The presence and distribution of 7 cytokines was examined immunohistologically in labial salivary gland (LSG) specimens from patients with primary Sjögren's syndrome (SS) and control subjects. The cytokines interleukin (IL)-1 beta IL-6, tumor necrosis factor (TNF) alpha and interferon (IFN) gamma were identified in defined parts of LSG from patients but not in the corresponding parts of control glands: (a) LSG acinar epithelium expressed IL-1 beta, (b) blood vessels located in both normal LSG stroma and within lymphocytic infiltrates expressed IL-1 beta, IL-6 and IFN gamma, and (c) lymphocytic infiltrates expressed IL-1 beta, IL-6 and TNF alpha. All four cytokines were expressed by salivary ducts within both patient and control specimens, but with generally greater intensity in patients. IL-1 alpha, IL-4 and TNF beta (lymphotoxin) could not be detected in any of the specimens from patients or controls. The locations of cytokines in LSG suggests possible mechanisms of immunologically mediated parenchymal damage in primary SS.