Antibody subtypes and estimated titers by SPR.

aThe ratios indicate the agreement between the summed SPR signals from the binding of secondary detection antibodies specific for IgG1, IgG2, IgG3 and IgG4 (numerator) to the initial SPR signal generated by the anti-FVIII antibodies in plasma that bound to the immobilized FVIII (denominator). bMultiple measurements (n) were made when sufficient plasma was available. cStandard deviations are reported for these experiments in parentheses. dND = Not Determined because the low total IgG titer made estimates of ratios and %Ig subtypes unreliable.