“…By four different methods (Jukes & King, 1979; Chang & Casali, 1994; Insel et al , 1995; Davi et al , 1996), the numbers of silent and replacement mutations in the CDR and FR regions of the Ig rearrangement were used to detect the presence of antigen selection. In the CDR:FR ratio method, 14 rearrangements showed a ratio >0·3, suggesting antigen selection (Table I; Chang & Casali, 1994; Varade et al , 1995; Davi et al , 1996; Miranda et al , 1999). In a total of four patients, the R:S mutation ratio was >2·9 or infinity, but in only two of these cases was the CDR/FR mutation ratio also >0·3.…”