Long-term changes in milk component immunoglobulins reflect milk oral immunotherapy outcomes in Finnish children.

BACKGROUND: Milk oral immunotherapy (OIT) may increase the amount of milk protein that can be ingested without triggering an allergic reaction. It is important to understand why some patients benefit from the treatment while others do not. OBJECTIVE: The aim was to define the differences in the milk allergen component-specific (casein, α-lactalbumin, ß-lactoglobulin) immunoglobulin (sIg [sIgE, sIgG4, and sIgA]) levels relative to the long-term outcomes of milk OIT. METHODS: In this long-term, open-label follow-up study, 286 children started milk OIT between 2005 and 2015. Follow-up data were collected at two points: the post-buildup phase and long term (range 1-11 years, median 6 years). Comparisons of sIg levels were made among three outcome groups of self-reported long-term milk consumption (high-milk dose, low-milk dose, and avoidance). RESULTS: A total of 168 (59%) of the 286 patients on OIT participated. Most patients (57%) were in the high-dose group; here, 80% of these patients had a baseline casein sIgE value less than 28 kUA/L, they had the lowest casein sIgE levels at all time (p < .001), their casein sIgG4/IgE levels increased, and long-term casein sIgA was highest compared with the low-dose and avoidance groups (p = .02). Low-milk dose group had the highest casein sIgG4/IgE levels in long term (p = .002). CONCLUSION: The baseline Ig profiles and responses to milk OIT differed depending on long-term milk consumption. Lower casein sIgE levels were associated with better outcome. Milk casein sIgA differed in the long term among high-milk consumers.

Interaction of mediators and effector cells in cashew nut-induced anaphylaxis.

BACKGROUND: The underlying mechanisms of an immediate food-induced allergic reaction involve mast cell degranulation and recruitment of other effector cells, such as lymphocytes, eosinophils, and basophils. How the interaction of various mediators and cells results in anaphylaxis is not fully understood. OBJECTIVE: To evaluate changes in platelet-activating factor (PAF), platelet-activating factor acetylhydrolase (PAF-AH), tryptase, eosinophils, basophils, and eosinophil cationic protein (ECP) in cashew nut-induced anaphylaxis. METHODS: Open cashew nut challenges were performed on 106 children (aged 1-16 years), sensitized to cashew nut, with earlier allergic reaction to cashew nut or no known exposure. PAF, PAF-AH, tryptase, ECP, eosinophils, and basophils were measured at 4 time points. RESULTS: Of 72 challenges with positive results, 34 were defined as anaphylactic. Eosinophil count decreased progressively during an anaphylactic reaction at all 4 time points (P < .005*) compared with baseline. Although significant PAF elevation was observed 1 hour from moderate-to-severe reaction (P = .04*), PAF seemed to peak especially in anaphylaxis but did not achieve statistical significance. PAF peak ratio (peak PAF/baseline PAF) was significantly greater in anaphylactic reactions compared with the no-anaphylaxis group (P = .008*). Maximal percentage change in eosinophils revealed negative correlation to severity score and PAF peak ratio (Spearman's rho -0.424 and -0.516, respectively). Basophils decreased significantly in moderate-to-severe reactions and in anaphylaxis (P < .05*) compared with baseline. Delta-tryptase (peak tryptase minus baseline) did not differ significantly between anaphylaxis and the no-anaphylaxis subgroups (P = .05). CONCLUSION: PAF is a specific anaphylaxis biomarker. Marked decline of eosinophils during anaphylaxis may be related to robust secretion of PAF reflecting migration of eosinophils to target tissues.

Optimizing tools for evaluating challenge outcomes in children with cashew nut allergy.

