PIP and Sjogren syndrome: In the study by Di Giorgi et al., it was confirmed that in the saliva of patients with primary Sjögren’s syndrome (pSjS), as well as in individuals in the preclinical phase of the disease (positive for SSA/Ro antibodies but without clinical symptoms), there are alterations in the expression of MUC5B, prolactin-inducible protein (PIP), cystatin C, and lipocalin-1 [49].