Plasma cell populations in labial salivary glands from patients with and without Sjögren's syndrome.

Plasma cells expressing IgG, IgA and IgM were quantified in labial salivary glands from patients with Sjögren's syndrome (n = 25) and compared with glands from patients with a variety of systemic diseases (n = 32) and normal individuals (n = 15). Based on qualitative and quantitative analysis, glands from the systemic disease group were divided into normal histology (n = 24) and non-specific inflammation (n = 8) groups. There were no significant differences in cell densities or Ig class proportions between histologically normal glands from patients and those from normal volunteers. Total immunocyte densities were significantly increased in sialadenitis (P < 0.025) and Sjögren's syndrome (P < 0.001) compared with normal histology glands. In both the sialadenitis and Sjögren's syndrome groups there were significant increases in IgG and IgM cell densities (IgG, P < 0.006; IgM, P < 0.001) and proportions (IgG, P < 0.05; IgM, P < 0.001). There were no significant differences in immunocyte densities or proportions between the sialadenitis and Sjögren's syndrome groups except for a lower percentage proportion of IgA cells in the latter (P < 0.038). In all groups the total and individual Ig-class cell densities showed significant positive correlations with extent of leucocyte infiltration (P < 0.01) and negative correlations between IgA and IgG and/or IgM cell proportions. Analysis of the plasma cell data alone and in combination with quantifiable histological parameters failed to yield specific or sensitive diagnostic information. The results suggest that changes in glandular plasma cell populations in Sjögren's syndrome are non-specific.