BACKGROUND: The incidence of cashew nut anaphylaxis is increasing and there is a need for accurate diagnostic tests. Age-specific cutoffs in children are lacking. Changes in serum tryptase levels are not well documented in pediatric food allergy, except in anaphylaxis. OBJECTIVE: To evaluate the ability of various tests to diagnose cashew nut allergy and to predict reaction severity. We also investigated changes in tryptase and their correlation to reaction severity. METHODS: We performed an open cashew nut challenge on 106 children (aged 1-16 years), who were sensitized to cashew nut with either previous allergic reaction to cashew nut or no known exposure. We analyzed the accuracy of Ana o 3 immunoglobulin E (IgE), cashew nut IgE, skin prick test, basophil activation test (BAT), and combinations thereof to diagnose cashew nut allergy and to predict reaction severity. Tryptase level was measured at the baseline and during an allergic reaction. RESULTS: A total of 72 children had positive challenge outcomes. Ana o 3 IgE seemed to be the best single test to diagnose cashew allergy, with a 0.97 kU/L cutoff exhibiting 94.1% specificity and 61.1% sensitivity. Though BAT values of at least 22.8% best predicted reaction severity, with 91.7% specificity and 60.7% sensitivity, the cutoffs were age-specific. Tryptase levels increased substantially 1 to 2 hours after the first allergic symptoms compared with baseline. CONCLUSION: Ana o 3 IgE seems to be the best diagnostic test in pediatric cashew nut allergy, and test combinations do not seem to improve the diagnostics. Cutoffs are age-specific. BAT is promising in predicting reaction severity. Tryptase levels should be measured 1 to 2 hours after initiation of an allergic reaction.

Filamin A Is Required for Optimal T Cell Integrin-Mediated Force Transmission, Flow Adhesion, and T Cell Trafficking.

T cells traffic from the bloodstream into tissues to perform their functions in the immune system and are therefore subjected to a range of different mechanical forces. Integrins are essential for T cell trafficking into the tissues, as they mediate firm adhesion between the T cell and the endothelium under shear flow conditions. In addition, integrins are important for the formation of the contact between the T cell and the APC required for T cell activation. The actin-binding protein filamin A (FlnA) provides an important link between the integrin and the actin cytoskeleton. FlnA has been reported to function as an integrin inhibitor by competing with talin. However, its role in regulating integrin-dependent immune functions in vivo is currently poorly understood. In this study, we have investigated the role of FlnA in T cells, using T cell-specific FlnA knockout mice. We report that FlnA is required for the formation of strong integrin-ligand bonds under shear flow and for the generation of integrin-mediated T cell traction forces on ligand-coated hydrogels. Consequently, absence of FlnA leads to a reduction in T cell adhesion to integrin ligands under conditions of shear flow, as well as reduced T cell trafficking into lymph nodes and sites of skin inflammation. In addition, FlnA is not needed for T cell activation in vivo, which occurs in shear-free conditions in lymphoid organs. Our results therefore reveal a role of FlnA in integrin force transmission and T cell trafficking in vivo.

Serum chitinase-like protein YKL-40 is linked to small airway function in children with asthmatic symptoms.

BACKGROUND: Lung function impairment among asthmatic children begins in early life, and biomarkers for identifying this impairment are needed. The chitinase-like protein YKL-40 has been associated with asthma and lung function in adults, but studies in children have yielded conflicting results. We evaluated the potential of YKL-40 and other systemic biomarkers for identifying lung function deficits in children with asthmatic symptoms. METHODS: We determined the levels of serum YKL-40, periostin, and high-sensitivity C-reactive protein (hs-CRP) from the blood samples of 49 children with asthmatic symptoms. Lung function was assessed with impulse oscillometry (IOS) and spirometry, combined with an exercise challenge and a bronchodilator test. Fractional exhaled nitric oxide was measured at multiple flow rates. RESULTS: Serum levels of YKL-40 showed significant correlations with most IOS indices at baseline (P = .008-.039), but there was no association between YKL-40 and spirometry parameters. Neither periostin nor hs-CRP were associated with baseline lung function. Children with a significant response in either the exercise challenge or the bronchodilator test had increased serum levels of YKL-40 (P = .003) and periostin (P = .035). YKL-40 correlated significantly with the blood neutrophil count (rs  = .397, P = .005) but was not associated with biomarkers of eosinophilic inflammation. CONCLUSION: Serum YKL-40 is a potential biomarker for lung function deficits in children with asthmatic symptoms. These deficits appear to be focused on small airways and may remain undetected with spirometry.

