Figure 2

PCA of murine (A) and human (B) nephritic parameters (68). PCA biplots aim to optimally display variances and not correlations. The angles between the various biplot axes indicate the correlations between the parameters (shown as arrows). Similarly, the position of the samples of individual mice (shown as the signs 1, 2 and 3 for group 1–3 mice) relative to the arrows, indicates which variable(s) have had the largest effect on disease progression. The result of the biplots demonstrates that groups emerging from this analysis perfectly correlated with the groups of BW mice, as defined by Licht et al. (20), defined as prenephritic BW mice (group 1), BW mice with deposits of EDSs in the mesangial matrix (group 2) or with deposits in the GBM (group 3). In (B), a similar biplot was generated for the human data, where the three patients with low DNaseI expression levels are included. The most striking observation in these biplots is that the DNaseI vector points away from the individuals with severe lupus nephritis (to the left in the biplots), demonstrating that loss of DNaseI correlates inversely with disease progression, whereas MMP-2, MMP-9, TLRs and EDSs associated with GBM are clustered and points at the most severely diseased murine and human individuals, in harmony with statistical analyses demonstrated by Thiyagarajan et al. (68). This figure is modified from Thiyagarajan et al. (68).