Threshold hypothesis of osteoclast activation

Osteoclast activation is assumed to occur only after passing a putative threshold. Anti-TNF therapy may ideally lead to total inhibition of bioactive TNF. In other patients, anti-TNF therapy may reduce TNF activity below the threshold of osteoclast activation; these patients may continue having signs and symptoms of rheumatoid arthritis. In yet another group of patients, the TNF activity may be reduced, but not to a level that goes below the threshold of osteoclast activation; in these patients, there will be more inflammation than in (c) and some residual destruction – in relation to other therapies, such as methotrexate, the destruction will be significantly less at a similar level of inflammatory signs and symptoms of rheumatoid arthritis [79]. CDAI, Clinical Disease Activity Index; CRP, C-reactive protein.Copyright information:Taken from "The need for prognosticators in rheumatoid arthritis. Biological and clinical markers: where are we now?"http://arthritis-research.com/content/10/3/208Arthritis Research & Therapy 2008;10(3):208-208.Published online 29 May 2008PMCID:PMC2483438.