capacity of cells within DWB under a variety of stimulation conditions to inform clinicians on the extent of immune dysregulation in septic patients.

Synergistic effects of sulopenem in combination with cefuroxime or durlobactam against Mycobacterium abscessus.

Mycobacterium abscessus (Mab) affects patients with immunosuppression or underlying structural lung diseases such as cystic fibrosis (CF). Additionally, Mab poses clinical challenges due to its resistance to multiple antibiotics. Herein, we investigated the synergistic effect of dual ß-lactams [sulopenem and cefuroxime (CXM)] or the combination of sulopenem and CXM with ß-lactamase inhibitors [BLIs-avibactam (AVI) or durlobactam (DUR)]. The sulopenem-CXM combination yielded low minimum inhibitory concentration (MIC) values for 54 clinical Mab isolates and ATCC19977 (MIC50 and MIC90 ≤0.25 µg/mL). Similar synergistic effects were observed in time-kill studies conducted at concentrations achievable in clinical settings. Sulopenem-CXM outperformed monotherapy, yielding ~1.5 Log10 CFU/mL reduction during 10 days. Addition of BLIs enhanced this antibacterial effect, resulting in an additional reduction of CFUs (~3 Log10 for sulopenem-CXM and AVI and ~4 Log10 for sulopenem-DUR). Exploration of the potential mechanisms of the synergy focused on their interactions with L,D-transpeptidases (Ldts; LdtMab1-LdtMab4), penicillin-binding-protein B (PBP B), and D,D-carboxypeptidase (DDC). Acyl complexes, identified via mass spectrometry analysis, demonstrated the binding of sulopenem with LdtMab2-LdtMab4, DDC, and PBP B and CXM with LdtMab2 and PBP B. Molecular docking and mass spectrometry data suggest the formation of a covalent adduct between sulopenem and LdtMab2 after the nucleophilic attack of the cysteine residue at the ß-lactam carbonyl carbon, leading to the cleavage of the ß-lactam ring and the establishment of a thioester bond linking the LdtMab2 with sulopenem. In conclusion, we demonstrated the biochemical basis of the synergy of sulopenem-CXM with or without BLIs. These findings potentially broaden the selection of oral therapeutic agents to combat Mab. IMPORTANCE: Treating infections from Mycobacterium abscessus (Mab), particularly those resistant to common antibiotics like macrolides, is notoriously difficult, akin to a never-ending struggle for healthcare providers. The rate of treatment failure is even higher than that seen with multidrug-resistant tuberculosis. The role of combination ß-lactams in inhibiting L,D-transpeptidation, the major peptidoglycan crosslink reaction in Mab, is an area of intense investigation, and clinicians have utilized this approach in the treatment of macrolide-resistant Mab, with reports showing clinical success. In our study, we found that cefuroxime and sulopenem, when used together, display a significant synergistic effect. If this promising result seen in lab settings, translates well into real-world clinical effectiveness, it could revolutionize current treatment methods. This combination could either replace the need for more complex intravenous medications or serve as a "step down" to an oral medication regimen. Such a shift would be much easier for patients to manage, enhancing their comfort and likelihood of sticking to the treatment plan, which could lead to better outcomes in tackling these tough infections. Our research delved into how these drugs inhibit cell wall synthesis, examined time-kill data and binding studies, and provided a scientific basis for the observed synergy in cell-based assays.

TEMPORAL CHANGES IN INNATE AND ADAPTIVE IMMUNITY DURING SEPSIS AS DETERMINED BY ELISPOT.

