<prompt> To rule out rheumatoid arthritis, most important among the followings is?HLA DR8HLA DQ1HLA B27HLA DR4  <response>: DR4 is strongly associated with RAalso with Type 1 DM Pemphigus vulgaris.Other optionsHLA-B27 is associated with seronegative spondyloarthropathies ankylosing spondylitis, Psoriatic arthritis, Reiters syndrome, reactive arthritis and acute anterior uveitisHLA DR8 is associated with Type 1 DM.HLA DQ1 is associated with pemphigus vulgaris. 