Whisker plots of successive platelet counts of the 24 patients with immune thrombocytopenic purpura whose response to rituximab persisted at week 48. The central horizontal bold line is the median; the lower and upper box limits are the 1st and 3rd quartiles, respectively; and the whiskers extend to the most extreme data points, which do not exceed 1.5× the interquartile range of the box.