Relationships between smooth muscle and cytoskeleton antibodies in human serum samples

In order to characterize the relationship between smooth muscle antibodies (SMA) and antibodies directed to the cytoskeleton components (microfilaments, intermediate filaments and microtubules), 338 serum samples from patients with various diseases and from healthy control subjects were tested for SMA and anti-cytoskeleton antibodies using a conventional immunofluorescence method employing traditional substrates and vinblastine-treated fibroblasts. The correspondence between SMA and these antibodies turned out to be incomplete and more evident for anti-microfilaments and anti-microtubules than for anti-intermediate filaments antibodies. Our data confirm that SMA are a quite heterogeneous family of antibodies, whose specificities are not entirely related to the cytoskeleton components. Studies with purified antigens will probably characterize these specificities.