BAFF (BLyS, TALL-1, THANK, zTNF4) is a member of the TNF superfamily that specifically regulates B lymphocyte proliferation and survival. Mice transgenic (Tg) for BAFF develop an autoimmune condition similar to systemic lupus erythematosus. We now demonstrate that BAFF Tg mice, as they age, develop a secondary pathology reminiscent of Sjogren's syndrome (SS), which is manifested by severe sialadenitis, decreased saliva production, and destruction of submaxillary glands. In humans, SS also correlates with elevated levels of circulating BAFF, as well as a dramatic upregulation of BAFF expression in inflamed salivary glands. A likely explanation for disease in BAFF Tg mice is excessive survival signals to autoreactive B cells, possibly as they pass through a critical tolerance checkpoint while maturing in the spleen. The marginal zone (MZ) B cell compartment, one of the enlarged B cell subsets in the spleen of BAFF Tg mice, is a potential reservoir of autoreactive B cells. Interestingly, B cells with an MZ-like phenotype infiltrate the salivary glands of BAFF Tg mice, suggesting that cells of this compartment potentially participate in tissue damage in SS and possibly other autoimmune diseases. We conclude that altered B cell differentiation and tolerance induced by excess BAFF may be central to SS pathogenesis.

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Association of BAFF/BLyS overexpression and altered B cell differentiation with Sjögren’s syndrome

The term "Sjogren's syndrome" (SS) is frequently used to describe the occurrence of keratoconjunctivis sicca and xerostomia in association with an autoimmune disorder. However, well-defined criteria for the classification of SS have not been established, and this diagnosis is being applied to a wide spectrum of conditions, ranging from clear "autoimmune" disease in some patients, to sicca complaints without evidence of a systemic immune process in elderly patients. Here, we review the clinical and laboratory features of patients referred for evaluation of sicca symptoms. In particular, we emphasize the need for care in choosing the site for minor salivary gland biopsy, and we describe the histologic features that aid in the evaluation of these biopsy specimens. In an attempt to identify a population of patients whose conditions might have a common etiopathogenesis and, thus, a common treatment program, we propose the following criteria for a diagnosis of SS: 1) objective evidence of keratoconjunctivis sicca, as documented by rose bengal or fluorescein dye staining; 2) objective evidence of diminished salivary gland flow; 3) minor salivary gland biopsy, obtained through normal mucosa, with the specimen containing at least 4 evaluable salivary gland lobules, and having an average of at least 2 foci/4 mm2; 4) evidence of a systemic autoimmune process, as manifested by the presence of autoantibodies, such as rheumatoid factor and/or antinuclear antibody. The diagnosis of "definite SS" would be made when all 4 criteria are met; the diagnosis of "possible SS" would be made when 3 criteria are present. Specific exclusions for this diagnosis are preexisting lymphoma, graft-versus-host disease, sarcoidosis, and acquired immunodeficiency disease.(ABSTRACT TRUNCATED AT 250 WORDS)

https://onlinelibrary.wiley.com/doi/pdf/10.1002/art.1780290501

Sjögren's syndrome. Proposed criteria for classification

Neurologic manifestations in primary Sjögren syndrome: a study of 82 patients.

Tear physiology and dry eyes.

Xerostomia is an unsatisfactory diagnostic criterion for the salivary component of Sjogren's syndrome (SS). To determine the diagnostic usefulness of the presence of focal sialadenitis in labial salivary gland (LSG) biopsy specimens, 362 patients suspected of having SS prospectively underwent a unique LSG biopsy procedure. The pattern and severity of LSG inflammation were compared with measurements of parotid flow rate, and the presence or absence of symptomatic xerostomia, major salivary gland enlargement, keratoconjunctivitis sicca (KCS), and other connective tissue diseases (CTD). LSG biopsy focus scores of >1 correlated more closely with the diagnoses of KCS alone and with KCS plus a CTD than did either reduced parotid flow rate or symptoms of xerostomia (P < 0.0005 and P < 0.05, respectively). Focal sialadenitis in an adequate LSG specimen is an objective criterion and a more disease-specific feature of SS than xerostomia or any other feature of salivary disease. The salivary component of SS should be redefined as the presence of LSG focal sialadenitis.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/art.1780270205

Labial salivary gland biopsy in sjögren's syndrome

A labial biopsy technique is described and was used to study 40 patients with connective tissue disease and 60 postmortem subjects. More than one focus of lymphocytes per 4 sq mm of minor salivary tissue was found to be a consistent finding in patients with Sjogren's disease. The labial biopsy is shown to be a further valuable investigative procedure in such patients.

https://jcp.bmj.com/content/jclinpath/21/5/656.full.pdf

D. M. Chisholm

Papers

Labial salivary gland biopsy in Sjögren's disease