Alternate virtual populations exhibit distinct mechanistic patterns that distinguish populations that respond well to rituximab. (A) Mechanistic differences in the VPops were apparent from a heatmap analysis. VPops were ordered by increasing ACR-N response to rituximab. The color indicates the weight on the higher axis bin, since each axis was split into two bins for assigning weights with MAPEL. Darker red implies a higher weight on the higher-valued bin, meaning the activity governed by the axis is generally high in the VPop. (B) Differences were apparent between VPops with greater responses to rituximab and those with less than the mean response. VPops with a mean ACR-N response greater than 48 (white boxes) were contrasted with virtual populations with less than the observed clinical mean response (grey boxes). Interquartile ranges are also depicted by the box widths. The heavy black line shows the median. Mechanistic axes are ordered from the largest difference between the medians at the top of the figure to least differentiated at the bottom of the figure.