Evidence for peripheral immune activation in amyotrophic lateral sclerosis.

There is evidence of the activity of immune system in the spinal cords of patients with amyotrophic lateral sclerosis (ALS), however; few studies to date have explored the status of peripheral immune response in ALS patients. Blood samples from 284 ALS patients and 217 aged-match controls were evaluated, and parameters of T cell subset, humoral immunity, and complement system activation were observed. CD4+ T lymphocytes and circulating immune complexes (CICs) were significantly decreased, and component C3 was significantly increased in ALS patients compared with normal controls. Patients with severe or moderate impairment had a higher CD4+ T cell percentage and a lower IgG levels when compared to those with mild impairment. There was an inverse correlation between CD4 T cell percentage and both revised ALS Functional Rating Scale (ALSFRS-R) score and disease duration, but the correlation was positive between IgG level and both ALSFRS-R score and disease duration among ALS patients. These correlations were gender-specific. This investigation demonstrated the existence of peripheral immune abnormalities in ALS patients.