Patients with sporadic amyotrophic lateral sclerosis (sALS) show inflammation in the spinal cord and peripheral blood. The inflammation is driven by stimulation of macrophages by aggregated superoxide dismutase 1 (SOD1) through caspase1, interleukin 1 (IL1), IL6 and chemokine signaling. Inflammatory gene activation is inhibited in vitro by tocilizumab, a humanized antibody to IL6 receptor (IL6R). Tocilizumab inhibits global interleukin-6 (IL6) signaling, a key mechanism in chronic rheumatoid disorders. Here we studied in vivo baseline inflammatory gene transcription in peripheral blood mononuclear cells (PBMCs) of 10 sALS patients, and the effects of tocilizumab (Actemra(R)) infusions. At baseline, one half of ALS subjects had strong inflammatory activation (Group 1) (8 genes up regulated >4-fold, P<0.05 vs. controls) and the other half (Group 2) had weak activation. All patients showed greater than four-fold up regulation of MMP1, CCL7, CCL13 and CCL24. Tocilizumab infusions in the Group 1 patients resulted in down regulation of inflammatory genes (in particular IL1β), whereas in the Group 2 patients in up regulation of inflammatory genes. Post-infusion serum and CSF concentrations of tocilizumab inhibited caspase1 activation in vitro. Three of 5 patients receiving tocilizumab infusions showed time-limited attenuation of clinical progression. In conclusion, inflammation of sALS patients at baseline is up- or down-regulated in comparison to controls, but is partially normalized by tocilizumab infusions.
Keywords: ActemraR; Amyotrophic lateral sclerosis; CCL20; CCL24; caspase1; interleukin1; interleukin6; macrophage; superoxide dismutase1; tocilizumab.