PDE-4 inhibitors, glial cell inhibitors for cognition?

I've just recently become interested in PDE-4 inhibitors since learning about Harvard and Tufts neuroscientist Dr. Michael Van ElZakker's work on chronic fatigue: http://hhv-6foundation.org/news/cfs-a-herpesvirus-infection-of-the-vagus-nerve

TL:dr of his hypothesis is that infection of the vagus nerve by neurotropic viruses such as HHV-6 contribute to inflammation by establishing latency in the vagus nerve, and reactivating during periods of stress or illness causing the release of proinflammatory cytokines.

A proposed treatment is PDE-4 inhibiting drugs, such as glial cell inhibitors like lbudilast. This drug is not available in the US, so I'm wondering how I can go about this on my own. I've learned that caffeine is a non selective PDE inhibitor, and is perhaps the most helpful thing for me right now. Kanna/Zembrin seems promising, but I don't see many people using it.

I've seen quite a few posts about PDE inhibitors when searching on this sub, but mostly research papers that I have a hard time understanding. The immune system is not something I know much about.

Any suggestions or anecdotes would be awesome.
If you're interested in more on Van ElZakker's work:

Paper on the…