Salivary epidermal growth factor (EGF) in Sjögren's syndrome: association between salivary EGF levels and the severity of intraoral manifestations

Abstract

  Sjögren's syndrome (SS) is a chronic inflammatory autoimmune disease characterized by lymphocytic infiltration of the exocrine glands, especially the salivary and lacrimal glands. As a result of salivary gland dysfunction, most patients with SS have xerostomia, related to a reduced salivary flow rate. In addition to the discomfort due to xerostomia, dry mouth can cause various intraoral manifestations such as refractory stomatitis, ulcer and atrophic changes in the oral mucosa and tongue, and patients' quality of life (QOL) is impaired severely. These manifestations are believed to be caused mainly by a decrease in the clearance in the oral cavity owing to hyposalivation. However, since saliva has several beneficial physiological effects on the intraoral environment, qualitative changes in sialochemistry should also be considered a cause of the refractory intraoral manifestations in SS. Salivary epidermal growth factor (EGF) is considered an important cytoprotective factor against injuries, and it contributes to wound healing in the oral cavity. We evaluated changes in salivary EGF levels and assessed the association between salivary EGF levels and the severity of intraoral manifestations in SS patients. The results showed that the salivary EGF levels decreased with the progression of SS, and this deterioration in saliva quality as well as hyposalivation could play a role in the pathogenesis of refractory intraoral manifestations in SS patients. Our findings provide new target for therapeutic intervention in SS.