Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2007

Redefining Memory: Building the Case for Adaptive NK Cells

Classically, natural killer (NK) cells have been defined by nonspecific innate killing of virus-infected and tumor cells. However, burgeoning evidence suggests that the functional repertoire of NK cells is far more diverse than has been previously appreciated, thus raising the possibility that there may be unexpected functional specialization and even adaptive capabilities among NK cell subpopulations. Some of the first evidence that NK cells respond in an antigen-specific fashion came from experiments revealing that subpopulations of murine NK cells were able to respond to a specific murine cytomegalovirus (MCMV) protein and that in the absence of T and B cells, murine NK cells also mediated adaptive immune responses to a secondary challenge with specific haptens. These data have been followed by demonstrations of NK cell memory of viruses and viral antigens in mice and primates. Herein, we discuss different forms of NK cell antigen specificity and how these responses may be tuned to specific viral pathogens, and we provide assessment of the current literature that may explain molecular mechanisms of the novel phenomenon of NK cell memory.

Probiotic Dahi containing Lactobacillus acidophilus and Bifidobacterium bifidum modulates immunoglobulin levels and cytokines expression in whey proteins sensitised mice

BACKGROUND

Cow milk allergy is the most common food allergy in children. So far, no effective treatment is available to prevent or cure food allergy. This study investigated whether orally administrated probiotics could suppress sensitisation in whey proteins (WP)-induced allergy mouse model. Two types of probiotic Dahi were prepared by co-culturing Dahi bacteria (Lactococcus lactis ssp. cremoris NCDC-86 and Lactococcus lactis ssp. lactis biovar diacetylactis NCDC-60) along with selected strain of Lactobacillus acidophilus LaVK2 and Bifidobacterium bifidum BbVK3. Mice were fed with probiotic Dahi (La-Dahi and LaBb-Dahi) from 7 days before sensitisation with WP, respectively, in addition to milk protein-free basal diet, and control group received no supplements.

RESULTS

Feeding of probiotic Dahi suppressed the elevation of whey proteins-specific IgE and IgG response of WP-sensitised mice. In addition, sIgA levels were significantly (P < 0.001) increased in intestinal fluid collected from mice fed with La-Dahi. Production of T helper (Th)-1 cell-specific cytokines, i.e. interferon-γ (IFN-γ), interleukin (IL)-12, and IL-10 increased, while Th2-specific cytokines, i.e. IL-4 decreased in the supernatant of cultured splenocytes collected from mice fed with probiotic Dahi as compared to the other groups. Moreover, the splenic mRNA levels of IFN-γ, interleukin-10 were found to be significantly increased, while that of IL-4 decreased significantly in La-Dahi groups, as compared to control groups.

CONCLUSION

Results of the present study indicate that probiotic Dahi skewed Th2-specific immune response towards Th1-specific response and suppressed IgE in serum. Collectively, this study shows the potential use of probiotics intervention in reducing the allergic response to whey proteins in mice. © 2015 Society of Chemical Industry.

Oral tolerance induced by transfer of food antigens via breast milk of allergic mothers prevents offspring from developing allergic symptoms in a mouse food allergy model

We examined whether maternal exposure to food antigens during lactation and maternal allergic status would affect the development of food allergy in offspring. OVA-sensitized or OVA-nonsensitized BALB/c female mice were exposed or unexposed to OVA during lactation. After weaning, their offspring were systemically sensitized twice with OVA and repeatedly given OVA by oral intubation. While 97.1% of the mice breastfed by OVA-nonsensitized and OVA-unexposed mothers developed allergic diarrhea, 59.7% of the mice breastfed by OVA-exposed nonallergic mothers during lactation and 24.6% of the mice breastfed by OVA-exposed allergic mothers during lactation developed food allergy. Furthermore, OVA was detected in breast-milk from OVA-exposed nonallergic mothers during lactation (4.6 ± 0.5 μg/mL). In addition, OVA-specific IgG1 titers were markedly increased in breast milk from allergic mothers (OVA-sensitized and OVA-unexposed mother: 11.0 ± 0.5, OVA-sensitized and OVA-exposed mother: 12.3 ± 0.3). Our results suggest that oral tolerance induced by breast milk-mediated transfer of dietary antigens along with their specific immunoglobulins to offspring leads to antigen-specific protection from food allergy.

