Structural and biochemical analyses of the nuclear IκBζ protein in complex with the NF-κB p50 homodimer.

As part of the efforts to understand nuclear IκB function in NF-κB-dependent gene expression, we report an X-ray crystal structure of the IκBζ ankyrin repeat domain in complex with the dimerization domain of the NF-κB p50 homodimer. IκBζ possesses an N-terminal α helix that conveys domain folding stability. Affinity and specificity of the complex depend on a small portion of p50 at the nuclear localization signal. The model suggests that only one p50 subunit supports binding with IκBζ, and biochemical experiments confirm that IκBζ associates with DNA-bound NF-κB p50:RelA heterodimers. Comparisons of IκBζ:p50 and p50:κB DNA complex crystallographic models indicate that structural rearrangement is necessary for ternary complex formation of IκBζ and p50 with DNA.

Clinical, Immunological, and Genetic Features in Patients with NFKB1 and NFKB2 Mutations: a Systematic Review.

BACKGROUND: Inborn errors of immunity (IEIs) encompass various diseases with diverse clinical and immunological symptoms. Determining the genotype-phenotype of different variants in IEI entity precisely is challenging, as manifestations can be heterogeneous even in patients with the same mutated gene. OBJECTIVE: In the present study, we conducted a systematic review of patients recorded with NFKB1 and NFKB2 mutations, two of the most frequent monogenic IEIs. METHODS: The search for relevant literature was conducted in databases including Web of Science, PubMed, and Scopus. Information encompassing demographic, clinical, immunological, and genetic data was extracted from cases reported with mutations in NFKB1 and NFKB2. The comprehensive features of manifestations in patients were described, and a comparative analysis of primary characteristics was conducted between individuals with NFKB1 loss of function (LOF) and NFKB2 (p52-LOF/IκBδ-gain of function (GOF)) variants. RESULTS: A total of 397 patients were included in this study, 257 had NFKB1 mutations and 140 had NFKB2 mutations. There were 175 LOF cases in NFKB1 and 122 p52LOF/IκBδGOF cases in NFKB2 pivotal groups with confirmed functional implications. NFKB1LOF and p52LOF/IκBδGOF predominant cases (81.8% and 62.5% respectively) initially presented with a CVID-like phenotype. Patients with NFKB1LOF variants often experienced hematologic autoimmune disorders, whereas p52LOF/IκBδGOF patients were more susceptible to other autoimmune diseases. Viral infections were markedly higher in p52LOF/IκBδGOF cases compared to NFKB1LOF (P-value < 0.001). NFKB2 (p52LOF/IκBδGOF) patients exhibited a greater prevalence of ectodermal dysplasia and pituitary gland involvement than NFKB1LOF patients. Most NFKB1LOF and p52LOF/IκBδGOF cases showed low CD19 + B cells, with p52LOF/IκBδGOF having more cases of this type. Low memory B cells were more common in p52LOF/IκBδGOF patients. CONCLUSIONS: Patients with NFKB2 mutations, particularly p52LOF/IκBδGOF, are at higher risk of viral infections, pituitary gland involvement, and ectodermal dysplasia compared to patients with NFKB1LOF mutations. Genetic testing is essential to resolve the initial complexity and confusion surrounding clinical and immunological features. Emphasizing the significance of functional assays in determining the probability of correlations between mutations and immunological and clinical characteristics of patients is crucial.

Expression of SUMO and NF-κB genes in hepatitis B virus-associated hepatocellular carcinoma patients: An observational study.

