Allergic Diseases and Immune-Mediated Food Disorders in Pediatric Acute-Onset Neuropsychiatric Syndrome

Background: The prevalence and impact of allergic and immune-mediated food disorders in pediatric acute-onset neuropsychiatric syndrome (PANS) are mostly unknown. Objective: We sought to explore the prevalence of atopic dermatitis (AD), asthma, allergic rhinitis (AR), IgE-mediated food allergies (FAs), and other immune-mediated food disorders requiring food avoidance in patients with PANS. In addition, to further understand the extent of food restriction in this population, we investigated the empiric use of dietary measures to improve PANS symptoms. Methods: Pediatric patients in a PANS Clinic and Research Program were given surveys regarding their caregiver burdens, allergic and food-related medical history, and whether food elimination resulted in perception of improvement of PANS symptoms. A review of health records was conducted to confirm that all responses in the survey were concordant with documentation of each patient's medical chart. Results: Sixty-nine (ages 4-20 years) of 80 subjects who fulfilled PANS criteria completed the surveys. Thirteen (18.8%) had AD, 11 (15.9%) asthma, 33 (47.8%) AR, 11 (15.9%) FA, 1 (1.4%) eosinophilic gastrointestinal disorders, 1 (1.4%) food protein-induced enterocolitis syndrome, 3 (4.3%) milk protein-induced proctocolitis syndrome, and 3 (4.3%) celiac disease. Thirty subjects (43.5%) avoided foods due to PANS; elimination of gluten and dairy was most common and was associated with perceived improvement of PANS symptoms (by parents). This perceived improvement was not confirmed with objective data. Conclusions: The prevalence of allergic and immune-mediated food disorders in PANS is similar to the general population as reported in the literature, with the exception of AR that appears to be more prevalent in our PANS cohort. More research will be required to establish whether diet or allergies influence PANS symptoms.

Genetic and mechanistic diversity in pediatric hemophagocytic lymphohistiocytosis

The HLH-2004 criteria are used to diagnose hemophagocytic lymphohistiocytosis (HLH), yet concern exists for their misapplication, resulting in suboptimal treatment of some patients. We sought to define the genomic spectrum and associated outcomes of a diverse cohort of children who met the HLH-2004 criteria. Genetic testing was performed clinically or through research-based whole-exome sequencing. Clinical metrics were analyzed with respect to genomic results. Of 122 subjects enrolled over the course of 17 years, 101 subjects received genetic testing. Biallelic familial HLH (fHLH) gene defects were identified in only 19 (19%) and correlated with presentation at younger than 1 year of age (P < .0001). Digenic fHLH variants were observed but lacked statistical support for disease association. In 28 (58%) of 48 subjects, research whole-exome sequencing analyses successfully identified likely molecular explanations, including underlying primary immunodeficiency diseases, dysregulated immune activation and proliferation disorders, and potentially novel genetic conditions. Two-thirds of patients identified by the HLH-2004 criteria had underlying etiologies for HLH, including genetic defects, autoimmunity, and malignancy. Overall survival was 45%, and increased mortality correlated with HLH triggered by infection or malignancy (P < .05). Differences in survival did not correlate with genetic profile or extent of therapy. HLH should be conceptualized as a phenotype of critical illness characterized by toxic activation of immune cells from different underlying mechanisms. In most patients with HLH, targeted sequencing of fHLH genes remains insufficient for identifying pathogenic mechanisms. Whole-exome sequencing, however, may identify specific therapeutic opportunities and affect hematopoietic stem cell transplantation options for these patients.

Vehicular exhaust particles promote allergic airway inflammation through an aryl hydrocarbon receptor-notch signaling cascade

BACKGROUND

Traffic-related particulate matter (PM) has been linked to a heightened incidence of asthma and allergic diseases. However, the molecular mechanisms by which PM exposure promotes allergic diseases remain elusive.

OBJECTIVE

We sought to determine the expression, function, and regulation of pathways involved in promotion of allergic airway inflammation by PM.

METHODS

We used gene expression transcriptional profiling, in vitro culture assays, and in vivo murine models of allergic airway inflammation.

RESULTS

We identified components of the Notch pathway, most notably Jagged 1 (Jag1), as targets of PM induction in human monocytes and murine dendritic cells. PM, especially ultrafine particles, upregulated TH cytokine levels, IgE production, and allergic airway inflammation in mice in a Jag1- and Notch-dependent manner, especially in the context of the proasthmatic IL-4 receptor allele Il4raR576. PM-induced Jag1 expression was mediated by the aryl hydrocarbon receptor (AhR), which bound to and activated AhR response elements in the Jag1 promoter. Pharmacologic antagonism of AhR or its lineage-specific deletion in CD11c(+) cells abrogated the augmentation of airway inflammation by PM.

