The association of mannose-binding lectin 2 polymorphisms with outcome in very low birth weight infants

A meta-analysis of the association between inflammatory cytokine polymorphism and neonatal sepsis

OBJECTIVE

The purpose of this study is to investigate the relationship between single nucleotide polymorphisms of inflammatory cytokines and neonatal sepsis through meta-analysis.

METHODS

We collected research literature on the correlation between inflammatory cytokine polymorphisms and neonatal sepsis published before August 2023 through computer searches of databases such as PubMed, Embase, etc. The Stata 14.0 software was utilized for Meta-analysis. To assess heterogeneity, the chi-squared Q-test and I2 statistics were used. The Egger and Begg tests were conducted to determine the possibility of publication bias.

RESULTS

After reviewing 1129 articles, 29 relevant articles involving 3348 cases and 5183 controls were included in the study. The meta-analysis conducted on IL-1βrs1143643 polymorphism revealed significant findings: the T allele genotype has a lower risk of neonatal sepsis(P = 0.000, OR = 0.224, 95% CI: 0.168-0.299), while the TC and TT genotypes showed an increased risk(TC: P = 0.000,OR = 4.251, 95% CI: 2.226-8.119; TT: P = 0.019,OR = 2.020, 95% CI: 1.122-3.639). Similarly, newborns with the IL-6-174 CC genotype had a significantly higher risk of sepsis(P = 0.000,OR = 1.591, 95% CI: 1.154-2.194), while those with the IL-8-rs4073 TT (P = 0.003,OR = 0.467, 95% CI: 0.280-0.777)and TT + AA(P = 0.003,OR = 0.497, 95% CI: 0.315-0.785) genotypes had a significantly lower risk of sepsis. For the IL-10-1082 gene, newborns with the AA genotype(P = 0.002,OR = 1.702, 95% CI: 1.218-2.377), as well as those with the AA + GA genotype(P = 0.016,OR = 1.731, 95% CI: 1.108-2.705), had a significantly higher risk of sepsis. Lastly, newborns carrying the TNF-α-308 A allele (P = 0.016,OR = 1.257, 95% CI: 1.044-1.513)or the AA genotype(P = 0.009,OR = 1.913, 95% CI: 1.179-3.10) have a significantly increased risk of sepsis. Notwithstanding, additional studies must be included for validation. Applying these cytokines in clinical practice and integrating them into auxiliary examinations facilitates the early detection of susceptible populations for neonatal sepsis, thereby providing a new diagnostic and therapeutic approach for neonatal sepsis.

Collectins and ficolins in neonatal health and disease

The immune system starts to develop early in embryogenesis. However, at birth it is still immature and associated with high susceptibility to infection. Adaptation to extrauterine conditions requires a balance between colonization with normal flora and protection from pathogens. Infections, oxidative stress and invasive therapeutic procedures may lead to transient organ dysfunction or permanent damage and perhaps even death. Newborns are primarily protected by innate immune mechanisms. Collectins (mannose-binding lectin, collectin-10, collectin-11, collectin-12, surfactant protein A, surfactant protein D) and ficolins (ficolin-1, ficolin-2, ficolin-3) are oligomeric, collagen-related defence lectins, involved in innate immune response. In this review, we discuss the structure, specificity, genetics and role of collectins and ficolins in neonatal health and disease. Their clinical associations (protective or pathogenic influence) depend on a variety of variables, including genetic polymorphisms, gestational age, method of delivery, and maternal/environmental microflora.

The association between mannose binding lectin gene polymorphisms and the risk of neonatal sepsis: An updated meta-analysis

Objectives

To evaluate the relationship between mannose-binding lectin (MBL) polymorphism and neonatal sepsis to provide ideas for early diagnosis and control of neonatal sepsis using meta-analysis.

Methods

The China National Knowledge Infrastructure, WanFang Data, China Biological Medicine Disc, PubMed, Embase, Cochrane Library, and Web of Science databases were electronically searched to collect studies on the association between the MBL gene variants and the risk of neonatal sepsis. Original articles from case-control and cohort studies on the relationship between MBL polymorphisms and neonatal sepsis were considered eligible. Meta-analysis was performed using Stata 15.0 software. The chi-square-based Q test and I² statistics were used to assess heterogeneity. Forest plots were used to display the results graphically. Potential publication bias was assessed using the Egger and Begg tests and funnel plots.

