Reactive oxygen species (ROS) are produced by living organisms as a result of normal cellular metabolism and environmental factors, such as air pollutants or cigarette smoke. ROS are highly reactive molecules and can damage cell structures such as carbohydrates, nucleic acids, lipids, and proteins and alter their functions. The shift in the balance between oxidants and antioxidants in favor of oxidants is termed “oxidative stress.” Regulation of reducing and oxidizing (redox) state is critical for cell viability, activation, proliferation, and organ function. Aerobic organisms have integrated antioxidant systems, which include enzymatic and nonenzymatic antioxidants that are usually effective in blocking harmful effects of ROS. However, in pathological conditions, the antioxidant systems can be overwhelmed. Oxidative stress contributes to many pathological conditions and diseases, including cancer, neurological disorders, atherosclerosis, hypertension, ischemia/perfusion, diabetes, acute respiratory distress syndrome, idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, and asthma. In this review, we summarize the cellular oxidant and antioxidant systems and discuss the cellular effects and mechanisms of the oxidative stress.

Food allergy can result in considerable morbidity, impairment of quality of life, and healthcare expenditure. There is therefore interest in novel strategies for its treatment, particularly food allergen immunotherapy (FA-AIT) through the oral (OIT), sublingual (SLIT), or epicutaneous (EPIT) routes. This Guideline, prepared by the European Academy of Allergy and Clinical Immunology (EAACI) Task Force on Allergen Immunotherapy for IgE-mediated Food Allergy, aims to provide evidence-based recommendations for active treatment of IgE-mediated food allergy with FA-AIT. Immunotherapy relies on the delivery of gradually increasing doses of specific allergen to increase the threshold of reaction while on therapy (also known as desensitization) and ultimately to achieve post-discontinuation effectiveness (also known as tolerance or sustained unresponsiveness). Oral FA-AIT has most frequently been assessed: here, the allergen is either immediately swallowed (OIT) or held under the tongue for a period of time (SLIT). Overall, trials have found substantial benefit for patients undergoing either OIT or SLIT with respect to efficacy during treatment, particularly for cow's milk, hen's egg, and peanut allergies. A benefit post-discontinuation is also suggested, but not confirmed. Adverse events during FA-AIT have been frequently reported, but few subjects discontinue FA-AIT as a result of these. Taking into account the current evidence, FA-AIT should only be performed in research centers or in clinical centers with an extensive experience in FA-AIT. Patients and their families should be provided with information about the use of FA-AIT for IgE-mediated food allergy to allow them to make an informed decision about the therapy.

Background: The European Academy of Allergy and Clinical Immunology (EAACI) is developing Guidelines for Allergen Immunotherapy (AIT) for IgEmediated Food Allergy. To inform the development of clinical recommendations, we sought to critically assess evidence on the effectiveness, safety and cost-effectiveness of AIT in the management of food allergy. Methods: We undertook a systematic review and meta-analysis that involved searching nine international electronic databases for randomized controlled trials (RCTs) and nonrandomized studies (NRS). Eligible studies were independently assessed by two reviewers against predefined eligibility criteria. The quality of studies was assessed using the Cochrane Risk of Bias tool for RCTs and the Cochrane ACROBAT-NRS tool for quasi-RCTs. Random-effects meta-analyses were undertaken, with planned subgroup and sensitivity analyses.

Urticaria is a common disease in children. In contrast to the ease of its diagnosis, etiologic factors are often difficult to determine. In order to study whether differences exist among various forms of urticaria in childhood and whether the patterns of different types of urticaria differ between adults and children, we extensively studied the possible causes of urticaria in children. Fifty-four children (23 girls and 31 boys; ages 1-19 years) with various forms of urticaria were included in the study. In all cases, questions about food allergies, food additive intolerance, drug intake, signs of infection, causes of physical urticaria, insect bites, and personal and family history of atopy were asked. Clinical characteristics of the disease, such as duration, recurrence, and associated angioedema and symptoms of anaphylaxis were also investigated. Detailed laboratory tests, including serologic, autoimmune, and allergic analyses, were conducted to reveal the probable etiologies of urticaria. Of the study patients, 68.5% and 31.5% were diagnosed as having acute and chronic urticaria, respectively. The patient group with chronic urticaria was older and included more boys than the acute group. In the acute urticaria group, infection was the most frequently documented cause (48.6%), followed by drugs (5.4%), and food allergies (2.7%), whereas in chronic urticaria, physical factors were the leading cause (52.94%). The most frequently documented infection was urinary tract infection, followed by serologically determined infections of Chlamydia pneumoniae and Helicobacter pylori. In this study we found indications that infections were frequently associated with urticaria, which suggests that urticaria management should include a survey of certain infectious agents in addition to a detailed history.

Background: Chronic spontaneous urticaria (CSU) in childhood is infrequent, and information about the disease in children is limited. We attempted to investigate its etiologic factors, natural course, and predictors of prognosis. Methods: All children aged ≤18 years followed for CSU during an 8-year period were analyzed retrospectively, and the final outcomes were queried via a telephone interview. Results: One hundred patients (male/female ratio 1.27) with a median age of 9.2 years (range 0.7–17.2) at symptoms onset were evaluated. The median follow-up was 2.5 years (range 0.2–18.1). An autologous serum skin test was positive in 46.7% of the subjects (n = 45), with a female predominance (71.4%) (p = 0.023). In 13.8% of the children, ANA titers were over 1/100. Food allergy (n = 1), thyroid autoantibodies (n = 3), possible collagen disease (n = 1), and drug usage (deferoxamine) (n = 1) were found to be associated factors. Infections could not be confirmed as the cause of CSU. Recovery was seen in 16.5, 38.8, and 50.0% of the children after 12, 36, and 60 months, respectively. Though in multivariate analysis none of the factors, including age, gender, autologous serum skin test positivity, the presence of angioedema, or other allergic diseases, appeared to predict the prognosis, in univariate analysis being female and being older than 10 years of age predicted an unfavorable prognosis. Conclusion: The etiology of CSU in children is mainly related to an autoreactive background, as in adults. CSU has a favorable prognosis, and resolution is seen in half of the children within 5 years. Girls older than 10 years may have an unfavorable prognosis.