C3 and urinary tract infection: Mutant C3 showed a reduced binding to CD46 led to a decrease in proteolytic inactivation of C3b which may be a part of molecular mechanism of pathogenesis atypical hemolytic uremic syndrome.[7,8] It has also been reported that CD46 enhances the internalization of E coli in urinary tract infection, making chronic urinary tract infection difficult to recover.[9]