Results

Twenty-two studies, including 4565 cases and 12,746 controls, were included in this meta-analysis. Meta-analysis showed a significant relationship between MBL rs1800450 (codon 54, G > A) and neonatal sepsis in the variant vs. wild types. However, the analysis showed MBL exon 1 gene polymorphism (A/O), MBL rs5030737 (codon 52, C > T), and rs1800451 (codon 57, G > A), involved in existing research, were not associated with the risk of sepsis in neonates.

Conclusions

Current evidence shows that MBL rs1800450 is associated with neonatal culture-proven sepsis. Owing to the limited quantity and quality of the included studies, more high-quality studies are required to verify the above conclusion.

Association between innate immunity gene polymorphisms and neonatal sepsis development: a systematic review and meta-analysis

BACKGROUND

The aim of this meta-analysis was to analyze all available data from studies investigating associations between polymorphisms in genes responsible for innate immunity and neonatal sepsis development.

METHODS

A comprehensive literature search, reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-S guidelines, was performed with no language restriction. Studies derived using the PICO (population, intervention, comparison and outcomes) strategy, with data on the genotype distribution for innate immunity gene polymorphisms in newborns with and without sepsis. Data were analyzed using Review Manager. The Cochran-Mantel-Haenszel test was used to calculate odds ratios with 95% confidence intervals. Heterogeneity was tested using the I² index.

RESULTS

From a total of 9428 possibly relevant articles, 33 qualified for inclusion in this systematic review. According to the STrengthening the REporting of Genetic Association Studies, 23 studies were found to be of moderate quality, while 10 were of low quality. The results showed an association of the mannose-binding lectin (MBL) exon 1 genetic polymorphism with the risk of culture-proven sepsis. Toll-like receptor (TLR) 4 rs4986791 genotype distribution suggests its association with the increased risk of culture-proven sepsis. The certainty of evidence per GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) varied from very low to low. Publication bias was not detected.

CONCLUSIONS

Out of the 11 investigated single-nucleotide polymorphisms, this meta-analysis found a possible association between the risk for culture-proven sepsis and MBL exon 1 and TLR4 rs4986791 polymorphisms. There is an evident need for larger well-designed, multicentric observational studies investigating inflammatory gene polymorphisms in neonatal sepsis.

Role of MBL2 Polymorphisms in Sepsis and Survival: A Pilot Study and In Silico Analysis

Sepsis is a serious infection-induced syndrome with serious ramifications, especially in intensive care units. Global concern motivated the investigation of the role of related genes’ polymorphism in predicting the liability to infection, sepsis, septic shock and survival. Among these genes is the gene encoding mannose-binding lectin (MBL), with its remarkable importance in the immune system. However, the previous studies showed conflicting results and ambiguity that urged us to engage with this issue in the Egyptian population. Prediction of functional and structural impacts of single nucleotide polymorphisms (SNPs) was done using in silico methods. A prospective observational study was conducted in intensive care units; one hundred and thirty patients were followed up. Genotyping was performed using real-time polymerase chain reaction (RT-PCR) technology. MBL SNPs showed a remarkable high frequency in our population, as well. No significant association was found between MBL2 genotypes and any of our analyses (sepsis, septic shock and survival). Only septic shock and age were independently associated with time of survival by Cox regression analysis. Our study may confirm the redundancy of MBL and the absence of significant impact on sepsis liability and mortality in adult patients.

Mannose-binding lectin gene polymorphism and the susceptibility of sepsis: A meta-analysis

Objective

To assess the association between the Mannose-binding lectin (MBL) gene polymorphism and the susceptibility to sepsis using a meta-analysis.

Methods

The publications were searched on PubMed, Embase, and Web of Science databases up to December 1, 2019 for relevant literature.

