X-linked primary immunodeficiency associated with hemizygous mutations in the moesin (MSN) gene.

Lagresle-Peyrou C, Luce S, Ouchani F, Soheili TS, Sadek H, Chouteau M, Durand A, Pic I, Majewski J, Brouzes C, Lambert N, Bohineust A, Verhoeyen E, Cosset FL, Magerus-Chatinet A, Rieux-Laucat F, Gandemer V, Monnier D, Heijmans C, van Gijn M, Dalm VA, Mahlaoui N, Stephan JL, Picard C, Durandy A, Kracker S, Hivroz C, Jabado N, de Saint Basile G, Fischer A, Cavazzana M, André-Schmutz I.

Source : J. Allergy Clin. Immunol.

2017 Jul 10

Pmid : 27405666

Abstract

BACKGROUND: We investigated 7 male patients (from 5 different families) presenting with profound lymphopenia, hypogammaglobulinemia, fluctuating monocytopenia and neutropenia, a poor immune response to vaccine antigens, and increased susceptibility to bacterial and varicella zoster virus infections.

OBJECTIVE: We sought to characterize the genetic defect involved in a new form of X-linked immunodeficiency.

METHODS: We performed genetic analyses and an exhaustive phenotypic and functional characterization of the lymphocyte compartment.

RESULTS: We observed hemizygous mutations in the moesin (MSN) gene (located on the X chromosome and coding for MSN) in all 7 patients. Six of the latter had the same missense mutation, which led to an amino acid substitution (R171W) in the MSN four-point-one, ezrin, radixin, moesin domain. The seventh patient had a nonsense mutation leading to a premature stop codon mutation (R533X). The naive T-cell counts were particularly low for age, and most CD8+ T cells expressed the senescence marker CD57. This phenotype was associated with impaired T-cell proliferation, which was rescued by expression of wild-type MSN. MSN-deficient T cells also displayed poor chemokine receptor expression, increased adhesion molecule expression, and altered migration and adhesion capacities.

CONCLUSION: Our observations establish a causal link between an ezrin-radixin-moesin protein mutation and a primary immunodeficiency that could be referred to as X-linked moesin-associated immunodeficiency.

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