Molecular investigations implicate human endogenous retroviruses as mediators of anti-retroviral antibodies in autoimmune rheumatic disease

Polymerase chain reaction using specific primers, failed to detect HTLV-I a mplicons in patients with rheumatic diseases previously shown to possess an tibodies to retroviral products. However, by employing broad spectrum oligo nucleotide primers, 135 bp amplicons were generated from peripheral blood m ononuclear cells and synovial fluid cells. Subsequent cloning and DNA seque ncing revealed homology to a number of exogenous and human endogenous retro viruses (HERVs). Furthermore, in combining the presence of type B and C rel ated endogenous retroviruses, a significant association (p=0.014) was appar ent for chronic autoimmune rheumatic diseases as compared to controls. Reve rse transcription polymerase chain reaction of RNA derived from patients, h ealthy controls and cell lines (U937, BJAB, human endothelial lung fibrobla sts) demonstrated ubiquitous expression of HERV-K10 and RTVL-H2. Furthermor e messenger RNA expression of HERV-K10 was enhanced in fibroblasts infected with human cytomegalovirus. It is plausible that subsequent production of HERV peptides could explain the presence of anti-retroviral antibodies in c ohorts of patients with autoimmune rheumatic diseases.