Figure 2

Principal component analysis of the three study groups. The groups consisted of 20 probands with a systemic autoimmune disease (green), their 20 unaffected twins (blue), or 40 unrelated, matched controls (red), respectively. The analysis uses 104 oligo probes that exhibited statistically significant differential gene expression (multiple comparison-adjusted P values (false discovery rate) of less than 0.1) between probands and unrelated, matched controls. C, unrelated, matched control; P, proband; PC, principal component; U, unaffected twin.