 Systemic lupus erythematosus SLE is an autoimmune disease in autoimmune illness, the immune system in the body attacks its own cells, leading to illness. It is not completely understood how this disease develops in the body. In a normal person, there is a tolerance of antigens substances that make antibodies, which protect the body from disease-causing agents. Research in mice suggests that defects in certain types of cells can make the body lose this tolerance, therefore recognizing antigens made in the body as foreign, and mounting an immune response to the self, thus causing autoimmune disease. In this study, the researchers will look at these potentially defective cells in people with SLE and other autoimmune diseases and compare them to cells in healthy participants, as well as looking at the blood of first-degree relatives of people with autoimmune disease. 