ABSTRACT: Background: The inability to evaluate host immunity in a rapid quantitative manner in patients with sepsis has severely hampered development of novel immune therapies. The enzyme-linked immunospot (ELISpot) assay is a functional bioassay that measures the number of cytokine-secreting cells and the relative amount of cytokine produced at the single-cell level. A key advantage of ELISpot is its excellent dynamic range enabling a more precise quantifiable assessment of host immunity. Herein, we tested the hypothesis that the ELISpot assay can detect dynamic changes in both innate and adaptive immunity as they often occur during sepsis. We also tested whether ELISpot could detect the effect of immune drug therapies to modulate innate and adaptive immunity. Methods: Mice were made septic using sublethal cecal ligation and puncture. Blood and spleens were harvested serially, and ex vivo interferon γ and TNF-α production were compared by ELISpot and enzyme-linked immunosorbent assay. The capability of ELISpot to detect changes in innate and adaptive immunity due to in vivo immune therapy with dexamethasone, IL-7, and arginine was also evaluated. Results: ELISpot confirmed a decreased innate and adaptive immunity responsiveness during sepsis progression. More importantly, ELISpot was also able to detect changes in adaptive and innate immunity in response to immune-modulatory reagents, for example, dexamethasone, arginine, and IL-7, in a readily quantifiable manner, as predicted by the reagents known mechanisms of action. ELISpot and enzyme-linked immunosorbent assay results tended to parallel one another although some differences were noted. Conclusion: ELISpot offers a unique capability to assess the functional status of both adaptive and innate immunity over time. The results presented herein demonstrate that ELISpot can also be used to detect and follow the in vivo effects of drugs to ameliorate sepsis-induced immune dysfunction. This capability would be a major advance in guiding new immune therapies in sepsis.

Inhibiting Mycobacterium abscessus Cell Wall Synthesis: Using a Novel Diazabicyclooctane ß-Lactamase Inhibitor To Augment ß-Lactam Action.

Mycobacterium abscessus (Mab) infections are a growing menace to the health of many patients, especially those suffering from structural lung disease and cystic fibrosis. With multidrug resistance a common feature and a growing understanding of peptidoglycan synthesis in Mab, it is advantageous to identify potent ß-lactam and ß-lactamase inhibitor combinations that can effectively disrupt cell wall synthesis. To improve existing therapeutic regimens to address serious Mab infections, we evaluated the ability of durlobactam (DUR), a novel diazobicyclooctane ß-lactamase inhibitor to restore in vitro susceptibilities in combination with ß-lactams and provide a biochemical rationale for the activity of this compound. In cell-based assays, susceptibility of Mab subsp. abscessus isolates to amoxicillin (AMOX), imipenem (IMI), and cefuroxime (CXM) was significantly enhanced with the addition of DUR. The triple drug combinations of CXM-DUR-AMOX and IMI-DUR-AMOX were most potent, with MIC ranges of ≤0.06 to 1 µg/mL and an MIC50/MIC90 of ≤0.06/0.25 µg/mL, respectively. We propose a model by which this enhancement may occur, DUR potently inhibited the ß-lactamase BlaMab with a relative Michaelis constant (Ki app) of 4 × 10-3 ± 0.8 × 10-3 µM and acylation rate (k2/K) of 1 × 107 M-1 s-1. Timed mass spectrometry captured stable formation of carbamoyl-enzyme complexes between DUR and LdtMab2-4 and Mab d,d-carboxypeptidase, potentially contributing to the intrinsic activity of DUR. Molecular modeling showed unique and favorable interactions of DUR as a BlaMab inhibitor. Similarly, modeling showed how DUR might form stable Michaelis-Menten complexes with LdtMab2-4 and Mab d,d-carboxypeptidase. The ability of DUR combined with amoxicillin or cefuroxime and imipenem to inactivate multiple targets such as d,d-carboxypeptidase and LdtMab2,4 supports new therapeutic approaches using ß-lactams in eradicating Mab. IMPORTANCE Durlobactam (DUR) is a potent inhibitor of BlaMab and provides protection of amoxicillin and imipenem against hydrolysis. DUR has intrinsic activity and forms stable acyl-enzyme complexes with LdtMab2 and LdtMab4. The ability of DUR to protect amoxicillin and imipenem against BlaMab and its intrinsic activity along with the dual ß-lactam target redundancy can explain the rationale behind the potent activity of this combination.

Research Priorities for Plasma and Platelet Transfusion Strategies in Critically Ill Children: From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding.