Alterations in signaling pathways and modulation of cell metabolism are associated with the pathogenesis of cancers, including hepatocellular carcinoma (HCC). Small ubiquitin-like modifier (SUMO) proteins and NF-κB family play major roles in various cellular processes. The current study aims to determine the expression profile of SUMO and NF-κB genes in HCC tumors and investigate their association with the clinical outcome of HCC. The expression of 5 genes - SUMO1, SUMO2, SUMO3, NF-κB p65, and NF-κB p50 - was quantified in tumor and adjacent non-tumor tissues of 58 HBV-related HCC patients by real-time quantitative PCR and was analyzed for the possible association with clinical parameters of HCC. The expression of SUMO2 was significantly higher in HCC tumor tissues compared to the adjacent non-tumor tissues (P = .01), while no significant difference in SUMO1, SUMO3, NF-κB p65, and NF-κB p50 expression was observed between HCC tumor and non-tumor tissues (P > .05). In HCC tissues, a strong correlation was observed between the expression of SUMO2 and NF-κB p50, between SUMO3 and NF-κB p50, between SUMO3 and NF-κB p65 (Spearman rho = 0.83; 0.82; 0.772 respectively; P < .001). The expression of SUMO1, SUMO2, SUMO3, NF-κB p65, and NF-κB p50 was decreased in grade 3 compared to grades 1 and 2 in HCC tumors according to the World Health Organization grades system. Our results highlighted that the SUMO2 gene is upregulated in tumor tissues of patients with HCC, and is related to the development of HCC, thus it may be associated with the pathogenesis of HCC.

Selective regulation of a defined subset of inflammatory and immunoregulatory genes by an NF-κB p50-IκBζ pathway.

The five NF-κB family members and three nuclear IκB proteins play important biological roles, but the mechanisms by which distinct members of these protein families contribute to selective gene transcription remain poorly understood, especially at a genome-wide scale. Using nascent transcript RNA-seq, we observed considerable overlap between p50-dependent and IκBζ-dependent genes in Toll-like receptor 4 (TLR4)-activated macrophages. Key immunoregulatory genes, including Il6, Il1b, Nos2, Lcn2, and Batf, are among the p50-IκBζ-codependent genes. IκBζ-bound genomic sites are occupied at earlier time points by NF-κB dimers. However, p50-IκBζ codependence does not coincide with preferential binding of either p50 or IκBζ, as RelA co-occupies hundreds of genomic sites with the two proteins. A common feature of p50-IκBζ-codependent genes is a nearby p50/RelA/IκBζ-cobound site exhibiting p50-dependent binding of both RelA and IκBζ. This and other results suggest that IκBζ acts in concert with RelA:p50 heterodimers. Notably, p50-IκBζ-codependent genes comprise a high percentage of genes exhibiting the greatest differential expression between TLR4-stimulated and tumor necrosis factor receptor (TNFR)-stimulated macrophages. Thus, our genome-centric analysis reveals a defined p50-IκBζ pathway that selectively activates a set of key immunoregulatory genes and serves as an important contributor to differential TNFR and TLR4 responses.

NF-κB1 deficiency promotes macrophage-derived adrenal tumors but decreases neurofibromas in HTLV-I LTR-Tax transgenic mice.

Human T-cell leukemia virus type I (HTLV-I) is an oncogenic virus whose infection can cause diverse diseases, most notably adult T-cell leukemia/lymphoma (ATL or ATLL), an aggressive and fatal malignancy of CD4 T cells. The oncogenic ability of HTLV-I is mostly attributed to the viral transcriptional transactivator Tax. Tax alone is sufficient to induce specific tumors in mice depending on the promotor used to drive Tax expression, thereby being used to understand HTLV-I tumorigenesis and model the tumor types developed in Tax transgenic mice. Tax exerts its oncogenic role predominantly by activating the cellular transcription factor NF-κB. Here, we report that genetic deletion of NF-κB1, the prototypic member of the NF-κB family, promotes adrenal medullary tumors but suppresses neurofibromas in mice with transgenic Tax driven by the HTLV-I Long Terminal Repeat (LTR) promoter. The adrenal tumors are derived from macrophages. Neoplastic macrophages also infiltrate the spleen and lymph nodes, causing splenomegaly and lymphadenopathy in mice. Nevertheless, the findings could be human relevant, because macrophages are important target cells of HTLV-I infection and serve as a virus reservoir in vivo. Moreover, the spleen, lymph nodes and adrenal glands are the most common sites of tumor cell infiltration in HTLV-I-infected patients. These data provide new mechanistic insights into the complex interaction between Tax and NF-κB, therefore improving our understanding of HTLV-I oncogenic pathogenesis. They also expand our knowledge and establish a new animal model of macrophage neoplasms and adrenal tumors.

