The article seems a little confused. We've known for a long time that the immune system affects behaviour (see "sickness behaviour").
If I'm understanding this correctly, the key fact seems to be that that IFN-y is used both as an immune signalling cytokine, as well as being used for communication within the brain.
Oh god, a chord plot. There's a harbinger of bogosity if ever there was one. Still...
Interferon gamma is a pretty interesting part of the IFN cascade. Immune mechanisms control so, so much more than what foreign crap in your body gets attacked. Tumor suppression, clearance of aging adult stem cells, turnover of blood -- without our robust immune systems we, as a species and as mammals, simply would not exist.
The human genome is about 45% repetitive elements, many of them ancient retroviruses that integrated into the germ cells of our primate ancestors. Somewhat amazingly, not only does the innate immune system guard against their mobilization, but also their presence in the major histcompatibility complex (MHC, the "self/nonself" ID card) has seemingly been co-opted to increase the diversity available to the immune system itself. Repeats are used as a trigger to clear stem cells that are past their "sell by" date long before they can turn into cancers, at least as long as certain safeguards are active. Once the safeguards are defeated, it gets grim fast.
The immune system is at least as complicated as the brain. It is the result of eons of evolutionary arms race, and it is both fearsome and glorious.
I must be more cynical than average because all I can think of is how it feels like almost all research done in the last few decades is turning out to be utterly bogus. Replication crisis, and so on.
Actually, UVA is where they found evidence of lymphatics bridging from the meninges, so this likely a related group carrying out experiments they were able to start in advance of the lymphatics publication because, neighbors.
