SP1 and peeling skin syndrome: A study that detected tissue-specific antibodies in pSS reported that serum anti-CA-IV and parotid secretory protein (PSP) antibodies were more frequently positive in patients with pSS than in HCs, and salivary anti-CA-IV, salivary protein (SP)-1 and PSP IgG were higher in patients with pSS than in HCs [54].