A) Control minor salivary gland illustrating acini, ducts and minimal periductal infiltration. H&E, original magnification 10X. B) Extensive mononuclear cell infiltration and tissue disruption in Sjögren’s syndrome MSG lead to compromised secretory function. Periductal lymphoid infiltrate extends into the acini and throughout parenchyma. Original magnification 10X. C) Immunohistochemical staining for CD68 positive macrophages in representative SS MSG indicates myeloid cells in the mononuclear cell infiltrate. 40X. D) Staining for a tissue component of the plasminogen activation system, tissue plasminogen activator (tPA), demonstrates positive staining in regions of inflammatory cell infiltrate and in some ductal cells. E) Limited evidence of tPA staining in noninflamed MSG tissues. F,G) Salivary gland tissue from SS patient with FS of 7 stained for CD68 (F) and tPA (G) showing staining in infiltrate and ducts. H,I) Higher magnification of CD68 (H) and tPA (I) staining from SS patient with FS = 9.5. J,K) SS (FS=10) MSG tissue stained for CD68 macrophages (J) (arrow denotes CD68+ macrophages appearing to invade duct) which are stained with tPA (K, arrow), but ductal cells are also tPA positive (K).