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T and B cell abnormalities, pneumocystis pneumonia, and chronic lymphocytic leukemia associated with an AIOLOS defect in patients.

Hye Sun KuehnJingjie ChangMotoi YamashitaJulie E NiemelaChengcheng ZouKazuki OkuyamaJunji HaradaJennifer L StoddardCristiane J Nunes-SantosBrigette BoastRyan M BaxterElena W Y HsiehMary GarofaloThomas A FleisherTomohiro MorioIchiro TaniuchiCullen M DutmerSergio D Rosenzweig
Published in: The Journal of experimental medicine (2021)
AIOLOS/IKZF3 is a member of the IKAROS family of transcription factors. IKAROS/IKZF1 mutations have been previously associated with different forms of primary immunodeficiency. Here we describe a novel combined immunodeficiency due to an IKZF3 mutation in a family presenting with T and B cell involvement, Pneumocystis jirovecii pneumonia, and/or chronic lymphocytic leukemia. Patients carrying the AIOLOS p.N160S heterozygous variant displayed impaired humoral responses, abnormal B cell development (high percentage of CD21low B cells and negative CD23 expression), and abrogated CD40 responses. Naive T cells were increased, T cell differentiation was abnormal, and CD40L expression was dysregulated. In vitro studies demonstrated that the mutant protein failed DNA binding and pericentromeric targeting. The mutant was fully penetrant and had a dominant-negative effect over WT AIOLOS but not WT IKAROS. The human immunophenotype was recapitulated in a murine model carrying the corresponding human mutation. As demonstrated here, AIOLOS plays a key role in T and B cell development in humans, and the particular gene variant described is strongly associated with immunodeficiency and likely malignancy.
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