Blunted HPA axis responsiveness to stress in atopic patients is associated with the acuity and severeness of allergic inflammation

Previously we could demonstrate attenuated responsiveness of the hypothalamus-pituitary-adrenal (HPA) axis to stress in patients with chronic allergic inflammatory disease (i.e., atopic dermatitis, allergic asthma). The present study was designed to investigate HPA axis function in an acute manifestation of allergy. Patients with seasonal allergic rhinitis (SAR; n = 20) and non-atopic controls (n = 20) were exposed to a standardized laboratory stressor ('Trier Social Stress Test'; TSST). Cortisol responses to the TSST and cortisol awakening responses (CAR) were measured in SAR subjects while suffering from acute symptoms of SAR (pollen season), and during a non-active state of their disease (pollen-free season). To assess the acuity and severity of SAR, eosinophil and basophil numbers and SAR symptomatology were determined. Non-allergic control subjects were examined at identical times during the year. To control for possible sequence effects, a cross-over design was used. SAR patients showed significantly increased symptom severity (t = 9.4; p<.001) as well as eosinophil (F(1,31) = 9.8; p<.01) and basophil (F(1,38) = 6.4; p<.05) numbers during the pollen season when compared to a pollen-free period. When exposed to the TSST, significantly attenuated cortisol responses were found in SAR subjects during acute manifestation of the disease (pollen season) when compared to the pollen-free season (F(16,456) = 1.65; p<.05). In SAR patients, there was a significant negative correlation between symptom severity and the cortisol response to the stressor (r = .53; p<.05). No significant between-group or between-condition differences with respect to the CAR could be determined (all p>.05). These findings support previous data of attenuated HPA axis responsiveness to stress in atopic conditions and further, suggest that HPA axis hyporesponsiveness in atopy may be linked to the severity of the allergic inflammatory process.

Adaptive immune responses mediated by natural killer cells

Adaptive immunity has traditionally been considered a unique feature of vertebrate physiology. Unlike innate immune responses, which remain essentially unchanged upon exposure to a recurrent challenge with the same stimulus, adaptive immune cells possess the ability to learn and remember. Thus, secondary adaptive responses to a previously encountered challenge are qualitatively and/or quantitatively distinct from those elicited by a primary encounter. Besides this capacity to acquire long-lived memory, the second cardinal feature of adaptive immunity is antigen specificity. It has been generally believed that only T and B cells can develop antigen-specific immunologic memory, because these lymphocytes uniquely express recombination-activating gene (RAG) proteins, which are necessary for somatic rearrangement of V(D)J gene segments to assemble diverse antigen-specific receptors. However, recent work has uncovered discrete subsets of murine natural killer (NK) cells capable of mediating long-lived, antigen-specific recall responses to a variety of hapten-based contact sensitizers. These NK cells appear to use distinct, RAG-independent mechanisms to generate antigen specificity. Murine NK cells have also recently been shown to develop memory upon viral infection. Here, we review recent evidence indicating that at least some NK cells are capable of mediating what appears to be adaptive immunity and discuss potential mechanisms that may contribute to RAG-independent generation of antigenic diversity and longevity.

Temperature modulated histamine-itch in lesional and nonlesional skin in atopic eczema - a combined psychophysical and neuroimaging study

BACKGROUND

Itch is the major symptom of many allergic diseases; yet it is still difficult to measure objectively. The aim of this study was to use an evaluated itch stimulus model in lesional (LS) and nonlesional (NLS) atopic eczema (AE) skin and to characterize cerebral responses using functional magnetic resonance imaging (fMRI).

