Systemic Lupus Erythematosus: The TLR7→BAFF→IFN Loop, A20 Dysfunction, and Epstein-Barr Virus in a Convergent Model

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by a type I interferon signature, B cell hyperactivity, and loss of CD8-mediated control of Epstein-Barr virus (EBV). Here we present a convergent model integrating five EBV mechanisms that simultaneously amplify the TLR7→IRF7→BAFF→IFN feedback loop and disable the CD8 response that should control it. The model integrates: (1) BGLF2-mediated STAT2 degradation in CD8 T cells, confirmed across 924 SLE patients (GSE65391); (2) LMP1 constitutive CD40 signaling compensating for low CD40LG; (3) EBNA2 reprogramming of B cells as antigen-presenting cells (Younis/Robinson 2025, Sci TM); (4) EBERs activating TLR7 → IFN production; and (5) LMP1 driving NF-κB through defective A20 (TNFAIP3, rs2230926). Key findings: STAT2 is significantly reduced in SLE CD8 cells, identifying BGLF2-mediated STAT2 degradation as the mechanistic link between EBV and CD8 dysfunction. A20 (rs2230926) dysfunction removes the brake on LMP1-driven NF-κB activation. The TLR7→BAFF→IFN loop is invariant across all affected organs (renal, mucocutaneous, hematologic) — a pre-existing systemic state rather than organ-specific. EBNA2 reprogramming of EBV-infected B cells into antigen-presenting cells drives autoreactive Tph and DN2 B cell expansion. Data sources: GSE65391 (n=924 pediatric SLE), GSE135779 (363,083 single cells), GSE50772, GSE81622, GSE72326, GSE119079, GSE72509 (n=996), GSE58484, GSE118253 (ATAC-seq), Baños 2021 (bone marrow CD34+), Younis/Robinson 2025 (EBV-seq). Without EBV, the core phenomena of SLE lack a mechanistic framework. With EBV — including BGLF2 degradation of STAT2, LMP1 hijacking of CD40, EBNA2 reprogramming of B cells, EBER activation of TLR7, and LMP1 exploitation of broken A20 — they converge into a testable model with immediate therapeutic implications including sirolimus for mTOR blockade and maribavir for reducing EBV viral load.