The env mRNA expression level of HERV-K (HML-2) was significantly upregulated in pemphigus vulgaris patients in comparison to healthy controls, suggesting HERV-K (HML-2) expression could be measured as a possible diagnostic tool for detection of pemphigus vulgaris and monitoring of the treatment (Karimi et al., 2019). Here, ERVW-1 is linked to pemphigus vulgaris.