Attempts towards a serological diagnosis of ankylosing spondylitis.

Polytene chromosomes of salivary glands as well as nuclear proteins from Kc-cells of Drosophila melanogaster have been used as substrate to identify and evaluate the diagnostic value of crossreacting antibodies present in sera of AS patients. The diagnostic significance of the recently described anti-93D antibody (Lakomek et al., 1984) was confirmed by screening sera of patients with definite or suspected AS using cytoimmunofluorescence on the polytene chromosomes. In addition, four new antibodies could be identified in AS sera by immunoblotting. Simultaneous detection of these antibodies supports the diagnosis of AS and is most useful in diagnosis of early stages of this disease.