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J Exp Med. 2014 Mar 10;211(3):413-26. doi: 10.1084/jem.20131424. Epub 2014 Feb 17.

Consequences of the recurrent MYD88(L265P) somatic mutation for B cell tolerance.

Author information

1
Department of Immunology, John Curtin School of Medical Research, 2 Australian Phenomics Facility, The Australian National University, Canberra, Australian Capital Territory 0200, Australia.

Abstract

MYD88(L265P) has recently been discovered as an extraordinarily frequent somatic mutation in benign monoclonal IgM gammopathy, Waldenström's macroglobulinemia, and diffuse large B cell lymphoma. In this study, we analyze the consequences for antigen-activated primary B cells of acquiring MYD88(L265P). The mutation induced rapid B cell division in the absence of exogenous TLR ligands and was inhibited by Unc93b1(3d) mutation and chloroquine or TLR9 deficiency, indicating continued dependence on upstream TLR9 activation. Proliferation and NF-κB activation induced by MYD88(L265P) were nevertheless rapidly countered by the induction of TNFAIP3, an NF-κB inhibitor frequently inactivated in MYD88(L265P)-bearing lymphomas, and extinguished by Bim-dependent apoptosis. MYD88(L265P) caused self-reactive B cells to accumulate in vivo only when apoptosis was opposed by Bcl2 overexpression. These results reveal checkpoints that fortify TLR responses against aberrant B cell proliferation in response to ubiquitous TLR and BCR self-ligands and suggest that tolerance failure requires the accumulation of multiple somatic mutations.

PMID:
24534189
PMCID:
PMC3949567
DOI:
10.1084/jem.20131424
[Indexed for MEDLINE]
Free PMC Article

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