Immunoglobulin levels are higher at multiple sclerosis onset - a part of natural history?

Background: Changes in immunoglobulin (Ig) levels may occur in association with various drugs targeting immunity, including disease-modifying drugs (DMD) and corticosteroids (CS) used to treat multiple sclerosis (MS). However, kinetics of Ig levels during the natural history of MS is poorly described. Objective: To describe the natural history of the Ig levels in MS. Methods: Monocentric retrospective study examining changes in Ig levels in relation with CS intake in a series of 304 consecutive MS patients (and 1204 samples) followed or hospitalized for 7 years in a single centre. Ig levels are routinely collected in MS patients followed in our centre. Results: IgG levels were higher in samples taken at diagnosis than in those taken after the onset of MS symptoms. This effect was also observed in patients remaining free of DMD or CS since onset. On the other hand, overall Ig levels remained stable across fixed time points ranging from 1 to 20 years after onset Conclusion: An unanticipated finding of this study was the transient higher IgG levels in samples taken at onset, which suggests that strong inflammatory processes may occur early.