Increased levels of type I and III collagen and hyaluronan in scleroderma skin

The aminoterminal propeptide of type III procollagen (PIIINP) and the carboxyterminal propeptide of type I procollagen (PICP) and hyaluronan (HA) were measured in plasma and suction blister fluid from 13 systemic sclerosis patients and 11 healthy volunteers. Suction blisters and skin biopsies were from the transition zone between normal skin and scleroderma, and uninvolved abdominal skin of patients. The median value of suction blister PIIINP from the transition zone was 38% higher than suction blister PIIINP from uninvolved skin. PIIINP was localized to the dermis by immunohistochemical techniques. PICP and HA levels in blisters from the transition zone were 87% and 53%, respectively, above the levels measured in uninvolved skin. Furthermore, PICP and HA blister levels from the transition zone were 67% and 63%, respectively, higher than the levels measured in healthy volunteers. In plasma from scleroderma patients levels of PIIINP and HA were 38% and 127% higher, respectively, than in plasma of healthy volunteers. The plasma PICP level was not significantly higher in scleroderma patients. Finally, PICP, PIIINP and HA levels were several times higher in suction blister fluid than in plasma. The data indicate that a fibrogenetic process takes place in the transition zone of scleroderma. The method may be used to monitor the progression of scleroderma skin lesions in vivo.