Sjögren's: An Autoimmune Disease
Like other autoimmune diseases, Sjögren's syndrome results from the immune system mistakenly attacking healthy tissue. The autoimmune response is not fully understood and may have multiple causes, including mimicry molecules, immature T cells, and leaky gut syndrome. Mimicry molecules excite the immune system to attack molecules they resemble. Immature T cells are those that have not been “trained” long enough in the thymus and cannot properly differentiate between harmful antigens and healthy tissues. Finally, leaky gut syndrome, characterized by an overly permeable intestinal wall, can arouse an allergic response by releasing large molecules into the bloodstream. In general, allergic reactions were found to be more common in people with Sjögren's syndrome (Tishler 1998).
When healthy tissues such as excretion glands are attacked because of an autoimmune response, they become clogged with circulating immune complexes (Brito-Zeron 2005). These large molecules are formed by the combination of an antibody and an antigen. When lodged in the salivary and lachrymal glands (produce tears), they block these glands from supplying their watery and mucosal secretions.
Some researchers think that the underlying cause of autoimmune disorders (like Sjögren's) may be a flawed T cell response. T cells are lymphocytes that are “trained” in the thymus gland for their role in the immune system. However, if T cells are not “schooled” long enough in the thymus before being released, they tend to behave erratically, attacking healthy tissue.
Patients with Sjögren's show significant defects in T cell immunity (Gerli 1989). Japanese researchers found that estrogen deficiency contributes to this dysfunctional T cell response (Ishimaru 1999).
Depression, which is associated with Sjögren's (Stevenson 2004), can trigger the production of cytokines that interfere with salivary and lachrymal gland production.