TNF and pulmonary fibrosis: In the same way, CD300c2 enhances high-mobility group box protein-1 (HMGB-1)-induced macrophage activation to produce tumor necrosis factor (TNF), which is a leukocyte chemoattractants, resulting in the accumulation of augmented immune cells, inflammation, and the aggravation of lung fibrosis (Table 1) [60].