Pathogenesis of Sjögren's syndrome

Area of Science:

• Immunology
• Pathology
• Oncology

Background:

• Sjögren's syndrome (SS) is a systemic autoimmune disorder targeting exocrine glands, marked by lymphocytic infiltration.
• Patients with SS develop autoantibodies like rheumatoid factor (RF) and antinuclear antibodies (ANA).
• Genetic factors, such as HLA-DR3, are linked to primary SS susceptibility.

Purpose of the Study:

• To investigate the role of HLA class II expression in SS pathogenesis.
• To analyze the immune cell infiltrates and autoantibody production within salivary glands (SGs) in SS.
• To explore the association between SS and the development of non-Hodgkin's B-cell lymphoma.

Main Methods:

• Analysis of HLA-DR antigen expression on epithelial cells in SS salivary glands.
• Characterization of infiltrating immune cells (CD4+ T cells) and cytokine production (IL-2, interferon-gamma).
• Detection of immunoglobulin gene rearrangements in B cells from SS salivary glands using Southern blot.

Main Results:

• SS salivary gland epithelial cells exhibit high HLA-DR antigen expression, unlike normal glands.
• Salivary glands are infiltrated by CD4+ T cells producing pro-inflammatory cytokines.
• B cells in SS salivary glands show specific kappa light chain usage (VKIIIb) and undergo clonal expansion, indicating a predisposition to lymphoma.

Conclusions:

• High HLA class II expression on salivary gland epithelium may underlie HLA-associated susceptibility in SS.
• The salivary gland microenvironment in SS supports autoimmunity and B-cell clonal expansion.
• SS offers a unique model for studying the progression from autoimmune disease to B-cell lymphoma.