With regard to KIR genes, in comparison to subjects with acute viral encephalitis subjects without encephalitis showed respectively a higher frequency of 2DS4 (88.8% vs. 63.3%; p = 0.011); 2DS5 (52.7% vs. 20%; p = 0.006), and 3DS1 (61.1% vs. 20%; p < 0.001). This evidence concerns the gene KIR3DL1 and encephalitis.