MPO and systemic lupus erythematosus: The presence of high titres of P-ANCA and anti-MPO with multi-antigenicity, the positive anti-histone antibodies and the lack of immunoglobulin and complement deposition histopathogically are features that have been described with drug-induced ANCA vasculitis[2,3] rather than with drug-induced lupus or with primary vasculitis.