Box and whisker plot for the expression of the CD19+ up-regulated gene set in each of the 3 empiric illness classes. Boxes indicate the lower quartile, median and upper quartile values. Whiskers are located at extreme values within 1.5 times the inter-quartile range from the ends of each box. Outliers are displayed with a red '+'. The plot is annotated with the null probability for the difference in median expression between the NF and CFS subject groups.