Baseline MBL levels in donors and recipients stratified by MBL2 coding genotype. A wild-type MBL2 coding region is A and a region with a mutation is O, thus A/A denotes a wild-type homozygote; A/O, a heterozygote; and O/O, a mutation homozygote. (A) Mannan-binding recipient (R) versus donor (D) A/A; Mann-Whitney, P < .001. R versus D A/O; P = NS. (B) C4-deposition recipient (R) versus donor (D) A/A; P < .001. R versus D A/O; P = not significant.