Fig. 1.

Alloimmunization rates and rs660 genotype. A Frequency of alloimmunization in patients that received first transfusion before (closed bars) or after (open bars) the age of 5 (or all ages – shaded bars) in the function of rs660 genotype. The differences between alloimmunization rates in patients first transfused before or after the age of 5 were significant (Fisher's exact test) for T/T (p = 0.043), but not for C/T (p = 1.00) genotype, or for both groups together (0.195). Exact patient numbers are given above the bars. B Mean (± SE) SCD severity scores in patients with C/T or T/T genotype. Scores represent cumulative score B, calculated as described C Frequency of hydroxyurea treatment in patients with C/T or T/T genotype.