A specialized multi-disciplinary care program for children with sepsis and multiple organ dysfunction-associated immune dysregulation.

The complex physiology and medical requirements of children with sepsis and multiple organ dysfunction syndrome (MODS) challenge traditional care coordination models. While the involvement of multiple clinical subspecialty services is often necessary to support different care processes and individual organ system dysfunctions, it can also delay the diagnostic process, monitoring, and treatment. The logistics of coordinating with many specialty providers for critically ill patients are challenging and time consuming, and often can result in fragmented communication. To address these and other related issues, we developed a new multi-disciplinary consult service focused on streamlining diagnostics, management, and communication for patients with sepsis and MODS-associated immune dysregulation. The service, called the Program in Inflammation, Immunity, and the Microbiome (PrIIMe), is now a hospital-wide clinical consult service at our institution caring for a broad group of patients with immune dysregulation, particularly focusing on patients with sepsis and MODS. In this paper, we summarize the development, structure, and function of the program, as well as the initial impact. This information may be helpful to clinicians and healthcare leaders who are developing multi-disciplinary consult services for children with complex care needs, especially those with sepsis and MODS-associated immune dysregulation. IMPACT: The care of children with sepsis and multiple organ dysfunction-associated immune dysregulation requires rapid and flexible involvement of multiple clinical subspecialists that is difficult to achieve without fragmented care and delayed decision making. In this narrative review we describe the development, structure, and function of a multi-disciplinary consult service at a children's hospital dedicated to helping coordinate management and provide continuity of care for patients with sepsis and multiple organ dysfunction-associated immune dysregulation. This information may be helpful to clinicians and healthcare leaders who are developing multi-disciplinary consult services for children with complex care needs, especially those with sepsis and MODS-associated immune dysregulation.

Incorporating joint pain screening into the pediatric dermatologic examination.

BACKGROUND/OBJECTIVES: Joint manifestations are a feature of many pediatric skin disorders, among them psoriasis, autoimmune and autoinflammatory diseases, hypermobility disorders, and as an adverse effect of certain medications. Identifying joint disease early is important for intervention and prevention of chronic damage. However, pediatric musculoskeletal complaints are common and determining whether symptoms warrant a rheumatology referral for arthritis can be challenging. METHODS: Pediatric dermatologists were surveyed for their comfort in screening for joint disease. Through literature review and interviews with three pediatric rheumatologists, key joints involved in disorders with skin manifestations and arthritis were identified and the essential evaluations were determined. RESULTS: Of 100 surveyed practicing board-certified pediatric dermatologists, 79% did not feel confident in their ability to perform a joint-focused physical examination, a key step in screening for joint disease. A rapid joint examination technique (R-JET) was developed, along with an accompanying three-question survey and body diagram for patient self-report of symptoms. A video demonstration of the R-JET was created as a teaching tool. CONCLUSIONS: Teaching and incorporation of a rapid screening examination for arthritis by pediatric dermatologists has the potential to identify pediatric arthritis earlier, facilitate referral, and reduce the risk of progressive joint disease. These instruments can easily be incorporated into a pediatric dermatology office visit.

Common variable immunodeficiency-associated endotoxemia promotes early commitment to the T follicular lineage.

BACKGROUND: Although chiefly a B-lymphocyte disorder, several research groups have identified common variable immunodeficiency (CVID) subjects with numeric and/or functional TH cell alterations. The causes, interrelationships, and consequences of CVID-associated CD4+ T-cell derangements to hypogammaglobulinemia, autoantibody production, or both remain unclear. OBJECTIVE: We sought to determine how circulating CD4+ T cells are altered in CVID subjects with autoimmune cytopenias (AICs; CVID+AIC) and the causes of these derangements. METHODS: Using hypothesis-generating, high-dimensional single-cell analyses, we created comprehensive phenotypic maps of circulating CD4+ T cells. Differences between subject groups were confirmed in a large and genetically diverse cohort of CVID subjects (n = 69) by using flow cytometry, transcriptional profiling, multiplex cytokine/chemokine detection, and a suite of in vitro functional assays measuring naive T-cell differentiation, B-cell/T-cell cocultures, and regulatory T-cell suppression. RESULTS: Although CD4+ TH cell profiles from healthy donors and CVID subjects without AICs were virtually indistinguishable, T cells from CVID+AIC subjects exhibited follicular features as early as thymic egress. Follicular skewing correlated with IgA deficiency-associated endotoxemia and endotoxin-induced expression of activin A and inducible T-cell costimulator ligand. The resulting enlarged circulating follicular helper T-cell population from CVID+AIC subjects provided efficient help to receptive healthy donor B cells but not unresponsive CVID B cells. Despite this, circulating follicular helper T cells from CVID+AIC subjects exhibited aberrant transcriptional profiles and altered chemokine/cytokine receptor expression patterns that interfered with regulatory T-cell suppression assays and were associated with autoantibody production. CONCLUSIONS: Endotoxemia is associated with early commitment to the follicular T-cell lineage in IgA-deficient CVID subjects, particularly those with AICs.

