Such a restriction has been shown both in diseases mediated by IgG1 and by IgG4 autoantibodies, and strong associations to specific—mainly class II—HLA haplotypes have been detected, with odds ratios exceeding 8 in disorders such as encephalitis with autoantibodies against leucine-rich glioma-inactivated protein 1 (LGI1) and contactin-associated protein 2 (caspr2) (171), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) with autoantibodies against neurofascin 155 (NF155) (185) and IgLON5 disease (220). This evidence concerns the gene CNTNAP2 and viral encephalitis.