Fig. 4.

Analysis of NAT-neutralising antibody (NAB) in vitro. a Cell-bound NAT mean fluorescence intensity (MFI) on HL60 cells after adding different dilutions of blinded NAB-positive or NAB-negative serum samples. MFI values were compared with those of non-loaded (NO) and maximally loaded (MAX) control cells. b Example standard curves (solid line with error bars) after adding NAB-positive (NAB pos) or NAB-negative (NAB neg) serum samples. c Cell-bound NAT decreases (relative to baseline MFI) over time after the addition of control solution without NAB (solid line with error bars) or different NAB volumes [10 μl and 50 μl]. Dotted line represents the MFI of non-loaded cells. d Free NAT, cell-bound NAT and VLA-4 expression levels in a patient over infusion time who was tested positive for NAB during NAT infusion therapy