In the experiment shown in Figure 1, (M-CSF)-M2 cells were stimulated with a mixture (1:1) of human LTF (hLTF) and LTF-specific IgG autoantibodies (affinity purified from RA sera) for 18 h followed by quantitation of TNFα, IL-1β, IL-6, and IL-10 in the culture supernatant. This evidence concerns the gene CSF1 and rheumatoid arthritis.