Medicinal cannabis can be helpful for reducing the discomfort of chronic pain in autoimmune inflammatory conditions like Ankylosing Spondylitis. Whole plant preparations are often beneficial for this type of chronic pain. I would suggest that any cannabis preparation used for relief of discomfort in Ankylosing Spondylitis be rich in CBD, as there is laboratory evidence that this cannabinoid can play a role in calming the immune/inflammatory cascade that causes the spondylitis. One easy way to address this is with vape pens, which are available in a variety of CBD:THC ratios. I would start with 1:1 and go from there.