Buhner wrote that taking Astragalus when you have chronic Lyme could cause an autoimmune type response.
“The reason for not recommending it is that astragalus raises the parts of the immune system that are overactivated in chronic lyme. Those parts of the immune system are highly effective against lyme early on and help prevent or reduce the disease but if they are low to begin with and you are infected the infection can spread more easily. After awhile the immune system does ratchet up those parts to attack the lyme bacteria but by then the spirochete has altered itself and is no longer very affected by them, those parts of the immune system then begin to cause some of the lyme symptoms people have making the disease a kind of autoimmune problem. ”
http://buhnerhealinglyme.com/herbs/astragalus-contraindicated/But people have taken it with chronic Lyme with no issues.