This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
HLA associated with rhaumatoid ahritis 
Select and explain. 
A. HLA-B27, B. HLA-DR4, C. HLA-CW6, D. HLA-B8
B: HLA-DR4
Answer: B: HLA-DR4 
Explanation: HLA-DR4 (DR4) is an HLA-DR serotype that recognizes the DRB1*04 gene products. The DR4 serogroup is large and has a number of moderate frequency alleles spread over large regions of the worldDR4 is associated with extraaicularrheumatoid ahritis, hydralazine-induced female systemic lupus erythematosus, pemphigoid gestationis, pemphigus foliaceus, obstructive hyperophic cardiomyopathy, IgA nephropathy, 'shared syndrome'-systemic sclerosis/rheumatoid ahritis and polymyalgia rheumatica