Mannose-binding Lectin Gene Research Articles

Mannose-binding lectin gene polymorphism and chronic hepatitis B infection in children

Background/Aims:Mannose-binding lectin (MBL) is a member of innate immune system that activates complement system through lectin pathway. MBL deficiency is associated with susceptibility to infectious diseases. In this study, the relation between MBL gene polymorphism and chronic hepatitis B infection in children is evaluated.Patients and Methods:The study included 67 children with chronic hepatitis B and 99 healthy controls. The hepatitis B patients were divided into immuntolerant, chronic inactive, and treatment groups according to their laboratory findings. MBL gene codon 52, 54, and 57 polymorphisms were studied with polymerase chain reaction in all patients and controls. The associations of MBL gene polymorphism with clinical, laboratory, and histopathologic findings were evaluated.Results:Homozygous codon 54 polymorphism of MBL was found significantly higher in chronic hepatitis B patients than controls. Rate of the polymorphism was similar in all groups and, responsive and nonresponsive patients in the treatment group.Conclusions:The hepatitis B patients who are homozygous for codon 54 of MBL are prone to develop chronic infection. Longitudinal studies with larger groups are needed.

Mannose binding lectin (MBL) 2 gene polymorphism & its association with clinical manifestations in systemic lupus erythematosus (SLE) patients from western India.

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease characterized by production of autoantibodies. Mannose binding lectin (MBL) is an important element of the innate defense system. t0 he present study was undertaken to determine whether variant alleles in MBL2 gene were associated with disease severity in SLE patients. The MBL alleles [-550, -221, +4, Codon 52, Codon 54 and Codon 57] were studied by PCR- RFLP (restriction fragment length polymorphism) method in 100 SLE patients fulfilling ACR (American College of Rheumatology) criteria along with 100 healthy controls. SLE disease activity was evaluated using SLE Disease Activity Index (SLEDAI) score. Homozygosity for MBL variant allele (O/O) was observed in 24 per cent of the SLE patients compared to 16 per cent of the normal controls, while no difference was found for heterozygosity (A/O) (37 vs 35%). A significant difference was reported in incidence of double heterozygosity for mutant allele B and D (B/D) among SLE patients as against control group ( p = 0.015). MBL genotypes did not show any association with renal involvement. In this study from western India, MBL gene polymorphism showed an influence as a possible risk factor for susceptibility to SLE, but had no direct effect on disease characteristics. Further studies need to be done on a larger number of SLE patients in different regions of the country.

Extreme high prevalence of a defective mannose-binding lectin (MBL2) genotype in native South American West Andean populations.

Mannose-binding lectin (MBL) is one of the five recognition molecules in the lectin complement pathway. Common variant alleles in the promoter and structural regions of the human MBL gene (MBL2) influence the stability and serum concentration of the protein. Epidemiological studies have shown that MBL2 variant alleles are associated with susceptibility to and the course of different types of infectious and inflammatory conditions. However, it has been suggested that these alleles are maintained in different populations due to selected advantages for carriers. We investigated the MBL2 allelic variation in indigenous individuals from 12 different West Central South America localities spanning from the desert coast, high altitude Andean plates and the Amazon tropical forest within the territories of Peru (n = 249) (Departments of Loreto, Ucayali, Lambayeque, Junin, Ayacucho, Huancayo and Puno), and Ecuador (n = 182) (Region of Esmeraldas and Santo Domingo de los Colorados). The distribution of MBL2 genotypes among the populations showed that the defective variant LYPB haplotype was very common. It showed the highest frequencies in Puno (Taquile (0.80), Amantani (0.80) and Anapia (0.58) islander communities of the Lake Titicaca), but lower frequencies of 0.22 in Junin (Central Andean highland) and Ucayali (Central Amazonian forest), as well as 0.27 and 0.24 in the Congoma and Cayapa/Chachis populations in the Amazonian forest in Ecuador were also observed. Our results suggest that the high prevalence of the MBL2 LYPB variant causing low levels of functional MBL in serum may mainly reflect a random distribution due to a population bottleneck in the founder populations.

