Thus owing to the fact that many studies are beginning to implicate the immune response to HSV-1 and its various cell populations (e.g. microglia, CD8+ T cells) in causing widespread CNS pathology such as acute encephalitis, our finding of a higher frequency of some KIR haplotype (AA haplotype) and of some HLA allele such as HLA-C2 or HLA-A-BW4 may represent, to the best of our knowledge, the first report offering promising information about the immunologic background of patients with acute viral encephalitis. Here, HLA-A is linked to viral encephalitis.