Hirsh D. Komarow

Targeted Disruption of Pyrin, the FMF Protein, Causes Heightened Sensitivity to Endotoxin and a Defect in Macrophage Apoptosis

Familial Mediterranean fever (FMF) is an inherited disorder characterized by recurrent episodes of fever and inflammation. Most patients with FMF carry missense mutations in the C-terminal half of the pyrin protein. To study the physiologic role of pyrin, we generated mice expressing a truncated pyrin molecule that, similar to FMF patients, retains the full PYRIN domain. Bacterial lipopolysaccharide (LPS) induces accentuated body temperatures and increased lethality in homozygous mutant mice. When stimulated, macrophages from these mice produce increased amounts of activated caspase-1 and, consequently, elevated levels of mature IL-1beta. Full-length pyrin competes in vitro with caspase-1 for binding to ASC, a known caspase-1 activator. Apoptosis is impaired in macrophages from pyrin-truncation mice through an IL-1-independent pathway. These data support a critical role for pyrin in the innate immune response, possibly by acting on ASC, and suggest a biologic basis for the selection of hypomorphic pyrin variants in man.

Cold Urticaria, Immunodeficiency, and Autoimmunity Related to PLCG2 Deletions

BACKGROUND Mendelian analysis of disorders of immune regulation can provide insight into molecular pathways associated with host defense and immune tolerance. METHODS We identified three families with a dominantly inherited complex of cold-induced urticaria, antibody deficiency, and susceptibility to infection and autoimmunity. Immunophenotyping methods included flow cytometry, analysis of serum immunoglobulins and autoantibodies, lymphocyte stimulation, and enzymatic assays. Genetic studies included linkage analysis, targeted Sanger sequencing, and next-generation whole-genome sequencing. RESULTS Cold urticaria occurred in all affected subjects. Other, variable manifestations included atopy, granulomatous rash, autoimmune thyroiditis, the presence of antinuclear antibodies, sinopulmonary infections, and common variable immunodeficiency. Levels of serum IgM and IgA and circulating natural killer cells and class-switched memory B cells were reduced. Linkage analysis showed a 7-Mb candidate interval on chromosome 16q in one family, overlapping by 3.5 Mb a disease-associated haplotype in a smaller family. This interval includes PLCG2, encoding phospholipase Cγ(2) (PLCγ(2)), a signaling molecule expressed in B cells, natural killer cells, and mast cells. Sequencing of complementary DNA revealed heterozygous transcripts lacking exon 19 in two families and lacking exons 20 through 22 in a third family. Genomic sequencing identified three distinct in-frame deletions that cosegregated with disease. These deletions, located within a region encoding an autoinhibitory domain, result in protein products with constitutive phospholipase activity. PLCG2-expressing cells had diminished cellular signaling at 37°C but enhanced signaling at subphysiologic temperatures. CONCLUSIONS Genomic deletions in PLCG2 cause gain of PLCγ(2) function, leading to signaling abnormalities in multiple leukocyte subsets and a phenotype encompassing both excessive and deficient immune function. (Funded by the National Institutes of Health Intramural Research Programs and others.).

Concerted action of wild-type and mutant TNF receptors enhances inflammation in TNF receptor 1-associated periodic fever syndrome

TNF, acting through p55 tumor necrosis factor receptor 1 (TNFR1), contributes to the pathogenesis of many inflammatory diseases. TNFR-associated periodic syndrome (TRAPS, OMIM 142680) is an autosomal dominant autoinflammatory disorder characterized by prolonged attacks of fevers, peritonitis, and soft tissue inflammation. TRAPS is caused by missense mutations in the extracellular domain of TNFR1 that affect receptor folding and trafficking. These mutations lead to loss of normal function rather than gain of function, and thus the pathogenesis of TRAPS is an enigma. Here we show that mutant TNFR1 accumulates intracellularly in peripheral blood mononuclear cells of TRAPS patients and in multiple cell types from two independent lines of knockin mice harboring TRAPS-associated TNFR1 mutations. Mutant TNFR1 did not function as a surface receptor for TNF but rather enhanced activation of MAPKs and secretion of proinflammatory cytokines upon stimulation with LPS. Enhanced inflammation depended on autocrine TNF secretion and WT TNFR1 in mouse and human myeloid cells but not in fibroblasts. Heterozygous TNFR1-mutant mice were hypersensitive to LPS-induced septic shock, whereas homozygous TNFR1-mutant mice resembled TNFR1-deficient mice and were resistant to septic shock. Thus WT and mutant TNFR1 act in concert from distinct cellular locations to potentiate inflammation in TRAPS. These findings establish a mechanism of pathogenesis in autosomal dominant diseases where full expression of the disease phenotype depends on functional cooperation between WT and mutant proteins and also may explain partial responses of TRAPS patients to TNF blockade.

