Characterization of the clinical and immunologic phenotype and management of 157 individuals with 56 distinct heterozygous NFKB1 mutations

Abstract

Background: An increasing number of NFKB1 variants are being identified in patients with heterogeneous immunologic phenotypes.

Objective: To characterize the clinical and cellular phenotype as well as the management of patients with heterozygous NFKB1 mutations.

Methods: In a worldwide collaborative effort, we evaluated 231 individuals harboring 105 distinct heterozygous NFKB1 variants. To provide evidence for pathogenicity, each variant was assessed in silico; in addition, 32 variants were assessed by functional in vitro testing of nuclear factor of kappa light polypeptide gene enhancer in B cells (NF-κB) signaling.

Results: We classified 56 of the 105 distinct NFKB1 variants in 157 individuals from 68 unrelated families as pathogenic. Incomplete clinical penetrance (70%) and age-dependent severity of NFKB1-related phenotypes were observed. The phenotype included hypogammaglobulinemia (88.9%), reduced switched memory B cells (60.3%), and respiratory (83%) and gastrointestinal (28.6%) infections, thus characterizing the disorder as primary immunodeficiency. However, the high frequency of autoimmunity (57.4%), lymphoproliferation (52.4%), noninfectious enteropathy (23.1%), opportunistic infections (15.7%), autoinflammation (29.6%), and malignancy (16.8%) identified NF-κB1-related disease as an inborn error of immunity with immune dysregulation, rather than a mere primary immunodeficiency. Current treatment includes immunoglobulin replacement and immunosuppressive agents.

Conclusions: We present a comprehensive clinical overview of the NF-κB1-related phenotype, which includes immunodeficiency, autoimmunity, autoinflammation, and cancer. Because of its multisystem involvement, clinicians from each and every medical discipline need to be made aware of this autosomal-dominant disease. Hematopoietic stem cell transplantation and NF-κB1 pathway-targeted therapeutic strategies should be considered in the future.

Keywords: NF-κB1-related phenotype; NFKB1 mutation; NFKB1 variant; autosomal dominant; common variable immunodeficiency; reduced penetrance.

FIG 1.

Localization of NFKB1 mutations. Numbers indicate amino acid positions. Horizontal black bars delineate the location of 4 different groups of damaging NFKB1 mutations. For each mutation, the number of carriers is indicated. GAPDH, Glyceraldehyde-3-phosphate dehydrogenase.

FIG 2.

Subcellular localization, expression, and activity of distinct types of NFKB1 variants. HEK293T cells were transiently transfected with N-terminal GFP-fused constructs, as indicated. Nuclei were stained with Hoechst 33342 (blue). A, Haploinsufficiency mutations caused aberrant signals, whereas p50-like proteins (precursor-skipping variants) were localized to the nucleus. Missense variants (introduced into the full-length p105) produced signals that were indistinguishable from WT p105. B, PMA/ionomycin treatment caused clumping of the p.Ile87Ser mutant. C, Western Blot analysis (1) confirmed that transfected WT and transfected mutant p105 each underwent processing to p50, and (2) revealed the limited expression of the p.Ile87Ser variant. GAPDH was used as loading control. D, Loss of luciferase reporter activity with p.Arg57Cys and p.Ile87Ser mutants. Relative light units were normalized to cotransfected Renilla luciferase. Mock not shown. DNA amounts were compensated with nonrelated plasmid DNA. Depicted data represent the results from 2 to 4 experimental repeats, and additional data can be found in Fig E6. HEK293T, Human embryonic kidney 293T; PMS, phorbol myristate acetate.

FIG 3.

Clinical course and survival rate of NFKB1 cohort. A, Cumulative percentage of symptomatic patients who developed infections, autoimmunity, lung disease, and cancer. B, Kaplan-Meier survival curve with 95% CI (dotted lines).

FIG 4.

Exemplary CT and MRI findings and histopathology in patients with damaging heterozygous NFKB1 mutations. (A) and (C) from the same patient. Polypoid shifting of the ethmoidal cells as well as both sinus maxillares. Lower displacement of the frontal sinus and the sphenoid sinus. (B) and (D) from the same patient. Hepatosplenomegaly. Multiple liver hemangiomas and small liver cysts. Additional signs of focal nodular hyperplasia. Individual cystic lesions of the spleen. Widening of the portal vein due to possible portal venous hypertension. E-J, Several CT scans from different patients showing multiple pulmonary nodules, bronchiectasis with inflammatory changes, and interstitial lung disease. K and L, Hepatitis with T-cell–dominant lymphocytic inflammation. Fig 4, K, Portal (asterisk) and intralobular (arrowhead) inflammation. Fig 4, L, Higher magnification image showing intralobular lymphocytes and epithelioid cells, reminiscent of microgranulomas, with apoptosis of hepatocytes (nuclear remnants highlighted by arrowhead). M, CD3-positive T cells encircling an apoptotic hepatocyte, suggestive of T-cell–driven damage. N, Corresponding area to Fig 4, M, showing CD4-positive T cells, few monocytes, and intrasinusoidal macrophages (Kupffer cells). O-Q, Slightly chronic gastritis with patchy lymphocytic inflammation of the antrum (Fig 4, O, P highlighted by arrowhead) and corpus (Fig 4, Q highlighted by arrowhead). R, Chronic lymphocytic peribronchitis. Magnifications indicated by bars. CT, Computed tomography; MRI, magnetic resonance imaging.

FIG 5.

Main clinical findings in patients with damaging NFKB1 mutations. Percentage distribution of clinical manifestations (A), and infection types (B). CMV, Cytomegalovirus; GLILD, granulomatous-lymphocytic interstitial lung disease; HAV, hepatitis A virus; IBD, inflammatory bowel disease; JC virus, John Cunningham virus.