Platelet aggregation triggered by mIgG₁antiplatelet CD9 antibody Alb-6. Lag time in minutes (mean ± SEM) is shown for platelets from the variant individual and the three wild-type FcγRIIA genotypes. *Lag time is significantly shorter (P < .05) for K/Q¹²⁷, R/R¹³¹ and Q/Q¹²⁷, R/R¹³¹ than for Q/Q¹²⁷, H/R¹³¹ and Q/Q¹²⁷, H/H¹³¹.