During 3 years treatment of primary progressive multiple sclerosis with glatiramer acetate, specific antibodies switch from IgG1 to IgG4

In this study we analyzed the humoral immune response to glatiramer acetate in 16 GA-treated primary progressive MS patients and 9 placebo patients from the PROMiSe study. We have demonstrated that all multiple sclerosis patients (n = 16) continuously treated with GA for 3 years developed anti-GA antibodies that peaked at month 3 and remained elevated during the whole study. We have also demonstrated that initially GA-reactive antibodies of the IgG1 subclass predominate, peaking at month 9 of therapy, but after 9 months IgG1 decreases while anti-GA antibodies of the IgG4 subclass increase and remain high for the 3 years of follow-up. These results support a shift from Th1 to Th2 in the antibody response to glatiramer acetate treatment.