Food allergies

Development of Histamine in Fresh and Canned Tuna Steaks Stored under Different Experimental Temperature Conditions

Among biogenic amines, histamine is most frequently involved in foodborne intoxication. To evaluate histamine formation in tuna, several storage conditions were reproduced. An LC-MS/MS method was used for analytical determinations. Fresh tuna samples (not contaminated and grafted with tuna muscle naturally incurred with histamine at 6000 mg/kg) were stored at 4, 12, and 20 °C, and daily samples were collected for 6 days. The development of histamine was observed only in grafted tuna samples. At 4 °C, histamine formation progressed from 12.8 mg/kg (day 1) up to 68.2 mg/kg (day 6). At 12 °C, higher concentrations developed (23.9 mg/kg on day 1 up to 2721.3 mg/kg on day 6) relative to 20 °C (from 12.0 to 1681.0 mg/kg). It was found that at 4 °C, if grafted tuna was submerged in oil, histamine formation progressed more slowly. In a naturally contaminated sample, it was observed that the histamine distribution was uniform, while the normal cooking process did not affect the histamine level. Furthermore, it was found that the use of histamine-contaminated equipment for food handling may result in histamine formation in food. These results confirm the importance of implementing good hygiene practices and respecting the cold chain.

Follow-Up of a Rare Case of Eosinophilic Gastroenteritis Associated with Persistent Blood Eosinophilia and Multiple Food Allergies

Eosinophilic gastroenteritis (EGE) is a subgroup of the eosinophilic gastro-intestinal disorders (EGIDs), characterized by eosinophilic infiltration and chronic inflammation of the gastrointestinal tract. These are rare diseases with still incompletely elucidated causes and mechanisms, with frequently delayed diagnosis and variable outcome. Despite increased interest in eosinophilic diseases in recent years, fewer data have been published on EGE and no standardized diagnostic and therapeutic approach exists. This paper reports the case of a young male patient diagnosed with EGE in 2017 based on clinical and histopathological criteria and constantly monitored during five years. Besides gastrointestinal eosinophilic infiltration, biopsies also revealed eosinophilic infiltration of the oesophagus, despite no declared characteristic oesophageal symptoms. We found increased specific IgE to multiple foods and progressive blood hypereosinophilia which preceded EGE diagnosis by three years. The EGE management included selective dietary restrictions and pharmacologic therapy based on daily budesonide non-enteric coated tablets, proton pumps inhibitors, antihistamines, cromoglycate, correction of iron, calcium and vitamin D deficiencies. The clinical outcome was good, while blood eosinophilia and endoscopic appearance remained almost unchanged. After one year the patient complained of respiratory symptoms suggesting asthma, needing continuous combined inhaled therapy. The reported case is illustrative for complex presentation, diagnosis and outcome of a rare case of mucosal chronic EGE associated with oesophageal involvement, peripheral eosinophilia, multiple food allergies and asthma.

Chemokine receptors in allergic diseases

Under homeostatic conditions, as well as in various diseases, leukocyte migration is a crucial issue for the immune system that is mainly organized through the activation of bone marrow-derived cells in various tissues. Immune cell trafficking is orchestrated by a family of small proteins called chemokines. Leukocytes express cell-surface receptors that bind to chemokines and trigger transendothelial migration. Most allergic diseases, such as asthma, rhinitis, food allergies, and atopic dermatitis, are generally classified by the tissue rather than the type of inflammation, making the chemokine/chemokine receptor system a key point of the immune response. Moreover, because small antagonists can easily block such receptors, various molecules have been developed to suppress the recruitment of immune cells during allergic reactions, representing potential new drugs for allergies. We review the chemokines and chemokine receptors that are important in asthma, food allergies, and atopic dermatitis and their respectively developed antagonists.

The Vagus Nerve in Appetite Regulation, Mood, and Intestinal Inflammation

Although the gastrointestinal tract contains intrinsic neural plexuses that allow a significant degree of independent control over gastrointestinal functions, the central nervous system provides extrinsic neural inputs that modulate, regulate, and integrate these functions. In particular, the vagus nerve provides the parasympathetic innervation to the gastrointestinal tract, coordinating the complex interactions between central and peripheral neural control mechanisms. This review discusses the physiological roles of the afferent (sensory) and motor (efferent) vagus in regulation of appetite, mood, and the immune system, as well as the pathophysiological outcomes of vagus nerve dysfunction resulting in obesity, mood disorders, and inflammation. The therapeutic potential of vagus nerve modulation to attenuate or reverse these pathophysiological outcomes and restore autonomic homeostasis is also discussed.

Microarray and allergenic activity assessment of milk allergens

BACKGROUND

Cow's milk is one of the most common causes of food allergy affecting approximately 2.5% of infants in the first years of their life. However, only limited information regarding the allergenic activity of individual cow's milk allergens is available.

