Salivary β2-Microglobulin, Na+, and Cortisol Levels, and Salivary Glands' Uptakes in Sialoscintigraphy in Sjögren Disease.

Objective: For early diagnosis and inquiry into the pathophysiology of Sjögren disease (SjD), salivary secretion and component levels, and salivary glands' uptakes in sialoscintigraphy were examined, in this cross-sectional study.

Methods: Patients who visited our hospital with suspected SjD between April 2016 and March 2020 were checked for unstimulated salivary secretion and β2-microglobulin, Na+, and cortisol levels in saliva. The patients who showed any abnormal salivary test results underwent sialoscintigraphy; the uptakes in the parotid, submandibular, and thyroid glands were compared using paired t test.

Results: Sixty-five patients (female/male 51/14, 64.5 ± 13.7 years) were checked for saliva. The secretion was 0.39 ± 0.43 mL/min. The component levels were 1.98 ± 1.45 mg/dL for β2-microglobulin (n = 61), 15.9 ± 15.3 mEq/L for Na+ (n = 61), and 0.20 ± 0.18 μg/dL for cortisol (n = 56). A significant negative correlation was observed between the secretion and each component level. A significant positive correlation was found between the 2 out of the 3 component levels. Sialoscintigraphy of 52 patients showed significantly lower uptake in the submandibular glands than in the parotid glands (submandibular/parotid ratio: 0.51 ± 0.36, left; 0.54 ± 0.39, right). The total uptake in the 4 salivary glands was lower, but not significantly, than that in the thyroid gland.

Conclusions: In patients with suspected SjD, a decreased salivary secretion correlated with a high level of any of β2-microglobulin, Na+, and cortisol; the 2 of the 3 levels correlated positively. Sialoscintigraphy showed that the submandibular glands were involved to a greater extent than the parotid glands were. The total salivary gland uptake may be lower than that in thyroid.