CD4 and Autoimmunity: IVIg targets both cellular and soluble mediators of autoimmunity and inhibits the disease by multi-pronged mutually nonexclusive mechanisms such as neutralization of anti-cytokine autoantibodies by broad-spectrum anti-idiotypic antibodies, induction of B cell tolerance, inhibition of cellular proliferation, regulation of immunoglobulin repertoire, suppression of innate antigen presenting cells and inhibition of T cell help to B cells, and expansion of CD4+CD25+ regulatory T cells, the cells that are critical for maintaining immune tolerance and to suppress autoimmunity [51], [52].