CONCLUSION

PM activates an AhR-Jag1-Notch cascade to promote allergic airway inflammation in concert with proasthmatic alleles.

Long-term sinonasal outcomes of aspirin desensitization in aspirin exacerbated respiratory disease

OBJECTIVE

This study aimed to assess sinonasal outcomes in patients with aspirin exacerbated respiratory disease (AERD) undergoing aspirin desensitization following endoscopic sinus surgery (ESS).

STUDY DESIGN

Case series with chart review.

SETTING

University hospital.

SUBJECTS AND METHODS

A retrospective review of sinonasal outcomes was conducted for 30 AERD patients undergoing aspirin desensitization and maintenance therapy following ESS. Sinonasal outcomes were prospectively assessed by the Sinonasal Outcomes Test-22 (SNOT-22) and endoscopic polyp grading system. Data were collected preoperatively, 1 and 4 weeks postsurgery (before desensitization), and 1, 6, 12, 18, 24, and 30 months after aspirin desensitization.

RESULTS

Twenty-eight of 30 patients (93.3%) successfully completed aspirin desensitization, whereas 2 of 30 (6.7%) were unable to complete desensitization due to respiratory intolerance. Of the 21 patients who successfully completed a minimum of 24 weeks of follow-up, 20 (95.2%) patients demonstrated sustained endoscopic and symptomatic improvement for a median follow-up period of 33 months. After surgical treatment but before desensitization, patients experienced significant reductions in SNOT-22 and polyp grade scores. In the first 6 months after aspirin desensitization, patients experienced further significant reductions in SNOT-22 scores, whereas polyp grade remained stable. The improvements in symptom endoscopic scores were preserved throughout the follow-up period after desensitization. No patients required additional sinus surgery. One patient had to discontinue aspirin therapy due to gastrointestinal side effects. No other adverse reactions to aspirin were noted.

CONCLUSION

Aspirin desensitization following ESS appears to be a well-tolerated and effective adjunctive therapy for long-term control of nasal polyposis in patients with AERD.

Primary Immune Deficiency Treatment Consortium (PIDTC) report

The Primary Immune Deficiency Treatment Consortium (PIDTC) is a network of 33 centers in North America that study the treatment of rare and severe primary immunodeficiency diseases. Current protocols address the natural history of patients treated for severe combined immunodeficiency (SCID), Wiskott-Aldrich syndrome, and chronic granulomatous disease through retrospective, prospective, and cross-sectional studies. The PIDTC additionally seeks to encourage training of junior investigators, establish partnerships with European and other International colleagues, work with patient advocacy groups to promote community awareness, and conduct pilot demonstration projects. Future goals include the conduct of prospective treatment studies to determine optimal therapies for primary immunodeficiency diseases. To date, the PIDTC has funded 2 pilot projects: newborn screening for SCID in Navajo Native Americans and B-cell reconstitution in patients with SCID after hematopoietic stem cell transplantation. Ten junior investigators have received grant awards. The PIDTC Annual Scientific Workshop has brought together consortium members, outside speakers, patient advocacy groups, and young investigators and trainees to report progress of the protocols and discuss common interests and goals, including new scientific developments and future directions of clinical research. Here we report the progress of the PIDTC to date, highlights of the first 2 PIDTC workshops, and consideration of future consortium objectives.

How the practice of allergy shows the promise and challenge of personalized medicine

Personalized medicine seeks to stratify therapies according to individual characteristics, and by so doing improve effectiveness and reduce complications. However, there are not many models of care that is highly stratified within a single diagnosis in this manner. One potential model is the practice of allergy, in which care is tailored to specific allergens for individual patients within the broader context of care for rhinitis or asthma. Allergists have already confronted many of the same regulatory issues anticipated for personalized medicine. The history of allergy practice also anticipates some of the patient safety concerns that may arise from tracking and using highly personalized medical information. Finally, the therapy of allergy and asthma has been at the forefront of attempts to incorporate pharmacogenomics information into patient care. Individualized therapy has always been central to the practice of allergy, and so provides a useful proving ground for personalized medicine as a concept of care.

DOCK8 immune deficiency as a model for primary cytoskeletal dysfunction

DOCK8 deficiency is a newly described primary immune deficiency resulting in profound susceptibility to cutaneous viral infections, elevated IgE levels, and eosinophilia, but lacking in the skeletal manifestations commonly seen in hyper IgE syndrome, which it otherwise resembles. Although little is known about the DOCK8 protein, it resembles other atypical guanine exchange factors in the DOCK family, and is known to bind to CDC42. This suggests that a likely role for DOCK8 is in modulating signals that trigger cytoskeletal reorganization. As a result, DOCK8 may also be related to other immune deficiencies that involve the cytoskeleton and Rho GTPase signaling pathways, such as Wiskott-Aldrich syndrome and Rac2 deficiency.