OBJECTIVES: To present a list of high-priority research initiatives for the study of plasma and platelet transfusions in critically ill children from the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding. DESIGN: Systematic review and consensus conference of international, multidisciplinary experts in platelet and plasma transfusion management of critically ill children. SETTING: Not applicable. PATIENTS: Critically ill pediatric patients at risk of bleeding and receiving plasma and/or platelet transfusions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A panel of 13 experts developed research priorities for the study of plasma and platelet transfusions in critically ill children which were reviewed and ratified by the 29 Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding experts. The specific priorities focused on the following subpopulations: severe trauma, traumatic brain injury, intracranial hemorrhage, cardiopulmonary bypass surgery, extracorporeal membrane oxygenation, oncologic diagnosis or stem cell transplantation, acute liver failure and/or liver transplantation, noncardiac surgery, invasive procedures outside of the operating room, and sepsis and/or disseminated intravascular coagulation. In addition, tests to guide plasma and platelet transfusion, as well as component selection and processing, were addressed. We developed four general overarching themes and 14 specific research priorities using modified Research and Development/University of California, Los Angeles methodology. CONCLUSIONS: Studies are needed to focus on the efficacy/harm, dosing, timing, and outcomes of critically ill children who receive plasma and/or platelet transfusions. The completion of these studies will facilitate the development of evidence-based recommendations.

Executive Summary of Recommendations and Expert Consensus for Plasma and Platelet Transfusion Practice in Critically Ill Children: From the Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding (TAXI-CAB).

OBJECTIVES: Critically ill children frequently receive plasma and platelet transfusions. We sought to determine evidence-based recommendations, and when evidence was insufficient, we developed expert-based consensus statements about decision-making for plasma and platelet transfusions in critically ill pediatric patients. DESIGN: Systematic review and consensus conference series involving multidisciplinary international experts in hemostasis, and plasma/platelet transfusion in critically ill infants and children (Transfusion and Anemia EXpertise Initiative-Control/Avoidance of Bleeding [TAXI-CAB]). SETTING: Not applicable. PATIENTS: Children admitted to a PICU at risk of bleeding and receipt of plasma and/or platelet transfusions. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: A panel of 29 experts in methodology, transfusion, and implementation science from five countries and nine pediatric subspecialties completed a systematic review and participated in a virtual consensus conference series to develop recommendations. The search included MEDLINE, EMBASE, and Cochrane Library databases, from inception to December 2020, using a combination of subject heading terms and text words for concepts of plasma and platelet transfusion in critically ill children. Four graded recommendations and 49 consensus expert statements were developed using modified Research and Development/UCLA and Grading of Recommendations, Assessment, Development, and Evaluation methodology. We focused on eight subpopulations of critical illness (1, severe trauma, intracranial hemorrhage, or traumatic brain injury; 2, cardiopulmonary bypass surgery; 3, extracorporeal membrane oxygenation; 4, oncologic diagnosis or hematopoietic stem cell transplantation; 5, acute liver failure or liver transplantation; 6, noncardiac surgery; 7, invasive procedures outside the operating room; 8, sepsis and/or disseminated intravascular coagulation) as well as laboratory assays and selection/processing of plasma and platelet components. In total, we came to consensus on four recommendations, five good practice statements, and 44 consensus-based statements. These results were further developed into consensus-based clinical decision trees for plasma and platelet transfusion in critically ill pediatric patients. CONCLUSIONS: The TAXI-CAB program provides expert-based consensus for pediatric intensivists for the administration of plasma and/or platelet transfusions in critically ill pediatric patients. There is a pressing need for primary research to provide more evidence to guide practitioners.

A Peptide-Based Checkpoint Immunomodulator Alleviates Immune Dysfunction in Murine Polymicrobial Sepsis.

ABSTRACT: Sepsis-induced immunosuppression involves both innate and adaptive immunity and is associated with the increased expression of checkpoint inhibitors, such as programmed cell-death protein 1 (PD-1). The expression of PD-1 is associated with poor outcomes in septic patients, and in models of sepsis, blocking PD-1 or its ligands with antibodies increased survival and alleviated immune suppression. While inhibitory antibodies are effective, they can lead to immune-related adverse events (irAEs), in part due to continual blockade of the PD-1 pathway, resulting in hyperactivation of the immune response. Peptide-based therapeutics are an alternative drug modality that provide a rapid pharmacokinetic profile, reducing the incidence of precipitating irAEs. We recently reported that the potent, peptide-based PD-1 checkpoint antagonist, LD01, improves T-cell responses. The goal of the current study was to determine whether LD01 treatment improved survival, bacterial clearance, and host immunity in the cecal-ligation and puncture (CLP)-induced murine polymicrobial sepsis model. LD01 treatment of CLP-induced sepsis significantly enhanced survival and decreased bacterial burden. Altered survival was associated with improved macrophage phagocytic activity and T-cell production of interferon-γ. Further, myeloperoxidase levels and esterase-positive cells were significantly reduced in LD01-treated mice. Taken together, these data establish that LD01 modulates host immunity and is a viable therapeutic candidate for alleviating immunosuppression that characterizes sepsis and other infectious diseases.

