A neomorphic mutation in the interferon activation domain of IRF4 causes a dominant primary immunodeficiency.

The Journal of experimental medicine 2023 Jun 05

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Here, we report on a heterozygous interferon regulatory factor 4 (IRF4) missense variant identified in three patients from a multigeneration family with hypogammaglobulinemia. Patients' low blood plasmablast/plasma cell and naïve CD4 and CD8 T cell counts contrasted with high terminal effector CD4 and CD8 T cell counts. Expression of the mutant IRF4 protein in control lymphoblastoid B cell lines reduced the expression of BLIMP-1 and XBP1 (key transcription factors in plasma cell differentiation). In B cell lines, the mutant IRF4 protein as wildtype was found to bind to known IRF4 binding motifs. The mutant IRF4 failed to efficiently regulate the transcriptional activity of interferon-stimulated response elements (ISREs). Rapid immunoprecipitation mass spectrometry of endogenous proteins indicated that the mutant and wildtype IRF4 proteins differed with regard to their respective sets of binding partners. Our findings highlight a novel mechanism for autosomal-dominant primary immunodeficiency through altered protein binding by mutant IRF4 at ISRE, leading to defective plasma cell differentiation. © 2023 Thouenon et al.

Citation

Romane Thouenon, Loïc Chentout, Nidia Moreno-Corona, Lucie Poggi, Emilia Puig Lombardi, Benedicte Hoareau, Yohann Schmitt, Chantal Lagresle-Peyrou, Jacinta Bustamante, Isabelle André, Marina Cavazzana, Anne Durandy, Jean-Laurent Casanova, Lionel Galicier, Jehane Fadlallah, Alain Fischer, Sven Kracker. A neomorphic mutation in the interferon activation domain of IRF4 causes a dominant primary immunodeficiency. The Journal of experimental medicine. 2023 Jun 05;220(6)