Results

A total of 32 studies (21 adult and 11 pediatric studies) were selected for analysis. Overall, in the three models of MBL +54 A/B gene polymorphisms, namely the dominant model BB + AB vs. AA ( p = 0.03), the recessive model BB vs. AB + AA ( p < 0.00001), and the allele model B vs. A ( p = 0.04), MBL +54 A/B was significantly related to the risk of sepsis. In the adult group, the MBL A/O gene polymorphism was associated with the risk of sepsis in the dominant model AO + OO vs. AA ( p = 0.006) as well as in the allele model O vs. A ( p = 0.04). The MBL +54 A/B gene polymorphism was significantly related to the risk of sepsis in the recessive model and, therefore, may increase the risk of sepsis. In the pediatric group, no polymorphic loci were significantly associated with sepsis in any of the three models. The results of the publication bias test demonstrated no publication bias in an unadjusted estimate of the relationship between MBL A/O and −211Y/X gene polymorphism and sepsis.

Conclusions

The polymorphisms of MBL that are related to the occurrence of sepsis are primarily A/O and +54 A/B, while −221Y/X and −550H/L have no clear relationship with the susceptibility of sepsis in various age groups or different models.

Mannose-Binding Lectin Levels in Late-Onset Sepsis in Preterm Infants: Results from a Prospective Study in a Tertiary Care Center

Introduction: This study aimed to determine the association between serum mannose-binding lectin (MBL) levels, gene polymorphisms and late-onset sepsis (LOS) in preterm infants. Methods: Infants with <37 gestational weeks were categorized into two groups according to the presence of LOS during their hospitalization. An MBL level <700 ng/ml was defined as deficiency, <400 ng/ml as severe deficiency. Codon 54 and 57 polymorphisms of MBL2 gene were analyzed. Results: Overall, 153 preterm infants were included. MBL deficiency was found to be more common in the LOS group (p = 0.02). The rate of Gram-negative sepsis was higher in MBL2 variant-type (p = 0.01). In the logistic regression analysis, MBL levels <700 ng/ml were found to have a significant effect on LOS development (odds ratio: 2.692, 95% confidence interval 1.196-5.8, p = 0.02). Conclusions: MBL deficiency is an important risk factor for the development of LOS. Furthermore, there is an association between MBL2 gene polymorphism and Gram-negative sepsis.

Mannose-binding lectin gene polymorphism and its effect on short term outcomes in preterm infants

OBJECTIVE

Mannose-binding lectin, which belongs to the collectin family, is an acute-phase reactant that activates the complement system. This study aimed to investigate the effect of MBL2 gene polymorphism on short-term outcomes in preterm infants.

METHOD

Infants of <37 gestational weeks who were admitted to the neonatal intensive care unit during a two-year period were enrolled in this prospective study. The neonates were categorized into two groups according to their MBL2 genotypes. Normal MBL2 genotype was defined as MBL2 wild-type (AA genotype), whereas mutant MBL2 genotype was defined as MBL2 variant-type (AO/OO genotype). The relationship between MBL2 genotype and short-term morbidity and mortality was evaluated.

RESULTS

During the two-year study period, 116 preterm infants were enrolled in this study. In MBL2 variant-type, mannose-binding lectin levels were significantly lower and incidences of mannose-binding lectin deficiency (MBL level<700ng/mL) were higher (p<0.001). In this group, the prevalence of respiratory distress syndrome and mortality was significantly higher (p<0.001, p=0.03 respectively). In the MBL2 wild-type group, the prevalence of necrotizing enterocolitis (NEC) was higher (p=0.01). Logistic regression analyses revealed that MBL2 variant-type had a significant effect on respiratory distress syndrome development (odds ratio, 5.1; 95% confidence interval, 2.2-11.9; p<0.001).

CONCLUSIONS

MBL2 variant-type and mannose-binding lectin deficiency are important risk factors for respiratory distress syndrome development in preterm infants. Additionally, there is an association between MBL2 wild-type and NEC. Further studies on this subject are needed.

