Sjögren’s disease patients with no hyposalivation and with short oral dryness complaints contain more T cells in salivary gland parenchyma

Abstract

Abstract Objective Ninety-five percent of patients with the Sjögren’s disease (SjD) experience hyposalivation, which studies suggest is not strongly associated with salivary gland (SG) lymphocytic infiltration. Resident CD8+ T cells have recently been associated with SG pathology in SjD. We investigated the relationship between CD4+ T cell, CD8+ T cell, NK cell and macrophages number in the parenchyma of SjD patient SGs, and SG dysfunction. Methods Quantification of CD4+ T cells, CD8+ T cells, NK cells and macrophages was performed using immunohistochemistry in parenchyma areas of SSA+ SjD patient parotid SGs with normal or reduced unstimulated and stimulated whole saliva (UWS, SWS), and different durations of subjective dryness complaints. Non-SjD sicca patients were included as controls. Results We observed a significant increase in CD4+ T-cell (0.63%) and CD8+ T-cell frequency (0.77%) in parenchyma of SjD SGs compared with sicca controls (0.20% and 0.29%, respectively). NK and macrophages proportions did not differ significantly. A trend for increase in CD4+ and CD8+ T-cell frequency in SjD patient SGs with healthy levels of UWS and SWS flow, and with shortest oral dryness complaints, was observed compared with those with established flow rate reduction and longer dryness complaints. CD69 expression analysis suggests that CD4+/CD8+ T-cell populations may be derived from a mixture of tissue resident and infiltrated cells. Conclusion Our data imply that the pre-SG disease stage in SjD is associated with an increase in CD4+ and CD8+ T cells in saliva-producing tissue areas.