They do provoke an immune response thats why some people get paranoid when they smoke weed, its the body freaking out and getting a massive histamine overload, not anaphylactic but still a stress response.

Everyone ive met who gets paranoid from weed will get hives if you rub fresh ground dry weed really hard into their inner forearm skin, while others who dont get paranoid from smoking do not get hives.

Anti-histamines make you sleepy and relaxed, the opposite is true, just straight up histamines make you amped up and anxious.