Patients with common variable immunodeficiency with autoimmune cytopenias exhibit hyperplastic yet inefficient germinal center responses.

BACKGROUND: The lack of pathogen-protective, isotype-switched antibodies in patients with common variable immunodeficiency (CVID) suggests germinal center (GC) hypoplasia, yet a subset of patients with CVID is paradoxically affected by autoantibody-mediated autoimmune cytopenias (AICs) and lymphadenopathy. OBJECTIVE: We sought to compare the physical characteristics and immunologic output of GC responses in patients with CVID with AIC (CVID+AIC) and without AIC (CVID-AIC). METHODS: We analyzed GC size and shape in excisional lymph node biopsy specimens from 14 patients with CVID+AIC and 4 patients with CVID-AIC. Using paired peripheral blood samples, we determined how AICs specifically affected B-and T-cell compartments and antibody responses in patients with CVID. RESULTS: We found that patients with CVID+AIC displayed irregularly shaped hyperplastic GCs, whereas GCs were scarce and small in patients with CVID-AIC. GC hyperplasia was also evidenced by an increase in numbers of circulating follicular helper T cells, which correlated with decreased regulatory T-cell frequencies and function. In addition, patients with CVID+AIC had serum endotoxemia associated with a dearth of isotype-switched memory B cells that displayed significantly lower somatic hypermutation frequencies than their counterparts with CVID-AIC. Moreover, IgG+ B cells from patients with CVID+AIC expressed VH4-34-encoded antibodies with unmutated Ala-Val-Tyr and Asn-His-Ser motifs, which recognize both erythrocyte I/i self-antigens and commensal bacteria. CONCLUSIONS: Patients with CVID+AIC do not contain mucosal microbiota and exhibit hyperplastic yet inefficient GC responses that favor the production of untolerized IgG+ B-cell clones that recognize both commensal bacteria and hematopoietic I/i self-antigens.

High-dose intravenous immunoglobulin is strongly associated with hemolytic anemia in patients with Kawasaki disease.

BACKGROUND: Hemolysis is a reported side effect of intravenous immunoglobulin (IVIG) therapy in adults, but pediatric data are scarce. We determined the frequency of IVIG-associated hemolysis in patients with Kawasaki disease (KD) and characterized risk factors for hemolysis. We hypothesized that hemolysis is more common in children with KD than adults with other disorders, and hemolysis risk is related to IVIG dose and degree of inflammation. STUDY DESIGN AND METHODS: This was an 8-year, single-center, retrospective cohort study. A total of 419 KD patients were identified; 123 had pre- and post-treatment complete blood counts allowing for assessment of anemia. Hemolytic anemia was defined as decrease in hemoglobin after IVIG greater than 1 g/dL with immunohematologic or biochemical studies supporting hemolysis. RESULTS: 123 patients were stratified as having hemolysis (n = 18, 15%) or nonhemolysis (n = 105, 85%). Patients with hemolysis were more likely to have complete versus incomplete KD (65% vs. 39%, p = 0.04) and refractory versus nonrefractory course (78% vs. 16%, p < 0.001). Patients receiving 4 g/kg versus 2 g/kg IVIG were more likely to hemolyze (89% vs. 34%, p < 0.001). Patients with hemolysis had mostly non-O blood group (94%), positive direct antiglobulin tests (89%), and positive eluates (72%). Two-thirds of patients with hemolysis required RBC transfusion. CONCLUSIONS: Hemolysis occurred in 15% of KD patients evaluated for anemia and is strongly associated with high-dose (4 g/kg) IVIG. KD patients receiving high-dose IVIG should have close hematologic monitoring to identify hemolysis.

