Genotyping of the FcγRIIa, FcγRIIIa, GM, and KM alleles from 777 participants in a randomized trial of recombinant adenovirus HIV-1 vaccine revealed epistatic involvement of several allotypes in the acquisition of HIV infection: KM1/3-GM3/17 in Caucasians (p = 0.0246), KM1/3-GM5/21 (p = 0.0016) in all participants, and GM23+/–FcγRIIIa (p = 0.0060; p = 0.0085) in all participants (125, 126). Here, FCGR3A is linked to HIV infectious disease.