Induction of dendritic cell differentiation by IFN-alpha in systemic lupuserythematosus

Dendritic cells (DCs) are important in regulating both immunity and toleran ce. Hence, we hypothesized that systemic lupus erythematosus (SLE), an auto immune disease characterized by autoreactive B and T cells, may be caused b y alterations in the functions of DCs. Consistent with this, monocytes from SLE patients' blood were found to function as antigen-presenting cells, in vitro. Furthermore, serum from SLE patients induced normal monocytes to di fferentiate into DCs. These DCs could capture antigens from dying cells and present them to CD4-positive T cells. The capacity of SLE patients' serum to induce DC differentiation correlated with disease activity and depended on the actions of interferon-alpha (IFN-alpha). Thus, unabated induction of DCs by IFN-alpha may drive the autoimmune response in SLE.