Impact of passive smoking, cooking with solid fuel exposure, and MBL/MASP-2 gene polymorphism upon susceptibility to tuberculosis

To explore the impact of passive smoking, cooking with solid fuel, mannose-binding lectin (MBL) gene, MBL-associated serine proteases 2 (MASP-2) gene, and gene-environment interactions on the susceptibility to tuberculosis (TB) in non-smokers. A total of 205 TB patients and 216 healthy controls were recruited to participate in this case-control study. PCR with sequence-specific primers (PCR-SSP) technology was leveraged to genotype rs7096206 of MBL genes and rs2273346 and rs6695096 of MASP-2 genes. Demographic data and information on exposures of participants were collected. Unconditioned logistic regression analysis was conducted to identify associations between the various factors and TB, and marginal structural linear odds models were used to estimate the interactions. Passive smoking and cooking with solid fuel were associated with the risk of TB, with odds ratios (OR) of 1.58 and 2.93, respectively (p<0.05). Genotype CG at rs7096206 of MBL genes (OR 2.02) and genotype TC at rs6695096 of MASP-2 genes (OR 1.67) were more prevalent in the TB patients than in healthy controls (p<0.05). The relative excess risk of interaction (RERI) between rs7096206 of MBL genes and passive smoking or cooking with solid fuel exposure was 1.86 (95% confidence interval (CI) 0.59-3.16) and 2.66 (95% CI 1.85-3.47), respectively. The RERI between rs6695096 of MASP-2 genes and cooking with solid fuel exposure was 3.70 (95% CI 2.63-4.78), which was also a positive interaction. However, the RERI between rs6695096 of MASP-2 genes and passive smoking was not statistically significant. Passive smoking, cooking with solid fuel, and polymorphisms of MBL (rs7096206) and MASP-2 (rs6695096) genes were associated with susceptibility to TB in non-smokers, and there were gene-environment interactions among them. Further studies are needed to explore details of the mechanisms of association.

Mannose-binding lectin gene as a modifier of the cystic fibrosis phenotype in Argentinean pediatric patients

BackgroundThere is a considerable variation in the phenotype and course of the disease in cystic fibrosis (CF) even in patients with the same CFTR genotype, suggesting that other factors are important for prognosis. Mannose-binding lectin (MBL) has been proposed as one of these factors. We therefore investigated the influence of MBL2 gene variants on disease severity, age at acquisition of Pseudomonas aeruginosa, and survival in CF patients. MethodsMBL2 variants were studied in 106 Argentinean pediatric CF patients carrying two severe CFTR mutations. Clinical phenotype was defined according to the Shwachman score and lung function tests. Age at infection with P. aeruginosa and age at death were also recorded. ResultsMBL insufficiency was associated with a 3.5-fold risk of having a severe phenotype (CI 95%: 1.2–10.3, p=0.03). It was also associated with an earlier onset of infection with P. aeruginosa (p=0.035). No statistically significant differences were found in FEV1 and survival. ConclusionsMBL insufficiency was associated with detrimental progression of the disease. These results together with previous findings suggest that the effect of MBL2 expression may be a major determinant of the severity of the clinical phenotype in patients with CF.

Differences in Mannose-Binding Lectin Gene Polymorphisms in Different Diseases

Differences in Mannose-Binding Lectin Gene Polymorphisms in Different Diseases

Mannose-binding lectin gene polymorphism and risk factors for cardiovascular disease in postmenopausal women

