Our finding that ROS production after ligation of ICAM-1 by purified SSc antibodies with or without crosslinking was more sensitive to concentration effects than VCAM-1 expression (Fig. 3B), suggests that there are altered sensitivities in signal transduction pathways leading to VCAM-1 expression, or expression of other pro-inflammatory or protective genes activated via ROS, and will also be further investigated. This evidence concerns the gene ICAM1 and systemic sclerosis.