Serum and CSF measles antibody levels increase over time in patients with multiple sclerosis or clinically isolated syndrome.

In general, measles virus (MV) immunoglobulin G (IgG) antibody titres decline over time. However, we found that serum and CSF MV antibody titres increased with age (slope=0.038, p<0.001 and slope=0.022, p=0.008), respectively, and disease duration (slope=0.031, p=0.002 and slope=0.032, p=0.005), respectively, in patients with multiple sclerosis (MS) or clinically isolated syndrome (CIS). The age dependency of serum antibody levels differed between patients and controls (slope=0.038 versus -0.004, p<0.001). The increasing MV antibody titres over time in MS/CIS patients support a general nonspecific stimulation of B cells and plasma cells that is not confined only to the CNS/CSF compartment.