Soluble CD44 Levels in Sera of the Patients With Sarcoidosis Uveitis

Abstract

Abstract: : Purpose: CD44 is a lymphocyte surface marker contributing to the adhesion of lymphocytes to extracellular matrix. CD 44 also exists densely on the surface of type 2 alveolar cells of the patients with sarcoidosis. Recently, there is a report that degradating products of CD44, soluble CD44 (sCD44), is present in high concentration in the sera of the patients with leukemia, autoimmune diseases and sarcoidosis. To clarify whether sCD44 is useful as a diagnostic marker for sarcoidosis induced uveitis, we measured sCD44 concentrations in sera of patients with various uveitis. Materials & methods: We measured the concentration of serum sCD44 levels by ELISA in 121 patients with uveitis who have not been treated with systemic immunosuppressive agents yet. As a control, serum sCD44 levels were also measured in age–matched 32 healthy adults. Results: Soluble CD44 levels in sera (ng/ml) were significantly elevated in patients with pathologically–diagnosed sarcoidosis(n=14): 618±252 (Mann Whitney's U–test, p<.001), clinically–diagnosed sarcoidosis (n=7): 844±277 (p<.0001), and sarcoidosis suspected patients (n=20): 489±138 (p<.001) compared with those of healthy controls (n=32): 357±81. On the other hand, it tended to be higher, but not singnificantly, in the sera of patients with Harada disease (n=14): 470±125, Tuberculotic uveaitis (n=6): 487±119, HTLV–1 associated uveitis (n=4): 474±84. Soluble CD44 levels in the sera of the patients with other types of uveitis (Behcet’s disease (n=11): 390±120 , acute anterior uveitis (n=12): 380±118, Fuch’s hetero chromic iridocyclitis (n=5): 424±188, and other uveitis (n=28): 391±121) were similar to those in healthy adults. Serum sCD44 were especially higher in the patients with sarcoidosis within 3 years from the onset (p=.009) than those more than 3 years from the onset. Conclusions: Serum sCD44 can be a useful diagnostic marker of sarcoidosis–induced uveitis. Setting of cut–off value around 500 ng/ml or 550 ng/ml may be adequate. Serum sCD44 levels of patients with sarcoidosis may decrease as the time from the onset proceeds.

Keywords: uveitis-clinical/animal model • clinical laboratory testing • inflammation