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The SARS-CoV-2 pandemic has indeed been one of the most significant problems facing the world in the last decade. It has affected (directly or indirectly) the entire population and all age groups. Children have accounted for 1.7% to 2% of the diagnosed cases of COVID-19. COVID-19 in children is usually associated with a mild course of the disease and a better survival rate than in adults. In this review, we investigate the different mechanisms which underlie this observation. Generally, we can say that the innate immune response of children is strong because they have a trained immunity, allowing the early control of infection at the site of entry. Suppressed adaptive immunity and a dysfunctional innate immune response is seen in adult patients with severe infections but not in children. This may relate to immunosenescence in the elderly. Another proposed factor is the different receptors for SARS-CoV-2 and their differences in expression between these age groups. In infants and toddlers, effective immune response to viral particles can be modulated by the pre-existing non-specific effect of live attenuated vaccines on innate immunity and vitamin D prophylaxis. However, all the proposed mechanisms require verification in larger cohorts of patients. Our knowledge about SARS-CoV-2 is still developing. [ABSTRACT FROM AUTHOR]

Recurrent respiratory tract infections (RRTIs) present a very important problem in paediatric praxis. As true immunodeficiencies are rare, one of the most important factors assumed to contribute to increased respiratory morbidity is atopy. Several preparations of natural origin have been used for the prevention of RRTIs, and some of the most effective immunomodulators are biologically active polysaccharides - e.g. ß-glucans. In our randomised, double-blind, placebo-controlled study, we investigated the prevalence of atopy in a group of children with RRTIs and the potential anti-allergic effect of pleuran (ß-glucan isolated from Pleurotus ostreatus) on basic laboratory markers of allergic inflammation. We confirmed that atopy may be an important factor contributing to the increased respiratory morbidity in children with RRTIs. The active treatment with pleuran resulted in a significant reduction of peripheral blood eosinophilia and stabilised the levels of total IgE in serum. This was more evident in atopic subjects. Pleuran showed a potential anti-allergic effect. This previously non-described effect could expand the application of this natural immunomodulator also as a complementary adjuvant therapy in allergic patients. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ultraviolet (UV) radiation, particularly UVB radiation, is one of the major risk factors for environmentally influenced skin disorders. β-D-glucans represent a class of natural compounds, and their use in the cosmetic and pharmaceutical industries is increasing. The goal of this study was to evaluate the soothing effect of a β-glucan pleuran-based cream against skin alterations caused by a solar simulator (UVA/UVB exposure) and to assess the efficacy of the cream after 30 days of use on the face and body in 20 human subjects with all skin types (sensitive, atopic, and normal) and phototypes II and III. The study consisted of the following two tests: one short term and one long term. In the short-term test, the minimal erythemal dose was determined by applying a pattern of radiation consisting of six doses of UVA+UVB radiation and was visually assessed 24 h after UV exposure. In the long-term test, pleuran-based cream was applied twice a day on both the nonirradiated face and body of all subjects for a 30-day period. Subsequently, noninvasive techniques such as skin moisture, skin brightness/radiance, skin elasticity, and total antioxidant capability were utilized. The pleuran-based cream had a positive effect on erythema induced by UV exposure, with visibly reduced erythema compared to the control area. Moreover, long-term use of the cream over a 30-day period improved all monitored skin parameters on the face and body. In summary, these results indicate that β-glucans can be used as an active ingredient with UV light-protective and soothing properties after UV exposure for the cosmetic and pharmaceutical industries.

In this paper we shortly discuss epidemiological data on the relationship between asthma and atopy according to recent personal and literature epidemiological publications. The coexistence in several subjects of asthma (and of other "atopic" diseases) and IgE hyperproduction generated the dogma that these two biological conditions are mainly genetic in origin and are linked by a strong casual relationship. In the last decades atopy increased at 5-10 % annual rate and at present atopy prevalence, although variable in different countries, reaches somewhere the prevalence of more than 60 %. Similarly, asthma prevalence increased in the last decades, especially so in western and English speaking countries, reaching in certain countries prevalence values higher than 40 %. For these reasons, although certainly dependent on a genetic predisposition, atopy and asthma can nowadays be considered to be largely determined by environmental factors. Moreover, the analysis of epidemiological data derived from studies conducted worldwide, showed that the prevalence of the two conditions were clearly not correlated so that in certain countries with a 50-60% prevalence of atopy asthma prevalence is lower than 2-6 %, while in other countries asthma prevalence is double than atopy prevalence. Further, in countries with high atopy, the prevalence this conditions is high both in asthmatics and in normal subjects and in the places where asthma prevalence reaches high levels this condition is high both in atopic and non atopic people. In conclusion, epidemiological data show that environmental factors affecting asthma prevalence are different from those affecting atopy prevalence and that subjects bearing one of the two conditions don't show any preferential tendency to develop the other one. From aetiological and pathogenetic point of view asthma and atopy appear to be independent conditions We therefore believe that the association between asthma and atopy demonstrated in almost all the "population studies" (atopy prevalence has always been found 20-30 % higher in asthmatics than in non asthmatic subjects) doesn't prove the existence of a "causal" relationship between the two conditions: this could be a kind of association without causative meaning as is the association between blond hair and blue eyes which in no way can be considered a prove that one of the two conditions is the cause of the other.