Severe immunosuppression and not a cytokine storm characterizes COVID-19 infections.

COVID-19-associated morbidity and mortality have been attributed to a pathologic host response. Two divergent hypotheses have been proposed: hyperinflammatory cytokine storm; and failure of host protective immunity that results in unrestrained viral dissemination and organ injury. A key explanation for the inability to address this controversy has been the lack of diagnostic tools to evaluate immune function in COVID-19 infections. ELISpot, a highly sensitive, functional immunoassay, was employed in 27 patients with COVID-19, 51 patients with sepsis, 18 critically ill nonseptic (CINS) patients, and 27 healthy control volunteers to evaluate adaptive and innate immune status by quantitating T cell IFN-É£ and monocyte TFN-α production. Circulating T cell subsets were profoundly reduced in COVID-19 patients. Additionally, stimulated blood mononuclear cells produced less than 40%-50% of the IFN-É£ and TNF-α observed in septic and CINS patients, consistent with markedly impaired immune effector cell function. Approximately 25% of COVID-19 patients had increased IL-6 levels that were not associated with elevations in other canonical proinflammatory cytokines. Collectively, these findings support the hypothesis that COVID-19 suppresses host functional adaptive and innate immunity. Importantly, IL-7 administered ex vivo restored T cell IFN-É£ production in COVID-19 patients. Thus, ELISpot may functionally characterize host immunity in COVID-19 and inform prospective therapies.

Consensus Recommendations for RBC Transfusion Practice in Critically Ill Children From the Pediatric Critical Care Transfusion and Anemia Expertise Initiative.

OBJECTIVES: To date, there are no published guidelines to direct RBC transfusion decision-making specifically for critically ill children. We present the recommendations from the Pediatric Critical Care Transfusion and Anemia Expertise Initiative. DESIGN: Consensus conference series of multidisciplinary, international experts in RBC transfusion management of critically ill children. SETTING: Not applicable. INTERVENTION: None. SUBJECTS: Children with, or children at risk for, critical illness who receive or are at risk for receiving a RBC transfusion. METHODS: A panel of 38 content and four methodology experts met over the course of 2 years to develop evidence-based, and when evidence lacking, expert consensus-based recommendations regarding decision-making for RBC transfusion management and research priorities for transfusion in critically ill children. The experts focused on nine specific populations of critically ill children: general, respiratory failure, nonhemorrhagic shock, nonlife-threatening bleeding or hemorrhagic shock, acute brain injury, acquired/congenital heart disease, sickle cell/oncology/transplant, extracorporeal membrane oxygenation/ventricular assist/ renal replacement support, and alternative processing. Data to formulate evidence-based and expert consensus recommendations were selected based on searches of PubMed, EMBASE, and Cochrane Library from 1980 to May 2017. Agreement was obtained using the Research and Development/UCLA Appropriateness Method. Results were summarized using the Grading of Recommendations Assessment, Development, and Evaluation method. MEASUREMENTS AND RESULTS: The Transfusion and Anemia Expertise Initiative consensus conference developed and reached consensus on a total of 102 recommendations (57 clinical [20 evidence based, 37 expert consensus], 45 research recommendations). All final recommendations met agreement, defined a priori as greater than 80%. A decision tree to aid clinicians was created based on the clinical recommendations. CONCLUSIONS: The Transfusion and Anemia Expertise Initiative recommendations provide important clinical guidance and applicable tools to avoid unnecessary RBC transfusions. Research recommendations identify areas of focus for future investigation to improve outcomes and safety for RBC transfusion.

Haptoglobin improves shock, lung injury, and survival in canine pneumonia.

