[genomer]

I wasn't aware of the variability in thymic involution. I guess most studies focus on averages. If you have links to more information about these outliers I'd be very interested in reading up on them.

The most recent literature that I'm seeing is showing the most pronounced time of thymus involution occurring around puberty, suggesting a programmed switch from a growing to reproductive phase of life.

"Regardless of the seemingly crucial role of the thymus in preserving homeostasis, its involution in humans and other mammals begins in childhood and peaks around puberty, resulting in an almost completely non-functional organ in aging." https://www.sciencedirect.com/science/article/pii/S156816372...

In this light the following makes sense (stopping or suppressing the switch to a reproductive life). "Castrating rodents before puberty or reducing the levels of sex hormones [e.g., by using Lupron, which desensitizes the luteinizing hormone-releasing hormone (LHRH) receptors] can attenuate or markedly recover the involution process in aging mice."

[nextos]

This study presents a gene expression marker for recent thymic emigrants and shows variability increases with age: https://insight.jci.org/articles/view/93739/figure/5

A much older study with different markers shows something similar: https://www.pnas.org/doi/epdf/10.1073/pnas.070061597