METHODS

Thermal modulation was performed on a histamine stimulus in randomized order on LS or NLS in rapid alternating order from 32 degrees C (warm) to 25 degrees C (cold). Subjective itch ratings were recorded. Additionally, fMRI measurements were used to analyze the cerebral processing (n = 13). Healthy skin (HS) of age-matched volunteers served as control (n = 9).

RESULTS

Mean VAS itch intensity was significantly (P < 0.0001) higher during the relative cold [55.2 +/- 8.3% (LS); 48.6 +/- 8.2% (NLS)] compared to the relative warm blocks [36.0 +/- 7.3% (LS); 33.7 +/- 7.6% (NLS)]. Compared to HS, the itch response was delayed in LS and NLS. Itch intensity was perceived highest in LS, followed by NLS and HS. For NLS, fMRI revealed at the beginning of the itch provocation a cerebral deactivation pattern in itch processing structures (thalamus, prefrontal, cingulate, insular, somatosensory and motor cortex). During the course of stimulation, the cerebral deactivation was reduced with time and instead an activation of the basal ganglia occurred. In contrast LS showed an activation instead of deactivation pattern already at the beginning of the stimulation in the above mentioned structures.

CONCLUSIONS

Moderate short-term temperature modulation led to a reproducible, significant enhancement of histamine-induced itch with the strongest effect in LS. The differences in itch perception and itch kinetics between healthy volunteers and NLS in patients point towards an ongoing central inhibitory activity patients with AE, especially at the beginning of the itch provocation.

Maternal peanut exposure during pregnancy and lactation reduces peanut allergy risk in offspring

BACKGROUND

Maternal allergy is believed to be a risk factor for peanut allergy (PNA) in children. However, there is no direct evidence of maternal transmission of PNA susceptibility, and it is unknown whether maternal peanut exposure affects the development of PNA in offspring.

OBJECTIVE

To investigate the influence of maternal PNA on offspring reactions to the first peanut exposure, and whether maternal low-dose peanut exposure during pregnancy and lactation influences these reactions and peanut sensitization in a murine model.

METHODS

Five-week-old offspring of PNA C3H/HeJ mothers (PNA-Ms) were challenged intragastrically with peanut (first exposure), and reactions were determined. In a subset of the experiment, PNA-Ms were fed a low dose of peanut (PNA-M/PN) or not fed peanut (PNA-M/none) during pregnancy and lactation. Their 5-week-old offspring were challenged intragastrically with peanut, and reactions were determined. In another subset of the experiment, offspring of PNA-M/PN or PNA-M/none were sensitized with peanut intragastrically for 6 weeks, and serum peanut-specific antibodies were determined.

RESULTS

PNA-M offspring exhibited anaphylactic reactions at first exposure to peanut that were associated with peanut-specific IgG(1) levels and prevented by a platelet activation factor antagonist. In a subset experiment, PNA-M/PN offspring showed significantly reduced first-exposure peanut reactions, increased IgG(2a), and reduced mitogen-stimulated splenocyte cytokine production compared with PNA-M/none offspring. In an additional experiment, PNA-M/PN offspring showed reduction of peanut-specific IgE to active peanut sensitization.

CONCLUSION

We show for the first time maternal transmission of susceptibility to first-exposure peanut reactions and active peanut sensitization. Low-dose peanut exposure during pregnancy and lactation reduced this risk.

Allergic skin disease: major highlights and recent advances

AD, urticaria, and ACD account for a large percentage of the skin disorders that present at medical offices and emergency departments. With a high degree of morbidity, these diseases can be extremely difficult to manage. Consequently, these diseases continue to be the focus of much of the new research in the field. Recent studies have furthered the understanding of the complex relationship between immune and nonimmune factors in the pathogenesis of these disorders. This research has quickly led to the development of new treatment modalities and protocols for patient care, especially for AD. However, further discovery will be necessary to optimize the management of these often-vexing conditions.

