The present invention provides methods and compositions for treating
immune complex associated diseases (ICAD), such as SLE, rheumatoid
arthritis, and hepatitis-C related immune complex disease (e.g.,
cryoglobulinemia) in a subject having an ICAD or at risk for developing
ICAD. The invention is based upon the surprising finding that
chromatin-containing immune complexes activate autoreactive B cells and
dendritic cells by a dual receptor engagement process which, in both cell
types, involves a Toll-like receptor (TLR). The methods of treating ICAD
comprise administering a compound to an individual in need thereof that
either 1) inhibits formation of the immune complex either by preventing
formation and/or binding to the TLR, or 2) interferes with binding of an
autoantigen-containing immune complex (or the antigenic component
thereof) to the TLR, or 3) inhibits signaling pathways initiated by dual
engagement of BCR and TLR (in B cells) or FcR and TLR (in dendritic
cells) via immune complexed or uncomplexed autoantigens.