Cellular immunity to cartilage proteoglycans: relevance to the pathogenesis of ankylosing spondylitis

Cellular immunity to cartilage proteoglycans may be responsible for sustaining chronic inflammation in ankylosing spondylitis. This hypothesis was examined by measuring peripheral blood and synovial fluid mononuclear cell proliferation in five preparations of human cartilage proteoglycan monomer in vitro. Peripheral blood mononuclear cells from 25 patients and synovial fluid mononuclear cells from five patients were compared with those from normal and disease control subjects matched for age. No significant differences were found between the three groups. This suggests that autoimmune responses to cartilage proteoglycans are unlikely to play a significant part in the pathogenesis of ankylosing spondylitis.