BackgroundInflammatory responses may be altered in postmenopausal women and predispose to cardiovascular disease (CVD). Genetic factors can also influence susceptibility to CVD. Mannose-binding lectin (MBL) is a component of the innate immune system and an activator of the complement cascade. We evaluated the association of genetic polymorphism of MBL (MBL2) on risk factors for CVD in postmenopausal women. MethodsIn this cross-sectional study, 311 Brazilian women (age ≥45 years and amenorrhea ≥12 months) were included. Exclusion criteria: presence of previous or current CVD, insulin dependent diabetes, chronic kidney disease, autoimmune diseases and cancer. Clinical, anthropometric and biochemical assessments were performed to evaluate the cardiovascular risk factors. DNA was extracted from buccal cell and polymorphisms at codons 54 and 57 in the MBL2 were determined by polymerase chain reaction (PCR). For statistical analysis, the chi-square and logistic regression (odds ratio, OR) were used. ResultsThe presence of the polymorphic allele for codon 54 was found in 25.8% of women (A/B=22.6%, B/B=3.2%) and for codon 57 in 12.2% (A/C=10.8%, C/C=1.4%). The polymorphism at codon 54 was significantly associated with the presence of hypertension (OR 0.55, 95% CI 0.31–0.99, p=0.044) and insulin resistance assessed by HOMA-IR (OR 0.46, 95% CI 0.24–0.91, p=0.025). No significant associations were observed between the polymorphism at codon 57 with risk factors for CVD. ConclusionIn postmenopausal women, the polymorphism at codon 54 of the MBL2 was associated with lower risk for hypertension and insulin resistance that are important risk factors for CVD.

Functional characterization of mannose-binding lectin in zebrafish: Implication for a lectin-dependent complement system in early embryos

The lectin pathway involves recognition of pathogen-associated molecular patterns by mannose-binding lectin (MBL), and the subsequent activation of associated enzymes, termed MBL-associated serine proteases (MASPs). In this study, we demonstrate that the transcript of MBL gene is present in the early embryo of zebrafish, and MBL protein is also present in the embryo. In addition, we show that recombinant zebrafish MBL was able to bind the Gram-negative bacterium Escherichia coli and the Gram-positive bacterium Staphylococcus aureus, and rMBL was able to promote the phagocytosis of E. coli and S. aureus by macrophages, indicating that like mammalian MBL, zebrafish MBL performs a dual function in both pattern recognition and opsonization. Importantly, we show that microinjection of anti-MBL antibody into the early developing embryos resulted in a significantly increased mortality in the embryos challenged with Aeromonas hydrophila (pathogenic to zebrafish); and injection of rMBL into the embryos (resulting in increase in MBL in the embryo) markedly promoted their resistance to A. hydrophila; and this promoted bacterial resistance was significantly reduced by the co-injection of anti-MBL antibody with rMBL but not by the injection of anti-actin antibody with rMBL. These suggest that the lectin pathway may be already functional in the early embryos in zebrafish before their immune system is fully matured, protecting the developing embryos from microbial infection. This work provides a new angle to understand the immune role of the lectin pathway in early development of animals.

Gene polymorphisms and febrile neutropenia in acute leukemia--no association with IL-4, CCR-5, IL-1RA, but the MBL-2, ACE, and TLR-4 are associated with the disease in Turkish patients: a preliminary study.

The aim of this study was to investigate the mannose-binding lectin 2 (MBL-2), interleukin (IL)-4, Toll-like receptor 4 (TLR-4), angiotensin converting enzyme (ACE), chemokine receptor 5 (CCR-5), and IL-1 receptor antagonist (RA) gene polymorphisms (GPs) in acute leukemias (ALs) and to evaluate their roles in febrile neutropenia (FN) resulting from chemotherapy. The study included 60 AL patients hospitalized between the period of July 2001 and August 2006. Polymorphisms for the genes ACE(I/D), CCR-5, IL-1RA, MBL-2, TLR-4, and IL-4 were typed by polymerase chain reaction (PCR) and/or PCR-restriction fragment length polymerase. Genotype frequencies for these genes were compared in the patient and control groups. The relationships between the genotypes and the body distribution of infections, pathogens, the duration of neutropenia, and febrile episodes in AL patients were evaluated. No significant differences in either the genotype distribution or the allelic frequencies of TLR-4, IL-4, CCR-5, IL-1RN GPs were observed between patients and healthy controls. The AB/BB genotype (53.3%) in the MBL-2 gene was found to be significantly higher in the AL patients compared with control groups. There were correlations between the presence of MBL-2, TLR-4, and ACE polymorphisms and clinical parameters due to FN. Overall, bacteremia was more common in MBL BB and ACE DD. Gram-positive bacteremia was more common in ACE for ID versus DD genotype. Gram-negative bacteremia was more common for both the MBL-2 AB/BB genotype and TLR-4 AG genotype. Median durations of febrile episodes were significantly shorter in ACE DD and MBL AB/BB. Although TLR-4, ACE, and MBL-2 GPs have been extensively investigated in different clinical pictures, this is the first study to evaluate the role of these polymorphisms in the genetic etiopathogenesis of FN in patients with ALs. As a conclusion, TLR-4, ACE, and MBL-2 genes might play roles in the genetic etiopathogenesis of FN in patients with ALs.

