PROS1 and peeling skin syndrome: The study investigated differences in low molecular weight salivary proteins (1-10 kDa) in pSS patients compared to HC. Seven m/z (mass-to-charge) (m/z 1068.1, 1196.2, 1738.4, 3375.3, 3429.3, 3449.7 and 3490.6 ratio peaks with significant differences between the 2 groups with 5 peptides being up-regulated and 2 down-regulated in the pSS patients compared to HC subjects. In the validation phase, 4 out of 5 pSS patients were diagnosed as pSS, and 4 of the 5 healthy controls were diagnosed as HC.