MUC5B and peeling skin syndrome: MUC5b output did not correlate significantly with the Xerostomia Inventory score (p = 0.828 and p = 0.296 for patients with pSS and patients treated with radiotherapy respectively) (Fig. 3e), in contrast to protein output which correlated with the Xerostomia Inventory score in pSS (p = 0.023) (Fig. 3f).