Background: Interferon beta (INFbeta) may induce the expression of several proteins, including neopterin, considered a biological marker of INFbeta activity.
Objectives: The aim of this study was to determine the serum neopterin concentration at the beginning of, and during, IFNbeta-1a therapy in relapsing-remitting multiple sclerosis (r-r MS) patients, and to look for a possible correlation between protein synthesis and the clinical course of the disease.
Methods: Thirteen r-r MS patients were treated with INFbeta-1a (i.m. 6 MIU/week) for 2 years. Blood samples for neopterin determinations were taken daily over a period of 1 week at the end of each 6 months of therapy, and tested for neutralizing antibodies (NABs).
Results: Neopterin levels peaked 24-48 h post-injection and returned to baseline after 120 h. After 1 year of therapy, four patients dropped out of the study because of progression of the disease: in these subjects a significant decrement of neopterin was observed.
Conclusion: Neopterin baseline values were not found to decrease over the 2 years of therapy, and neopterin may be considered to be a useful marker of responsiveness to IFNbeta.