Determination of procollagen type I carboxyterminal propeptide in Japanese patients with systemic sclerosis

Our objective was to clarify the relationship between the serum levels of procollagen type I carboxyterminal propeptide (PICP) and the extent of skin sclerosis or pulmonary fibrosis in patients with systemic sclerosis (SSc). Thirty-eight SSc patients and 36 control subjects were examined for serum PICP levels using enzyme-linked immunosorbent assay. SSc patients were divided into two subgroups according to the grade of skin sclerosis. Mean PICP level in the SSc patients was significantly higher than that in the normal controls. In 53% of the SSc patients, the serum PICP levels were elevated more than 3 SD above the mean control value. The SSc patients with elevated serum PICP levels showed a high incidence of pulmonary fibrosis of diffuse skin sclerosis compared to those with normal PICP levels. Moreover, in 17 patients with pulmonary fibrosis there was an increase in the percentage of patients with elevated PICP levels in the group with diffuse SSc compared to that in the limited SSc group. Furthermore, there was a significant negative correlation between PICP levels and partial pressure of arterial oxygen levels (r=−0.744). We conclude that serum PICP levels may be a useful parameter for the evaluation of skin sclerosis and pulmonary fibrosis of SSc patients.