LF plays an important role in host defense, upon its release from the neutrophil (26). LF also enhances natural killer cell activity in immune defense (135) and can restrict the entry of the virus into host cells during infection. As part of the host's inflammatory response, leucocytes, including neutrophils, release LF from their granules, where it is normally stored. Activated neutrophils also release chromatin fibers, known as neutrophil extracellular traps (NETs), which trap and kill, amongst others, bacteria (1, 136). These NETs likewise modulate both acute and chronic inflammation (137, 138). NETs are also found in various autoimmune conditions such as rheumatoid arthritis, systemic lupus erythematosus (139, 140). Interestingly, 106 human neutrophils can release 15 μg of LF (26). In addition to DNA and histones, NET fibers contain extranuclear proteins and proteins such as elastase, myeloperoxidase (MPO), and LF (141). LF may also serve as an intrinsic inhibitor of NETs release into the circulation, and may therefore be central in controlling NETs release (1). See Figure 3.