Murine models of Sjögren's syndrome. Immunohistologic analysis of different strains.

Lacrimal gland inflammation develops in several strains of autoimmune mice, including MRL/Mp-lpr/lpr (MRL/lpr), MRL/Mp-+/+ (MRL/+), and NZBxNZW F1 hybrids (NZB/W). These mice all develop an autoimmune disease characterized by glomerulonephritis and autoantibody formation, but each strain has unique clinical features and immunologic abnormalities. Previous studies have suggested that the intrinsic immunologic defect in MRL/lpr mice may be at the level of T cells, while in NZB/W mice it appears to be B cell-mediated. Immunohistologic analysis of the lacrimal gland lesions was performed on all three strains. Although T cells predominated (MRL/lpr 85%, MLR/+ 78%, and NZB/W 57%), differences in the immunohistologic profiles did exist. NZB/W mice had a significantly higher percentage of B cells (33% vs. 10% for MRL/lpr and 13% for MRL/+) and a correspondingly lower percentage of T cells. MRL/lpr mice differed from MRL/+ mice in that they exhibited a significantly higher percentage of helper T cells (63% vs. 49%) and a lower percentage of suppressor/cytotoxic T cells (14% vs. 30%). Class II antigen expression could be detected on the mononuclear cells at inflammatory sites within the lacrimal glands of all three strains, suggesting T cell activation and an active autoimmune immunologic event occurring in the lacrimal gland.