During the last half-century, numerous antiinflammatory agents were tested in dozens of clinical trials and have proven ineffective for treating septic shock. The observation in multiple studies that cell-free hemoglobin (CFH) levels are elevated during clinical sepsis and that the degree of increase correlates with higher mortality suggests an alternative approach. Human haptoglobin binds CFH with high affinity and, therefore, can potentially reduce iron availability and oxidative activity. CFH levels are elevated over approximately 24-48 hours in our antibiotic-treated canine model of S. aureus pneumonia that simulates the cardiovascular abnormalities of human septic shock. In this 96-hour model, resuscitative treatments, mechanical ventilation, sedation, and continuous care are translatable to management in human intensive care units. We found, in this S. aureus pneumonia model inducing septic shock, that commercial human haptoglobin concentrate infusions over 48-hours bind canine CFH, increase CFH clearance, and lower circulating iron. Over the 96-hour study, this treatment was associated with an improved metabolic profile (pH, lactate), less lung injury, reversal of shock, and increased survival. Haptoglobin binding compartmentalized CFH to the intravascular space. This observation, in combination with increasing CFHs clearance, reduced available iron as a potential source of bacterial nutrition while decreasing the ability for CFH and iron to cause extravascular oxidative tissue injury. In contrast, haptoglobin therapy had no measurable antiinflammatory effect on elevations in proinflammatory C-reactive protein and cytokine levels. Haptoglobin therapy enhances normal host defense mechanisms in contrast to previously studied antiinflammatory sepsis therapies, making it a biologically plausible novel approach to treat septic shock.

Restoration of T Cell function in multi-drug resistant bacterial sepsis after interleukin-7, anti-PD-L1, and OX-40 administration.

BACKGROUND: Multidrug resistant (MDR) bacterial pathogens are a serious problem of increasing importance facing the medical community. MDR bacteria typically infect the most immunologically vulnerable: patients in intensive care units, patients with extensive comorbidities, oncology patients, hemodialysis patients, and other immune suppressed individuals are likely to fall victim to these pathogens. One promising novel approach to treatment of MDR bacteria is immuno-adjuvant therapy to boost patient immunity. Success with this strategy would have the major benefit of providing protection against a number of MDR pathogens. OBJECTIVES: This study had two main objectives. First, immunophenotyping of peripheral blood mononuclear cells from patients with sepsis associated with MDR bacteria was performed to examine for findings indicative of immunosuppression. Second, the ability of three immuno-adjuvants with distinct mechanisms of action to reverse CD4 and CD8 T cell dysfunction, a pathophysiological hallmark of sepsis, was evaluated. RESULTS: Septic patients with MDR bacteria had increased expression of the inhibitory receptor PD-1 and its ligand PD-L1 and decreased monocyte HLA-DR expression compared to non-septic patients. All three immuno-adjuvants, IL-7, anti-PD-L1, and OX-40L, increased T cell production of IFN-γ in a subset of septic patients with MDR bacteria: IL-7 was most efficacious. There was a strong trend toward increased mortality in patients whose T cells failed to increase IFN-γ production in response to the three treatments. CONCLUSION: Immuno-adjuvant therapy reversed T cell dysfunction, a key pathophysiological mechanism in septic patients with MDR bacteria.

Effects of platelet-sparing leukocyte reduction and agitation methods on in vitro measures of hemostatic function in cold-stored whole blood.

BACKGROUND: Agitation of platelet units stored at room temperature is performed routinely to maintain platelet function, and leukoreduction of blood products is the standard of care in many countries to reduce immune consequences of transfusion. The effect of agitation and leukoreduction on whole blood stored at 4°C requires investigation, as reductions in hemostatic capacity of whole blood may reduce its efficacy in treating trauma-induced coagulopathy and platelet dysfunction. We hypothesize that agitation of whole blood will not affect hemostatic function and that leukoreduction will reduce hemostatic function of whole blood. METHODS: In this in vitro randomized controlled study, 21 units of leukoreduced and 20 nonleukoreduced whole blood units were each randomly assigned into four agitation groups. Hemostatic parameters were measured using viscoelastic assays (rotational thromboelastometry-Extrinsic Screening Test (ROTEM-EXTEM) and thromboelastography (TEG) platelet mapping), impedance aggregometry (agonists-adenosine phosphate, arachidonic acid, thrombin receptor activating peptide, and collagen), and a thrombin generation assay from these whole blood units before and after filtration and on 0, 5, 10, and 15 days of storage at 4°C. RESULTS: Leukoreduction compared to nonleukoreduction reduced platelet concentration on Day 0. Viscoelastic measures and thrombin generation parameters revealed significant reduction in hemostatic function between the leukoreduced units and the nonleukoreduced units at a few time points. Leukoreduced units consistently demonstrated reduced platelet aggregation compared to the nonleukoreduced units. Agitation methods did not significantly affect any of the hemostatic parameters examined. CONCLUSIONS: Leukoreduction of whole blood with a platelet-sparing filter caused a moderate but significant reduction in some measures of whole blood hemostatic function most evident early in storage. The benefits of leukoreduction should be weighed against the potential reduced hemostatic function of leukoreduced units. Agitation of whole blood is not required to maintain hemostatic function. LEVEL OF EVIDENCE: In vitro randomized controlled trial, level 1.

