In particular, three autoantibodies, of both IgM and IgG subclasses, were produced in Was−/− mice independently of the treatment: BPI (antimicrobial protein that binds and neutralizes LPS of Gram-negative bacteria) (36), anti-Ku antibody (a rare type of antinuclear antibody typical of myositis) (37), and anti-SRP54 (signal recognition particle involved in targeting secretory proteins to the rough endoplasmic reticulum membrane) (38). Here, SRP54 is linked to myositis disease.