A recent pharmacovigilance study also reported some associations between the class of ICI and specific iRAE-Ns; particularly, they found that non-infectious encephalitis/myelitis are more frequent with anti-PD-1/PD-L1 than with anti-CTLA-4, while Guillain-Barre syndrome and non-infectious meningitis are less frequently reported with anti-PD-1/PD-L1 compared with anti-CTLA4 monotherapy [14]. This evidence concerns the gene CTLA4 and myelitis.