To evaluate, in a cohort of 566 patients with systemic lupus erythematosus (SLE) drawn from 11 European centres: (i) the prevalence of ANCAs and their subspecificities in a large series of European SLE patients; (ii) the possible associations of ANCA with the most common clinical manifestations of the disease; and (iii) whether ANCAs correlate with some of the autoantibodies commonly found in SLE.
ANCA detection was performed by indirect immunofluorescence (IIF), and by ELISA for lactoferrin (LF), myeloperoxydase (MPO), proteinase3 (PR3) and lysozyme (LZ) subspecificities.
The prevalence of ANCA was 16.4% (IIF). The prevalence of LF was 14.3%, LZ 4.6%, MPO 9.3%, and PR3 1.7%. Our results show that ANCA is associated with certain clinical manifestations of SLE. In particular, positive correlations were found between IIF ANCA and serositis (p = 0.026), livedo reticularis (p = 0.01), venous thrombosis (p = 0.03) and arthritis (p = 0.04), while anti-LF antibodies were associated with serositis (p = 0.05) and livedo reticularis (p < 10(-3). Nevertheless, multivariate analysis demonstrated that other autoantibodies, such as aCL and SSA/Ro, are more closely correlated than ANCA with some of the aforementioned clinical features.
Our results demonstrate that ANCA are detectable in SLE sera and that some of them are associated with particular clinical manifestations. Whether ANCA plays a direct pathogenetic role in the vascular damage of SLE or only represents an epiphenomenon or a marker of disease activity remains to be elucidated.