Cow milk allergy symptoms are reduced in mice fed dietary synbiotics during oral sensitization with whey

Cow milk allergy is the most common food allergy in children. So far, no effective treatment is available to prevent or cure food allergy. The purpose of this study was to compare effects of dietary supplementation with a prebiotic mixture (Immunofortis), a probiotic strain [Bifidobacterium breve M-16V], or a synbiotic diet combining both on the outcome of the allergic response when provided during oral sensitization with whey in mice. Mice were fed diets containing 2% (wt:wt) Immunofortis and/or the B. breve M-16V (n = 6/group). The acute allergic skin response was determined by measuring ear swelling. Antigen-induced anaphylaxis was scored. Furthermore, whey-specific serum immunoglobulins and mouse mast cell protease-1 (mMCP-1) were determined. In mice fed the synbiotic mixture, the allergic skin response and the anaphylactic reaction were strongly reduced compared with whey-sensitized mice fed the control diet (P < 0.01). Immunofortis or B. breve M-16V alone were significantly less effective in reducing the allergic skin response than the synbiotic diet and did not reduce the anaphylactic reaction. The whey-specific IgE and IgG(1) responses were not affected; however, IgG(2a) was greater in all treated groups than in the control group (P < 0.05). Serum mMCP-1 concentrations, reflecting mucosal mast cell degranulation, were lower in mice fed synbiotics compared with those fed the control diet (P < 0.01). Dietary supplementation with Immunofortis, B. breve M-16V, and particularly the synbiotic mixture, provided during sensitization, reduces the allergic effector response in a murine model of IgE-mediated hypersensitivity that mimics the human route of sensitization. This model shows the potential for dietary intervention with synbiotics in reducing the allergic response to food allergens.

Current immunological approaches for management of allergic rhinitis and bronchial asthma

A large population world over is affected with allergic diseases and asthma. Pharmacotherapy for allergic diseases and asthma is effective in controlling symptoms but on discontinuation of medication, symptoms reoccur. In contrast, immunotherapy modifies and corrects the underlying pathological immune responses in an antigen-specific manner. Immunotherapy shows an increase in IgG (blocking antibody) that competes with IgE for allergen, inhibiting the release of inflammatory mediators. Recent studies suggest that immunotherapy acts by modifying CD4+ T-cell responses either by immune deviation, T-cell anergy and/or both. Current immunological approaches for management of allergies and asthma involve immunization with native allergen, modified allergen, peptides/cDNA of allergen, anti-IgE, adjuvants coupled allergen, including immunostimulatory DNA sequences, cytokines, and bacterial products. These approaches modulate the immune response and are intended to give long-term benefit.

Advances in allergic skin disease, anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects in 2008

This review highlights some of the research advances in anaphylaxis, and hypersensitivity reactions to foods, drugs, and insects and in allergic skin disease that were reported in the Journal in 2008. Key epidemiologic observations include a rise in anaphylaxis in a population-based study and lower rates of peanut allergy in Israel, where infants consume peanut early compared with the United Kingdom, where dietary introduction is generally delayed. Advances in food allergy diagnosis include IgE epitope mapping that discloses the likelihood and severity of allergy; studies correlating likelihood of clinical reactivity on the basis of food-specific IgE to sesame, peanut, milk, and tree nuts; and an observation that a low baseline angiotensin-converting enzyme level may be associated with having pharyngeal edema during a reaction. Molecular, immunologic, and genetic studies are discerning pathways that are key in development of food allergy, identifying new modalities to interrupt mast cell degranulation, and elucidating risks associated with penicillin allergy. Regarding treatment, clinical studies show a majority of children with milk and egg allergy tolerate these proteins in modest amounts when they are extensively heated in baked goods, and studies show promise for oral immunotherapy to treat milk allergy and sublingual immunotherapy for honey bee venom hypersensitivity. The importance of skin barrier dysfunction has continued to be highlighted in the pathophysiology of atopic dermatitis (AD). Research has also continued to identify immunologic defects that contribute to the propensity of patients with AD to develop viral and bacterial infection. New therapeutic approaches to AD, urticaria, and angioedema have been reported including use of probiotics, biologics, vitamin D, and skin barrier creams.