Complement deficiencies and dysregulation: Pathophysiological consequences, modern analysis, and clinical management

Complement defects are associated with an enhanced risk of a broad spectrum of infectious as well as systemic or local inflammatory and thrombotic disorders. Inherited complement deficiencies have been described for virtually all complement components but can be mimicked by autoantibodies, interfering with the activity of specific complement components, convertases or regulators. While being rare, diseases related to complement deficiencies are often severe with a frequent but not exclusive manifestation during childhood. Whereas defects of early components of the classical pathway significantly increase the risk of autoimmune disorders, lack of components of the terminal pathway as well as of properdin are associated with an enhanced susceptibility to meningococcal infections. The impaired synthesis or function of C1 inhibitor results in the development of hereditary angioedema (HAE). Furthermore, complement dysregulation causes renal disorders such as atypical hemolytic uremic syndrome (aHUS) or C3 glomerulopathy (C3G) but also age-related macular degeneration (AMD). While paroxysmal nocturnal hemoglobinuria (PNH) results from the combined deficiency of the regulatory complement proteins CD55 and CD59, which is caused by somatic mutation of a common membrane anchor, isolated CD55 or CD59 deficiency is associated with the CHAPLE syndrome and polyneuropathy, respectively. Here, we provide an overview on clinical disorders related to complement deficiencies or dysregulation and describe diagnostic strategies required for their comprehensive molecular characterization - a prerequisite for informed decisions on the therapeutic management of these disorders.

Gut Microbiota Disorder, Gut Epithelial and Blood-Brain Barrier Dysfunctions in Etiopathogenesis of Dementia: Molecular Mechanisms and Signaling Pathways

Emerging evidences indicate a critical role of the gut microbiota in etiopathogenesis of dementia, a debilitating multifactorial disorder characterized by progressive deterioration of cognition and behavior that interferes with the social and professional functions of the sufferer. Available data suggest that gut microbiota disorder that triggers development of dementia is characterized by substantial reduction in specific species belonging to the Firmicutes and Bacteroidetes phyla and presence of pathogenic species, predominantly, pro-inflammatory bacteria of the Proteobacteria phylum. These changes in gut microbiota microecology promote the production of toxic metabolites and pro-inflammatory cytokines, and reduction in beneficial substances such as short chain fatty acids and other anti-inflammatory factors, thereby, enhancing destruction of the gut epithelial barrier with concomitant activation of local and distant immune cells as well as dysregulation of enteric neurons and glia. This subsequently leads to blood-brain barrier dysfunctions that trigger neuroinflammatory reactions and predisposes to apoptotic neuronal and glial cell death, particularly in the hippocampus and cerebral cortex, which underlie the development of dementia. However, the molecular switches that control these processes in the histo-hematic barriers of the gut and brain are not exactly known. This review integrates very recent data on the molecular mechanisms that link gut microbiota disorder to gut epithelial and blood-brain barrier dysfunctions, underlying the development of dementia. The signaling pathways that link gut microbiota disorder with impairment in cognition and behavior are also discussed. The review also highlights potential therapeutic options for dementia.

MBL2 gene polymorphisms in HHV-8 infection in people living with HIV/AIDS

Background

Host genetic factors such as MBL2 gene polymorphisms cause defects in the polymerization of MBL protein and result in a functional deficiency and/or in low serum levels that can influence susceptibility to various viral infections. The aim of this study was to estimate the frequency of alleles, genotypes and haplotypes related to -550, -221 and exon 1 polymorphisms of the MBL2 gene and investigate their association with HHV-8 in people living with HIV/AIDS (PLWHA), as well as the impacts on CD4 cell count and HIV viral load in HIV/HHV-8 coinfected and HIV monoinfected patients.

Results

A cross sectional study in PLWHA, with and without HHV-8 infection, exploring associations between different factors, was performed in the outpatient infectious and parasitic diseases clinic at a referral hospital. Genomic DNA extractions from leukocytes were performed using a commercial Wizard^®Genomic DNA Purification kit (Promega, Madison, WI). The promoter region (-550 and -221) was genotyped with the TaqMan system (Applied TaqMan Biosystems^® genotyping Assays), and the structural region (exon1) was genotyped with Express Sybr Greener Supermix kit (Invitrogen, USA). In total, 124 HIV/HHV-8 coinfected and 213 HIV monoinfected patients were analysed. Median TCD4 counts were significantly lower in HIV/HHV-8 coinfected patients, whereas the mean of the first and last viral load of HIV did not present significant difference. There was no difference in frequency between the LL, YY and AA genotypes between the HIV/HHV-8 coinfected or HIV monoinfected patients. However, in a multivariate analysis, coinfected patients with the intermediate expression haplotype of the MBL2 gene had an odds ratio of 3.1-fold (CI = 1.2–7.6) of their last CD4 cell count being below 350 cells/mm³. Among the coinfected individuals, four developed KS and presented the intermediate expression MBL haplotype, with three being HYA/LXA and one being LYA/LYO.

