A placebo-controlled phase II study with ALS patients who were genotyped for Asp358Ala polymorphism of the IL-6 receptor gene showed that tocilizumab treatment was safe and well-tolerated and alleviated C-reactive protein (CRP) levels in CSF relevant to IL-6 receptor Asp358Ala genotype. This evidence concerns the gene CRP and amyotrophic lateral sclerosis.