Dehydroepiandrosterone (DHEA) and its sulfated form dehydroepiandrosterone sulfate (DHEAS) are the most abundant circulating steroid hormones in humans. In animal studies, their low levels have been associated with age-related involuntary changes, including reduced lifespan. Extrapolation of animal data to humans turned DHEA into a 'superhormone' and an 'anti-aging' panacea. It has been aggressively marketed and sold in large quantities as a dietary supplement. Recent double-blind, placebo-controlled human studies provided evidence to support some of these claims. In the elderly, DHEA exerts an immunomodulatory action, increasing the number of monocytes, T cells expressing T-cell receptor gamma/delta (TCRγδ) and natural killer (NK) cells. It improves physical and psychological well-being, muscle strength and bone density, and reduces body fat and age-related skin atrophy stimulating procollagen/sebum production. In adrenal insufficiency, DHEA restores DHEA/DHEAS and androstenedione levels, reduces total cholesterol, improves well-being, sexual satisfaction and insulin sensitivity, and prevents loss of bone mineral density. Normal levels of CD4+CD25(hi) and FoxP3 (forkhead box P3) are restored. In systemic lupus erythematosus, DHEA is steroid-sparing. In an unblinded study, it induced remission in the majority of patients with inflammatory bowel disease. DHEA modulates cardiovascular signalling pathways and exerts an anti-inflammatory, vasorelaxant and anti-remodelling effect. Its low levels correlate with increased cardiovascular disease and all-cause mortality. DHEA/DHEAS appear protective in asthma and allergy. It attenuates T helper 2 allergic inflammation, and reduces eosinophilia and airway hyperreactivity. Low levels of DHEAS accompany adrenal suppression. It could be used to screen for the side effects of steroids. In women, DHEA improves sexual satisfaction, fertility and age-related vaginal atrophy. Many factors are responsible for the inconsistent/negative results of some studies. Overreliance on animal models (DHEA is essentially a human molecule), different dosing protocols with non-pharmacological doses often unachievable in humans, rapid metabolism of DHEA, co-morbidities and organ-specific differences render data interpretation difficult. Nevertheless, a growing body of evidence supports the notion that DHEA is not just an overrated dietary supplement but a useful drug for some, but not all, human diseases. Large-scale randomised controlled trials are needed to fine-tune the indications and optimal dosing protocols before DHEA enters routine clinical practice.

Atopic disorders are a major global health problem. The prevalence of asthma, allergic rhinitis and atopic dermatitis has been increasing over the last four decades, both in the industrialized and developing countries. It seems to be related to changes in the social structure, increasing industrialization, pollution and dietary changes. Many hypotheses link the allergy epidemic to stringent hygiene, dominance of a westernized lifestyle and an accelerated pace of life. Dietary antioxidants, lipids, sodium, vitamin D seem also to be implicated. We endeavour to review the most relevant theories with a special emphasis on the hygiene, antioxidative, lipid and air pollution hypotheses. It is however important to note that none of them explains all the aspects of unprecedented rise in the prevalence of allergic disorders. A complex interplay between host's immune response, invading pathogens, diversity of environmental factors and genetic background seems to be of a particular importance. Current allergy epidemic is multifactorial and basic and epidemiologic studies are warranted to further our understanding of this phenomenon.

According to the World Health Organization by the 27 March 2021, there have been 125 781 957 confirmed cases of COVID-19 (SARS-CoV-2), including 2,759,432 deaths. 1 COVID-19-related mortality is substantial (2% overall) and higher in high-risk individuals (>10%).Current treatment options are limited. Trials and real-life experience confirm that COVID-19 vaccines drastically reduce the severity of COVID infections, prevent deaths and curb the spread of the pandemic. 2 As of

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