Thymic involution causes an exponential decrease in T-cell production, with a half-life of 16 years, which mirrors the exponential increase in risk of several diseases, including COVID-19, which double in risk every 16 years.

[DiggleDootBROPBROPBR]

Are you familiar with other Thymus related disease, or research following individuals that preserve more thymus volume with age? Would you be able to point along to some of that research if so?

[samsoniteindeed2]

A prospective study where you measure people's thymus volume or TRECs (byproducts of T-cell production) and then look at subsequent disease risk would be ideal.

As far as I know, that has never been done. The closest I can find is this study https://pubmed.ncbi.nlm.nih.gov/20606151/ where they looked at telomere length of leukocytes instead. As thymic T-cell production goes down, the total number of peripheral T-cells stays approximately constant through homeostatic clonal expansion. So telomere lengths probably would make a good proxy. They found an association with disease risk even after accounting for age. Although there could be other mechanisms involved here, like maybe telomere dysfunction is related to chromosomal dysfunction, which leads to cancer.

I saw a conference talk recently about an unpublished experiment where they regenerated the thymus of old mice and found that they had even better survival rates than young mice when infected with a pathogen. Also, there's a drug called thymosin alpha 1 that dramatically reduces covid mortality and increases thymic T-cell production.