TLR7 gain-of-function genetic variation causes human lupus
Publication Year 2022-04-27,Volume 605,Issue #7909,Page 349-356
Journal Title
Although circumstantial evidence supports enhanced Toll-like receptor 7 (TLR7) signalling as a mechanism of human systemic autoimmune disease(1-7), evidence of lupus-causing TLR7 gene variants is lacking. Here we describe human systemic lupus erythematosus caused by a TLR7 gain-of-function variant. TLR7 is a sensor of viral RNA(8),(9) and binds to guanosine(10)-(12). We identified a de novo, previously undescribed missense TLR7(Y264H) variant in a child with severe lupus and additional variants in other patients with lupus. The TLR7(Y264H) variant selectively increased sensing of guanosine and 2',3'-cGMP(10-12), and was sufficient to cause lupus when introduced into mice. We show that enhanced TLR7 signalling drives aberrant survival of B cell receptor (BCR)-activated B cells, and in a cell-intrinsic manner, accumulation of CD11c(+) age-associated B cells and germinal centre B cells. Follicular and extrafollicular helper T cells were also increased but these phenotypes were cell-extrinsic. Deficiency of MyD88 (an adaptor protein downstream of TLR7) rescued autoimmunity, aberrant B cell survival, and all cellular and serological phenotypes. Despite prominent spontaneous germinal-centre formation in Tlr7(Y264H) mice, autoimmunity was not ameliorated by germinal-centre deficiency, suggesting an extrafollicular origin of pathogenic B cells. We establish the importance of TLR7 and guanosine-containing self-ligands for human lupus pathogenesis, which paves the way for therapeutic TLR7 or MyD88 inhibition.
WEHI Research Division(s)
Structural Biology
PubMed ID
Open Access at Publisher's Site
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Creation Date: 2022-05-03 09:18:27
Last Modified: 2022-06-16 11:06:31
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