Fig. 4.

The inter-individual and inter-sample type variation in 52 pre-selected proteins is represented in heatmap form and reordered by hierarchical cluster analysis revealing distinguishing expression patterns. Each patient sample is represented by a single numbered column; plasma (Pl, blue) and synovial fluid (Sy, red). 30 of the proteins consistently overexpressed at twofold higher levels than in the corresponding fluid are highlighted (by *). The location of spots from the comparative heatmap is shown in Fig. 1. Observed arbitrary clusters of co-regulated proteins (C1 and C2) fluid ‘specific’ expression patterns (C3 and C4) are indicated. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)