Autoantibodies in systemic lupus erythematosus and urticarial vasculitis.

OBJECTIVE: Urticarial vasculitis (UV) is both a primary disorder and a cutaneous vasculitic manifestation in patients with connective tissue diseases. We examined the prevalence of autoantibodies to vascular endothelial cells (aECA) and anti-Clq antibodies in patients with UV.

METHODS: ELISA were used to detect aECA and anti-Clq autoantibodies, and we tested for correlation with UV in 4 patient groups: healthy controls, patients with systemic lupus erythematosus (SLE) with and without UV, patients with primary systemic vasculitides with UV, and patients with hypocomplementemic urticarial vasculitis syndrome (HUVS).

RESULTS: aECA were detected in 82% of patients with SLE with UV and 70% of patients with HUVS. In contrast, aECA were found in 32% of patients with SLE without UV and 14% of patients with primary UV. Anti-Clq antibodies were present in all patients with HUVS, but in < 20% in the other 3 groups. Antineutrophil cytoplasmic antibodies were detected in only one patient.

CONCLUSION: Although the development of UV is likely to be multifactorial, the high prevalence of aECA in HUVS and SLE with UV suggests that this antibody is associated with vasculitis and may have a role in the pathogenesis of UV in these patients.