When a person has severe lower back pain, doctors often order blood tests for arthritis and a genetic marker called HLAB27. Positive tests often lead to a diagnosis of ankylosing spondylitis, an arthritis of the spine. 

Most doctors think that ankylosing spondylitis is an autoimmune disease in which a person's immunity is so stupid that it attacks and destroys the joints in his back, rather than just doing its job of protecting a person from infection. However, several recent papers show that ankylosing spondylitis may actually be caused by infection. 

One recent paper shows that people who have this condition are more likely to have genital infections with mycoplasma, chlamydia and ureaplasma 

(1). Virtually all patients have changes in their gut similar to those seen in another so-called autoimmune disease called Crohn's disease 

(2). Other evidence of infection is that sufferers often have high blood levels of IGG and IGA antibodies that the body produces to kill Klebsiella bacteria that normally live in the intestines of healthy people (3,4,5,5A) and that the disease appears to be transmissible 

(6). The surface structure of Klebsiella contains 2 molecules similar to that of a genetic marker for ankylosing spondylitis called HLA-B27. When the pain is severe, large amounts of Klebsiella are found in stool samples, and those with ankylosing spondylitis often have intestinal ulcers in the end of the small intestine. A low starch diet that reduces the concentration of klebsiella has been reported to alleviate the back pain 

(7). Another recent study shows that ankylosing spondylitis may be spread from person to person. The next step is to see if long-term treatment with antibiotics, such as doxycycline, azithromycin, metronidazole or a quinolone can be effective in treating ankylosing spondylitis. 

The disease rarely goes away by itself (12). Please check with your doctor.