A 40 year old woman has severe, disabling rheumatoid ahritis. Rheumatoid factor is positive. What would a biopsy of the synovium of her knee most likely reveal?
A nearly normal synovium with scattered inflammatory cells A non-proliferative synovitis with abscess formation A non-proliferative synovitis with many neutrophils A proliferative synovitis with many lymphocytes, macrophages, and plasma cells