Spontaneous control of HCV is associated with expression of HLA-B 57 and preservation of targeted epitopes.

BACKGROUND & AIMS: HLA class I alleles are linked to spontaneous control of hepatitis C virus (HCV) and human immunodeficiency virus-1, but for HCV the roles of particular alleles and corresponding CD8(+) T-cell responses remain incompletely defined. We aimed to determine the correlations between these alleles and natural outcomes of HCV and determine associated key T-cell responses. METHODS: In a cohort of HCV individuals, we determined HLA class I alleles, HCV outcomes, T-cell responses, and examined sequence data for mutational changes within key epitopes. RESULTS: Carriage of HLA-B 57 was associated with a higher rate of viral clearance (risk ratio = 2.0; 95% confidence interval: 1.2-3.4), while HLA-B 08 was associated with a lower rate (risk ratio = 0.34; 95% confidence interval: 0.1-0.9]. Two HLA-B 57-restricted T-cell epitopes were targeted in spontaneous clearance; subjects with chronic viremia expressing HLA-B 57 harbored HCV strains with a high frequency of mutations in key residues. HLA-B 57-mediated escape was supported by diminished immune recognition of these variants and acute HCV infection revealing viral evolution toward less recognized variants. Analysis of a genotype 1b strain from a single-source HCV outbreak in which HLA-B 57 was not protective revealed sequence variations that interfere with immunogenicity, thereby preventing HLA-B 57-mediated immune pressure. CONCLUSIONS: Our data indicate a role of HLA-B 57-restricted CD8(+) T-cell responses in mediating spontaneous clearance and evolution in HCV infection, and viral strains containing epitope variants that are less recognized abrogate the protective effects of HLA-B 57. The finding that HLA-B 57-mediated antiviral immunity is associated with control of both human immunodeficiency virus-1 and HCV suggests a common shared mechanism of a successful immune response against persistent viruses.

Reduced frequencies of NKp30+NKp46+, CD161+, and NKG2D+ NK cells in acute HCV infection may predict viral clearance.

BACKGROUND & AIMS: While the majority of HCV-infected patients progress to chronic hepatitis, a small fraction of individuals are able to clear the virus. Resolution of infection occurs within the first few weeks to months of infection, suggesting that innate immune functions may be critical for early control. Epidemiologic data support a role for particular NK cell receptor bearing populations in this control, yet the mechanism by which NK cells respond to HCV early in infection is unknown. METHODS: Changes in the phenotype and function of NK cells were investigated in a cohort of 43 individuals identified during various stages of HCV infection with different clinical outcomes. RESULTS: Acute, chronic, and resolved HCV infections were characterized by an expansion of CD56(neg) NK cells. Furthermore, increased levels of HLA-C-binding KIR(+) NK cells were observed in HCV resolvers, while all stages of HCV infection were associated with reduced percentages of NKG2D(+), NKp30(+), and NKp46(+) NK cells, and a slight increase in the ability of NK cells to respond to target cells bearing the ligands for these receptors. In contrast, NKG2A(+) and CD94(+) NK cells were elevated in acute and chronic HCV infection, but not in resolved infection. Most importantly, in acute infection, lower frequencies of NKp30(+), NKp46(+), CD161(+), and NKG2D(+) NK cells were observed in patients who were subsequently able to clear HCV infection than in those becoming chronically infected. CONCLUSIONS: These data implicate particular populations of NK cells in the early control and clearance of HCV infection.

Defining the directionality and quality of influenza virus-specific CD8+ T cell cross-reactivity in individuals infected with hepatitis C virus.

