Serum amyloid A gene transcription in synovial cells during retroviral arthritis

In situ hybridization was used to demonstrate serum amyloid A (SAA) gene expression in arthritic joint tissue from lentivirus-infected sheep and goats. SAA gene transcription occurs in isolated individual synovial cells and occasional giant cells but not in uninfected or uninflamed synovial tissue. These findings support the notion (derived from in vitro observations) that at least one member of the SAA gene/protein family may function as an autocrine collagenase inducer in inflammatory arthritis. Since we used heterologous DNA probes derived from human clones, our findings also support the growing evidence for interspecies conservation of SAA genes.