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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]

Severe acute respiratory syndrome caused by a novel 2019 coronavirus (SARS-CoV2) represents one of the most studied infectious diseases of today. The number of scientific reports and publications increases exponentially day by day. While the majority of infected subjects are asymptomatic or show mild symptoms, there is an important proportion of patients who requires hospitalization and, sometimes, intensive care. Immune response to novel coronavirus is complex, involves both innate and adaptive immunity, and is biphasic. Significant differences were observed when comparing severe and non-severe patients. Analysis of the reported results from clinical trials clearly show an involvement of specific cellular immunity (predominantly leucopenia, decreased counts of CD3+, CD4+, and CD8+ T lymphocytes, changes of T cell compartment) and the so-called cytokine storm, which is associated with worsening of symptoms and the promotion of lung damage. An interesting finding regarding eosinopenia that can have both diagnostic and prognostic value is reported by some authors. Examination of selected immune parameters could help to identify severe patients with the risk of unfavorable course of the disease, predict the prognosis and recognize improvement in the clinical status. Moreover, detailed analysis of the immune changes could help to select novel prospective therapeutic strategies. [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]

Innumerable articles have tried to solve the “continuing enigma of atopic and nonatopic asthma” but notwithstanding the strenuous efforts to substantiate the few well-known clinico-epidemiologic differences between these two forms of asthma most studies have hitherto generated inconclusive statements. In a recent study based on the review of epidemiologic studies conducted worldwide in unselected populations of children, we documented that the prevalence of atopic asthma (AA) was high in the populations with a high prevalence of atopy. We systematically reviewed 36 articles that studied 48 populations of unselected children and reported prevalence rates for asthma and atopy in the total sample and in the subpopulations. No significant difference was found in the prevalence of asthma cases in the quartiles of childhood populations subdivided for the prevalence of atopy. In addition, atopy did not increase significantly in the subgroups of populations subdivided by asthma quartiles. In both subgroups, however, AA increased with increasing atopy or with increasing asthma (p < 0.001). Using a positive skin-prick test reaction to define cases of asthma as cases of AA is misleading because the prevalence of subjects so defined is heavily influenced by the environmentally generated changes in the prevalence of atopy or asthma. Asthma in a child should be labeled as a case of AA only if skin-prick tests yield a positive reaction and the clinical history documents asthma symptoms triggered by allergen exposure. [ABSTRACT FROM AUTHOR]

Knowing about spontaneous variations in the fractional concentration of exhaled nitric oxide (FENO) could improve monitoring of airway inflammation in asthmatic children. We aimed to assess FENO variations (expiratory flow 50 mL/sec) in subjects maintained in similar environmental conditions. We tested spirometry and FENO in symptom-free asthmatic children (9 corticosteroid-naive, 8 corticosteroid-treated) during a 1-week stay in a countryside sanatorium and in their healthy relatives (n = 12) staying in the immediate neighborhood on summer holiday (total 29 children, M/F:14/15, 5.8-16.8 yrs). Testing sessions were repeated every 12 hours (8:00 am, 8:00 pm) for 2 days and again on day 7. Measurements were defined as reproducible when they agreed with an intraclass correlation coefficient (ICC) above 0.60; deviation from mean differences was assessed by the coefficient of repeatability (CR = 2 SD). Lung function remained constant throughout the week in all groups. Baseline FENO levels in corticosteroid-naive asthmatic children tended to decrease at the end of the week (from 13.9 ppb, 95% CI 12.2-19.1 to 9.2 ppb, 95% CI 5.8-15.9, p = 0.057). No differences were found between nocturnal and diurnal FENO. Within-session reproducibility for two FENO measurements was high (ICC 0.99 in all groups and CR, 0.9 to 1.3 ppb). Between-session FENO reproducibility at 12 hours and 24 hours was still high for each group but decreased markedly after 6 days in corticosteroid-naive asthmatic children (ICC 0.79 and CR 9.6 ppb at 24 hours vs. ICC 0.13 and CR 20.8 ppb after 6 days), whereas it decreased slightly in corticosteroid-treated asthmatics (from ICC 0.89 and CR 3.1 ppb to ICC 0.88 and CR 3.0 ppb) and healthy children (from ICC 0.79 and CR 4.8 ppb to ICC 0.65 and CR 5.7 ppb). In conclusion, in healthy subjects and in asthmatic children receiving therapy with inhaled corticosteroids (but not in corticosteroid-naive subjects), FENO measurements are reproducible across a week. [ABSTRACT FROM AUTHOR]

One of the highly prevalent viral pathogens among children and adults causing infection, clinically presenting as herpes labialis, is herpes simplex virus type 1 (HSV-1). The long-term administration of acyclovir, a standard regimen for therapy against HSV-1 infections, can cause viral resistance against this drug. Therefore, the development of natural drugs with low toxicity that are able to enhance host antiviral defense against HSV infection is needed. β-Glucans represent a type of biologically active molecules possessing antiviral properties. The goal of this study was to investigate the clinical and immunomodulatory effect of β-glucan pleuran (insoluble β-1,3/1,6-D-glucan isolated from Pleurotus ostreatus) based supplements on the duration and intensity of herpes symptoms and on the incidence rate and duration of acute respiratory symptoms and intercurrent diseases in HSV-1 positive patients. Ninety patients were randomised into active and placebo groups. Active treatment with pleuran in systemic application caused a significantly shorter duration of herpes simplex symptoms compared to the placebo group. During the preventive phase (120 days), the duration and severity of respiratory symptoms were lower in the active group compared to the placebo group; however, a significant difference was found only in the case of cough. No significant side effects were observed during both phases of the clinical trial (acute and preventive). Obtained results suggest that the use of pleuran seems to be a promising approach in the treatment of acute HSV-1 with beneficial effect on the respiratory tract symptoms and infections. [ABSTRACT FROM AUTHOR]

Preschool children are particularly susceptible to recurrent upper and lower respiratory tract infections due to their immune immaturity and other contributing factors. Preventing and/or treating children suffering from recurrent respiratory tract infections (RRTIs) is challenging, and it is important to provide more clinical evidence about the safety and efficacy of natural immunomodulating preparations, including β-glucans. The aim of the present study was to assess the incidence of respiratory tract infections (RTIs) in children with a history of RRTIs for a period of 6 months (3 months of pleuran supplementation and 3 months of follow-up) compared with the same period from October to March of the previous year prior to enrolment in the study. A total of 1,030 children with a mean age of 3.49 ± 1.91 years from seven countries were included in this study. The total number of RTIs observed during the study period was significantly lower compared to the same period of the previous year (7.07 ± 2.89 vs. 3.87 ± 3.19; p  < 0.001). Analysis of each type of RTI revealed significant reductions in the mean number and duration of infections for all RTI subtypes compared to the previous year. This study also confirmed the beneficial safety profile of pleuran supplementation. In conclusion, pleuran supplementation represents an interesting and prospective supplement in preventing respiratory infections and reveals new strategies for supporting immune functions in the paediatric population., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2022 Rennerova, Picó Sirvent, Carvajal Roca, Paśnik, Logar, Milošević, Majtan and Jesenak.)

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.