OBJECTIVE

To analyse the frequency of IgE reactivity and to determine the allergenic activity of individual cow's milk allergens.

METHODS

A nitrocellulose-based microarray, based on purified natural and recombinant cow's milk allergens was used to determine IgE reactivity profiles using sera from 78 cow's milk-sensitized individuals of varying ages. The allergenic activity of the individual allergens was tested using patients' sera for loading rat basophil leukaemia cells (RBL) expressing the α-chain of the human receptor FcεRI.

RESULTS

Using the microarray and the RBL assay, cow's milk allergens were assessed for frequency of IgE recognition and allergenic activity. Moreover, the RBL assay allowed distinguishing individuals without or with mild clinical reactions from those with severe systemic or gastrointestinal symptoms as well as persons who grew out cow's milk allergy from those who did not.

CONCLUSIONS

Component-resolved testing using milk allergen microarrays and RBL assays seems to provide useful additional diagnostic information and may represent a basis for future forms of prophylactic and therapeutic strategies for cow's milk allergy.

The role of mast cells in eosinophilic esophagitis

Eosinophilic esophagitis (EE) is a chronic inflammatory disease of the esophagus which is characterized by the presence of dense infiltrate of eosinophilic leukocytes restricted to this organ mucosa. Accumulating published evidence suggests a strong role of mast cells in the inflammatory infiltrate in the physiopathology of EE. We have reviewed published articles with relevant information about the presence and possible role of mast cells in EE. Although mast cells have been studied indirectly in EE, reported data allow us to confirm that the number of mast cells infiltrating the esophageal epithelium in adult and child patients with EE is higher with respect to the normal state and in gastroesophageal reflux disease. Mast cells linked to IgE, which are not found in other conditions, have been identified in EE. Despite that fact, an anaphylactic reaction history after exposure to allergens is not common in these patients. Therefore, the mast cells' function in EE could be dependent on T lymphocytes, as suggested by a mast cell gene expression analysis. Bi-directional crosstalk is established between mast cells and eosinophils, hence establishing interesting hypotheses regarding their relationship to EE physiopathology. Mast cells' function as an immune response leader seems to substitute for their effector functions in EE, while at the same time opening new research pathways for consideration of these cells as a therapeutic target in EE. However, the inefficiency of therapies that inhibit mast cell functions while they are effective in other respiratory tract diseases results in the need for specific studies to identify the real function of such complex cells in the physiopathology of EE. There is indirect proof of the role of mast cells in EE, while many doubts exist about their activation mechanism, which does not seem to be IgE-mediated. Specific approach studies are needed to clarify the function of these cells in the physiopathology of EE, which could be a possible therapeutic target.

Influence of food allergy on gut barrier function and CD4+CD25+ regulatory T cells in food allergic mice

AIM: To investigate the gut barrier functional changes of ovalbumin-induced allergic mice and to determine whether there is bacteria translocation; and to observe changes of CD4⁺CD25⁺ regulatory T cells in FA mice spleen in order to shed light on relationship between CD4⁺CD25⁺ regulatory T cells and food allergy.

METHODS: Twenty BALB/c mice on ovalbulmin (OVA)-free diet were randomly divided into experimental group and control group. The mice in experimental group were sensitized with OVA while mice in control group were given normal saline (NS). The intestinal microbial flora was detected by culturing the feces. The secretory immunoglobulin A (sIgA) in intestinal mucus and the diamine oxidase (DAO) in blood serum were analyzed using ELISA. The mesenteric lymph nodes (MLN), homogenated tissues of livers, lungs, kidneys, and NS used for peritoneal lavage were cultured to determine bacterial translocation. The number of CD4⁺CD25⁺ regulatory T cells (CD4⁺CD25⁺ Treg cells) in spleens was estimated using flow cytometry.

RESULTS: The number of probiotics in experimental group was significantly lower than that of the control group (Lactobacillus: P = 0.006; Bifidobacterium: P = 0.016). In contrast, the number of conditional pathogenic bacteria was significantly higher than that of control group (Escherichia coli: P = 0.001; Bacteroides: P = 0.001). Compared with the control group, sIgA (0.107 ± 0.012 vs 0.086 ± 0.008, P = 0.001) in intestinal mucus, DAO (0.357 ± 0.025 vs 0.179 ± 0.035, P = 0.001) in blood serum and frequency of bacteria translocation (47.8% vs 15.6%, P = 0.001) were significantly higher in experimental group. The number of CD4⁺CD25⁺ Treg cells was significantly lower in experimental group (4.350% ± 0.619% vs 6.488% ± 2.313%, P = 0.001).

CONCLUSION: Intestinal flora imbalance and high intestinal permeability in ovalbumin-induced allergic mice suggest gut barrier dysfunction. The phenomenon of bacteria translocation is verified in FA mice. Down-regulation of CD4⁺CD25⁺ Treg cells may play an important role in food allergy.