A recombinant hypoallergenic parvalbumin mutant for immunotherapy of IgE-mediated fish allergy

IgE-mediated allergy to fish is a frequent cause of severe anaphylactic reactions. Parvalbumin, a small calcium-binding protein, is the major fish allergen. We have recently isolated a cDNA coding for carp parvalbumin, Cyp c 1, and expressed in Escherichia coli a recombinant Cyp c 1 molecule, which contained most IgE epitopes of saltwater and freshwater fish. In this study, we introduced mutations into the calcium-binding domains of carp parvalbumin by site-directed mutagenesis and produced in E. coli three parvalbumin mutants containing amino acid exchanges either in one (single mutants; Mut-CD and Mut-EF) or in both of the calcium-binding sites (double mutant; Mut-CD/EF). Circular dichroism analyses of the purified derivatives and the wild-type allergen showed that Mut-CD/EF exhibited the greatest reduction of overall protein fold. Dot blot assays and immunoblot inhibition experiments performed with sera from 21 fish-allergic patients showed that Mut-CD/EF had a 95% reduced IgE reactivity and represented the derivative with the least allergenic activity. The latter was confirmed by in vitro basophil histamine release assays and in vivo skin prick testing. The potential applicability for immunotherapy of Mut-CD/EF was demonstrated by the fact that mouse IgG Abs could be raised by immunization with the mutated molecule, which cross-reacted with parvalbumins from various fish species and inhibited the binding of fish-allergic patients' IgE to the wild-type allergen. Using the hypoallergenic carp parvalbumin mutant Mut-CD/EF, it may be possible to treat fish allergy by immunotherapy.

Oral administration of an IL-10-secreting Lactococcus lactis strain prevents food-induced IgE sensitization

BACKGROUND

Because tolerance to food is potentially modulated by IL-10, strategies to prevent food allergy should favor an increased delivery of IL-10 to the gut.

OBJECTIVES

We hypothesized that administration of a Lactococcus lactis transfected to secrete murine IL-10 could prevent sensitization in a mouse model of food allergy.

METHODS

Before each oral sensitization with beta-lactoglobulin in the presence of cholera toxin, young mice were administered the transfected Lactococcus lactis. Antigen-induced anaphylaxis after oral challenge assessed clinical protection achieved by the pretreatment. Serum and feces antigen-specific antibody concentrations were sequentially measured. Antibody titers were correlated with antibody and IL-10-secreting cell numbers in the spleen and in Peyer patches.

RESULTS

Pretreatment with transfected Lactococcus lactis contributed to diminish anaphylaxis significantly, and inhibit antigen-specific serum IgE and IgG(1) production strongly. In addition, transfected Lactococcus lactis increased the production of antigen-specific IgA in the gut. Variations of antibody levels in the serum and the gut correlated with the numbers of antibody-producing cells. In addition, the presence of exogenous IL-10 in the gut by transfected Lactococcus lactis induced IL-10 secretion by Peyer patches cells. Increased IL-10 titers were also measured in the plasma.

CONCLUSION

These results suggest that a microorganism bioengineered to deliver IL-10 in the gut can decrease food-induced anaphylaxis and provide an option to prevent IgE-type sensitization to common food allergens.

CLINICAL IMPLICATIONS

Nonpathogenic IL-10-producing microorganisms in the gut could have a potential to prevent systemic food-induced anaphylaxis.

Lavender oil inhibits immediate-type allergic reaction in mice and rats

We studied the effects of lavender oil on mast cell-mediated immediate-type allergic reactions in mice and rats. Lavender oil (1:500, 1:100, 1:10, 1:1, 1:0) inhibited concentration-dependently mast cell-dependent ear swelling response induced by compound 48/80 in mice by both topical and intradermal application. Lavender oil (1:500, 1:100, 1:10, 1:1, 1:0) inhibited concentration-dependently passive cutaneous anaphylaxis induced by anti-dinitrophenyl (DNP) IgE in rats by both topical and intradermal application. Lavender oil (1:500, 1:100, 1:10, 1:1, 1:0) also inhibited concentration-dependently the histamine release from the peritoneal mast cells by compound 48/80 or anti-DNP IgE. Moreover, lavender oil (1:1000, 1:100, 1:10, 1:0) had a significant inhibitory effect on anti-DNP IgE-induced tumour necrosis factor-alpha secretion from peritoneal mast cells. These results indicate that lavender oil inhibits immediate-type allergic reactions by inhibition of mast cell degranulation in-vivo and in-vitro.