Impulse oscillometry in the evaluation of diseases of the airways in children

OBJECTIVE To provide an overview of impulse oscillometry and its application to the evaluation of children with diseases of the airways. DATA SOURCES Medline and PubMed search, limited to English language and human disease, with keywords forced oscillation, impulse oscillometry, and asthma. STUDY SELECTIONS The opinions of the authors were used to select studies for inclusion in this review. RESULTS Impulse oscillometry is a noninvasive and rapid technique requiring only passive cooperation by the patient. Pressure oscillations are applied at the mouth to measure pulmonary resistance and reactance. It is employed by health care professionals to help diagnose pediatric pulmonary diseases such asthma and cystic fibrosis; assess therapeutic responses; and measure airway resistance during provocation testing. CONCLUSIONS Impulse oscillometry provides a rapid, noninvasive measure of airway impedance. It may be easily employed in the diagnosis and management of diseases of the airways in children.

Tree pollen peaks are associated with increased nonviolent suicide in women

SIR—Research on seasonality of suicide has identified a highly replicated and robust peak in late spring and a somewhat less consistent peak in late summer and early fall. While a number of psychosocial and environmental factors, such as increased exposure to light in the spring, have been suggested to be associated with the spring peak, none satisfactorily explains the temporal association of the peak in suicide with the proposed environmental trigger. Based on the influence of cytokines on mood, cognition, and behavior in healthy individuals and patients with medical and psychiatric conditions, the reciprocal immune–brain interactions, and the cytokine expression during allergic reactions, we hypothesized that tree pollen (which peaks in spring) and ragweed pollen (which peaks in late summer/ early fall) may act as environmental triggers for suicide in vulnerable individuals. We explored this hypothesis by comparing the suicide rates before, during and after periods of peak atmospheric pollen. Tree and ragweed pollen data were obtained from the American Academy of Allergy, Asthma, & Immunology for the years 1995–1998 for the continental US and Canada. Periods of allergen exposure were derived from histograms expressing pollen counts as particles per cubic meter (p/m) on a log scale from 0 to 1000 (y-axis) by months (x-axis) within each year. Raters identified three periods for each allergen in time units of quartermonths at each location for up to 4 years divided as follows: a prepollen period (pollen countso10p/m3 for trees and omid-way on the log scale between 1 and 10p/m for ragweed), a peak-pollen period (4100p/m for trees and4mid-way on the log scale between 10 and 100p/m for ragweed), and a postpollen period when concentrations returned to the prepollen levels. Intervals with intermediate pollen counts were discarded. Suicide data were obtained from the General Mortality Database compiled by the National Center for Health Statistics. Each suicide was classified by county and state of occurrence, date, sex, age, and type (violent, nonviolent, other, or unknown) based on the ICD-9 codes. Suicides by other or unknown means accounted for 6% of the total. For annual rates, person-years were estimated by summing each county’s population from the 2000 Census across the years of observation by sex and age categories. For the analysis of rates and relative rates (RRs) by allergen season and pollen-level period, person-years were estimated by multiplying the population for each age and sex category in each county by the total number of days in each pollen-level period (1⁄4number of quarter months days per quarter month (1⁄47.6 days)) summed across years of observation and divided by 365.25 days per year. Annual and seasonal suicide rates, RRs, and their standard errors were estimated in Poisson’s regression models. RRs for each allergen season and suicide type were estimated setting the prepollen period as the referent and peak and postpollen periods as indicator variables. Since interaction by sex and age was found to be significant, rates and RRs for the effect of allergen exposure were calculated separately by the four age by sex strata. A post hoc analysis of a possible confounding effect of light (using a proxy measure, ‘sunshine’) was performed for the specific pollen periods that showed significant differences in suicide rates using mixed effects repeated measures ANOVAwith pollenperiod and year as within-location effects. The total population of these counties in 2000 was 37 824174 (Table 1). The total number of quarter months of peak-pollen was 670 in the tree season (mean1⁄414.3) and 476 in the ragweed season (mean1⁄49.5). In 92705 505 person-years, 9528 suicides were recorded (rate1⁄410.3/100 000 personyears, 95% confidence interval (CI)1⁄410.1, 10.5) (Table 2). As in other population-based samples of completed suicide, the rate in males was greater than in females (RR1⁄4 4.1, 95% CI1⁄43.9, 4.3), and greater in older people compared with younger (RR1⁄41.4, 95% CI1⁄41.3, 1.5). The rate in older males was greater than in younger males (RR1⁄41.8, 95% CI1⁄4 1.7, 1.9). No difference by age was seen in females. A total of 2417 suicides were recorded in the tree season and 1811 in the ragweed season (Table 3). During the tree allergy season, there was a two-fold increase in the rate of nonviolent suicides among younger females in the peak-pollen period compared with the prepollen period (95% CI1⁄4 1.3, 3.0) (Table 3). There was no difference between the postpollen period and the prepollen period. In older females, the rate of nonviolent suicide in the postpollen period was 4.6 times that of the prepollen period (95% CI1⁄41.2, 17.8), with no increase in the peak-pollen period relative to the prepollen period (Table 3). It is unlikely that a greater exposure to natural light during the peak-pollen season would have spuriously increased suicide rates in younger women, because a greater suicide rate was found in the peak-pollen period, while a greater ‘sunshine’ was found in the postpollen period. However, in older women, it is possible that a greater light exposure during the postpollen period could have spuriously inflated the rate of suicide during that period. The differences in the tree pollen period effect between younger and older women may also represent a consequence of Molecular Psychiatry (2005) 10, 232–238 & 2005 Nature Publishing Group All rights reserved 1359-4184/05

