Evaluation of Peripheral Immune Activation in Amyotrophic Lateral Sclerosis

Abstract Background: Accumulating evidence has revealed that immunity plays an important role in amyotrophic lateral sclerosis (ALS) progression. However, the results regarding the serum levels of immunoglobulin and complement are inconsistent in patients with ALS. Although immune dysfunctions have also been reported in patients with other neurodegenerative diseases, few studies have explored whether immune dysfunction in ALS is similar to that in other neurodegenerative diseases.Methods: Serum levels of immunoglobulin and complement were measured in 245 patients with ALS, 65 patients with multiple system atrophy (MSA), 60 patients with Parkinson’s disease (PD), and 82 healthy controls (HCs). The serum levels of immunoglobulin and complement were compared among different groups, and the differences in the levels of immunoglobulin and complement between ALS patients and HCs were evaluated using meta-analysis including data from this study. In addition, the association between vitamins and clinical ALS characteristics were evaluated.Results: Patients with ALS had higher C4 levels than did HCs. No significant differences existed between patients with ALS and other neurodegenerative diseases in IgG, IgA, IgM, C3, or C4 levels. The IgA levels were lower in early-onset ALS patients than in late-onset ALS patients. The correlations between age at onset of ALS and IgG or IgA levels were significantly positive.Conclusions: Peripheral immunity abnormalities existed in patients with ALS, and lower IgA levels were associated with early-onset ALS.