Kinetics of the development and recovery of the lung from IgE-mediated inflammation: dissociation of pulmonary eosinophilia, lung injury, and eosinophil-active cytokines

Events occurring up to 16 d after antigen challenge were characterized using a novel protocol employing four bronchoscopies, two segmental antigen challenge (SAC) procedures (on Days 1 and 2), and six bronchoalveolar lavages (BALs) (on Days 1, 2, 9, and 16) in three groups: ragweed allergic asthmatics with dual phase airway reactions (AA-D), allergic asthmatics with a single early airway reaction (AA-S), and nonallergic nonasthmatic control subjects. In AA-D subjects, SAC produced a marked eosinophilic inflammatory response at 24 h associated with eosinophil degranulation (eosinophil cationic protein [ECP] in BAL fluid) and lung injury, which largely resolved by Day 16. When the second antigen-challenged segment (SAC performed on Day 2) was lavaged 7 d after challenge (Day 9), a persistent pulmonary eosinophilia was noted accompanied by minimal elevations in ECP and albumin. Eosinophil-active cytokines showed unique patterns: interleukin-5 (IL-5) increased in the antigen segment on Day 2 then returned to baseline after 7 d; granulocyte-macrophage colony-stimulating factor (GM-CSF) peaked at Day 2 but was persistently elevated throughout Day 16 in antigen segments, and increased in control segments at late time points; IL-3 levels were constant and similar in antigen and control segments. Changes were specific to AA-D subjects in comparison with control subjects. Elements of the IgE-mediated pulmonary inflammatory response differ markedly in their development and resolution.

Safety and tolerability of omalizumab in children with allergic (IgE-mediated) asthma

OBJECTIVE

This pooled analysis assessed the safety of omalizumab in children with allergic (immunoglobulin E-mediated) asthma.

STUDY DESIGN

Two double-blind, placebo-controlled studies in children (6 to < 12 years) with moderate-to-severe allergic asthma investigated the efficacy/safety of omalizumab. Children on optimized asthma care (inhaled corticosteroids ± other controller medications) were randomized (2:1) to omalizumab (75-375  mg  sc, q2 or q4 wk) or placebo. Pooled safety findings from these trials are presented in this publication.

RESULTS

The safety population included 926 children (omalizumab, n = 624; placebo, n = 302). Adverse events (AEs) were more frequently reported in the placebo (91.7%) than omalizumab (89.7%) group. The most common AEs were nasopharyngitis, upper respiratory tract infection and headache. Suspected treatment-related AEs included headache, erythema and urticaria; none of which were reported by ≥ 2% of patients receiving omalizumab. Serious AEs (SAEs) were reported by 3.4% and 6.6% of patients receiving omalizumab and placebo, respectively; the most common were appendicitis, pneumonia and bronchitis; no deaths were reported.

CONCLUSIONS

Omalizumab has an acceptable safety profile, with a risk of AEs similar to placebo. This, combined with its efficacy profile, suggests that omalizumab may provide an additional asthma management option for children (6 to < 12 years) uncontrolled with current therapy that follows established guidelines.

Omalizumab in the management of oral corticosteroid-dependent IGE-mediated asthma patients

BACKGROUND

Several studies have demonstrated the beneficial effects of omalizumab in asthma patients. Here we describe the drug's tolerance and oral corticosteroid sparing capacity in a long-term observational study.

METHODS

Thirty-two patients aged ≥18 years with obstructive airway disease and FEV(1) reversibility ≥12% and 200  mL, with an oral steroid requirement ≥7.5  mg per day of prednisolone during a period of ≥1 year, a positive prick test or in vitro reactivity (RAST) to at least one perennial aeroallergen and a baseline immunoglobulin E level ranking between 30-700  IU/mL were prospectively followed for 17.2  ±  8.5 months. Patients were visited once or twice a month, depending on their schedule for omalizumab administration.

