Like in the expression of IL-1β, both the phase (p<0.05) and the amplitude (p<0.05) in TNF-α expression were different between the cells derived from RA and OA synovium (Figure 4) confirming the near absent and misaligned self-sustained rhythmic expression of pro-inflammatory cytokines in RA cells. The gene discussed is IL1B; the disease is rheumatoid arthritis.