Nodules are associated with a positive RF (rheumatoid factor) titer and severe erosive arthritis.

Discussion The role of cellular immunity (Th1) in inflammatory bone loss such as that seen in osteomyelitis and erosive arthritis remains unclear.

Future studies in this area are needed to better understand how T cells producing both IFN-γ and RANKL mediate immunity and bone resorption, and to better elucidate their role in the pathogenesis of diseases such as osteomyelitis and erosive arthritis.