Expressions of TLR2, TLR4, TLR6, IL-17, and IL-23 in minor salivary glands of patients with SS and disease controls. (a) The expressions of TLR2, TLR4, and TLR6 in the minor salivary glands of patients with SS (upper panel) and disease controls who have sicca symptoms but do not fulfill the classification criteria for SS (lower panel). Hematoxylin and eosin (H&E) staining showed marked infiltration of inflammatory cells in salivary gland tissue of patients with SS (arrow in upper panel). Immunostaining was performed by using specific antibodies in patients with SS (n = 16) and disease controls (n = 5). Cells stained with each antibody are shown in brown. Intense staining of TLR2, TLR4, and TLR6 is observed in the ductal epithelial cells and infiltrating mononuclear cells in patients with SS, whereas isotype control did not show any immunoreactivity. (b) The labial salivary gland specimens were divided according to the grade (approximately 0 to 4) of lymphocytic infiltration (see Materials and methods). The cells showing positive staining of TLRs were enumerated visually at higher magnification (projected on a screen) by four individuals, and the mean values are presented in the form of a histogram. *P < 0.05, **P < 0.01. (c) Peripheral blood mononuclear cells were isolated from patients with SS (n = 5) and healthy controls (n = 5). The expressions of TLR2, TLR4, and TLR6 mRNA were evaluated by reverse transcription-polymerase chain reaction. *P < 0.05, **P < 0.01 compared with healthy controls. (d) IL-17 and IL-23 are highly expressed in the infiltrating mononuclear cells. Ductal epithelial cells are variably positive for IL-17 and IL-23. Expressions of IL-17 and IL-23 in the disease controls are quite weak in comparison with that in patients with SS. (e) Serum levels of IL-17, IL-23, and IL-6 were determined by enzyme-linked immunosorbent assay in patients with SS (n = 40) and healthy controls (n = 20). *P < 0.05, **P < 0.01 compared with healthy controls. IL, interleukin; SS, Sjögren's syndrome; TLR, Toll-like receptor.