Filamin A Regulates Neutrophil Adhesion, Production of Reactive Oxygen Species, and Neutrophil Extracellular Trap Release.

Neutrophils are of fundamental importance in the early immune response and use various mechanisms to neutralize invading pathogens. They kill endocytosed pathogens by releasing reactive oxygen species in the phagosome and release neutrophil extracellular traps (NETs) into their surroundings to immobilize and kill invading micro-organisms. Filamin A (FlnA) is an important actin cross-linking protein that is required for cellular processes involving actin rearrangements, such cell migration. It has also been shown to negatively regulate integrin activation and adhesion. However, its role in the regulation of ß2 integrin-dependent adhesion, as well as in other cellular functions in neutrophils, is poorly understood. Using a transgenic mouse model in which FlnA is selectively depleted in myeloid cells, such as neutrophils, we show that FlnA negatively regulates ß2 integrin adhesion to complement component iC3b and ICAM-1 in shear-free, but not shear-flow, conditions. FlnA deletion does not affect phagocytosis of Escherichia coli or Staphylococcus aureus or their intracellular killing. However, FlnA negatively regulates production of reactive oxygen species upon cell activation. Conversely, neutrophil activation through TLR4, as well as through activation by the Gram-negative bacteria E. coli, results in reduced NET production in FlnA-depleted neutrophils. Thus, FlnA is a negative regulator of ß2 integrin-dependent cell adhesion and reactive oxygen species production but is required for NET production in primary murine neutrophils.

Anti-Inflammatory Effects of Metformin Irrespective of Diabetes Status.

RATIONALE: The diabetes mellitus drug metformin is under investigation in cardiovascular disease, but the molecular mechanisms underlying possible benefits are poorly understood. OBJECTIVE: Here, we have studied anti-inflammatory effects of the drug and their relationship to antihyperglycemic properties. METHODS AND RESULTS: In primary hepatocytes from healthy animals, metformin and the IKKß (inhibitor of kappa B kinase) inhibitor BI605906 both inhibited tumor necrosis factor-α-dependent IκB degradation and expression of proinflammatory mediators interleukin-6, interleukin-1ß, and CXCL1/2 (C-X-C motif ligand 1/2). Metformin suppressed IKKα/ß activation, an effect that could be separated from some metabolic actions, in that BI605906 did not mimic effects of metformin on lipogenic gene expression, glucose production, and AMP-activated protein kinase activation. Equally AMP-activated protein kinase was not required either for mitochondrial suppression of IκB degradation. Consistent with discrete anti-inflammatory actions, in macrophages, metformin specifically blunted secretion of proinflammatory cytokines, without inhibiting M1/M2 differentiation or activation. In a large treatment naive diabetes mellitus population cohort, we observed differences in the systemic inflammation marker, neutrophil to lymphocyte ratio, after incident treatment with either metformin or sulfonylurea monotherapy. Compared with sulfonylurea exposure, metformin reduced the mean log-transformed neutrophil to lymphocyte ratio after 8 to 16 months by 0.09 U (95% confidence interval, 0.02-0.17; P=0.013) and increased the likelihood that neutrophil to lymphocyte ratio would be lower than baseline after 8 to 16 months (odds ratio, 1.83; 95% confidence interval, 1.22-2.75; P=0.00364). Following up these findings in a double-blind placebo controlled trial in nondiabetic heart failure (trial registration: NCT00473876), metformin suppressed plasma cytokines including the aging-associated cytokine CCL11 (C-C motif chemokine ligand 11). CONCLUSION: We conclude that anti-inflammatory properties of metformin are exerted irrespective of diabetes mellitus status. This may accelerate investigation of drug utility in nondiabetic cardiovascular disease groups. CLINICAL TRIAL REGISTRATION: Name of the trial registry: TAYSIDE trial (Metformin in Insulin Resistant Left Ventricular [LV] Dysfunction). URL: https://www.clinicaltrials.gov. Unique identifier: NCT00473876.

Optimal T Cell Activation and B Cell Antibody Responses In Vivo Require the Interaction between Leukocyte Function-Associated Antigen-1 and Kindlin-3.

