IFNA1 and systemic lupus erythematosus: In addition to ITAM-associated RRs, pDCs express an ITAM-associated FcR, FcγRIIa (CD32a), which is responsible for uptake and delivery of systemic lupus erythematosus (SLE) immune complexes (IC) in the endosomal compartment called the IFN signaling compartment, from where they trigger TLR9 signaling followed by massive IFN-I production (72, 76).