In patients with established pSS and decreased salivary flow (i.e. both patients with high focus/low flow and low focus/low flow), proteomics analysis showed a considerable reduction of the normal constituent of saliva (i.e. PRPs, cystatins, GCDFP15/PIP, carboanhydrase VI) directly correlated to the impairment of salivary flow and to the salivary gland damage. Here, PIP is linked to peeling skin syndrome.