TLR4 and autoimmune disease: Because Syk is a critical downstream signaling of FcγR (activated by the Fc portion of immunoglobulin) and is also a downstream signaling of TLR-4 and Dectin-1 [33], the presence of microbial molecules in the serum of FcγRIIb−/− mice [20] might synergistically activate inflammation through Syk, as mentioned in several autoimmune diseases [34, 35].