Successful Surgical Repair and Perioperative Management of 6-Month-Old With Total Anomalous Pulmonary Venous Return in a Developing Country: Considerations for the Treatment of Pulmonary Hypertension.

Total anomalous pulmonary venous return (TAPVR) is a rare congenital cardiac defect, accounting for 1.5-3% of cases of congenital heart disease. With prenatal ultrasonography, the majority of these patients are diagnosed in utero with definitive surgery performed during the neonatal period. However, as prenatal screening may not be available in developing countries, patients may present in later infancy. We present successful surgical repair of a 6-month-old infant with TAPVR who presented for medical care at 5 months of age in Lima, Peru. The late presentation of such infants and the limited resources available for the treatment of elevated pulmonary vascular resistance may impact successful surgical correction of such defects. The perioperative care of such infants in developing countries is discussed and strategies for managing postoperative pulmonary hypertension is reviewed.

Pediatric Anti-N-Methyl-d-Aspartate Receptor Encephalitis: A Review with Pooled Analysis and Critical Care Emphasis.

PURPOSE: Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is being recognized with increasing frequency among children. Given the paucity of evidence to guide the critical care management of these complex patients, we provide a comprehensive review of the literature with pooled analysis of published case reports and case series. METHODS: We performed a comprehensive literature search using PubMed, Scopus, EMBASE, and Web of Science for relevant published studies. The literature search was conducted using the terms NMDA, anti-NMDA, Anti-N-methyl-d-aspartate, pediatric encephalitis, and anti-NMDAR and included articles published between 2005 and May 1, 2016. RESULTS: Forty-eight references met inclusion criteria accounting for 373 cases. For first-line treatments, 335 (89.8%) received high-dose corticosteroids, 296 received intravenous immunoglobulin (79.3%), and 116 (31%) received therapeutic plasma exchange. In these, 187 children (50.1%) had a full recovery with only minor deficits, 174 patients (46.7%) had partial recovery with major deficits, and 12 children died. In addition, 14 patients were reported to require mechanical ventilation. CONCLUSION: Anti-NMDA encephalitis is a formidable disease with great variation in clinical presentation and response to treatment. With early recognition of this second most common cause of pediatric encephalitis, a multidisciplinary approach by physicians may provide earlier access to first- and second-line therapies. Future studies are needed to examine the efficacy of these current therapeutic strategies on long-term morbidity.

The influence of the storage lesion(s) on pediatric red cell transfusion.

PURPOSE OF REVIEW: This article will analyze and evaluate the current evidence regarding the use of older, longer-stored red blood cells (RBCs) for transfusion in pediatric patients and will examine some of the postulated mechanisms of injury related to prolonged refrigerated storage of RBCs and studies reporting clinical outcomes. RECENT FINDINGS: Three randomized controlled trials and seven observational studies have been conducted entirely in pediatric patients. The outcomes, mortality and morbidity in critically ill patients and children undergoing cardiac surgery, and necrotizing enterocolitis in premature infants, have been inconsistent. However, many of these studies have been confounded by study design, mixed patient populations, red cell preparation, and other factors. SUMMARY: Further exploration into the possible deleterious effects of older, longer-stored RBC transfusions on mortality and morbidity in different pediatric populations is merited. Understanding the potential mechanisms of injury should help explain the clinical findings.

Role of granulocyte transfusions in invasive fusariosis: systematic review and single-center experience.

