TH1 Cytokines are Produced in Labial Salivary Glands in Sjögren's Syndrome, but also in Healthy Individuals

The aim of the present study was to assess the T cell cytokines IFN-γ, IL-2, IL-4 and IL-5 in labial salivary glands ( LSG ) in Sjogren's syndrome (SS) and healthy controls using RT-PCR and immunohistochemistry. IFN-γ is always or almost always produced in SS and in healthy controls. IL-2 was also found in some samples, but IL-4 and IL-5 were not. Less than 2% of all inflammatory mononuclear cells contained immuoreactive IFN-γ or IL-2. Cytokine mRNA profile in LSGs in SS is skewed towards a T H 1 pattern. The classical T H 1 cytokines are also produced in normal glands, even in the absence of foci. T H 1 type response may play an active role as part of the mucosal associated lymphoid tissue/ responses, perhaps in prevention of reactivation of latent viruses. This may also make the exocrine glands a locus minoris resistentiae when the self tolerance is broken.