system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
To rule out rheumatoid arthritis, most important among the followings is?
assistant
The correct answer is  DR4 is strongly associated with RA(also with Type 1 DM Pemphigus vulgaris).

Other options

HLA-B27 is associated with seronegative spondyloarthropathies (ankylosing spondylitis, Psoriatic arthritis, Reiter’s syndrome, reactive arthritis) and acute anterior uveitis
HLA DR8 is associated with Type 1 DM.
HLA DQ1 is associated with pemphigus vulgaris.