TNF and amyotrophic lateral sclerosis: While aforementioned studies were carried out on blood monocytes, a recent study observed that ALS monocytes-derived macrophages had increased IL-6 and TNFα secretion levels when activated toward a pro-inflammatory state, suggesting that blood monocyte-derived macrophages kept at least some of their in vivo characteristic defects when in culture (Du et al., 2020).