A Study of the Use of Impulse Oscillometry in the Evaluation of Children With Asthma: Analysis of Lung Parameters, Order Effect, and Utility Compared With Spirometry

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Allergic rhinitis induces anxiety-like behavior and altered social interaction in rodents.

The ability to objectively measure lung function in children is critical in the assessment and treatment of asthma in this age group. We thus determined the effectiveness of impulse oscillometry (IOS) as a non‐invasive technique to assess lung function in children and in comparison to spirometry for sensitivity and specificity, testing variability, and the order effect of sequential testing of IOS and spirometry.

Vibratory Urticaria Associated with a Missense Variant in ADGRE2.

Epidemiological and clinical studies report higher incidences of anxiety and increased emotional reactivity in individuals suffering from respiratory allergies. To evaluate if respiratory allergies are capable of promoting anxiety-like behavior in rodents, we used models of allergic rhinitis and behavioral evaluations followed by assessment of mRNA for cytokines in relevant brain regions. Mice and rats were sensitized to ovoalbumin or pollen, respectively, following standard sensitization and challenge protocols. After challenge, the animals were evaluated in the open field, elevated plus-maze and resident-intruder tests. Cytokines and corticotropin-releasing factor expression were assessed in several brain regions by real-time RT-PCR and plasma corticosterone concentrations by radioimmunoassay. Mice and rats sensitized and exposed to allergen showed increased anxiety-like behavior and reduced social interaction without any overt behavioral signs of sickness. T-helper type 2 (T(H)2) cytokines were induced in both rats and mice in the olfactory bulbs and prefrontal cortex and remained unchanged in the temporal cortex and hypothalamus. The same results were found for CRF mRNA expression. No differences were observed in corticosterone concentrations 1h after the last behavioral test. These results show that sensitization and challenge with allergens induce anxiety across rodent species and that these effects were paralleled by an increased expression of T(H)2 cytokines and CRF in the prefrontal cortex. These studies provide experimental evidence that sensitized rodents experience neuroimmune-mediated anxiety and reduced social interaction associated with allergic rhinitis.

Acoustic rhinometry in the practice of allergy

Patients with autosomal dominant vibratory urticaria have localized hives and systemic manifestations in response to dermal vibration, with coincident degranulation of mast cells and increased histamine levels in serum. We identified a previously unknown missense substitution in ADGRE2 (also known as EMR2), which was predicted to result in the replacement of cysteine with tyrosine at amino acid position 492 (p.C492Y), as the only nonsynonymous variant cosegregating with vibratory urticaria in two large kindreds. The ADGRE2 receptor undergoes autocatalytic cleavage, producing an extracellular subunit that noncovalently binds a transmembrane subunit. We showed that the variant probably destabilizes an autoinhibitory subunit interaction, sensitizing mast cells to IgE-independent vibration-induced degranulation. (Funded by the National Institutes of Health.).

Assessment of clinical findings, tryptase levels, and bone marrow histopathology in the management of pediatric mastocytosis

OBJECTIVE To provide a comprehensive practical overview of the use of acoustic rhinometry in the practice of allergy. DATA SOURCES An all-inclusive PubMed search was conducted for articles on acoustic rhinometry that were published in peer-reviewed journals, between 1989 and 2006, using the keywords acoustic rhinometry, allergic rhinitis, and nasal provocation testing. STUDY SELECTION The expert opinion of the authors was used to select studies for inclusion in this review. RESULTS Acoustic rhinometry is a sound-based technique used to measure nasal cavity area and volume. It has been validated by comparison to measurements with computed tomography and magnetic resonance imaging. Acoustic rhinometry requires minimal patient cooperation and may be used in adults, children, and infants. It is used by medical practitioners to diagnose and evaluate therapeutic responses in conditions such as rhinitis and to measure nasal dimensions during allergen provocation testing. Acoustic rhinometry also provides a visual reflection of the nasal response to therapy, which may be useful in increasing compliance to prescribed medications. CONCLUSIONS Acoustic rhinometry is a safe, noninvasive, objective, and validated measure of nasal obstruction that appears to be of practical use in the diagnosis and management of inflammatory diseases of the upper airways.