Methotrexate and psoriasis: serum levels of aminoterminal propeptide of type III procollagen in long-term therapy

Aim. Long-term methotrexate (MTX) treatment can cause hepatic damage that may lead to the development of fibrosis or cirrhosis. The most reliable means of revealing such damage is liver biopsy, but it has been suggested that the scrum levels of the aminoterminal propeptide of type III procollagen (PIIINP) can be used for the non-invasive diagnosis and monitoring of fibrotic disease. The aim of this study was to monitor MTX-induced hepatotoxicity by means of serum PIIINP determinations. Methods. We studied 26 patients with psoriasis (17 with extensive plaque psoriasis, 3 with pustular psioriasis, 1 with psoriatic erythroderma, and 5 with plaque psoriasis unresponsive to treatment) being treated with MTX, the majority of whom had been treated for a long time. The mean cumulative dose was 609.73 mg, and the mean duration of treatment 11.82 months. Serum PIIINP levels were also measured in 2 control groups: 9 psoriatic patients without liver disease who had never received any systemic therapy for psoriasis, and 9 psoriatic patients with liver fibrosis and/or cirrhosis. Results. The serum PIIINP levels of 3 patients were above the reference range of 1.7-4.2 μg/L, whereas 23 (88.5%) had normal levels: mean PIIINP: 2.9 μg/L; range 1.66-4.55 μg/L). None of the 9 psoriatic patients who had never taken MTX had high PIIINP levels (mean 2.27 μg/L; range 1.48-3.20 μg/L), whereas all of the controls with fibrosis or cirrhosis had above-normal levels (mean 8.1279 μg/L; range 7.07-9.39 μg/L). Conclusion. PIIINP can be used as a reliable indicator of hepatic fibrogenesis. The number of liver biopsies of MTX-treated psoriatic patients with normal PIIINP levels can probably be reduced. An annual PIIINP assay is recommended after patients have received a cumulative MTX dose of 750 mg.