Direct evidence for the expression of multiple endogenous retroviruses in the synovial compartment in rheumatoid arthritis

Abstract

Objective. Circumstantial evidence links retroviruses (RVs) with human autoimmune diseases. The aim of the present study was to obtain direct evidence of RV gene expression in rheumatoid arthritis (RA). Methods. Synovial samples were obtained from patients with RA, patients with osteoarthritis (OA), and normal control subjects. Reverse transcription- polymerase chain reaction (RT-PCR) was performed using synovial RNA and primers to conserved sequences in the polymerase (pol) genes of known RVs. Results. PCR products (n = 857) were cloned and sequenced. Multiple pol transcripts, many with open reading frames, were expressed in every sample. Sequences were aligned and classified into 6 familie..