A CONFOCAL MICROSCOPY STUDY OF ANTICYTOSKELETAL ANTIBODY-ACTIVITY IN PATIENTS WITH CONNECTIVE-TISSUE DISEASE

The significance of the presence of antibodies to cytoskeleton protein s in patients with connective tissue diseases is not clear, as there i s a high level of these antibodies in healthy controls. In an attempt to improve the visualization of the immunofluorescence binding pattern of autoantibodies to cytoskeletal structures in cultured fibroblasts, we have used confocal microscopy. Of the 256 serum samples tested, 15 5 (61%) were reactive with cytoplasmic structures. These reactive samp les could be divided into seven patterns of binding, as determined by double-blind examination of single-section confocal images. While conf irming the results of previous immunofluorescence studies which have s hown that autoantibodies that bind to filamentous structures in the cy toplasm of cultured cells are common in patients with connective tissu e diseases, we were able to identify three patterns of cytoskeletal bi nding which may be useful as an adjunct to other tests for the diagnos is of some connective tissue diseases, in particular systemic sclerosi s (scleroderma) and rheumatoid arthritis/Sjogren's syndrome. None of t he seven patterns was exclusive to a particular disease. We conclude t hat confocal microscopy may be of limited use as an adjunct to other s erological assays in the diagnosis of some forms of connective tissue disease.