The mannose‐binding lectin gene FaMBL1 is involved in the resistance of unripe strawberry fruits to Colletotrichum acutatum

The fungal pathogen Colletotrichum acutatum is the causal agent of strawberry (Fragaria × ananassa) anthracnose. Although the fungus can infect strawberry fruits at both unripe and ripe stages, the symptoms appear only on red ripe fruits. On white unripe fruits, the pathogen becomes quiescent as melanized appressoria after 24 h of interaction. Previous transcriptome analysis has indicated that a mannose-binding lectin (MBL) gene is the most up-regulated gene in 24-h-infected white strawberries, suggesting a role for this gene in the low susceptibility of unripe stages. A time course analysis of the expression of this MBL gene, named FaMBL1 (Fragaria × ananassa MBL 1a), was undertaken to monitor its expression profile in white and red fruits at early interaction times: FaMBL1 was expressed exclusively in white fruit after 24 h, when the pathogen was quiescent. Agrobacterium-mediated transient transformation was used to silence and overexpress the FaMBL1 gene in 24-h-infected white and red strawberries, respectively. FaMBL1-silenced unripe fruits showed an increase in susceptibility to C. acutatum. These 24-h-infected tissues contained subcuticular hyphae, indicating pathogen penetration and active growth. In contrast, overexpression of FaMBL1 in ripe fruits decreased susceptibility; here, 24-h-infected tissues showed a high percentage of ungerminated appressoria, suggesting that the growth of the pathogen had slowed. These data suggest that FaMBL1 plays a crucial role in the resistance of unripe strawberry fruits to C. acutatum.

Mannose-binding lectin gene variants and infections in patients receiving autologous stem cell transplantation.

BackgroundSerious infections are common in patients undergoing autologous stem cell transplantation (ASCT) mainly because of the effects of immunosuppression. The innate immune system plays an important role in the defense against different infections. Mannose binding lectin (MBL) is a central molecule of the innate immune system. There are several promoter polymorphisms and structural variants of the MBL2 gene that encodes for this protein. These variants produce low levels of MBL and have been associated with an increased risk for infections.MethodsProspective cohort study. The incidence, severity of infections and mortality in 72 consecutive patients with hematologic diseases who underwent ASCT between February 2006 and June 2008 in a tertiary referral center were analyzed according to their MBL2 genotype. INNO-LiPA MBL2 was used for MBL2 gene amplification and genotyping. Relative risks (RR) (IC95%) as measure of association were calculated. Multivariate analysis was performed using logistic regression.ResultsA statistically significant higher number of fungal infections was found in patients with MBL2 variants causing low MBL levels (21.1%versus1.9%, p=0.016). In this MBL2 variant group infection was more frequently the cause of mortality than in the MBL2 wild-type group (p=0.05). Although not statistically significant, there was a higher incidence of major infections in the MBL2 variant group as well as a higher number of infections caused by gram-positive bacteria.ConclusionsLow-producer MBL2 genotypes were associated with an increased number of fungal infections in ASCT patients, which would suggest that MBL has a protective role against such infections. ASCT patients with MBL2 variant genotypes are more likely to die as a result of an infection.

Mannose-binding lectin gene, MBL2, polymorphisms are not associated with susceptibility to invasive pneumococcal disease in children.