INTERVENTION

blood analysis every six months; spirometry and nitric oxide measurement at every visit.

RESULTS

One patient who dropped out early was excluded. Follow-up period: the treatment benefited 83.9% (26/31) of the cohort; oral corticosteroids were reduced from 7.19 ± 11.1 to 3.29 ± 11.03  mg (p < 0.002) and withdrawn in 74.2% of patients. FEV(1) (percent predicted) was 64.4 ± 22.7 at the beginning and 62.9 ± 24.3 at the end. IgE at entry was 322.2 ± 334.2  IU/mL and increased 2.34-fold. Respiratory function and NO did not present statistically significant changes. We identified three groups of patients: the first (n = 17) receiving oral steroid at entry in whom the accumulated dose of oral steroids progressively decreased; another (n = 10) including patients who had quit oral steroids before starting omalizumab although they had not been instructed to do so and whose oral steroid dose at the end of follow-up was zero; and a third group (n = 4) that did not benefit from omalizumab treatment. The only relevant side effect was a flu-like syndrome which required discontinuation of treatment in one patient.

CONCLUSION

In our series, a substantial, safe decrease in oral corticosteroid requirements was observed due, at least to some extent, to omalizumab therapy. Oral corticosteroids were withdrawn in three-quarters of the patients. We were unable to identify a factor able to predict which patients would benefit most from omalizumab treatment.

Dysfunctional Gut Microbiome Networks in Childhood IgE-Mediated Food Allergy

The development of food allergy has been reported to be related with the changes in the gut microbiome, however the specific microbe associated with the pathogenesis of food allergy remains elusive. This study aimed to comprehensively characterize the gut microbiome and identify individual or group gut microbes relating to food-allergy using 16S rRNA gene sequencing with network analysis. Faecal samples were collected from children with IgE-mediated food allergies (n = 33) and without food allergy (n = 27). Gut microbiome was profiled by 16S rRNA gene sequencing. OTUs obtained from 16S rRNA gene sequencing were then used to construct a co-abundance network using Weighted Gene Co-expression Network Analysis (WGCNA) and mapped onto Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. We identified a co-abundance network module to be positively correlated with IgE-mediated food allergy and this module was characterized by a hub taxon, namely Ruminococcaceae UCG-002 (phylum Firmicutes). Functional pathway analysis of all the gut microbiome showed enrichment of methane metabolism and glycerolipid metabolism in the gut microbiome of food-allergic children and enrichment of ubiquinone and other terpenoid-quinone biosynthesis in the gut microbiome of non-food allergic children. We concluded that Ruminococcaceae UCG-002 may play determinant roles in gut microbial community structure and function leading to the development of IgE-mediated food allergy.

Studies on selection blockers. 5. Design, synthesis, and biological profile of sialyl Lewis x mimetics based on modified serine-glutamic acid dipeptides

We have rationally designed a sLe(x) mimetic based on molecular modeling, synthesized type II and type II' beta-turn dipeptides (3a,b), and evaluated their biological profiles both in vitro and in vivo. Against E-selectin-sLe(x) binding, the type II beta-turn dipeptide L-Ser-D-Glu 3a (IC50, 13 microM) and the type II' beta-turn dipeptide D-Ser-L-Glu 3b (IC50, 5.5 microM) were 20-100-fold more potent blockers than sLe(x) (1; IC50, 600 microM) and a 3'-sulfated Le(x) analog (2; IC50, 280 microM). On the other hand, other stereoisomers, such as L-Ser-L-Glu 3c and D-Ser-D-Glu 3d, were very weak blockers, with IC50 > 1000 microM for both 3c,d. Against the P- and L-selectins, despite much different stereochemistry of compounds 3a-d, the dipeptides 3a-d were all more potent blockers than either sLe(x) or compound 2. Interestingly, compound 3b provided significant in vivo efficacy against an immunoglobulin E-mediated skin reaction in a mouse model. These findings indicate that sLe(x) mimetics with type II and type II' beta-turn dipeptides could be useful in the design of an active selectin blocker in vitro and/or in vivo.

