Objectives: Cadherin-11 is a cell-cell adhesion molecule also involved in cellular migration and invasion. Experimental studies implicated this molecule in inflammatory arthritis and fibrosing conditions. Moreover, cadherin-11 protein is hyper-expressed on fibroblasts and macrophages in the skin of systemic sclerosis (SSc) patients, whereas the respective mRNA levels correlate with skin thickness. Herein, we searched for possible cadherin-11 expression also in cells that circulate in SSc peripheral blood.
Methods: Cadherin-11 mRNA was quantified by real-time reverse transcription-polymerase chain reaction in 3 ml blood samples obtained from 71 SSc patients (aged 53±2 years, 65 women) and 35 control non-SSc patients with Raynaud's phenomenon.
Results: Cadherin-11 mRNA transcripts were detected in blood samples from 39% of patients with diffuse SSc, versus 16% of those with limited SSc, versus 6% and 16% of patients with idiopathic or associated with other connective tissue diseases Raynaud's phenomenon, respectively (p=0.049). Cadherin-11 mRNA levels in SSc patients were increased by 3.74-fold comparing to controls (p=0.036). By multivariate logistic regression analysis we found that diffuse skin involvement correlated, independently of age, gender, disease duration, lung involvement, digital ulcers, inflammatory indices or anti-Scl-70 autoantibody presence, with cadherin-11 mRNA positivity (p=0.028), but also with increased cadherin-11 mRNA levels (≥3-fold of non-SSc levels, p=0.011).
Conclusions: Cadherin-11 may be hyper-expressed in the peripheral blood of diffuse SSc patients. Studies on the origin and possible pathogenic function of these circulating cells may shed light into the complex disease pathogenesis and further support the notion that cadherin-11 is a potential therapeutic target in SSc.