A role for TNF in crystal induced arthritis has been suggested by the demonstration that exposure of mononuclear and synovial cells to either monosodium urate monohydrate (MSUM) or CPPD crystals leads to TNF-α production that is able to stimulate the migration of neutrophils from circulating blood into the joints [17, 18]. The gene discussed is TNF; the disease is arthritic joint disease.