C5AR1 and hyperinsulinemic hypoglycemia, familial, 4: Inhibition or deficiency of other complement components have also been demonstrated to be effective in ameliorating injury, including inhibition of C1 by C1-inhibitor (C1-INH) [17], C4 deficiency or inhibition by C4 antibody [18], C5aR blockade [19], and factor B deficiency [20] or inhibition by factor B antibody [21].