Sialometry and sialochemistry: a non-invasive approach for diagnosing Sjogren's syndrome

Abstract

Background: Analysis of salivary variables has frequently been proposed as a diagnostic tool for Sjö-gren's syndrome (SS). Because univocal salivary reference values are lacking, it is currently rather difficult to use sialometry and sialochemistry for diagnosing SS unless major changes have occurred in salivary secretion and composition. Objective: To define reference values of several salivary variables, which offer a possible new and non-invasive means of diagnosing SS. Methods: Cut off points were selected from receiver operating characteristic curves of gland-specific sialometrical and sialochemical variables, which have proved to be potentially relevant for diagnosing SS in a previous study-that is, sodium, chloride, and phosphate concentration in stimulated parotid and submandibular/sublingual (SM/SL) saliva, unstimulated and stimulated SM/SL flow rates, and lag phase of parotid secretion, respectively. By combining the most discriminating variables, two different diagnostic approaches for SS were applied in a group of 100 patients and subsequently evaluated in a second group of 20 patients. The first approach was to combine variables by applying their cut off points into sets of criteria for a positive diagnosis of SS. The second approach was to construct a logistic regression model that predicts the true state of a patient (SS or non-SS). From both approaches, the tests with highest likelihood ratio combined with the smallest number of rejected cases were selected for clinical use. Results: The most accurate test combined the stimulated SM/SL flow rate and parotid sodium and chloride concentration as salivary variables for diagnosing SS; it had a sensitivity of 0.85 and a specificity of 0.96. The selected tests proved equally accurate in the second group of patients. Conclusions: Because the proposed non-invasive diagnostic tools can be easily applied, do not need a laboratory other than for routine blood testing, and are very accurate, gland-specific sialometry and sialochemistry may eventually replace other, more invasive, diagnostic techniques for diagnosing SS.

Rituximab treatment in patients with primary Sjögren's syndrome: An open‐label phase II study

“…This is usually accompanied by a change in the composition of parotid and submandibular/sublingual saliva (10,14,32). These parameters were the first to improve in our patients with early primary SS.…”

“…Levels of IgG, IgA, IgM, and ␤ 2 -microglobulin did not change in either group of patients. Monoclonal protein disappeared following treatment in the only patient who was positive for this protein at baseline (patient 14).…”

“…Flow rates were calculated, and sialochemical analysis was performed. Glandular saliva specimens obtained simultaneously from both individual parotid glands and the submandibular/sublingual glands were collected with Lashley cups (placed on the orifices of the Stensen duct) and by syringe aspiration (from the orifices of the Wharton duct located anteriorly in the floor of the mouth), respectively (14). Sialochemical analysis focused on the concentration of sodium in parotid saliva, because an increase in sodium is indicative of chronic sialadenitis (15).…”

“…The MFI is a 20-item self-report scale, which has been validated for SS (20) and is designed to objectively measure fatigue, including the following dimensions: 1) general fatigue, 2) physical fatigue, 3) mental fatigue, 4) reduced motivation, and 5) reduced activity. A higher score (possible range [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] indicates a higher level of fatigue. The SF-36 questionnaire, which has been used for measuring subjective well-being, has also been validated for SS (21).…”

Saliva as a diagnostic fluid in sports medicine: potential and limitations

“…Each salivary gland secretes a characteristic type of saliva, with different ionic (29) and protein (15) concentrations. Adults normally produce 0.5 to 1.5 l of saliva daily (11) .…”