Kindlin-3 is an important integrin regulator that is mutated in the rare genetic disorder, leukocyte adhesion deficiency type III, a disorder characterized by defective neutrophil trafficking and platelet function, leading to recurrent bacterial infections and bleeding. Kindlin-3 is also known to regulate T cell adhesion in vitro and trafficking in vivo, but whether the integrin/kindlin interaction regulates T or B cell activation in vivo is unclear. In this study, we used TTT/AAA ß2-integrin knock-in (KI) mice and TCR-transgenic (OT-II) KI mice, in which the integrin/kindlin connection is disrupted, to investigate the role of the integrin/kindlin interaction in T cell activation. We show that basal T cell activation status in these animals in vivo is normal, but they display reduced T cell activation by wild-type Ag-loaded dendritic cells in vitro. In addition, T cell activation in vivo is reduced. We also show that basal Ab levels are normal in TTT/AAA ß2-integrin KI mice, but B cell numbers in lymph nodes and IgG and IgM production after immunization are reduced. In conclusion, we show that the integrin/kindlin interaction is required for trafficking of immune cells, as well as for T cell activation and B cell Ab responses in vivo. These results imply that the immunodeficiency found in leukocyte adhesion deficiency type III patients, in addition to being caused by defects in neutrophil function, may be due, in part, to defects in lymphocyte trafficking and activation.

Blood cell integrins and diseases.

Integrins are adhesion molecules on the surface of cells. In blood cells they are responsible for rapid changes during adhesion of the cell to the endothelium. Deficiency or defective function of integrins will result in severe illnesses. Surprisingly, certain variants of integrins are associated with an increased risk of developing SLE. In autoimmune diseases and as a result of organ transplantations integrins participate in reactions in which leukocytes attack the body's own tissues. This has resulted in the development of drugs in antibody form for inhibition of the action of integrins. These drugs may, however, exhibit severe adverse effects.

The ß2 integrin-kindlin-3 interaction is essential for T-cell homing but dispensable for T-cell activation in vivo.

Kindlin-3 is mutated in the rare genetic disorder, leukocyte adhesion deficiency type III, which is characterized by deficient integrin-mediated adhesion of leukocytes and platelets. However, the specific roles of kindlin-3-ß2-integrin interactions in T-cell adhesion and homing and immune responses in vivo remain unclear. Here, we show that the TTT motif in ß2 integrins controls kindlin-3 binding. Mutation of the kindlin-3 binding site in ß2 integrins caused a loss of firm adhesion of T cells under both static and shear flow conditions and a reduction of T-cell homing to lymph nodes in vivo. However, atomic force microscopy studies of integrin-ligand bonds revealed that initial ligand binding could still occur, and 2-dimensional T-cell migration was reduced but not abolished by the TTT/AAA mutation in the ß2 integrin. Importantly, dendritic cell-mediated T-cell activation in vivo was normal in TTT/AAA ß2 integrin knock-in mice. Our results reveal a selective role of the kindlin-3-integrin association for lymphocyte functions in vivo; the integrin-kindlin-3 interaction is particularly important in adhesion strengthening under shear flow, and for T-cell homing to lymph nodes, but dispensable for T cell activation which occurs in a shear-free environment.

A sensory neuron-expressed IL-31 receptor mediates T helper cell-dependent itch: Involvement of TRPV1 and TRPA1.

