Ig‐producing immunocytes and epithelial expression of secretory component (SC) and HLA‐DR were evaluated by two‐colour immunofluorescence staining in 10 normal and 20 inflamed salivary glands; the latter included specimens from 10 patients with obstructive sialadenitis and 10 with Sjögren's syndrome (SS), Epithelium adjacent to T‐cell infiltrates showed extensive co‐expression of SC and HLA‐DR, suggesting that leucocyte‐derived cytokines were responsible for this concurrent up‐regulation. Clusters (>2 positive cells) of IgA‐producing cells were spatially related to DR‐positive ducts. The possibility is discussed that DR‐expressing epithelium contributes to local terminal differentiation of IgA‐producing plasma cells. A cytokine‐mediated up‐regulation of SC that simultaneously increases the transport capacity for polymeric IgA would constitute an efficient enhancement of secretory immunity