Patients with a history of thyroid disease are more likely to have MPO-ANCA than PR3-ANCA.9 Crescents in the presence of membranous nephropathy may also suggest another underlying disease process, such as lupus nephritis or anti-GBM disease.2 Although C1q deposits were found in the glomeruli on immunofluorescence, lupus was ruled out in this case in view of negative anti-dsDNA and normal complements. Here, MPO is linked to systemic lupus erythematosus.