Systemic lupus erythematosus (SLE) is one of the autoimmune diseases extensively studied by immunologists and physicians. The main focus regarding SLE pathophysiology has been placed on abnormal cell surface receptor function on lymphocytes. However, recent studies have revealed that defective clearance of apoptotic cells causes self-antigen accumulation, which could trigger the activation of autoreactive lymphocytes. Thus, here we review current findings about the association of the defective clearance of autoantigens and SLE, focusing on mutations in the DNase I locus and their relationship to SLE.