IL6 and systemic lupus erythematosus: The release of IL-6 from macrophages stimulated for 4 h with 1 μg/ml LPS was significantly higher in SLE patients vs. HC (SLE-NS vs. HC: 1172 ± 74.25 vs. 339.9 ± 41.37, p < 0.0001; SLE-S vs. HC = 728.8 ± 101.2 vs. 339.9 ± 41.37, p = 0.002) and in patients without serositis vs. patients with serositis (SLE-NS vs. SLE-S, p = 0.001) (Figure 4B).