Table 1: Highlighting Some Current Data Available on the Role Played by APCs, their FcγRs and TLRs and their Products

	SLE	RA	SSc
Genetics (associated genes important in the function of APCs)	HLA-DRB1/DQB1 [18,19] FcgRIIa and FcgRIIIa [20,21] IRF5 [22-24] STAT4 [27]	HLA-DRB1 [62-64] FcgRIIIa/b and FcgRIIb [69-72] IRF5 [73] STAT4 [74]	HLA-DR [127-129] IRF5 [130] STAT4 [132]
In vivo	Increased transcription of type I IFN regulated genes in peripheral blood cells. [31] Increased levels of IFNa correlated with disease severity. [30] Increased IL-12p70 levels correlating with SLEDAI. [40,41]	Increased TLR2, 3, 4, 7 expression and presence of endogenous TLR4 ligands in RA synovial tissue. [39, 77-79] Increased transcription of type I IFN regulated genes in blood. [88] IFNa expression in RA synovial tissue. [10]	Increased transcription of certain type I IFN regulated genes in peripheral blood cells. [135] Endogenous TLR4ligands in serum. [39] Myeloid APCs in diseased skin. [150-151]
In vitro	ICs from SLE patients induce the release of IFNa by plasmacytoid DCs via TLR7 and TLR9. [36,37] Monocyte-derived and myeloid DCs from SLE patients demonstrate increased maturation and cytokine release. [44]	RA synovial tissue fibroblasts and monocyte-derived DCs display an increased response to TLR stimulation. [39,80] ICs in synovial fluid induce TNFa release from monocytes. [92,93] TLR8 inhibition prevents spontaneous cytokine release by synovial tissue. [87]	Interferogenic activity of anti-topoisomerase ICs on plasmacytoid DCs. [137]
Animal models	TLR7-/- mice do not develop anti-Sm antibodies and have a less severe disease. [49] TLR7 over expression results in increased autoimmunity. [52] IFNaR-/- mice develop less severe lupus-like disease. [48]	FcgRIII-/- mice are protected from IC-induced arthritis. [97, 99] FcgRII-/- mice are more susceptible and have a worse arthritis. [101] Knocking out of TLR4 or the blockade of TLR4 reduces arthritis in multiple models. [102, 104] Syk inhibitors suppress inflammation and bone erosion. [100]	UCD 200 chicken, Tsk2 mice and bleomycin induced SSc show mononuclear cell infiltrates and autoantibody production. [152-156] Signaling through TLR4 in the bleomycin model induces autoantibody production. [158]
Treatment (drugs emphasizing the role played by APCs and their receptors)	HCQ and glucocorticoids [55,56] Anti-IFNa antibodies [57] Abetimus sodium [58]	HCQ and glucocorticoids [113-116] Abatacept [110-112] Chaperonin 10 [118] Syk inhibitor, R788 [121]