Circulating levels of active transforming growth factor β1 are reduced in diffuse cutaneous systemic sclerosis and correlate inversely with the modified Rodnan skin score

Abstract

Objectives. To determine the relationship between clinical features and circulating levels of active transforming growth factor (TGF) β1 in the major subsets of systemic sclerosis (SSc). Methods. In a cross-sectional study cases of diffuse cutaneous SSc (dose) (n = 27) or limited cutaneous SSc (dose) (n = 20) were compared with healthy controls (n = 22). Active and total TGFβ1 was measured in serum and plasma by a high-sensitivity enzyme-linked immunosorbent assay. Results. There were no significant differences between levels of total serum TGFβ1. However, cases of dcSSc had lower levels of active TGFβ1 than cases of lcSSc or controls. In addition, more cases of dcSSc (18/27; 66%, P<0.025) had no detectable active TGFβ1 than controls (7/22, 32%) or lcSSc (7/20, 35%). In dcSSc, serum active TGFβ1 levels correlated negatively with skin score and positively with disease duration. Conclusions. Contrary to expectation, levels of active TGFβ1 are reduced in dcSSc and this correlates with two variables known to associate with disease activity, shorter duration and more extensive skin sclerosis. This suggests that active TGFβ1 may be sequestered in active involved SSc skin and that serum levels are reduced despite strong evidence implicating TGFβ isoforms in the pathogenesis of fibrosis. Our findings may have implications for systemic TGFβ-trapping therapies in this disease. © The Author 2005. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved.