Increased serum levels of adhesion molecules ICAM-1 and VCAM-1 in systemic sclerosis are not specific for pulmonary manifestations.

Abstract

Studies suggest elevated serum intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) levels may be markers of pulmonary arterial hypertension in systemic sclerosis (SSc-PAH). We sought to evaluate whether ICAM-1 and VCAM-1 levels are useful screening biomarkers for incident SSc-PAH. In this cross-sectional study, four groups were selected from the Australian Scleroderma Cohort Study: group 1 (n = 15) had definite PAH; group 2 (n = 19) had interstitial lung disease (ILD); group 3 (n = 30) were SSc-controls; and group 4 (n = 34) were healthy controls. Serum ICAM-1 and VCAM-1 levels were measured using the Millipore Milliplex MAP Human 2-Plex Panel. There were no differences in ICAM-1 levels in the PAH versus ILD group (263.0 +/- 85.4 vs 380.4 +/- 168.3 ng/mL, p = 0.136), SSc-controls (263.0 +/- 85.4 vs 253.1 +/- 98.0 ng/mL, p = 1.00), or healthy controls (263.0 +/- 85.4 vs 201.8 +/- 57.2 ng/mL, p = 0.093). Similarly, there were no differences in VCAM-1 level in PAH versus ILD groups (1476.2 +/- 434.9 vs 1424.8 +/- 527.6 ng/mL, p = 1.00) and SSc-controls (1476.2 +/- 434.9 vs 1409.5 +/- 341.1 ng/mL, p = 1.00). SSc subjects had significantly higher levels of ICAM-1 (297.4 +/- 134.0 vs 201.8 +/- 57.2 ng/mL, p < 0.0001) and VCAM-1 compared to healthy controls (1432.7 +/- 427.4 vs 1125.6 +/- 273.4 ng/mL, p < 0.0001). Neither ICAM-1 nor VCAM-1 is a specific screening biomarker of SSc-PAH. Instead, increased levels of these adhesion molecules in SSc, irrespective of pulmonary complications, suggest that they may play a role in SSc pathogenesis.Copyright © 2018, International League of Associations for Rheumatology (ILAR).