The potential properties of such complexes suggested by studies with targeted deficiencies in C1q, MBL, or secreted IgM, which each have impaired control of inflammatory responses, and in some cases are predisposed to the development of autoimmune disease (Botto et al., 1998; Boes et al., 2000; Ehrenstein et al., 2000; Stuart et al., 2005). Here, MBL2 is linked to autoimmune disease.