Conclusions

Host genetic factors, such as -550, -221 and exon 1 polymorphisms, can be related to the may modify coinfections and/or to the development clinical manifestations caused by HHV-8, especially in HIV/HHV-8 coinfected patients who present the intermediate expression haplotypes of MBL.

Mannose-binding lectin and mannose-binding protein-associated serine protease 2 levels and infection in very-low-birth-weight infants

OBJECTIVE

The aim of this study was to explore the role of the lectin pathway in neonatal sepsis through the study of MBL and MASP2 levels and their relationship with infection in a cohort of very-low-birth-weight infants (VLBWI).

METHODS

MBL and MASP2 were measured in plasma samples of n = 89 VLBWI using ELISA and correlated with clinical parameters. MBL plasma levels were aligned with genotyping data of mbl2 exon 1 polymorphisms, rs1800450, rs1800451, and rs5030737.

RESULTS

MBL levels were clearly determined by MBL genotype, i.e., AA individuals had tenfold higher MBL levels than AO individuals. MBL and MASP2 levels did not correlate with gestational age, apart from MASP2 levels on day 7. During the first 21 days of life, we noted a gradual increase in both MBL and MASP2 levels. On day 7 of life, MASP2 levels in infants developing late-onset sepsis measured before the onset of symptoms were found to be lower, as compared to non-LOS infants.

CONCLUSIONS

In our cohort of VLBWI, MBL levels were genetically determined, but not associated with gestational age or sepsis in the first 21 days of life. Lower MASP2 levels on day 7 may indicate increased risk for late-onset infection.

Antimicrobial peptide LL-37 and recombinant human mannose-binding lectin express distinct age- and pathogen-specific antimicrobial activity in human newborn cord blood in vitro

Background: There is a need to prevent and treat infection in newborns. One approach is administration of antimicrobial proteins and peptides (APPs) such as LL-37, a membrane-active cathelicidin antimicrobial peptide, and mannose-binding lectin (MBL), a pattern-recognition protein that binds to microbial surface polysaccharides resulting in opsonization and complement activation. Low plasma/serum levels of LL-37 and of MBL have been correlated with infection and exogenous administration of these agents may enhance host defense. Methods: The antimicrobial activity of LL-37 (15 µg/ml) or rMBL (0.5, 2 and 10 µg/ml) was tested in hirudin-anticoagulated preterm and term human cord blood (N = 12-14) against Staphylococcus aureus (SA) USA 300 (2x10 4 CFU/ml), Staphylococcus epidermis (SE) 1457 (2x10 4 CFU/ml) and Candida albicans (CA) SC5314 (1x10 4 CFU/ml). After incubation (1, 45, or 180 min), CFUs were enumerated by plating blood onto agar plates. Supernatants were collected for measurement of MBL via ELISA. Results: Preterm cord blood demonstrated impaired endogenous killing capacity against SA and SE compared to term blood. Addition of LL-37 strongly enhanced antimicrobial/antifungal activity vs SA, SE and CA in term blood and SE and CA in preterm blood. By contrast, rMBL showed modest fungistatic activity vs CA in a sub-analysis of term newborns with high basal MBL levels. Baseline MBL levels varied within preterm and term cohorts with no correlation to gestational age. In summary, exogenous LL-37 demonstrated significant antimicrobial activity against SA, SE and CA in term and SE and CA in preterm human blood tested in vitro. rMBL demonstrated modest antifungal activity in term cord blood of individuals with high baseline MBL levels. Conclusions: To the extent that our in vitro results predict the effects of APPs in vivo, development of APPs for prevention and treatment of infection should take into account host age as well as the target pathogen.