Carboxyterminal propeptide of type I procollagen in cerebrospinal fluid in childhood and in children with leukemia undergoing intrathecal treatment.

We determined the reference interval for the carboxyterminal propeptide of type I procollagen (PICP), an indicator of the synthesis of type I collagen, in cerebrospinal fluid (CSF) by studying 32 infants and children, ages less than or equal to 15 years. The concentration of PICP is age dependent, with particularly high concentrations occurring in children younger than 1.5 years. In older children the concentration is stable (reference interval 20-92 micrograms/L). We also investigated the possibility that PICP in CSF could reflect local fibroproliferative changes in the arachnoid in a cohort of 42 children with acute lymphoblastic leukemia who were monitored by repeated sampling in connection with intrathecal therapy. Initially, there was no difference in PICP between the children with newly diagnosed leukemia and the controls. PICP concentrations were significantly higher (P less than 0.01) during intrathecal methotrexate therapy, with median values above the reference interval. Continuous corticosteroid treatment was associated with a significant decrease in PICP (P less than 0.02 and P less than 0.01, respectively, in two groups treated according to different protocols), close to the lower limit of the reference interval. Intrathecally administered methotrexate and systemic corticosteroid treatment are known to be associated with the development of arachnoiditis and with general repression of collagen synthesis, respectively. We conclude that PICP in CSF is a sensitive indicator of local fibroproliferation and ongoing collagen synthesis.