| It depends on how similar the 'antigens' on the allergens are to antigens on SARS-CoV-2. They're probably not super similar, so they wouldn't help the immune system fight better. Instead, it might do something equally valuable in teaching the immune system to chill-out via increased diversity of Treg cells. It's a big deal in kids because they still have a thymus, and they're training a TON of Tcells. https://www.immunology.org/public-information/bitesized-immu.... "As the name suggests regulatory T cells (also called Tregs) are T cells which have a role in regulating or suppressing other cells in the immune system. Tregs control the immune response to self and foreign particles (antigens) and help prevent autoimmune disease. Tregs produced by a normal thymus are termed ‘natural’. Treg formed by differentiation of naïve T cells outside the thymus, i.e. the periphery, or in cell culture are called ‘adaptive’." In this case, it might be a matter of exposing the immune system to more pathogens so that it doesn't freak out when it sees them: "In medicine, the hygiene hypothesis states that early childhood exposure to particular microorganisms (such as the gut flora and helminth parasites) protects against allergic diseases by contributing to the development of the immune system. In particular, a lack of exposure is thought to lead to defects in the establishment of immune tolerance. The time period for exposure begins in utero and ends at school age." https://en.wikipedia.org/wiki/Hygiene_hypothesis The immune system self-regulates. Otherwise it would constantly be freaking about about every food you eat or every particle in the air you breathe in or whatever. One of the primary issue with coronavirus is the cytokine storm resulting from the immune system freaking out, and one of the most effective front-line treatments is steroids to knock-down the immune system. So, by letting kids sneeze on each other and play in the mud and catch all the colds and stuff, you're allowing their immune system to develop 'tolerance' to benign stuff in the environment. There may be something like that at play here. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7365923/
Tang Y, Liu J, Zhang D, Xu Z, Ji J, Wen C. Cytokine Storm in COVID-19: The Current Evidence and Treatment Strategies. Front Immunol. 2020;11:1708. Published 2020 Jul 10. doi:10.3389/fimmu.2020.01708 "They define that “cytokine storm” is an activation cascade of auto-amplifying cytokine production due to unregulated host immune response to different triggers. The triggers involved infections, malignancy, rheumatic disorders, etc." Yeah, so cytokines are just immune system signaling molecules. For some reason, Coronavirus causes the immune system to completely lose it's shit in some people. So, it's theoretically plausible that the more coronaviruses (common colds) you were exposed to as a kid, the less your immune system will overreact because it's seen something similar before many times. |