NFKB1 variants were associated with the risk of Parkinson´s disease in male.

The NF-κB pathway is involved in the pathogenesis of neurological disorders that have inflammation as a hallmark, including Parkinson's disease (PD). Our objective was to determine whether common functional variants in the NFKB1, NFKBIA and NFKBIZ genes were associated with the risk of PD. A total of 532 Spanish PD cases (61% male; 38% early-onset, ≤ 55 years) and 300 population controls (50% ≤55 years) were genotyped for the NFKB1 rs28362491 and rs7667496, NFKBIA rs696, and NFKBIZ rs1398608 polymorphisms. We compared allele and genotype frequencies between early and late-onset, male and female, and patient's vs. controls. We found that the two NFKB1 alleles were significantly associated with PD in our population (p = 0.01; total patients vs. controls), without difference between Early and Late onset patients. The frequencies of the NFKB1 variants significantly differ between male and female patients. Compared to controls, male patients showed a significantly higher frequency of rs28362491 II (p = 0.02, OR = 1.52, 95%CI = 1.10-2.08) and rs28362491 C (p = 0.003, OR = 1.62, 95%CI = 1.18-2.22). The two NFKB1 variants were in strong linkage disequilibrium and the I-C haplotype was significantly associated with the risk of PD among male (p = 0.002). In conclusion, common variants in the NF-kB genes were associated with the risk of developing PD in our population, with significant differences between male and female. These results encourage further studies to determine the involvement of the NF-kB components in the pathogenesis of Parkinson´s disease.

Meet the authors: Vasty Osei Amponsa and Kylie J. Walters.

We talk to Vasty Osei Amponsa and Kylie J. Walters about their paper "hRpn13 shapes the proteome and transcriptome through epigenetic factors HDAC8, PADI4, and transcription factor NF-κB p50", their journeys across continents leading them to the NCI, and how Kylie tries to foster curiosity and a sense of belonging in her lab.

A large deletion in a non-coding regulatory region leads to NFKB1 haploinsufficiency in two adult siblings.

Mutations in NFkB pathway genes can cause inborn errors of immunity (IEI), with NFKB1 haploinsufficiency being a significant etiology for common variable immunodeficiency (CVID). Indeed, mutations in NFKB1 are found in 4 to 5% of in European and United States CVID cohorts, respectively; CVID representing almost » of IEI patients in European countries registries. This case study presents a 49-year-old patient with respiratory infections, chronic diarrhea, immune thrombocytopenia, hypogammaglobulinemia, and secondary lymphoma. Comprehensive genetic analysis, including high-throughput sequencing of 300 IEI-related genes and copy number variation analysis, identified a critical 2.6-kb deletion spanning the first untranslated exon and its upstream region. The region's importance was confirmed through genetic markers indicative of enhancers and promoters. The deletion was also found in the patient's brother, who displayed similar but milder symptoms. Functional analysis supported haploinsufficiency with reduced mRNA and protein expression in both patients. This case underscores the significance of copy number variation (CNV) analysis and targeting noncoding exons within custom gene panels, emphasizing the broader genomic approaches needed in medical genetics.

A common NFKB1 variant detected through antibody analysis in UK Biobank predicts risk of infection and allergy.

Infectious agents contribute significantly to the global burden of diseases through both acute infection and their chronic sequelae. We leveraged the UK Biobank to identify genetic loci that influence humoral immune response to multiple infections. From 45 genome-wide association studies in 9,611 participants from UK Biobank, we identified NFKB1 as a locus associated with quantitative antibody responses to multiple pathogens, including those from the herpes, retro-, and polyoma-virus families. An insertion-deletion variant thought to affect NFKB1 expression (rs28362491), was mapped as the likely causal variant and could play a key role in regulation of the immune response. Using 121 infection- and inflammation-related traits in 487,297 UK Biobank participants, we show that the deletion allele was associated with an increased risk of infection from diverse pathogens but had a protective effect against allergic disease. We propose that altered expression of NFKB1, as a result of the deletion, modulates hematopoietic pathways and likely impacts cell survival, antibody production, and inflammation. Taken together, we show that disruptions to the tightly regulated immune processes may tip the balance between exacerbated immune responses and allergy, or increased risk of infection and impaired resolution of inflammation.

