Identification of S100A9 as a marker of disease activity.

<p>The protein patterns among the PSC and choledocholithiasis (control) patients were compared. Intensities of 25 spots uniquely identified by mass spectrometry were measured using densitometry. The spot resembling S100A9 was markedly upregulated in the PSC patients with high activity (<b>B</b>) compared to those with low activity (<b>A</b>). Circled spots: haemoglobin (red), S100A9 (yellow), serum proteins (black), pancreatic enzymes (green), and others (blue). An evaluation of the relative amount of S100A9 in the spots demonstrated a clear upregulation of S100A9 in the PSC patients (<b>C</b>). Subgroup analyses of the PSC patients performed according to disease activity revealed a distinct increase in S100A9 in the PSC patients with high disease activity relative to those with low disease activity (<b>D</b>). The PSC patients were also stratified by their Mayo risk scores. (n: control = 6; PSC = 18; low MRS = 13; intermediate MRS = 5; low endoscopic = 12; high endoscopic = 6). The total S100 levels were significantly elevated in the PSC patients PSC (<b>F</b>) (*p<0.05; **p<0.005). The RT-PCR analyses of the brush cytology samples demonstrated marked upregulation of S100A9 expression (n = 8, 4 in the low activity group and 4 in the high activity group; p<0.05) (<b>G</b>).The brush cytology from the patients with unclear strictures demonstrated corresponding cytological findings. The cytology from a patient with low disease activity showed regular epithelial cells (arrowheads) (<b>H</b>), whereas the cytology from a patient with high disease activity showed leukocyte infiltrate (arrows) and altered epithelial cells (<b>I</b>).