The effect of a thromboxane A2 receptor antagonist BAY-u-3405 on experimental allergic reactions

The effect of a novel thromboxane A2 receptor antagonist, BAY-u-3405, on experimental allergic airway and skin reactions was studied in vivo. At doses of 3-30 mg/kg BAY-u-3405 clearly inhibited the U-46619-induced increase in respiratory resistance (Rrs) in guinea pigs. BAY-u-3405 at doses of 3 and 30 mg/kg inhibited the aerosolized antigen-induced biphasic increase in respiratory resistance in guinea pigs. Moreover, BAY-u-3405 inhibited repeated aeroantigen-induced airway hyperactivity and airway inflammation in mice. In IgE antibody-mediated biphasic skin reactions in mice, both immediate and late-phase reactions were inhibited by 10 mg/kg of BAY-u-3405. These results demonstrate the efficacy of BAY-u-3405 on the antigen-induced late-phase reactions in the airway and skin in guinea pigs and mice, and antigen-induced airway hyperactivity in mice.

An immunologically relevant rodent model demonstrates safety of therapy using a tumour-specific IgE

BACKGROUND

Designing biologically informative models for assessing the safety of novel agents, especially for cancer immunotherapy, carries substantial challenges. The choice of an in vivo system for studies on IgE antibodies represents a major impediment to their clinical translation, especially with respect to class-specific immunological functions and safety. Fcε receptor expression and structure are different in humans and mice, so that the murine system is not informative when studying human IgE biology. By contrast, FcεRI expression and cellular distribution in rats mirror that of humans.

METHODS

We are developing MOv18 IgE, a human chimeric antibody recognizing the tumour-associated antigen folate receptor alpha. We created an immunologically congruent surrogate rat model likely to recapitulate human IgE-FcεR interactions and engineered a surrogate rat IgE equivalent to MOv18. Employing this model, we examined in vivo safety and efficacy of antitumour IgE antibodies.

RESULTS

In immunocompetent rats, rodent IgE restricted growth of syngeneic tumours in the absence of clinical, histopathological or metabolic signs associated with obvious toxicity. No physiological or immunological evidence of a "cytokine storm" or allergic response was seen, even at 50 mg/kg weekly doses. IgE treatment was associated with elevated serum concentrations of TNFα, a mediator previously linked with IgE-mediated antitumour and antiparasitic functions, alongside evidence of substantially elevated tumoural immune cell infiltration and immunological pathway activation in tumour-bearing lungs.

CONCLUSION

Our findings indicate safety of MOv18 IgE, in conjunction with efficacy and immune activation, supporting the translation of this therapeutic approach to the clinical arena.

Specific IgE serum concentration is associated with symptom severity in children with seasonal allergic rhinitis

BACKGROUND

The impact of allergen-specific and total IgE serum levels before and during the pollen season on symptom severity as well as efficacy of treatment with anti-IgE requires further delineation.

METHODS

Birch and grass pollen allergic patients aged 6-17 years with seasonal allergic rhinitis (SAR) were analyzed for the association of IgE serum concentration with symptom severity and rescue medication use (combination: symptom load, SL) during the grass pollen season. Reference group A (n = 53) received placebo, while group B (n = 54) received Omalizumab (anti-IgE) monotherapy before and during the grass pollen season.

RESULTS

Patients on placebo with high baseline specific grass pollen IgE (>50 kU/l) had a significantly higher SL compared with those with low IgE levels (< or =50 kU/l): SL 1.28 vs 0.61, P = 0.015. This association was nonexistent in patients treated with anti-IgE. In contrast, baseline total IgE levels did not correlate with SL in any group. Patients with anti-IgE treatment and high free total IgE levels (>16.7 ng/ml) had a significantly higher SL compared with those with low free total IgE levels (< or =16.7 ng/ml): SL 0.63 vs 0.23, P = 0.031.

CONCLUSIONS

Baseline specific IgE, but not total IgE, is associated with symptom severity during the pollen season in children with SAR. Likewise, the symptom load in SAR patients with anti-IgE correlates with free total IgE levels. Although further research in larger populations is needed to confirm our findings, our data suggest that specific IgE can be used as a parameter for patient selection for this kind of treatment.

