Figure 2

Unsupervised hierarchical clustering of 57 samples based on microarray expression levels of the 81 differentially expressed genes between spondyloarthritis (SpA) patients and controls. Each time point is color-coded (baseline (H0): blue, 6 h (H6): red, 24 h (H24): green). Samples are clustered on the horizontal axis (top row: SpA patients, bottom row: healthy controls), with the length on the vertical axis representing the degree of correlation between samples.