The potential role of human endogenous retrovirus K10 in the pathogenesis of rheumatoid arthritis: a preliminary study.

OBJECTIVE To examine whether human endogenous retrovirus K10 is associated with autoimmune rheumatic disease. DESIGN A novel multiplex reverse transcription polymerase chain reaction (RT-PCR) system was developed to investigate HERV-K10 mRNA expression in patients with rheumatoid arthritis. METHODS 40 patients with rheumatoid arthritis, 17 with osteoarthritis, and 27 healthy individuals were recruited and total RNA was extracted from peripheral blood mononuclear cells (PBMCs) and analysed using multiplex RT-PCR for the level of HERV-K10 gag mRNA expression. Southern blot and DNA sequencing confirmed the authenticity of the PCR products. RESULTS Using the histidyl tRNA synthetase (HtRNAS) gene as a housekeeping gene in the optimised multiplex RT-PCR, a significantly higher level of HERV-K10 gag mRNA expression was found in rheumatoid arthritis than in osteoarthritis (p = 0.01) or in the healthy controls (p = 0.02). CONCLUSION There is enhanced mRNA expression of the HERV-K10 gag region in rheumatoid arthritis compared with osteoarthritis or healthy controls. This could contribute to the pathogenesis of rheumatoid arthritis.