LAIR1 and systemic lupus erythematosus: It is conceivable that in SLE patients would be present the auto-antigen(s) which is responsible for the disease, thus the observed downregulation of LAIR1 found in SLE patients and the strong increment in CD20+LAIR1− B cell fraction in a subgroup of patients would be linked to an in vivo downregulation of LAIR1 upon B cell activation.