BACKGROUND: Although the cytokine IL-31 has been implicated in inflammatory and lymphoma-associated itch, the cellular basis for its pruritic action is yet unclear. OBJECTIVE: We sought to determine whether immune cell-derived IL-31 directly stimulates sensory neurons and to identify the molecular basis of IL-31-induced itch. METHODS: We used immunohistochemistry and quantitative real-time PCR to determine IL-31 expression levels in mice and human subjects. Immunohistochemistry, immunofluorescence, quantitative real-time PCR, in vivo pharmacology, Western blotting, single-cell calcium imaging, and electrophysiology were used to examine the distribution, functionality, and cellular basis of the neuronal IL-31 receptor α in mice and human subjects. RESULTS: Among all immune and resident skin cells examined, IL-31 was predominantly produced by TH2 and, to a significantly lesser extent, mature dendritic cells. Cutaneous and intrathecal injections of IL-31 evoked intense itch, and its concentrations increased significantly in murine atopy-like dermatitis skin. Both human and mouse dorsal root ganglia neurons express IL-31RA, largely in neurons that coexpress transient receptor potential cation channel vanilloid subtype 1 (TRPV1). IL-31-induced itch was significantly reduced in TRPV1-deficient and transient receptor channel potential cation channel ankyrin subtype 1 (TRPA1)-deficient mice but not in c-kit or proteinase-activated receptor 2 mice. In cultured primary sensory neurons IL-31 triggered Ca(2+) release and extracellular signal-regulated kinase 1/2 phosphorylation, inhibition of which blocked IL-31 signaling in vitro and reduced IL-31-induced scratching in vivo. CONCLUSION: IL-31RA is a functional receptor expressed by a small subpopulation of IL-31RA(+)/TRPV1(+)/TRPA1(+) neurons and is a critical neuroimmune link between TH2 cells and sensory nerves for the generation of T cell-mediated itch. Thus targeting neuronal IL-31RA might be effective in the management of TH2-mediated itch, including atopic dermatitis and cutaneous T-cell lymphoma.

Acinetobacter species in the skin microbiota protect against allergic sensitization and inflammation.

BACKGROUND: The human commensal microbiota interacts in a complex manner with the immune system, and the outcome of these interactions might depend on the immune status of the subject. OBJECTIVE: Previous studies have suggested a strong allergy-protective effect for Gammaproteobacteria. Here we analyze the skin microbiota, allergic sensitization (atopy), and immune function in a cohort of adolescents, as well as the influence of Acinetobacter species on immune responses in vitro and in vivo. METHODS: The skin microbiota of the study subjects was identified by using 16S rRNA sequencing. PBMCs were analyzed for baseline and allergen-stimulated mRNA expression. In in vitro assays human monocyte-derived dendritic cells and primary keratinocytes were incubated with Acinetobacter lwoffii. Finally, in in vivo experiments mice were injected intradermally with A lwoffii during the sensitization phase of the asthma protocol, followed by readout of inflammatory parameters. RESULTS: In healthy subjects, but not in atopic ones, the relative abundance of Acinetobacter species was associated with the expression of anti-inflammatory molecules by PBMCs. Moreover, healthy subjects exhibited a robust balance between anti-inflammatory and TH1/TH2 gene expression, which was related to the composition of the skin microbiota. In cell assays and in a mouse model, Acinetobacter species induced strong TH1 and anti-inflammatory responses by immune cells and skin cells and protected against allergic sensitization and lung inflammation through the skin. CONCLUSION: These results support the hypothesis that skin commensals play an important role in tuning the balance of TH1, TH2, and anti-inflammatory responses to environmental allergens.

Topically applied ZnO nanoparticles suppress allergen induced skin inflammation but induce vigorous IgE production in the atopic dermatitis mouse model.

BACKGROUND: Metal oxide nanoparticles such as ZnO are used in sunscreens as they improve their optical properties against the UV-light that causes dermal damage and skin cancer. However, the hazardous properties of the particles used as UV-filters in the sunscreens and applied to the skin have remained uncharacterized. METHODS: Here we investigated whether different sized ZnO particles would be able to penetrate injured skin and injured allergic skin in the mouse atopic dermatitis model after repeated topical application of ZnO particles. Nano-sized ZnO (nZnO) and bulk-sized ZnO (bZnO) were applied to mechanically damaged mouse skin with or without allergen/superantigen sensitization. Allergen/superantigen sensitization evokes local inflammation and allergy in the skin and is used as a disease model of atopic dermatitis (AD). RESULTS: Our results demonstrate that only nZnO is able to reach into the deep layers of the allergic skin whereas bZnO stays in the upper layers of both damaged and allergic skin. In addition, both types of particles diminish the local skin inflammation induced in the mouse model of AD; however, nZnO has a higher potential to suppress the local effects. In addition, especially nZnO induces systemic production of IgE antibodies, evidence of allergy promoting adjuvant properties for topically applied nZnO. CONCLUSIONS: These results provide new hazard characterization data about the metal oxide nanoparticles commonly used in cosmetic products and provide new insights into the dermal exposure and hazard assessment of these materials in injured skin.