Long-term results of bone marrow transplantation in complete DiGeorge syndrome

BACKGROUND

Therapeutic options for DiGeorge syndrome (DGS) with profound T-cell deficiency are very limited. Thymic transplantation has shown promising results but is not easily available. Hematopoietic cell transplantation (HCT) has been successful in restoring immune competence in the short term.

OBJECTIVE

Present the long-term follow-up of 2 patients with complete DGS who received bone marrow transplants in the neonatal period from HLA-matched siblings, and perform a multicenter survey to document the status of other patients with DGS who have undergone HCT.

METHODS

Immune function assessment by immunophenotyping, lymphocyte proliferation, T-cell receptor excision circles, single nucleotide polymorphism mapping arrays, spectratyping, cytogenetics, and fluorescence in situ hybridization were used.

RESULTS

Among reported patients with DGS receiving HCT, survival is greater than 75%. Our patients are in their 20s and in good health. Their hematopoietic compartment shows continuous engraftment with mixed chimerism, normal T-cell function, and humoral immunity. Circulating T cells exhibit a memory phenotype with a restricted repertoire and are devoid of T-cell receptor excision circles.

CONCLUSION

These features suggest that T-cell reconstitution has occurred predominantly through expansion of the donors' mature T-cell pool. Although restricted, their immune systems are capable of providing substantial protection to infection and respond to vaccines. We conclude that bone marrow transplant achieves long-lived reconstitution of immune function in complete DGS and is a good alternative to thymic transplantation in patients with a suitable donor.

CLINICAL IMPLICATIONS

Bone marrow transplant in complete DGS using an HLA-matched sibling donor provides long-lasting immunity and is a suitable and more available alternative to thymic transplantation.

Two-tiered universal newborn screening strategy for severe combined immunodeficiency

Outcomes for infants with severe combined immunodeficiency (SCID) would be improved by universal newborn screening, but there are not yet screening tests of sufficient accuracy for the disorder. In a pilot study, we assessed the ability of a two-tiered strategy to improve accuracy. Dried blood samples from patients were assessed with two tests for lymphopenia: interleukin-7, a T-cell growth cytokine, and TRECs, a byproduct of T-cell receptor recombination. IL-7 screening has a specificity of 96.1% and TRECs have a specificity of 92.3%. Combining these tests in a two-tiered strategy increases specificity to 100% (97-100% CI). Sensitivity was 85% for IL-7 screening and 100% for TREC screening. A two-tiered strategy may be of sufficient accuracy to enable universal SCID screening, and should be assessed in a prospective trial.

Potential costs and benefits of newborn screening for severe combined immunodeficiency

OBJECTIVE

Severe combined immunodeficiency (SCID) is a rare, treatable disorder of the immune system. The incidence is unknown but may be more common than published estimates because infants frequently die of infection before diagnosis. SCID is a candidate for universal newborn screening, so there is a need to determine under which circumstances screening would be cost-effective.

STUDY DESIGN

We assumed a screening program for SCID would use T-cell lymphopenia as the screening criterion and performed a cost-utility analysis comparing universal screening with screening only those with a family history of SCID.

RESULTS

Assuming society is willing to pay $50,000 for every quality-adjusted life-year saved, a SCID screening test that cost less than $5 with a false-negative rate of 0.9% and a false-positive rate of 0.4% would be considered cost-effective. A nationwide screening program would cost an additional $23.9 million per year for screening costs but would result in 760 years of life saved per year of screening. The cost to detect 1 case of SCID would be $485,000.

CONCLUSION

SCID screening could result in a large benefit to detected individuals, making screening relatively cost-effective in spite of the low incidence of the disease. However, an adequate test is critical to cost-effectiveness.

Persistent parvovirus-associated chronic fatigue treated with high dose intravenous immunoglobulin

We report a 16-year-old boy with no evidence of immunodeficiency who had a 2-year history of chronic fatigue, low grade fever and slapped-cheek rash associated with chronic parvovirus B19 viremia. Prolonged intravenous immunoglobulin therapy resulted in resolution of his symptoms and viremia. Intravenous immunoglobulin may be useful in the resolution of parvovirus viremia regardless of immune status.

Role of nonspecific cross-reacting antigen, a CD66 cluster antigen, in activation of human granulocytes

Nonspecific cross-reacting antigen (NCA) is the name of a family of highly glycosylated bacterial-binding receptors found on human granulocytes and other tissues. These glycoproteins are members of the immunoglobulin supergene family and are related structurally to carcinoembryonic antigen. In this study, we demonstrate that ligation of granulocyte NCA results in the activation of the cells, as measured by degranulation and the flux of intracellular calcium. These studies further the proposition that NCA has a function in the immune response of granulocytes against bacterial infections.