Table 1.
Summary of HERVs associated with inflammatory diseases mainly through genetic, serological, and molecular studies.
| Diagnosis | HERV | Main results | References |
|---|---|---|---|
| MS | HERV-W | Meta-analysis of HERV-W viral protein and/or mRNA expression in peripheral blood, CSF, and brain of MS patients reveals an association between HERV-W and MS | Morandi et al., 2017 |
| Accumulated HERV-W Gag expression in axonal structures and endothelial cells of active MS lesions, HERV-W Env expression in macrophages is restricted to early MS lesions | Perron et al., 2005 | ||
| HERV-W Env is upregulated within MS plaques and correlated with the extent of active demyelination and inflammation, significantly greater accumulation of HERV-W-specific RNAs in MS brains vs. controls | Mameli et al., 2007 | ||
| HERV-W Env is dominantly expressed in macrophages and microglia in areas of active demyelination | van Horssen et al., 2016 | ||
| MSRV env is significantly increased in PBMC of MS patients | Perron et al., 2012; Garcia-Montojo et al., 2013 | ||
| HERV-W Env is present in macrophages within MS brain lesions with particular concentrations around vascular elements, elevated DNA copy numbers in MS patients vs. controls | Perron et al., 2012 | ||
| HERV-H | Higher antibody reactivity toward HERV-H Env and significantly higher expression of HERV-H Env epitopes on B cells and monocytes in patients with active MS | Brudek et al., 2009 | |
| HERV-K18 | Increase in MS risk among homozygous carriers of the K18.3 allele in an US American cohort | Tai et al., 2008 | |
| HERV-K18.3 haplotype is associated with MS susceptibility in a Spanish cohort | de la Hera et al., 2013 | ||
| HERV-Fc1 | Significant increase of HERV-Fc1 RNA in plasma, and HERV-H/F Gag in T cells and monocytes of patients with active MS compared to controls | Laska et al., 2012 | |
| Association of the HERV-Fc1 polymorphism rs391745 with bout-onset MS susceptibility in Southern European cohorts | Hansen et al., 2011; de la Hera et al., 2014 | ||
| HERF-Fc1 SNP rs391745 and HERV-K113 SNP rs2435031 synergize in influencing the risk of MS | Nexø et al., 2015; Nexø et al., 2016 | ||
| ALS | HERV-K | Increased HERV-K pol transcripts in brain tissue of ALS patients, HERV-K expression correlates with TDP-43 | Douville et al., 2011 |
| HERV-K is expressed in neurons of ALS patients, HERV-K expression is regulated by TDP-43 and causes retraction and beading of neurites in human neurons | Li et al., 2015 | ||
| SLE | HERV-E | HERV-E mRNA expression is higher in lupus CD4+ T-cells vs. healthy controls, and positively correlated with SLE disease activity | Wu et al., 2015 |
| HRES-1 | Small GTPase encoded by HRES-1 is overexpressed in lupus T-cells and contributes to mitochondrial dysfunction involved in SLE | Caza et al., 2014 | |
| HRES-1 locus at the 1q42 chromosomal region influences development and manifestations of SLE | Pullmann et al., 2008 | ||
| RA | HERV-K | Significantly higher serum autoantibodies against a peptide of HERV-K Env in RA patients vs. healthy controls | Mameli et al., 2017 |
| Significantly higher HERV-K viral loads in plasma samples from RA patients vs. healthy controls | Reynier et al., 2009 | ||
| HERV-K10 | Enhanced expression of HERV-K10 mRNA in RA | Ejtehadi et al., 2006 | |
| RA patients show significantly elevated levels of HERV-K Gag activity compared to controls | Freimanis et al., 2010 | ||
| Significantly elevated IgG antibody response to an HERV-K10 Gag peptide in patients with RA vs. controls | Nelson et al., 2014 | ||
| SS | HERV-K113 | HERV-K113 is found in 15.6% of 96 patients with SS | Moyes et al., 2005 |
| HIAP | Majority of patients with SS have serum antibodies to proteins of HIAP | Sander et al., 2005 | |
| JIA | HERV-K18 | HERV-K18 transcript expression significantly elevated in JIA patients vs. controls | Sicat et al., 2005 |
MS, Multiple sclerosis; ALS, Amyotrophic lateral sclerosis; SLE, Systemic lupus erythematosus; RA, Rheumatoid arthritis; SS, Sjögren's syndrome; JIA, Juvenile idiopathic arthritis.