Partial RAG deficiency in humans induces dysregulated peripheral lymphocyte development and humoral tolerance defect with accumulation of T-bet+ B cells

Nat Immunol. 2022 Aug;23(8):1256-1272. doi: 10.1038/s41590-022-01271-6. Epub 2022 Jul 28.

Abstract

The recombination-activating genes (RAG) 1 and 2 are indispensable for diversifying the primary B cell receptor repertoire and pruning self-reactive clones via receptor editing in the bone marrow; however, the impact of RAG1/RAG2 on peripheral tolerance is unknown. Partial RAG deficiency (pRD) manifesting with late-onset immune dysregulation represents an 'experiment of nature' to explore this conundrum. By studying B cell development and subset-specific repertoires in pRD, we demonstrate that reduced RAG activity impinges on peripheral tolerance through the generation of a restricted primary B cell repertoire, persistent antigenic stimulation and an inflammatory milieu with elevated B cell-activating factor. This unique environment gradually provokes profound B cell dysregulation with widespread activation, remarkable extrafollicular maturation and persistence, expansion and somatic diversification of self-reactive clones. Through the model of pRD, we reveal a RAG-dependent 'domino effect' that impacts stringency of tolerance and B cell fate in the periphery.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • B-Lymphocytes*
  • Cell Differentiation
  • DNA-Binding Proteins* / deficiency
  • DNA-Binding Proteins* / genetics
  • Homeodomain Proteins* / genetics
  • Humans
  • Immune Tolerance
  • Lymphocyte Count
  • Nuclear Proteins* / deficiency

Substances

  • DNA-Binding Proteins
  • Homeodomain Proteins
  • Nuclear Proteins
  • RAG2 protein, human
  • RAG-1 protein