Cross-reactivity of murine and recently human CD8(+) T cells between different viral peptides, i.e., heterologous immunity, has been well characterized. However, the directionality and quality of these cross-reactions is critical in determining their biological importance. Herein we analyzed the response of human CD8(+) T cells that recognize both a hepatitis C virus peptide (HCV-NS3) and a peptide derived from the influenza neuraminidase protein (Flu-NA). To detect the cross-reactive CD8(+) T cells, we used peptide-MHC class I complexes (pMHCs) containing a new mutant form of MHC class I able to bind CD8 more strongly than normal MHC class I complexes. T cell responses against HCV-NS3 and Flu-NA peptide were undetectable in normal donors. In contrast, some responses against the Flu-NA peptide were identified in HCV(+) donors who showed strong HCV-NS3-specific reactivity. The Flu-NA peptide was a weak agonist for CD8(+) T cells in HCV(+) individuals on the basis of novel pMHCs and functional assays. These data support the idea of cross-reactivity between the 2 peptides, but indicate that reactivity toward the Flu-NA peptide is highly CD8-dependent and occurs predominantly after priming during HCV infection. Our findings indicate the utility of the novel pMHCs in dissecting cross-reactivity and suggest that cross-reactivity between HCV and influenza is relatively weak. Further studies are needed to relate affinity and functionality of cross-reactive T cells.

Hepatitis C virus (HCV) sequence variation induces an HCV-specific T-cell phenotype analogous to spontaneous resolution.

Hepatitis C virus (HCV)-specific CD8(+) T cells in persistent HCV infection are low in frequency and paradoxically show a phenotype associated with controlled infections, expressing the memory marker CD127. We addressed to what extent this phenotype is dependent on the presence of cognate antigen. We analyzed virus-specific responses in acute and chronic HCV infections and sequenced autologous virus. We show that CD127 expression is associated with decreased antigenic stimulation after either viral clearance or viral variation. Our data indicate that most CD8 T-cell responses in chronic HCV infection do not target the circulating virus and that the appearance of HCV-specific CD127(+) T cells is driven by viral variation.

Juvenile Dermatomyositis: New Clues to Diagnosis and Therapy.

PURPOSE OF REVIEW: To identify clues to disease activity and discuss therapy options. RECENT FINDINGS: The diagnostic evaluation includes documenting symmetrical proximal muscle damage by exam and MRI, as well as elevated muscle enzymes-aldolase, creatine phosphokinase, LDH, and SGOT-which often normalize with a longer duration of untreated disease. Ultrasound identifies persistent, occult muscle inflammation. The myositis-specific antibodies (MSA) and myositis-associated antibodies (MAA) are associated with specific disease course variations. Anti-NXP-2 is found in younger children and is associated with calcinosis; anti-TIF-1γ+ juvenile dermatomyositis has a longer disease course. The diagnostic rash-involving the eyelids, hands, knees, face, and upper chest-is the most persistent symptom and is associated with microvascular compromise, reflected by loss of nailfold (periungual) end row capillaries. This loss is associated with decreased bioavailability of oral prednisone; the bioavailability of other orally administered medications should also be considered. At diagnosis, at least 3 days of intravenous methyl prednisolone may help control the HLA-restricted and type 1/2 interferon-driven inflammatory process. The requirement for avoidance of ultraviolet light exposure mandates vitamin D supplementation. SUMMARY: This often chronic illness targets the cardiovascular system; mortality has decreased from 30 to 1-2% with corticosteroids. New serological biomarkers indicate occult inflammation: ↑CXCL-10 predicts a longer disease course. Some biologic therapies appear promising.

Constrained chromatin accessibility in PU.1-mutated agammaglobulinemia patients.

The pioneer transcription factor (TF) PU.1 controls hematopoietic cell fate by decompacting stem cell heterochromatin and allowing nonpioneer TFs to enter otherwise inaccessible genomic sites. PU.1 deficiency fatally arrests lymphopoiesis and myelopoiesis in mice, but human congenital PU.1 disorders have not previously been described. We studied six unrelated agammaglobulinemic patients, each harboring a heterozygous mutation (four de novo, two unphased) of SPI1, the gene encoding PU.1. Affected patients lacked circulating B cells and possessed few conventional dendritic cells. Introducing disease-similar SPI1 mutations into human hematopoietic stem and progenitor cells impaired early in vitro B cell and myeloid cell differentiation. Patient SPI1 mutations encoded destabilized PU.1 proteins unable to nuclear localize or bind target DNA. In PU.1-haploinsufficient pro-B cell lines, euchromatin was less accessible to nonpioneer TFs critical for B cell development, and gene expression patterns associated with the pro- to pre-B cell transition were undermined. Our findings molecularly describe a novel form of agammaglobulinemia and underscore PU.1's critical, dose-dependent role as a hematopoietic euchromatin gatekeeper.