The multifunctional role of intrinsic disorder in NF-κB signaling.

The nuclear factor-κB (NF-κB) transcription activation system involves disordered regions of both the NF-κB dimers and their inhibitors, the IκBs. The system is well-studied both at the cellular and biophysical levels affording a unique opportunity to compare and contrast the conclusions from both types of experiments. Through a combination of both experiments and theory, we have discovered that the RelA/p50 heterodimer and its inhibitor IκBα operate under kinetic control. Intrinsically disordered parts of both proteins are directly involved in temporal control and their folding and unfolding determines the rates of various processes. In this review, we show how the dynamic state of the intrinsically disordered sequences define the rates of intracellular processes.

Case Report: A child with NFKB1 haploinsufficiency explaining the linkage between immunodeficiency and short stature.

We report the case of a patient with common variable immunodeficiency (CVID) presenting with short stature and treated with recombinant human growth hormone (rhGH). Whole exome sequencing revealed a novel single-nucleotide duplication in the NFKB1 gene (c.904dup, p.Ser302fs), leading to a frameshift and thus causing NFKB1 haploinsufficiency. The variant was considered pathogenic and was later found in the patient's mother, also affected by CVID. This is the first reported case of a patient with CVID due to NFKB1 mutation presenting with short stature. We analyzed the interconnection between NFKB1 and GH - IGF-1 pathways and we hypothesized a common ground for both CVID and short stature in our patient.

Long-term environmental metal exposure is associated with hypomethylation of CpG sites in NFKB1 and other genes related to oncogenesis.

BACKGROUND: Long-term environmental exposure to metals leads to epigenetic changes and may increase risks to human health. The relationship between the type and level of metal exposure and epigenetic changes in subjects exposed to high concentrations of metals in the environment is not yet clear. The aim of our study is to find the possible association of environmental long-term exposure to metals with DNA methylation changes of genes related to immune response and carcinogenesis. We investigated the association of plasma levels of 21 essential and non-essential metals detected by ICP-MS and the methylation level of 654 CpG sites located on NFKB1, CDKN2A, ESR1, APOA5, IGF2 and H19 genes assessed by targeted bisulfite sequencing in a cohort of 40 subjects living near metal mining area and 40 unexposed subjects. Linear regression was conducted to find differentially methylated positions with adjustment for gender, age, BMI class, smoking and metal concentration. RESULTS: In the metal-exposed group, five CpGs in the NFKB1 promoter region were hypomethylated compared to unexposed group. Four differentially methylated positions (DMPs) were associated with multiple metals, two of them are located on NFKB1 gene, and one each on CDKN2A gene and ESR1 gene. Two DMPs located on NFKB1 (chr4:102500951, associated with Be) and IGF2 (chr11:2134198, associated with U) are associated with specific metal levels. The methylation status of the seven CpGs located on NFKB1 (3), ESR1 (2) and CDKN2A (2) positively correlated with plasma levels of seven metals (As, Sb, Zn, Ni, U, I and Mn). CONCLUSIONS: Our study revealed methylation changes in NFKB1, CDKN2A, IGF2 and ESR1 genes in individuals with long-term human exposure to metals. Further studies are needed to clarify the effect of environmental metal exposure on epigenetic mechanisms and pathways involved.

NFκB1 inhibits memory formation and supports effector function of ILC2s in memory-driven asthma.

