Antibodies in systemic lupus antineutrophil cytoplasmic erythematosus: prevalence, disease activity correlations and organ system associations

Systemic Lupus Erythematosus (SLE) is a disease with multiorgan involvement and multiple autoantibody production including antineutrophil cytoplasmic antibodies (ANCA). Despite its reported prevalence in more than one third of SLE patients, the role of ANCA in the pathogenesis or otherwise in SLE remains unresolved. 131 SLE patients had been previously studied for various serologic parameters of disease activity. Their cumulative organ involvement in the course of their disease had also been determined and the Lupus Activity Index (LAI) calculated. Their stored sera were then screened for the presence of ANCA by two methods viz Indirect immunofluorescence (IIF) and also enzyme-linked immunosorbent assay (ELISA). ANCA was present in 24.8% of these SLE patients. The atypical ANCA pattern was predominant and accounted for an overall of 20.6%. Anti-MPO and anti-PR3 were detected in 1.5% of patients respectively. No association was found between ANCA positivity and disease activity. There was also no association of ANCA with specific organ involvement. Despite the high prevalence of ANCA especially the atypical variant in SLE, they probably represent only one of the wide repertoire of autoantibodies found in this disease. Routine testing for ANCA in lupus patients is therefore not recommended.