RAG1 splicing mutation causes enhanced B cell differentiation and autoantibody production

Autor: Qing Min, Xin Meng, Qinhua Zhou, Ying Wang, Yaxuan Li, Nannan Lai, Ermeng Xiong, Wenjie Wang, Shoya Yasuda, Meiping Yu, Hai Zhang, Jinqiao Sun, Xiaochuan Wang, Ji-Yang Wang
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: JCI Insight, Vol 6, Iss 19 (2021)
Druh dokumentu: article
ISSN: 2379-3708
DOI: 10.1172/jci.insight.148887
Popis: Hypomorphic RAG1 or RAG2 mutations cause primary immunodeficiencies and can lead to autoimmunity, but the underlying mechanisms are elusive. We report here a patient carrying a c.116+2T>G homozygous splice site mutation in the first intron of RAG1, which led to aberrant splicing and greatly reduced RAG1 protein expression. B cell development was blocked at both the pro-B to pre-B transition and the pre-B to immature B cell differentiation step. The patient B cells had reduced B cell receptor repertoire diversity and decreased complementarity determining region 3 lengths. Despite B cell lymphopenia, the patient had abundant plasma cells in the BM and produced large quantities of IgM and IgG Abs, including autoantibodies. The proportion of naive B cells was reduced while the frequency of IgD–CD27– double-negative (DN) B cells, which quickly differentiated into Ab-secreting plasma cells upon stimulation, was greatly increased. Immune phenotype analysis of 52 patients with primary immunodeficiency revealed a strong association of the increased proportion of DN B and memory B cells with decreased number and proportion of naive B cells. These results suggest that the lymphopenic environment triggered naive B cell differentiation into DN B and memory B cells, leading to increased Ab production.
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