Abstract
T ‐cells are present in the spinal cord from patients with amyotrophic lateral sclerosis (ALS), and could attack neurons or activate microglia through secretion of cytokines. We report that interferon (IFN)‐γ, tumour necrosis factor (TNF)‐α, interleukin (IL)‐2, IL‐4, IL‐5 and IL‐10 could not be detected in cerebrospinal fluid (CSF) samples from 15 ALS patients and 23 out of 25 controls with a multiplexed cytometric bead assay. In vivo activated T‐cell clones were established from CSF (n = 26) and blood (n = 21) of one ALS patient. The proliferative capacity of CSF T‐cell clones was lower than that of T‐cell clones from blood (p = 0.0007). All CD4+ CSF T‐cell clones produced IFN‐γ, compatible with a predominant T helper (h) 1 phenotype, but several T‐cell clones also produced Th2 cytokines. These data suggest that in vivo activated intrathecal T‐cells can be induced to secrete cytokines which may play a role in ALS.