Clinico-biologic aspects and evolutive tendencies in sacroiliitis.

A group of 103 patients with radiologic changes of sacroiliitis were investigated and followed up over a mean period of 3.5 years. The biologic explorations (nonspecific inflammatory tests, humoral immunologic determinations and serum fibronectin assay) as well as sacroiliac and spine radiographic examinations, were repeated every 6th-12th months. In 32 patients (31%) clinical, biologic and radiologic signs of evolutive disease, were detected. In such cases, sacroiliitis representing in fact a form of onset of ankylosing spondylitis, the HLA-B27 phenotype was also determined and was found present in 8 cases. Of the biologic tests the decrease of serum fibronectin proved the most significantly correlated with evolutive tendency of sacroiliitis.