Background: ILC2s are capable of generating memory. The mechanism of memory induction and memory-driven effector function (trained immunity) in ILC2s is unknown. Objective: NFκB1 is preferentially expressed at a high level in ILC2s. We examined the role of NFkB1 in memory induction and memory-driven effector function in a mouse model of asthma. Methods: Intranasal administration of Alternaria, flexivent, ELISA, histology, real-time PCR, western blot, flow cytometry and immunofluorescence staining. Results: NFκB1 was essential for the effector phase of memory-driven asthma. NFκB1 was critical for IL33 production, ILC2 generation, and production of type-2 cytokines, which resulted in eosinophilic inflammation and other features of asthma. NFκB1 induction of type-2 cytokines in ILC2s was independent of GATA3. NFκB1 was important for allergen induction of ILC3s and FoxP3+ Tregs. NFκB1 did not affect Th2 cells or their cytokine production. In contrast to its protagonistic role in the effector phase, NFκB1 had an antagonistic role in the memory phase. NFκB1 inhibited allergen-induced upregulation of memory-associated repressor and preparedness genes in ILC2s. NFκB1 upregulated RUNX1. NFκB1 formed a heterodimer with RUNX1 in ILC2s. Conclusions: NFκB1 positively regulated the effector phase but inhibited the induction phase of memory. The foregoing pointed to an interdependent antagonism between the memory induction and the memory effector processes. The NFκB1-RUNX1 heterodimer represented a non-canonical transcriptional activator of type-2 cytokines in ILC2s.

Inflammation and Neutrophil Oxidative Burst in a Family with NFKB1 p.R157X LOF and Sterile Necrotizing Fasciitis.

Loss-of-function (LOF) mutations in NFKB1, coding for p105, may cause common variable immunodeficiency due to dysregulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κΒ) pathway. Monoallelic LOF variants of NFKB1 can predispose to uncontrolled inflammation including sterile necrotizing fasciitis or pyoderma gangrenosum. In this study, we explored the impact of a heterozygous NFKB1 c.C936T/p.R157X LOF variant on immunity in sterile fasciitis patients and their family members. The p50 or p105 protein levels were reduced in all variant carriers. Interleukin-1ß (IL-1ß) and interleukin-8 (IL-8) levels were elevated in vitro, potentially contributing to the very high neutrophil counts observed during fasciitis episodes. Phosphorylation of p65/RelA was reduced in p.R157X neutrophils suggesting defective activation of canonical NF-κB. Oxidative burst after NF-κB-independent phorbol 12-myristate 13-acetate (PMA) stimulation was similar in both p.R157X and control neutrophils. Comparable amounts of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex subunits were found in p.R157X and control neutrophils. However, a compromised oxidative burst was observed in p.R157X neutrophils following activation of NF-κB-dependent mechanisms following stimulation of toll-like receptor 2 (TLR2) and Dectin-1. Neutrophil extracellular trap formation was not affected by p.R157X. In summary, the NFKB1 c.C936T/p.R157X LOF variant has an impact on inflammation and neutrophil function and may play a role in the pathogenesis of sterile necrotizing fasciitis.

Association between Polymorphism of Genes IL-1A, NFKB1, PAR1, TP53, and UCP2 and Susceptibility to Non-Small Cell Lung Cancer in the Brazilian Amazon.

Non-small cell lung cancer (NSCLC) accounts for the vast majority of cases of lung neoplasms. It is formed in multiple stages, with interactions between environmental risk factors and individual genetic susceptibility and with genes involved in the immune and inflammatory response paths, cell or genome stability, and metabolism, among others. Our objective was to evaluate the association between five genetic variants (IL-1A, NFKB1, PAR1, TP53, and UCP2) and the development of NSCLC in the Brazilian Amazon. The study included 263 individuals with and without lung cancer. The samples were analyzed for the genetic variants of NFKB1 (rs28362491), PAR1 (rs11267092), TP53 (rs17878362), IL-1A (rs3783553), and UCP2 (INDEL 45-bp), which were genotyped in PCR, followed by an analysis of the fragments, in which we applied a previously developed set of informative ancestral markers. We used a logistic regression model to identify differences in the allele and the genotypic frequencies among individuals and their association with NSCLC. The variables of gender, age, and smoking were controlled in the multivariate analysis to prevent confusion by association. The individuals that were homozygous for the Del/Del of polymorphism NFKB1 (rs28362491) (p = 0.018; OR = 0.332) demonstrate a significant association with NSCLC, which was similar to that observed in the variants of PAR1 (rs11267092) (p = 0.023; OR = 0.471) and TP53 (rs17878362) (p = 0.041; OR = 0.510). Moreover, the individuals with the Ins/Ins genotype of polymorphism IL-1A (rs3783553) demonstrated greater risk for NSCLC (p = 0.033; OR = 2.002), as did the volunteers with the Del/Del of UCP2 (INDEL 45-bp) (p = 0.031; OR = 2.031). The five polymorphisms investigated can contribute towards NSCLC susceptibility in the population of the Brazilian Amazon.