Inhalation of rod-like carbon nanotubes causes unconventional allergic airway inflammation.

BACKGROUND: Carbon nanotubes (CNT) represent a great promise for technological and industrial development but serious concerns on their health effects have also emerged. Rod-shaped CNT are, in fact, able to induce asbestos-like pathogenicity in mice including granuloma formation in abdominal cavity and sub-pleural fibrosis. Exposure to CNT, especially in the occupational context, happens mainly by inhalation. However, little is known about the possible effects of CNT on pulmonary allergic diseases, such as asthma. METHODS: We exposed mice by inhalation to two types of multi-walled CNT, rigid rod-like and flexible tangled CNT, for four hours a day once or on four consecutive days. Early events were monitored immediately and 24 hours after the single inhalation exposure and the four day exposure mimicked an occupational work week. Mast cell deficient mice were used to evaluate the role of mast cells in the occurring inflammation. RESULTS: Here we show that even a short-term inhalation of the rod-like CNT induces novel innate immunity-mediated allergic-like airway inflammation in healthy mice. Marked eosinophilia was accompanied by mucus hypersecretion, AHR and the expression of Th2-type cytokines. Exploration of the early events by transcriptomics analysis reveals that a single 4-h exposure to rod-shaped CNT, but not to tangled CNT, causes a radical up-regulation of genes involved in innate immunity and cytokine/chemokine pathways. Mast cells were found to partially regulate the inflammation caused by rod-like CNT, but also alveaolar macrophages play an important role in the early stages. CONCLUSIONS: These observations emphasize the diverse abilities of CNT to impact the immune system, and they should be taken into account for hazard assessment.

Inflammatory Cytokines in Middle Ear Effusion of Patients With Asthma, Chronic Rhinosinusitis With Nasal Polyps With or Without NSAID Intolerance.

OBJECTIVE: To measure the inflammatory cytokines of middle ear effusion (MEE) in otitis media (OM) associated with asthma and chronic rhinosinusitis with nasal polyps (CRSwNP) with or without nonsteroidal anti-inflammatory drug (NSAID) sensitivity to strengthen our assumption that OM is part of the same inflammatory entity. The potential individual differences between MEE inflammatory cytokines could be used in clinical practice for more individual characterization of the inflammation. STUDY DESIGN: Case-control study. SETTING: Tertiary referral center. PATIENTS: Convenience sample of 24 case patients with otitis media with effusion (OME) or chronic otitis media (COM), asthma, and CRSwNP, 14 of whom had NSAID intolerance, and 8 controls with OME but no history of asthma, CRSwNP, or NSAID intolerance. INTERVENTION: Diagnostic. MAIN OUTCOME AND MEASURE: Inflammatory cytokines including interleukins (IL)-4, IL-5, IL-6, IL-13, and interferon gamma (IFN-γ) in middle ear effusion. RESULTS: The MEE mass fractions of IL-5 ( p = 0.003) and IFN-γ ( p = 0.048) were higher among our case patients with OME/COM than among the controls. For IL-4 and IL-13, the mass fractions were also higher among the case patients than the controls, but this difference was not statistically significant ( p = 0.199 and p = 0.617, respectively). We found no difference between the IL-6 mass fractions of the groups. We found notable heterogeneity in individual patients' cytokine levels. CONCLUSIONS: According to our findings, OM, when present, should be considered part of the respiratory inflammatory process associated with asthma and CRSwNP. The individual differences in MEE cytokine levels could be useful as biomarkers.

Requirement of CCL17 for CCR7- and CXCR4-dependent migration of cutaneous dendritic cells.

