HLA B27 has been primarily associated with susceptibility to develop spondyloarthropathies, which are chronic, inflammatory joint diseases. Spondyloarthropathies include ankylosing spondylitis (AS), a subset of psoriatic arthritis, reactive arthritis, arthritis associated with inflammatory bowel disease, and undifferentiated spondyloarthropathy.
I knew all that. But there are over 100 different disorders now being linked to HLA B27, is Lupus one of them. Psoriatic arthritis and inflammatory bowel disease are now considered autoimmune disorders. There have been numerous diseases added recently to the suspected list of autoimmune disorders such as Schizophrenia. In the past HLA B27 was not correlated to autoimmunity but now obviously it is. I am positive for HLA B27 and have Lupus. My sister has autoimmune thyroid disorder and psoriatic arthritis. A brother has ulcerative colitis and years ago had Schizophrenia. I suspect a genetic HLA B27 connection to Lupus but as yet no one seems to have any knowledge.