Effect of Phlomis umbrosa root on mast cell-dependent immediate-type allergic reactions by anal therapy

The effect of aqueous extract of Phlomis umbrosa Turcz. (Labiatae) root (PUAE) on mast cell-dependent immediate-type allergic reaction by anal therapy was investigated. PUAE (0.01 to 1 g/kg) dose-dependently inhibited systemic anaphylaxis induced by compound 48/80 in mice. When PUAE was pretreated at the same concentrations with systemic anaphylaxis, the plasma histamine levels were reduced in a dose-dependent manner. PUAE (0.1 and 1 g/kg) also significantly inhibited local anaphylaxis activated by anti-DNP IgE. PUAE (0.001 to 1 mg/mL) dose-dependently inhibited the histamine release from rat peritoneal mast cells (RPMC) activated by compound 48/80 or anti-DNP IgE. The level of cyclic AMP (cAMP) in human mast cells (HMC-1 cells) when PUAE (1 mg/mL) was added, transiently and significantly increased compared with that of basal cells. In addition, PUAE (0.1 and 1 mg/mL) inhibited the secretion of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-6 in phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187-stimulated HMC-1 cells. These results provide evidence that anal therapy of PUAE may be beneficial in the treatment of allergic diseases.

Occupational asthma due to IgE mediated allergy to the flower Molucella laevis (Bells of Ireland)

BACKGROUND

About 25% of greenhouse flower and/or ornamental plant growers sensitised to workplace flowers or moulds have occupational asthma, a disease that is suffered by 8% of the growers who cultivate these crops.

AIM

To document a case of occupational asthma due to IgE mediated allergy to the flower Molucella laevis.

METHODS

and

RESULTS

There was a history of work related seasonal asthmatic and rhinoconjunctivitis symptoms in a Molucella laevis grower. Bronchial obstruction following exposure to Molucella laevis was documented by a fall in FEV(1) from 89% to 73% of predicted during seasonal exposure to Molucella laevis. Daily PEF measurements showed a fall from 500 to 250 l/min during this period following withdrawal of inhaled steroids. Bronchial reactivity to inhaled methacholine was increased (PC(20) 1.45 mg/ml). Confirmation of sensitisation to Molucella laevis flower pollen extract was done using an SPT and by demonstration of Molucella laevis specific serum IgE (18 IU/ml; class 4). Specific inhalation challenge with Molucella laevis extract provoked an early and late asthmatic reaction (EAR and LAR) with a fall in FEV(1) compared with control day of 40% and 53% respectively, with associated 5.1-fold increase in absolute sputum eosinophil cell counts and 2.9-fold increase in neutrophil cell counts.

Effect of kaempferol on IgE-mediated anaphylaxis in C57BL/6 mice and LAD2 cells

BACKGROUND

Immunoglobulin E (IgE)-mediated mast cell (MC) activation is crucial in multiple allergic diseases. Parkinson disease protein 7 (DJ-1) and Lyn kinase were reported as the receptor-proximal events in IgE receptor (FcεRI) signals in human MC. Kaempferol, a natural flavonol mainly derived from the rhizome of traditional Chinese herb Kaempferia galanga L. (Zingiberaceae), has been known to inhibit allergic reactions, but it was limited to the receptor-distal signals on rat basophilic leukemia cells. A thorough investigation of the inhibitory effects of kaempferol on human MC has not been done.

PURPOSE

To investigate the inhibitory effects of kaempferol on IgE-mediated anaphylaxis in vivo and in human MCs, as well as the mechanism underlying its effects, especially the receptor-proximal signals.

METHODS

IgE-mediated passive cutaneous anaphylaxis and systemic anaphylaxis model were applied to elucidate the antiallergic activity of kaempferol in vivo. The degranulation assay, calcium imaging, the release of cytokines and chemokines on the laboratory of allergic disease 2 (LAD2) cells were used to evaluate the antiallergic effect of kaempferol in vitro. Western blot analysis was performed to investigate the DJ-1/Lyn signaling pathway and downstream molecules. Kinase activity assay, immunofluorescence, and molecular docking were conducted to confirm the influence of kaempferol on DJ-1/Lyn molecules.

