Things you can have a look at:
deuterium depleted water (metabolic water tends to be deuterium depleted) that could reduce microbes growth,
hyperosmolarity, that tends to boost the immune system (search NFAT5/TonEBP),
oxytocin and vasopressin which might be involved in immune system and healing. Interestingly, these two hormones tend to bind silver and copper atoms well, while these have antimicrobial effects. Could their production lead to the distribution of these antimicrobial atoms on infection sites?
See some references in the last two research threads:
https://www.reddit.com/r/Dryfasting/comments/afmtwq/research_thread
https://www.reddit.com/r/Dryfasting/comments/g4a5qu/updated_research_thread/