IGM-containing immune complexes and antiphospholipid antibodies in patients with Sneddon's syndrome.

We report three patients with a Sneddon syndrome in whom predominantly small (500-900 kD) IgM-containing serum immune complexes were detectable. Furthermore, antiphospholipid antibodies and increased von Willebrand factor antigen were found in the sera of two cases. Especially the data demonstrating small circulating immune complex as suggest that Sneddon's syndrome, a rare vasculitis disorder, might immunologically be characterized by circulating IgM-containing immune complexes which, in addition, could play a role in the pathogenesis of this disease entity. The elevated antiphospholipid antibodies as well as the increased von Willebrand factor antigen in the sera of the investigated patients have to be considered as nonspecific vasculitis-associated phenomena.