This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity, Subject name: Pathology
HLA B27 is maximally associated with? 
Select and explain. 
A. Rheumatoid arthritis, B. Ankylosing spondylitis, C. Rieter syndrome, D. Psoriasis
B: Ankylosing spondylitis
Answer: B: Ankylosing spondylitis 
Explanation: Clinical Associations with HLA B27DisorderHLA-B27 (%)Ankylosing spondylitis90Reactive arthritis (Reither's syndrome )40-80Juvenile SpA70Inflammatory bowel disease35-75Psoriatic arthritisWith spondylitisWith peripheral arthritis 5015Undifferentiated SpA70Acute anterior uveitis50Aortic insufficiency, heart block80