Background: Sjögren's syndrome (SS) is an autoimmune chronic inflammatory disorder affecting the salivary and lacrimal glands. The aim of this study was to explore immunophenotypic features of chronic inflammatory reactions in the minor salivary glands in patients with primary SS (pSS).
Methods: Formalin-fixed, paraffin-embedded labial minor salivary gland tissue sections from randomly selected patients with pSS (n = 60) were investigated for the expression of CD21, CD23, CD35 and IgD by immunohistochemistry.
Results: Based on the distribution and staining pattern of CD21, CD23, CD35 and IgD in lymphoid aggregates, several stages of chronic inflammatory reactions were observed. In 12/60 (20%) patients, lymphoid infiltrates with germinal centre (GC)-like features such as extensive networks of CD21-, CD23- and CD35-positive cells were observed in the minor salivary gland tissue. Smaller networks and /or focal infiltrates with scattered CD21(+), CD23(+) and CD35(+) cells were observed in the remaining 48/60 (80 %) cases. When dividing patients according to the presence (GC+) or the absence (GC-) of GC in the minor salivary glands, the mean focus score was significantly higher in the GC+ patients (P < 0.05). Double staining of the minor salivary glands revealed focal infiltrates with follicular dentritic cell networks and B cells resembling normal GCs in tonsillar tissue.
Conclusion: A particular cellular profile was demonstrated in a sub-group of patients with pSS and could be linked to serological aberrations. These findings warrant further prospective studies.