High level of PD-1 expression on hepatitis C virus (HCV)-specific CD8+ and CD4+ T cells during acute HCV infection, irrespective of clinical outcome.

We monitored expression of PD-1 (a mediator of T-cell exhaustion and viral persistence) on hepatitis C virus (HCV)-specific CD8(+) and CD4(+) T cells from blood and liver during acute and chronic infections and after the resolved infection stage. PD-1 expression on HCV-specific T cells was high early in acute infection irrespective of clinical outcome, and most cells continued to express PD-1 in resolved and chronic stages of infection; intrahepatic expression levels were especially high. Our results suggest that an analysis of PD-1 expression alone is not sufficient to predict infection outcome or to determine T-cell functionality in HCV infection.

Enhancing communication and social engagement among clinicians and research teams to improve reliability of research recruitment.

The success of rare disease research relies heavily on robust partnerships with clinicians to help identify new patients and collect samples. Many studies for paediatric rheumatic diseases requiring pretreatment samples have suffered from slow enrolment rates due to the low incidence of disease and relative urgency to treat. Therefore, timely identification of all potentially eligible patients is crucial. The objective of this project was to apply quality improvement methods to increase the frequency and timeliness of identification of eligible patients with new paediatric rheumatic diagnoses to approach for research studies. A retrospective chart review was undertaken in our paediatric rheumatology clinic to measure the number of eligible patients identified for potential research recruitment between missed recruitment opportunities. Improvement methodology was used to integrate standardised communication between clinicians and the research team into clinic workflow, to leverage social feedback as positive reinforcement for good communication and to measure change in response to the interventions. The number of eligible patients identified between missed recruitment opportunities increased from every 0-1 patient to every 14 patients during the project period, corresponding to an increase in the overall identification rate from 32% to 91% of all eligible patients. Quality improvement methods can be used to successfully integrate research recruitment into routine clinical care and accelerate advances necessary to improve health outcomes.

Cytotoxic T-Lymphocyte-Associated Protein 4 Haploinsufficiency-Associated Inflammation Can Occur Independently of T-Cell Hyperproliferation.

Located contiguously on the long arm of the second chromosome are gene paralogs encoding the immunoglobulin-family co-activation receptors CD28 and cytotoxic T-lymphocyte-associated protein 4 (CTLA4). CD28 and CTLA4 share the same B7 ligands yet each provides opposing proliferative signals to T cells. Herein, we describe for the first time two unrelated subjects with coexisting CD28 and CTLA4 haploinsufficiency due to heterozygous microdeletions of chromosome 2q. Although their clinical phenotype, multi-organ inflammatory disease, is superficially similar to that of CTLA4 haploinsufficient autoimmune lymphoproliferative syndrome type V (ALPS5) patients, we demonstrate our subjects' underlying immunopathology to be distinct. Unlike ALPS5 T cells which hyperproliferate to T-cell receptor-mediated activation and infiltrate organs, T cells from our subjects are hypoproliferative and do not. Instead of T cell infiltrates, biopsies of affected subject tissues demonstrated infiltrates of lineage negative lymphoid cells. This histologic feature correlated with significant increases in circulating type 3 innate lymphoid cells (ILC3s) and ILC3 cytokines, interleukin 22, and interleukin-17A. CTLA4-Ig monotherapy, which we trialed in one subject, was remarkably effective in controlling inflammatory diseases, normalizing ILC3 frequencies, and reducing ILC3 cytokine concentrations.

Broadly directed virus-specific CD4+ T cell responses are primed during acute hepatitis C infection, but rapidly disappear from human blood with viral persistence.

