ABSTRACT
This chapter reviews how epigenetic mechanisms contribute to immune differentiation and function and how epigenetic abnormalities contribute to human autoimmune disease. The differentiation of hematopoietic precursor cells into lymphocytes and their subsequent activation by foreign antigens are key processes determining immune function. The importance of epigenetic mechanisms in immune differentiation and function is evidenced by immune diseases caused at least in part by epigenetic abnormalities. Lupus is characterized by autoantibody formation to nuclear antigens and immune complex deposition in tissues such as the kidney. The recipients developed anti-DNA antibodies and an immune complex glomerulonephritis as well as other histologic features of autoimmunity, depending on the strain. T-cell DNA methylation abnormalities in human lupus appear to be predicted by experimental demethylation of T cells in vitro. Rheumatoid arthritis, a systemic autoimmune disease that causes a deforming and disabling arthritis, is also associated with genome-wide T-cell DNA hypomethylation.
