Sjögren’s Syndrome: Interface of Immunology and Neurology

Sjogren’s syndrome (SS) is characterized by dry eyes and dry mouth, due to focal lymphocytic infiltrates of the lacrimal and salivary glands. SS patients also have a spectrum of extraglandular manifestations including skin, joint, pulmonary, renal, cardiovascular, hematopoietic, neurological, and lymphoid proliferation. Indeed, the neurological manifestations are among the most challenging perplexities for the clinical rheumatologists and other specialists involved in their care. In addition, SS patients have a high incidence of fatigue, self-described cognitive impairment, and myalgias that baffle the rheumatologist because they do not correlate closely with either glandular or extraglandular manifestations. An understanding of the neuropathies in SS seems a good starting point in approaching the unmet needs of the SS patient. In particular, it is necessary to move beyond the narrowly defined “innate” and “adaptive” immune response (i.e., T-cell-directed B-cell production of autoantibodies) to the more general “danger hypothesis” that includes interactions of the immune system with the brain (hypothalamic and adrenal axis), midbrain amplification of neurokines and pain pathways, and prostaglandin pathways that play a role in vascular tone and blood pressure regulation.