HLA-DRB1 and rheumatoid arthritis: In a separate Caucasian RA cohort, haplotypes containing HLA-DRB1*04:04 and HLA-DRB1*01:01, along with six single-nucleotide polymorphisms in the lymphotoxin alpha and tumor necrosis factor DNA-coding region, correlated strongly with therapeutic response in early RA (66).