Analysis of NFKB1 and NFKB2 gene expression in the blood of patients with sudden sensorineural hearing loss.

OBJECTIVES: Sudden Sensorineural Hearing Loss (SSNHL) is an increasingly common health problem today. Although the direct mortality rate of this disorder is relatively low, its impact on quality of life is enormous; this is why accurate identification of pathogenesis and influencing factors in the disease process can play an essential role in preventing and treating the disease. Acute inflammation, which leads to chronic inflammation due to aberrant expression of inflammation-mediating genes, may play a significant role in the pathogenesis of the disease. The essential Nuclear factor kappa B (NF-kB) pathway genes, NFKB1 and NFKB2, serve as prothrombotic agents when expressed abnormally, compromising the cochlea by disrupting the endolymphatic potential and causing SSNHL. METHODS: This study investigates the expression levels of NFKB1 and NFKB2 in peripheral blood (PB) through a quantitative polymerase chain reaction in 50 Iranian patients with SSNHL, and 50 healthy volunteers were of the same age and sex as controls. RESULTS: As a result, NFKB2 expression levels in patients were higher than in controls, regardless of sex or age (posterior beta = 0.619, adjusted P-value = 0.016), and NFKB1 expression levels did not show significant differences between patients and controls. The expression levels of NFKB1 and NFKB2 had significantly strong positive correlations in both SSNHL patients and healthy individuals (r = 0.620, P = 0.001 and r = 0.657, P 0.001, respectively), suggesting the presence of an interconnected network. CONCLUSION: NFKB2 has been identified as a significant inflammatory factor in the pathophysiology of SSNHL disease. Inflammation can play an essential role in developing SSNHL, and our findings could be used as a guide for future research.

IS -94INS/DELATTG POLYMORPHISM IN THE NUCLEAR FACTOR KAPPA-B1 GENE (NFKB1) ASSOCIATED WITH NECROTIZING ENTEROCOLITIS?

BACKGROUND: Abnormalities in the different stages of the intestinal maturation process cause metabolic and molecular changes. Among the genetic alterations associated with necrotizing enterocolitis, the -94ins/delATTG polymorphism in NFKB1 gene leads to unregulated activation of the NFKB protein due to an increase in the inherent pro-inflammatory state of the premature intestine. AIMS: To determine the prevalence of the -94ins/delATTG polymorphism in NFKB1 gene in neonates with and without necrotizing enterocolitis. METHODS: This is a case-control study, in which 25 neonates were evaluated as the case group and 50 neonates as the control group, of both genders. DNA was extracted from peripheral blood leukocytes, and the site encompassing the polymorphism was amplified by molecular techniques (polymerase chain reaction/polymorphism in restriction fragment length). RESULTS: Necrotizing enterocolitis was diagnosed in 25 (33%) neonates and, of these, 3 (12%) died. Male gender was more prevalent in both groups (p=0.1613): cases (52%) and controls (62%). Moderate and extreme preterm newborns were predominant in both groups: cases (80%) and controls (88%) (p=0.3036). Low birth weight and extremely low birth weight newborns were the most prevalent in cases (78%), and very low birth weight and extremely low birth weight were the most prevalent in controls (81%) (p=0.1073). Clinical treatment was successful in 72%, and hospital discharge was achieved in 88% of newborns with NEC. The -94ins/delATTG polymorphism in NFKB1 gene was not identified in all the 150 alleles analyzed (100%). CONCLUSIONS: The absence of the -94ins/delATTG polymorphism in NFKB1 gene in newborns with and without necrotizing enterocolitis does not rule out the possibility of alterations in this and/or in other genes in newborns with this condition, which reinforces the need for further research.

Long-term follow up of families with pathogenic NFKB1 variants reveals incomplete penetrance and frequent inflammatory sequelae.