RESULTS

Kaempferol dose-dependently attenuated ovalbumin/IgE-induced mice paw swelling, primary MC activation from paw skin, as well as rehabilitated the hypothermia, and reduced the serum concentrations of histamine, tumor necrosis factor-alpha, interleukin-8, and monocyte chemo-attractant protein-1. Additionally, kaempferol suppressed IgE-mediated LAD2 cell degranulation and calcium fluctuation. Remarkably, kaempferol was found to bind with DJ-1 protein, and initially prevented DJ-1 from translocating to the plasma membrane, thereby inhibited full activation of Lyn, and eventually restrained those receptor-distal signaling molecules, involved Syk, Btk, PLCγ, IP3R, PKC, MAPKs, Akt and NF-κB.

CONCLUSION

Kaempferol could be used as a DJ-1 modulator for preventing MC-mediated allergic disorders through attenuating Lyn activation.

IgE immunotherapy against cancer

The success of antibody therapy in cancer is consistent with the ability of these molecules to activate immune responses against tumors. Experience in clinical applications, antibody design, and advancement in technology have enabled antibodies to be engineered with enhanced efficacy against cancer cells. This allows re-evaluation of current antibody approaches dominated by antibodies of the IgG class with a new light. Antibodies of the IgE class play a central role in allergic reactions and have many properties that may be advantageous for cancer therapy. IgE-based active and passive immunotherapeutic approaches have been shown to be effective in both in vitro and in vivo models of cancer, suggesting the potential use of these approaches in humans. Further studies on the anticancer efficacy and safety profile of these IgE-based approaches are warranted in preparation for translation toward clinical application.

A study of IgE in immunoglobulin preparations for intravenous administration. I. IgE in intravenous IgG

We have studied the IgE content of different lots of commercial intravenous IgG preparations used in our day hospital as replacement therapy for patients with agammaglobulinemia. Two enzymatic methods were used: Phadezym and FAST. The average amounts of IgE detected in Endobulin and Sandoglobulin lots were very high with respect to serum values in the general population. In some lots we found low titers of specific IgE (RAST class 1) to house dust mite, rye grass and cow's milk. We also found in most preparations the presence of IgG anti-IgE which are usually present in sera from atopic patients. Despite a low post-infusion increase of serum IgE and the absence of sensitization or adverse reactions observed, a careful selection of donors with normal IgE levels may need to be recommended to manufacturers in the future.

Association between serum periostin levels and the severity of arsenic-induced skin lesions

Arsenic is a potent environmental toxicant and human carcinogen. Skin lesions are the most common manifestations of chronic exposure to arsenic. Advanced-stage skin lesions, particularly hyperkeratosis have been recognized as precancerous diseases. However, the underlying mechanism of arsenic-induced skin lesions remains unknown. Periostin, a matricellular protein, is implicated in the pathogenesis of many forms of skin lesions. The objective of this study was to examine whether periostin is associated with arsenic-induced skin lesions. A total of 442 individuals from low- (n = 123) and high-arsenic exposure areas (n = 319) in rural Bangladesh were evaluated for the presence of arsenic-induced skin lesions (Yes/No). Participants with skin lesions were further categorized into two groups: early-stage skin lesions (melanosis and keratosis) and advanced-stage skin lesions (hyperkeratosis). Drinking water, hair, and nail arsenic concentrations were considered as the participants' exposure levels. The higher levels of arsenic and serum periostin were significantly associated with skin lesions. Causal mediation analysis revealed the significant effect of arsenic on skin lesions through the mediator, periostin, suggesting that periostin contributes to the development of skin lesions. When skin lesion was used as a three-category outcome (none, early-stage, and advanced-stage skin lesions), higher serum periostin levels were significantly associated with both early-stage and advanced-stage skin lesions. Median (IQR) periostin levels were progressively increased with the increasing severity of skin lesions. Furthermore, there were general trends in increasing serum type 2 cytokines (IL-4, IL-5, IL-13, and eotaxin) and immunoglobulin E (IgE) levels with the progression of the disease. The median (IQR) of IL-4, IL-5, IL-13, eotaxin, and IgE levels were significantly higher in the early-and advanced-stage skin lesions compared to the group of participants without skin lesions. The results of this study suggest that periostin is implicated in the pathogenesis and progression of arsenic-induced skin lesions through the dysregulation of type 2 immune response.