Vigorous proliferative CD4(+) T cell responses are the hallmark of spontaneous clearance of acute hepatitis C virus (HCV) infection, whereas comparable responses are absent in chronically evolving infection. Here, we comprehensively characterized the breadth, specificity, and quality of the HCV-specific CD4(+) T cell response in 31 patients with acute HCV infection and varying clinical outcomes. We analyzed in vitro T cell expansion in the presence of interleukin-2, and ex vivo staining with HCV peptide-loaded MHC class II tetramers. Surprisingly, broadly directed HCV-specific CD4(+) T cell responses were universally detectable at early stages of infection, regardless of the clinical outcome. However, persistent viremia was associated with early proliferative defects of the HCV-specific CD4(+) T cells, followed by rapid deletion of the HCV-specific response. Only early initiation of antiviral therapy was able to preserve CD4(+) T cell responses in acute, chronically evolving infection. Our results challenge the paradigm that HCV persistence is the result of a failure to prime HCV-specific CD4(+) T cells. Instead, broadly directed HCV-specific CD4(+) T cell responses are usually generated, but rapid exhaustion and deletion of these cells occurs in the majority of patients. The data further suggest a short window of opportunity to prevent the loss of CD4(+) T cell responses through antiviral therapy.

Temporal dynamics of a predominant protease inhibitor-resistance mutation in a treatment-naive, hepatitis C virus-infected individual.

The dramatic antiviral activities of drugs that specifically inhibit hepatitis C virus replication can be tempered by baseline mutations that confer resistance. We describe the kinetics of an R155K mutation in hepatitis C virus (HCV) NS3 protease known to confer resistance to specific protease inhibitors in an individual coinfected with human immunodeficiency virus-1 and HCV. Longitudinal sequences revealed changes in the relative frequency with which this variant was observed independent of HCV replication levels, illustrating that this mutation coexists with wild-type strains in vivo in the absence of drugs. The persistence of drug-resistance mutations argues for baseline resistance genotyping at the time therapy is initiated to accurately predict the efficacy of treatment.

Immunologic evidence for lack of heterologous protection following resolution of HCV in patients with non-genotype 1 infection.

Chronic hepatitis C virus (HCV) infection is typically characterized by a lack of virus-specific CD4(+) T-cell-proliferative responses, but strong responses have been described in a subset of persons with persistent viremia. One possible explanation for these responses is that they were primed by an earlier resolved infection and do not recognize the current circulating virus. We defined all targeted epitopes using overlapping peptides corresponding to a genotype 1a strain in 44 patients chronically infected with different HCV genotypes (GT). Surprisingly, more HCV-specific CD4(+) T-cell responses were detected in patients with chronic non-GT1 infection compared with patients with chronic GT1 infection (P = .017). Notably, we found serologic evidence of a previous exposure to GT1 in 4 patients with non-GT1 infection, and these persons also demonstrated significantly more responses than non-GT1 patients in whom genotype and HCV serotype were identical (P < .001). Comparison of recognition of GT1-specific peptides to peptides representing autologous virus revealed the absence of cross-recognition of the autologous circulating virus. These data indicate that persistent HCV infection can occur in the presence of an HCV-specific T-cell response primed against a heterologous HCV strain, and suggest that clearance of 1 GT does not necessarily protect against subsequent exposure to a second GT.

Human leukocyte antigen-associated sequence polymorphisms in hepatitis C virus reveal reproducible immune responses and constraints on viral evolution.

UNLABELLED: CD8(+) T cell responses play a key role in governing the outcome of hepatitis C virus (HCV) infection, and viral evolution enabling escape from these responses may contribute to the inability to resolve infection. To more comprehensively examine the extent of CD8 escape and adaptation of HCV to human leukocyte antigen (HLA) class I restricted immune pressures on a population level, we sequenced all non-structural proteins in a cohort of 70 chronic HCV genotype 1a-infected subjects (28 subjects with HCV monoinfection and 42 with HCV/human immunodeficiency virus [HIV] coinfection). Linking of sequence polymorphisms with HLA allele expression revealed numerous HLA-associated polymorphisms across the HCV proteome. Multiple associations resided within relatively conserved regions, highlighting attractive targets for vaccination. Additional mutations provided evidence of HLA-driven fixation of sequence polymorphisms, suggesting potential loss of some CD8 targets from the population. In a subgroup analysis of mono- and co-infected subjects some associations lost significance partly due to reduced power of the utilized statistics. A phylogenetic analysis of the data revealed the substantial influence of founder effects upon viral evolution and HLA associations, cautioning against simple statistical approaches to examine the influence of host genetics upon sequence evolution of highly variable pathogens. CONCLUSION: These data provide insight into the frequency and reproducibility of viral escape from CD8(+) T cell responses in human HCV infection, and clarify the combined influence of multiple forces shaping the sequence diversity of HCV and other highly variable pathogens.