Human NK-cell repertoires form 5 broad groups according to inhibitory receptor phenotypes. NK-cell repertoires divide into KIR-dominant (left half of figure) and NKG2A-dominant (right half of figure) repertoires. (A) KIR-dominant repertoires further divide into 3, based on the frequencies of receptor-null cells and KIR-KIR coexpression (●). (B) Whereas frequencies of KIR single expression (○) and KIR-KIR coexpression (●) are similar in type 1 repertoires, KIR coexpression is less frequent in type 2 repertoires and even more so in type 3 repertoires. (C,D) NKG2A-dominant repertoires are further divided according to the frequency of receptor-null cells (C). The difference between type 4 (□) and type 5 (■) repertoires is apparent in panel D where the ratio of NKG2A coexpression with KIR against NKG2A single expression is higher in type 4 than type 5 repertoires. (E) Representative profiles of the 5 repertoire types.