Open AccessDirect evidence for the expression of multiple endogenous retroviruses in the synovial compartment in rheumatoid arthritis
Author(s) -
Nakagawa Kaku,
Brusic Vladimir,
McColl Geoffrey,
Harrison Leonard C.
Publication year - 1997
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/art.1780400407
Subject(s) - synovial fluid , rheumatoid arthritis , synovial membrane , gene , biology , polymerase chain reaction , arthritis , endogenous retrovirus , immunology , microbiology and biotechnology , osteoarthritis , medicine , genetics , pathology , genome , alternative medicine
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 transcriptionpolymerase 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 families (F1‐F6) that contained 33 groups of known and unknown endogenous RVs (ERVs), each distinguished by a specific, deduced peptide motif. The frequency of sequences in each family was similar between RA, OA, and normal synovial tissue, but differed significantly in RA synovial fluid cells. F1 sequences (undefined, but related to murine and primate type C RVs) were lower in frequency, F2 (ERV‐9‐related), F4 (HERV‐K‐related), and F6 (HERV‐L‐related) sequences were higher in frequency, and F3 (RTVL‐H‐related) sequences were not detected, in the RA synovial fluid cells compared with the RA synovial tissues. Conclusion . Multiple ERVs are expressed in normal and diseased synovial compartments, but specific transcripts can be differentially expressed in RA.