Deletion of ΔdblGata motif leads to increased predisposition and severity of IgE-mediated food-induced anaphylaxis response

BACKGROUND

Previous studies have revealed an important role for the transcription factor GATA-1 in mast cell maturation and degranulation. However, there have been conflicting reports with respect to the requirement of GATA-1 function in mast cell dependent inflammatory processes. Herein, we examine the requirement of GATA-1 signaling in mast cell effector function and IgE-mast cell-dependent anaphylaxis.

OBJECTIVE

To study the requirement of GATA-1 dependent signaling in the development and severity of IgE-mast cell-dependent anaphylaxis in mice.

METHODS

Wild type (Balb/c) and mutant ΔdblGata (Balb/c) mice were employed to study the role of GATA-1 signaling in in vitro IgE-mediated activation of bone marrow derived mast cells (BMMCs). Murine models of passive IgE-mediated and oral antigen-induced IgE-mediated anaphylaxis were employed in mice. Frequency of steady state mast cells in various tissues (duodenum, ear, and tongue), peritoneal cavity, and clinical symptoms (diarrhea, shock, and mast cell activation) and intestinal Type 2 immune cell analysis including CD4+ Th2 cells, type 2 innate lymphoid cells (ILC2), and IL-9 secreting mucosal mast cells (MMC9) were assessed.

RESULTS

In vitro analysis revealed that ΔdblGata BMMCs exhibit a reduced maturation rate, decreased expression of FcεRIα, and degranulation capacity when compared to their wildtype (WT) counterparts. These in vitro differences did not impact tissue resident mast cell numbers, total IgE, and susceptibility to or severity of IgE-mediated passive anaphylaxis. Surprisingly, ΔdblGata mice were more susceptible to IgE-mast cell-mediated oral antigen induced anaphylaxis. The increased allergic response was associated with increased Type 2 immunity (antigen-specific IgE, and CD4+ TH2 cells), MMC9 cells and small intestine (SI) mast cell load.

CONCLUSION

Diminished GATA-1 activity results in reduced in vitro mast cell FcεRIα expression, proliferation, and degranulation activity. However, in vivo, diminished GATA-1 activity results in normal homeostatic tissue mast cell levels and increased antigen-induced CD4+ Th2 and iMMC9 cell levels and heightened IgE-mast cell mediated reactions.

Anti-IgE and chemotherapy: a critical appraisal of treatment options for severe asthma

In this narrative review the scientific rationale for the development of a therapeutic modality for asthma based on decreasing the circulating and cell-bound levels of immunoglobulin-E (IgE) is outlined. The one drug that has so far entered clinical practice to do this is a humanised monoclonal antibody to the Fc portion of the IgE molecule, omalizumab. It is highly effective in reducing IgE blood levels and its established mode of delivery is by subcutaneous injection. The clinical trial development of omalizumab is reviewed and the published data and claims for its efficacy and role in clinical practice is critically appraised. The target group of omalizumab has become focused on severe asthmatics who are still symptomatic after being administered with high-dose inhaled corticosteroids plus long-acting beta-agonists. The strongest evidence for effect is in those with frequent severe exacerbations.

Naringenin ameliorates atopic dermatitis by inhibiting inflammation and enhancing immunity through the JAK2/STAT3 pathway

OBJECTIVE

Atopic dermatitis (AD) is an inflammatory skin disease. Naringenin (Nar) possesses an anti-inflammatory property. This paper attempts to discuss the functional mechanism of Nar in AD mice through the Janus kinase 2 (JAK2)/signal transducer and activation of transcription 3 (STAT3) pathway.

METHODS

Mouse models of DNFB-induced AD were established and treated with Nar, followed by intraperitoneal injection with the JAK2/STAT3 pathway activator Coumermycin A1. Dermatitis severity was scored and the thickness of right ear was measured. The pathological changes in dorsal skin tissues were observed by HE staining. The number of infiltrated mast cells and eosinophilic granulocytes was counted by TB staining. The serum IgE level and levels of TNF-α, IL-6, IFN-γ, IL-12, and IL-5 in dorsal skin tissues were measured by ELISA. The levels of p-JAK2, JAK2, p-STAT3, and STAT3 were determined by Western blot.