Chemokines are known to regulate the steady-state and inflammatory migration of cutaneous dendritic cells (DCs). The beta-chemokine CCL17, a ligand of CCR4, is inducibly expressed in a subset of DCs and is strongly up-regulated in atopic diseases. Using an atopic dermatitis model, we show that CCL17-deficient mice develop acanthosis as WT mice, whereas dermal inflammation, T helper 2-type cytokine production, and the allergen-specific humoral immune response are significantly decreased. Notably, CCL17-deficient mice retained Langerhans cells (LCs) in the lesional skin after chronic allergen exposure, whereas most LCs emigrated from the epidermis of allergen-treated WT controls into draining lymph nodes (LNs). Moreover, CCL17-deficient LCs showed impaired emigration from the skin after exposure to a contact sensitizer. In contrast, the absence of CCR4 had no effect on cutaneous DC migration and development of atopic dermatitis symptoms. As an explanation for the major migratory defect of CCL17-deficient DCs in vivo, we demonstrate impaired mobility of CCL17-deficient DCs to CCL19/21 in 3D in vitro migration assays and a blockade of intracellular calcium release in response to CCR7 ligands. In addition, responsiveness of CCL17-deficient DCs to CXCL12 was impaired as well. We demonstrate that the inducible chemokine CCL17 sensitizes DCs for CCR7- and CXCR4-dependent migration to LN-associated homeostatic chemokines under inflammatory conditions and thus plays an important role in cutaneous DC migration.

Intradermal cytosine-phosphate-guanosine treatment reduces lung inflammation but induces IFN-γ-mediated airway hyperreactivity in a murine model of natural rubber latex allergy.

Asthma and other allergic diseases are continuously increasing, causing considerable economic and sociologic burden to society. The hygiene hypothesis proposes that lack of microbial T helper (Th) 1-like stimulation during early childhood leads to increased Th2-driven allergic disorders later in life. Immunostimulatory cytosine-phosphate-guanosine (CpG)-oligodeoxynucleotide motifs are candidate molecules for immunotherapeutic studies, as they have been shown to shift the Th2 response toward the Th1 direction and reduce allergic symptoms. Using natural rubber latex (NRL)-induced murine model of asthma, we demonstrated that intradermal CpG administration with allergen reduced pulmonary eosinophilia, mucus production, and Th2-type cytokines, but unexpectedly induced airway hyperreactivity (AHR) to inhaled methacholine, one of the hallmarks of asthma. We found that induction in AHR was dependent on STAT4, but independent of STAT6 signaling. CpG treatment increased production of IFN-γ in the airways and shifted the ratio of CD4(+):CD8(+) T cells toward CD8(+) dominance. By blocking soluble IFN-γ with neutralizing antibody, AHR diminished and the CD4(+):CD8(+) ratio returned to CD4(+) dominance. These results indicate that increased production of IFN-γ in the lungs may lead to severe side effects, such as enhancement of bronchial hyperreactivity to inhaled allergen. This finding should be taken into consideration when planning prophylaxis treatment of asthma with intradermal CpG injections.

Attenuated expression of tenascin-C in ovalbumin-challenged STAT4-/- mice.

BACKGROUND: Asthma leads to structural changes in the airways, including the modification of extracellular matrix proteins such as tenascin-C. The role of tenascin-C is unclear, but it might act as an early initiator of airway wall remodelling, as its expression is increased in the mouse and human airways during allergic inflammation. In this study, we examined whether Th1 or Th2 cells are important regulators of tenascin-C in experimental allergic asthma utilizing mice with impaired Th1 (STAT4-/-) or Th2 (STAT6-/-) immunity. METHODS: Balb/c wildtype (WT), STAT4-/- and STAT6-/- mice were sensitized with intraperitoneally injected ovalbumin (OVA) followed by OVA or PBS airway challenge. Airway hyperreactivity (AHR) was measured and samples were collected. Real time PCR and immunohistochemistry were used to study cytokines and differences in the expression of tenascin-C. Tenascin-C expression was measured in human fibroblasts after treatment with TNF-α and IFN-γ in vitro. RESULTS: OVA-challenged WT mice showed allergic inflammation and AHR in the airways along with increased expression of TNF-α, IFN-γ, IL-4 and tenascin-C in the lungs. OVA-challenged STAT4-/- mice exhibited elevated AHR and pulmonary eosinophilia. The mRNA expression of TNF-α and IFN-γ was low, but the expression of IL-4 was significantly elevated in these mice. OVA-challenged STAT6-/- mice had neither AHR nor pulmonary eosinophilia, but had increased expression of mRNA for TNF-α, IFN-γ and IL-4. The expression of tenascin-C in the lungs of OVA-challenged STAT4-/- mice was weaker than in those of OVA-challenged WT and STAT6-/- mice suggesting that TNF-α and IFN-γ may regulate tenascin-C expression in vivo. The stimulation of human fibroblasts with TNF-α and IFN-γ induced the expression of tenascin-C confirming our in vivo findings. CONCLUSIONS: Expression of tenascin-C is significantly attenuated in the airways of STAT4-/- mice, which may be due to the impaired secretion of TNF-α and IFN-γ in these mice.

