PBMC from healthy individuals and from RA patients were stimulated with various B-cell and T-cell mitogens, superantigen, and TNF-α (10–100 ng/ml lipopolysaccharide, 0.5–5 μg/ml Concanavalin A, 10–100 ng/ml TNF-α, 10–100 ng/ml TSST-1, 0.5–5 μg/ml PHA) for 6–48 hours. This evidence concerns the gene TNF and rheumatoid arthritis.