Nuclear factor κ light-chain enhancer of activated B cells (NF-κB) family of evolutionarily conserved transcription factors are involved in key cellular signaling pathways. Previously, hypogammaglobulinemia and common variable immunodeficiency (CVID)-like phenotypes have been associated with NFKB1 variants and loss-of-function NFKB1 variants have been reported as the most common monogenic cause for CVID among Europeans. Here, we describe a Finnish cohort of NFKB1 carriers consisting of 31 living subjects in six different families carrying five distinct heterozygous variants. In contrast to previous reports, the clinical penetrance was not complete even with advancing age and the prevalence of CVID/hypogammaglobulinemia was significantly lower, whereas (auto)inflammatory manifestations were more common (42% of the total cohort). At current stage of knowledge, routine genetic screening of asymptomatic individuals is not recommended, but counseling of potential adult carriers seems necessary.

Cellular senescence marker p16INK4a and NFKB1 gene polymorphisms in lower gastro-intestinal acute graft versus host disease.

BACKGROUND: Lower gastrointestinal (GI) graft versus host disease (GVHD) represents a severe complication in allogeneic hematopoietic stem cell transplant (HSCT) recipients with high rates of transplant-related mortality. Deregulated innate immunity reactions are the features of its pathogenesis. Cellular senescence has been considered a program of the innate immunity. We focused on lower GI GVHD from the perspective of cellular senescence. OBJECTIVE: We analyzed the impact of p16INK4a expression, a hallmark of cellular senescence, in intestinal biopsies of patients with lower GI GVHD symptoms and NFKB1 gene polymorphisms (rs3774937 C/T and rs3774959 A/G) on HSCT outcome. STUDY DESIGN: Fifty-two single-center patients who presented with symptoms of lower GI GVHD were analyzed in a retrospective manner. Two SNPs located in the NFKB1 gene regions (rs3774937 C/T and rs3774959 A/G) were genotyped from the peripheral blood samples collected before the start of the conditioning. All patients underwent proctosigmoidoscopy with biopsy of the mucosa. The expression of p16INK4a was analyzed in normal intestinal crypts and stroma. RESULTS: Fifty-two patients (50% male) received HSCT for hematological diseases (acute leukemias in 67%) and developed lower GI symptoms. Patients with p16INK4a expression in the intestinal stroma were in lower risk of developing histological grade 3-4 aGVHD (RR 0.18 [95% CI 0.05-0.65]; p = 0.009). The multivariate linear regression confirmed the independent effect of p16INK4a expression on time of the lower GI aGVHD symptoms onset (Coef. 38.9 [95% CI 12.7-65.1]; p = 0.005). The NFKB1 rs3774937 CC and TT/TC genotype were present in 40 and 80% of patients with p16INK4a expression, respectively (p = 0.04). The rs3774959 AA and GG/AG genotype were present among 43 and 82% of patients with p16INK4a expression, respectively (p = 0.02). Expression of p16INK4a was associated with no clinical variable but NFKB1 genotype. CONCLUSIONS: Our results address possible new mechanisms that may lead to better understanding of HSCT-related immune complications. Cellular senescence may bring novel approaches in GVHD diagnostics and therapy.

Identification of novel NFKB1 and ICOS frameshift variants in patients with CVID.

Common variable immunodeficiency (CVID) is a 'late-onset' primary immunodeficiency characterized by variable manifestations and genetic heterogeneity. A monogenic cause of CVID has been reported in 10% of patients. In this study, we identified two novel pathogenic variants implicated in monogenic CVID by whole exome sequencing (WES) analysis: a heterozygous nuclear factor κB subunit 1 (NFKB1) p.G686fs mutation and a homozygous inducible T-cell co-stimulator (ICOS) p.L96Sfs mutation. The predicted crystal models indicated premature truncation of the two mutated proteins. Both variants were demonstrated as loss-of-function mutations and were associated with overlapped manifestations of respiratory fungal infection and splenomegaly. We further performed a detailed assessment of immunologic phenotypes and impaired lymphocyte functions in patients. Moreover, we discovered an association between monoclonal T-large granular lymphocyte proliferation and ICOS-deficient CVID for the first time. These observations lead to a new perspective on the underlying genetic heterogeneity of CVID.