Disturbed canonical nuclear factor of κ light chain signaling in B cells of patients with common variable immunodeficiency.

Keller B, Cseresnyés Z, Stumpf I, Wehr C, Fliegauf M, Bulashevska A, Usadel S, Grimbacher B, Rizzi M, Eibel H, Niesner R, Warnatz K (2017) Disturbed canonical nuclear factor of κ light chain signaling in B cells of patients with common variable immunodeficiency. J Allergy Clin Immunol 139(1), 220-231.

Abstract

BACKGROUND: Most patients with common variable immunodeficiency (CVID) present with severely reduced switched memory B-cell counts, and some display an increase of CD21low B-cell counts (CVID 21low), whereas others do not (CVID 21norm). Altered B-cell receptor (BCR) signaling might contribute to the defective memory formation observed in patients with CVID.

OBJECTIVE: We sought to investigate canonical nuclear factor of κ light chain (NF-κB) signaling in B cells from patients with CVID as a central pathway in B-cell differentiation.

METHODS: Degradation of inhibitor of κBα (IκBα) and p65 phosphorylation, nuclear translocation of p65, and regulation of target genes and cell function were investigated after different modes of B-cell stimulation.

RESULTS: BCR-mediated canonical NF-κB signaling was impaired in all mature naive CVID-derived B cells. This impairment was more profound in naive B cells from CVID 21low patients than CVID 21norm patients and most pronounced in CD21low B cells. The signaling defect translated into reduced induction of Bcl-xL and IκBα, 2 bona fide target genes of the canonical NF-κB pathway. CD40 ligand- and Toll-like receptor 9-mediated signaling were less strongly altered. Signaling in CD21low B cells but not CD21+ B cells of patients with HIV was similarly affected.

CONCLUSION: Combined with the previous description of disturbed Ca2+ signaling, the discovery of NF-κB signaling defects, especially in CVID 21low patients, suggests a broad underlying signaling defect affecting especially BCR-derived signals. Given the immune phenotype of monogenic defects affecting Ca2+ and NF-κB signaling, the latter is more likely to contribute to the humoral deficiency. The strongly disturbed BCR signaling of CD21low B cells is characteristic for this cell type and independent of the underlying disease.

Leibniz-HKI-Autor*innen

Zoltán Cseresnyés

Identifier

doi: 10.1016/j.jaci.2016.04.043

PMID: 27461466