HJB-RBCs and ISCs in asymptomatic and ASS-affected infants. Comparison of %HJB-RBCs (A) and %ISCs (B) at 3 to 6 and 18 months in asymptomatic (n = 22) and ASS infants (n = 7, for whom samples were available for analysis). **P < .005, Wilcoxon test.