Labial salivary gland biopsy in Sjögren's syndrome.

Labial salivary gland histopathology has long been considered to be the most disease-specific single test for diagnosis of Sjögren's syndrome. However, the diagnostic yield of widely used grading systems of focal lymphocytic sialoadenitis is rather low. Determination of the percentages IgA-, IgG-, IgM-, kappa-, and lambda-containing plasma cells in minor salivary glands obtained from a lower lip biopsy has recently been shown to be extremely valuable in Sjögren's syndrome, not only for diagnosis, but also for prognosis with regard to the development of systemic monoclonal lymphoproliferative disease. This technique greatly improves the value of labial salivary gland biopsy in Sjögren's syndrome.