CD40LG and systemic lupus erythematosus: The expression of CD40L on NKT cells is associated with the lipid antigen activation of these cells, since blocking CD40L with a monoclonal antibody leads to reduced production of IgG, IgM and IgA antibodies, as well as IgG anti-dsDNA antibodies, in a co-culture of NKT cells and autologous B cells from lupus patients [23].