BACKGROUND: Invasive Fusarium infection is relatively refractory to available antifungal agents. Invasive fusariosis (IF) occurs almost exclusively in the setting of profound neutropenia and/or systemic corticosteroid use. Treatment guidelines for IF are not well established, including the role of granulocyte transfusions (GTs) to counter neutropenia. STUDY DESIGN AND METHODS: We conducted a systematic review, identifying IF cases where GTs were used as adjunctive therapy to antifungal agents and also report a single-center case series detailing our experience (1996-2012) of all IF cases treated with antifungal agents and GTs. In the systematic review cases, GTs were predominantly collected from nonstimulated donors whereas, in the case series, they were universally derived from dexamethasone- and granulocyte-colony-stimulating factor-stimulated donors. RESULTS: Twenty-three patients met inclusion criteria for the systematic review and 11 for the case series. Response rates after GTs were 30 and 91% in the review and case series, respectively. Survival to hospital discharge remained low at 30 and 45%, respectively. Ten patients in the systematic review and three in the case series failed to achieve hematopoietic recovery and none of these survived. In the case series, donor-stimulated GTs generated mean "same-day" neutrophil increments of 3.35 × 10(9) ± 1.24 × 10(9) /L and mean overall posttransfusion neutrophil increments of 2.46 × 10(9) ± 0.85 × 10(9) /L. Progressive decrements in neutrophil response to GTs in two cases were attributed to GT-related HLA alloimmunization. CONCLUSION: In patients with IF, donor-stimulated GTs may contribute to high response rates by effectively bridging periods of neutropenia or marrow suppression. However, their utility in the absence of neutrophil recovery remains questionable.

Washing older blood units before transfusion reduces plasma iron and improves outcomes in experimental canine pneumonia.

In a randomized controlled blinded trial, 2-year-old purpose-bred beagles (n = 24), with Staphylococcus aureus pneumonia, were exchanged-transfused with either 7- or 42-day-old washed or unwashed canine universal donor blood (80 mL/kg in 4 divided doses). Washing red cells (RBC) before transfusion had a significantly different effect on canine survival, multiple organ injury, plasma iron, and cell-free hemoglobin (CFH) levels depending on the age of stored blood (all, P < .05 for interactions). Washing older units of blood improved survival rates, shock score, lung injury, cardiac performance and liver function, and reduced levels of non-transferrin bound iron and plasma labile iron. In contrast, washing fresh blood worsened all these same clinical parameters and increased CFH levels. Our data indicate that transfusion of fresh blood, which results in less hemolysis, CFH, and iron release, is less toxic than transfusion of older blood in critically ill infected subjects. However, washing older blood prevented elevations in plasma circulating iron and improved survival and multiple organ injury in animals with an established pulmonary infection. Our data suggest that fresh blood should not be washed routinely because, in a setting of established infection, washed RBC are prone to release CFH and result in worsened clinical outcomes.

Functional expression of the TMEM16 family of calcium-activated chloride channels in airway smooth muscle.

Airway smooth muscle hyperresponsiveness is a key component in the pathophysiology of asthma. Although calcium-activated chloride channel (CaCC) flux has been described in many cell types, including human airway smooth muscle (HASM), the true molecular identity of the channels responsible for this chloride conductance remains controversial. Recently, a new family of proteins thought to represent the true CaCCs was identified as the TMEM16 family. This led us to question whether members of this family are functionally expressed in native and cultured HASM. We further questioned whether expression of these channels contributes to the contractile function of HASM. We identified the mRNA expression of eight members of the TMEM16 family in HASM cells and show immunohistochemical evidence of TMEM16A in both cultured and native HASM. Functionally, we demonstrate that the classic chloride channel inhibitor, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB), inhibited halide flux in cultured HASM cells. Moreover, HASM cells displayed classical electrophysiological properties of CaCCs during whole cell electrophysiological recordings, which were blocked by using an antibody selective for TMEM16A. Furthermore, two distinct TMEM16A antagonists (tannic acid and benzbromarone) impaired a substance P-induced contraction in isolated guinea pig tracheal rings. These findings demonstrate that multiple members of this recently described family of CaCCs are expressed in HASM cells, they display classic electrophysiological properties of CaCCs, and they modulate contractile tone in airway smooth muscle. The TMEM16 family may provide a novel therapeutic target for limiting airway constriction in asthma.

Cerebellar metastatic papillary thyroid carcinoma in a pediatric patient with complex congenital heart disease.

This case describes the first pediatric case of metastatic papillary thyroid carcinoma (PTC) to the cerebellum as the presenting sign of cancer in a child with CHARGE syndrome and complex congenital heart disease. Diagnostic radiation exposure as a strong risk factor for PTC is discussed.