Immune deficiency caused by impaired expression of nuclear factor-kappaB essential modifier (NEMO) because of a mutation in the 5' untranslated region of the NEMO gene.
BACKGROUND
Nuclear factor-kappaB (NF-kappaB) is a key transcription factor that regulates both innate and adaptive immunity as well as ectodermal development. Mutations in the coding region of the IkappaB kinase gamma/NF-kappaB essential modifier (NEMO) gene cause X-linked ectodermal dysplasia with immunodeficiency.


OBJECTIVE
To determine the genetic cause of recurrent sinopulmonary infections and dysgammaglobulinemia in a patient with a normal NEMO coding sequence and his affected brother.


METHODS
TNF-alpha and IFN-alpha production in response to Toll-like receptor (TLR) stimulation was analyzed by ELISA, NEMO mRNA levels were measured by quantitative PCR, and NEMO protein expression was measured by Western blotting. NF-kappaB activation was assessed by nuclear translocation of p65 and luciferase reporter gene assays.


RESULTS
TLR-induced TNF-alpha and IFN-alpha production by PBMCs was impaired in the patient and his brother. Sequencing of the patient's NEMO gene revealed a novel mutation in the 5' untranslated region, which was also present in the brother, resulting in abnormally spliced transcripts and a 4-fold reduction in mRNA levels. NEMO protein levels in EBV transformed B cells and fibroblasts from the index patient were 8-fold lower than normal controls. NF-kappaB p65 nuclear translocation in the patient's EBV B cells after TLR7 ligation was defective. NF-kappaB-dependent luciferase gene expression in IL-1-stimulated fibroblasts from the patient was impaired.


CONCLUSIONS
This is the first description of immune deficiency resulting from low expression of a normal NEMO protein.
Mooster
Jana L
JL
Division of Immunology, Children's Hospital Boston, Boston, Mass 02115, USA.
Cancrini
Caterina
C
Simonetti
Alessandra
A
Rossi
Paolo
P
Di Matteo
Gigliola
G
Romiti
Maria Luisa
ML
Di Cesare
Silvia
S
Notarangelo
Luigi
L
Geha
Raif S
RS
McDonald
Douglas R
DR
D020121:5' Untranslated Regions / Q000235:genetics*; D002648:Child; D016207:Cytokines / Q000096:biosynthesis; D006801:Humans; D051550:I-kappa B Kinase / Q000032:analysis / Q000235:genetics*; D020672:I-kappa B Proteins / Q000378:metabolism; D007153:Immunologic Deficiency Syndromes / Q000209:etiology* / Q000235:genetics; D053583:Interleukin-1beta / Q000494:pharmacology; D008297:Male; D009154:Mutation; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism; D010766:Phosphorylation; D022821:RNA Splice Sites; D012333:RNA, Messenger / Q000032:analysis; D051193:Toll-Like Receptors / Q000502:physiology
D020121:5' Untranslated Regions; D016207:Cytokines; D020672:I-kappa B Proteins; C491731:IKBKG protein, human; D053583:Interleukin-1beta; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D022821:RNA Splice Sites; D012333:RNA, Messenger; D051193:Toll-Like Receptors; D000072000:NF-KappaB Inhibitor alpha; D051550:I-kappa B Kinase