MiR-155 is overexpressed in patients with atopic dermatitis and modulates T-cell proliferative responses by targeting cytotoxic T lymphocyte-associated antigen 4.

BACKGROUND: MicroRNAs (miRNAs) are short noncoding RNAs that suppress gene expression at the posttranscriptional level. Atopic dermatitis is a common chronic inflammatory skin disease characterized by the presence of activated T cells within the skin. OBJECTIVE: We sought to explore the role of miRNAs in the pathogenesis of atopic dermatitis. METHODS: Global miRNA expression in healthy and lesional skin of patients with atopic dermatitis was compared by using TaqMan MicroRNA Low Density Arrays. miR-155 expression in tissues and cells was quantified by means of quantitative real-time PCR. The cellular localization of miR-155 was analyzed by means of in situ hybridization. The regulation of cytotoxic T lymphocyte-associated antigen (CTLA-4) by miR-155 was investigated by using luciferase reporter assays and flow cytometry. CTLA-4 expression and functional assays were performed on T(H) cells overexpressing miR-155. RESULTS: miR-155 was one of the highest-ranked upregulated miRNAs in patients with atopic dermatitis. In the skin miR-155 was predominantly expressed in infiltrating immune cells. miR-155 was upregulated during T-cell differentiation/activation and was markedly induced by T-cell activators in PBMCs in vitro and by superantigens and allergens in the skin in vivo. CTLA-4, an important negative regulator of T-cell activation, was identified as a direct target of miR-155. Overexpression of miR-155 in T(H) cells resulted in decreased CTLA-4 levels accompanied by an increased proliferative response. CONCLUSION: miR-155 is significantly overexpressed in patients with atopic dermatitis and might contribute to chronic skin inflammation by increasing the proliferative response of T(H) cells through the downregulation of CTLA-4.

High Prevalence of Sensitization to Mites and Insects in Greenhouses Using Biologic Pest Control.

BACKGROUND: Mites and insects are widely used as biologic pest control in greenhouses. A few studies have reported sensitization to mites among greenhouse workers, but the prevalence of sensitization to pest control insects is not known. OBJECTIVE: We aimed to determine the prevalence of IgE-mediated sensitization to pests and their control organisms in the population of exposed greenhouse workers and the relationship between sensitization and allergic symptoms. METHODS: In a cross-sectional study, we interviewed 117 tomato and cucumber greenhouse workers from eight companies that use biologic pest control. Sensitization to nine organisms was assessed by serum-specific IgE measurement. We also measured fractional exhaled nitric oxide. RESULTS: The prevalence of specific sensitization to pests and pest control organisms was 50%; to mites, 29%; and to insects, 46%. Of the individual species, Macrolophus pygmaeus insect sensitization had the highest prevalence (46%). Asthma symptoms were significantly associated with sensitization to pest and pest control organisms (odds ratio [OR] = 3.9; 95% confidence interval [CI], 1.2-12.5) and with a fractional exhaled nitric oxide level of 25 ppb or greater (OR = 4.8; 95% CI, 1.7-13.8), indicating eosinophilic airway inflammation. Southeast Asian origin was significantly associated with sensitization (OR = 5.1; 95% CI, 2.1-12.1) and rhinitis (OR = 2.8; 95% CI, 1.2-6.3). CONCLUSIONS: Tomato and cucumber greenhouse workers were commonly sensitized to predatory insect M pygmaeus and pest control mites. Our findings stress the importance of surveilling and preventing work-related allergic diseases among greenhouse workers.