The diagnostic value of salivary fluid levels of beta 2-microglobulin, lysozyme and lactoferrin for primary Sjögren's syndrome.

In search of a simple non-invasive diagnostic test for primary Sjögren's syndrome (SS) the concentration of beta 2-microglobulin (beta 2-m), lysozyme (LZM) and lactoferrin (Lf) was measured in stimulated parotid saliva of 39 patients with primary SS, 42 patients suspected of the syndrome in whom the diagnosis could be excluded (NON-SS) and in 41 normal control individuals. Salivary fluid levels of beta 2-m, LZM and Lf exceeding the mean + 2 x standard deviation of healthy control values were found in respectively 58%, 23%, and 26% of the primary SS patients and in 7%, 11% and 0% of the NON-SS patients. The results of this study indicate that due to the low sensitivity the tests are not suitable as a screening procedure for patients suspected of having primary SS. However, measurement of beta 2-m in stimulated parotid saliva may be used as an adjunctive diagnostic test for primary SS.