To determine whether elevated soluble CD44 (sCD44) levels serve as a marker of inflammation and lymphoproliferation in primary Sjögren's syndrome (SS).
We measured sCD44 levels by ELISA in serum samples from a cross section of healthy individuals and patients seen in a rheumatology clinic for evaluation of possible primary SS.
Median serum levels of sCD44 were significantly higher in 48 healthy men compared to 52 healthy women (16 vs. 12 nmol/l; p = 0.0034). There was no relationship between serum levels of sCD44 and age or ethnic background. Slightly higher median levels of sCD44 were found in the serum of 37 women with primary SS compared to healthy women (14 vs. 12 nmol/l; p = 0.0402). However, these levels were comparable to those of 33 female patients without primary SS who were seen in the same clinic (p = 0.1233).
Serum levels of sCD44 were slightly higher in female patients with primary SS compared to healthy women, but they are not likely to discriminate between patients with and without primary SS in a rheumatology practice.