Also, in support of the HSV1-APOE connection are the studies showing that APOE-ε4 confers a strong risk of herpes labialis, a disorder of the peripheral nervous system known to be caused (usually) by HSV1 [3], [38] and also the studies showing the greater potential for HSV1 damage in infected APOE-ε4-transgenic mice compared to infected APOE-ε3 mice (reviewed in [32]). Here, APOE is linked to herpes labialis.