Antineutrophil cytoplasmic antibodies in systemic lupus erythematosus

To evaluate the prevalence of cytoplasmic (c) and peripheral (p) antineutrophil cytoplasmic antibodies (ANCA) using the indirect immunofluorescence (IIF) slide kit (INOVA) in patients with systemic lupus erythematosus (SLE) to correlate the presence of ANCA with disease activity and to determine if ANCA is associated with specific clinical manifestations.

One hundred and fourteen consecutive patients with SLE seen at The Wellesley Hospital Lupus Clinic, Toronto, Ontario in May and June, 1992 were assessed clinically, and blood drawn for routine serology and ANCA. Disease activity was measured using the SLE Disease Activity Index (SLEDAI). ANCA was measured by IIF.

Of the 114 patients, 12 (10.5%) had c-ANCA and 29 patients (25.4%) had p-ANCA. The titers of ANCA varied from 1:20 to 1:160. SLEDAI was 0 in 6 patients (5%), and 108 patients had some disease activity. Eighty-eight patients (77%) had mild to moderate active disease (SLEDAI < 10), and 20 (18%) patients had severe active disease (SLEDAI > or = 10).

No correlation was found between the presence of ANCA and SLEDAI either when analyzed as active-inactive (p = 0.75) or when correlated with degrees of disease activity (1-10: > 10) (p = 0.77). No correlation was found between p and c ANCA and the presence of vasculitis, renal, or CNS disease at the time of the assessment or at any time during the course of the disease. Thus ANCA was not associated with SLE disease activity or the presence of vasculitis in SLE.