Anti-endothelial
antibodies (AEA) have been described in patients with
rheumatoid arthritis (RA) complicated by
vasculitis. In this study we made use of an ELISA and immunoblot technique (IBT) to further characterize AEA of the
IgG class in serum of patients with
rheumatoid vasculitis (RV) and to investigate the relationship between the presence of
IgG-AEA and
vasculitis.
IgG-AEA as measured by ELISA or IBT could be detected in the serum from 20 of the 23 (87%) RV patients, in 2 out of 13 (15%) patients with RA and in one of 15 healthy donors. The IBT revealed reactivity of
IgG-AEA against a total of 12 bands of endothelial
antigens ranging in size from 16 to 68 kD.
IgG-AEA as measured by ELISA and IBT in serum samples of patients followed longitudinally were present more frequently and in higher titres in patients with active RV as compared to patients with
vasculitis in remission. A significant correlation was found between the presence of clinical signs of
vasculitis and serum
IgG-AEA reactivity against an endothelial membrane
antigen of 44 kD. These data show that the pattern of
IgG-AEA reactivity in the serum of RV patients is heterogeneous and suggest that
IgG-AEA against one particular
antigen is involved in the pathogenesis of RV.