RESULTS

Nar decreased dermatitis scores and right ear thickness, alleviated skin lesions, and reduced the number of infiltrated mast cells and eosinophilic granulocytes in AD mice. The serum IgE level and levels of TNF-α, IL-6, IFN-γ, IL-12, and IL-5 in dorsal skin tissues of AD mice were diminished after Nar treatment in a dose-dependent manner. Nar inhibited the activation of the JAK2/STAT3 pathway. The activation of the JAK2/STAT3 pathway partially nullified the therapeutic function of Nar on AD mice.

CONCLUSION

Nar protects mice from AD by inhibiting inflammation and promoting immune responses through the inhibition of the JAK2/STAT3 pathway.

Circulating microbiome analysis in patients with perioperative anaphylaxis

Background

Perioperative anaphylaxis is a rare and acute systemic manifestation of drug-induced hypersensitivity reactions that occurs following anesthesia induction; the two main classes of drugs responsible for these reactions being neuromuscular blocking agents (NMBA) and antibiotics. The sensitization mechanisms to the drugs are not precisely known, and few risk factors have been described. A growing body of evidence underlines a link between occurrence of allergy and microbiota composition. However, no data exist on microbiota in perioperative anaphylaxis. The aim of this study was to compare circulating microbiota richness and composition between perioperative anaphylaxis patients and matched controls.

Methods

Circulating 16s rDNA was quantified and sequenced in serum samples from 20 individuals with fully characterized IgE-mediated NMBA-related anaphylaxis and 20 controls matched on sex, age, NMBA received, type of surgery and infectious status. Microbiota composition was analyzed with a published bioinformatic pipeline and links with patients clinical and biological data investigated.

Results

Analysis of microbiota diversity showed that anaphylaxis patients seem to have a richer circulating microbiota than controls, but no major differences of composition could be detected with global diversity indexes. Pairwise comparison showed a difference in relative abundance between patients and controls for Saprospiraceae, Enterobacteriaceae, Veillonellaceae, Escherichia-Shigella, Pseudarcicella, Rhodoferax, and Lewinella. Some taxa were associated with concentrations of mast cell tryptase and specific IgE.

Conclusion

We did not find a global difference in terms of microbiota composition between anaphylaxis patient and controls. However, several taxa were associated with anaphylaxis patients and with their biological data. These findings must be further confirmed in different settings to broaden our understanding of drug anaphylaxis pathophysiology and identify predisposition markers.

Inflammation and oxidative stress impair preimplantation embryonic morphogenesis in allergic asthma model

The incidence of allergic asthma has been increasing worldwide in recent decades. Also, an increasing number of women are suffering from poor pregnancy outcome. However, the causal relationship between allergic asthma and embryonic growth in terms of cell morphogenesis has not been well elucidated. Here, we investigated the impact of allergic asthma on the morphogenesis of preimplantation embryos. Twenty-four female BALB/c were randomly divided into control (PBS), 50-μg (OVA1), 100-μg (OVA2) and 150-μg (OVA3). On Days-0 and -14, mice were induced intraperitoneally (i.p) with ovalbumin (OVA). On Days-21 until -23, mice were challenged with OVA via intranasal instillation (i.n). Control animals were sensitized and challenged with PBS. At the end of treatment (Day-25), 2-cell embryos were retrieved and cultured in vitro until the blastocysts hatched. Results showed reduced number of preimplantation embryos at all developing stages in all treated groups (p ≤ 0.0001). Uneven blastomere size, partial compaction- and cavitation-activity, low formation of trophectoderm (TE), as well as cell fragmentation were noted in all the treated groups. Maternal serum interleukin (IL)-4, immunoglobulin (Ig)-E and 8-hydroxydeoxyguanosine (8-OHdG) were notably high (p ≤ 0.0001, p ≤ 0.01) in contrast with low total antioxidant capacity (TAOC) (p ≤ 0.0001). Our findings indicated that OVA-induced allergic asthma had compromised cell morphogenesis through reduced blastomere cleavage division, partial compaction and cavitation-activity, impairment of TE production, and cell fragmentation leading to embryonic cell death via OS mechanism.