Most children are transiently colonized with Streptococcus pneumoniae, but very few develop invasive pneumococcal disease (IPD). Host genetic variation of innate immunity may predispose to IPD. We investigated the effect of genetic variation in the mannose-binding lectin gene, MBL2, on susceptibility and disease severity of IPD in previously healthy children aged <5 years. IPD cases were identified through national registries. DNA was obtained from the Danish Neonatal Screening Biobank. Pneumococcal serotypes were determined by Quellung reaction. The associations between MBL2 diplotypes and IPD susceptibility, serotypes, and outcome were investigated using logistic regression analysis. We included 372 cases with meningitis, 907 with bacteremia, and 1263 age- and sex-matched controls; 2372 individuals were successfully genotyped and assigned MBL2 diplotypes. The median age in our combined case series was 13 months. Children with defective diplotypes were not at higher risk for meningitis than children with other diplotypes (odds ratio [OR], 0.85; 95% confidence interval [CI], .56-1.28). Similar results were found for bacteremia (OR, 0.89; 95% CI, .68-1.15) as well as for all cases (OR, 0.87; 95% CI, .70-1.09). There was no association with susceptibility to recurrent IPD (n = 12) for children with defective diplotypes compared with cases with a single episode (OR, 0.53; 95% CI, .07-4.13) and with all controls (OR, 0.46; 95% CI, .06-3.56). There was no association between diplotypes and mortality or between diplotypes and pneumococcal serotypes. Defective MBL2 polymorphisms did not predict increased IPD susceptibility in children born in Northern Europe.

Determination of gene polymorphism and serum concentration of mannose-binding lectin in patients with psoriasis

Objective To determine the gene polymorphism and serum concentration of mannose-binding lectin (MBL) in patients with psoriasis,and to analyze the relationship between MBL and psoriasis.Methods Totally,67 patients with psoriasis vulgaris and 69 healthy human controls were enrolled in this study.Venous blood samples were obtained from all the subjects.Genomic DNA was extracted,and PCR-restriction fragment length polymorphism (PCR-RELP) analysis was conducted to determine the polymorphism at codon 54 of the MBL gene.Enzyme-linked immunosorbent assay was performed to measure the serum level of MBL.A chi-square goodness-of-fit test was carried out to evaluate Hardy-Weinberg equilibrium,t test to compare the serum concentration of MBL,and chi-square test to compare the frequency of genotypes and alleles of MBL gene codon 54.Results The patients with psoriasis showed higher frequency of GGC/GAC heterozygote but lower frequency of GGC/GGC homozygote (x2 =10.36,P ＜ 0.05),together with increased frequency of GAC allele but decreased frequency of GGC allele (x2 =8.31,P ＜ 0.05),at codon 54 of the MBL gene compared with the healthy controls.The variant allele GAC at codon 54 of the MBL gene was markedly associated with psoriasis (OR =3.383,95％ CI 1.585-7.211,P ＜ 0.05).The serum concentration of MBL was (2.193 7 ± 0.816 3) mg/L in patients with psoriasis,significantly lower than that in the healthy controls ((3.269 5±1.205 8) mg/L,t=6.11,P＜ 0.05).Conclusion MBL might be associated with the pathogenesis of psoriasis to some degree. Key words: Psoriasis; Mannose-binding lectins; Polymorphism, restriction fragment length

Association of mannose binding lectin codon 54 polymorphism with predisposition to Henoch–Schönlein purpura in childhood

Immune and inflammatory response activation is a common feature of systemic vasculitis. There is a protein called mannose binding lectin (MBL) that was reported to play an important role in innate immunity. MBL polymorphisms in the MBL gene cause predisposition to infectious and autoimmune diseases. There is no study in the literature investigating the association between MBL polymorphisms and Henoch-Schönlein purpura (HSP) to date. Therefore, the aim of this study is to determine the presence of any association between MBL gene variants and HSP in a child population. Codon 54 polymorphism in exon 1 of the MBL gene was investigated by polymerase chain reaction - restriction fragment length polymorphism method in 100 children diagnosed as having HSP and 100 age-matched healthy controls. The mutant B allele frequency was not significantly higher in the patient group (16%) compared to the control group (14%). AB genotype was found to be 28% and 26% in the patient group and healthy control group, respectively. AA genotype was found in 70% of the children with HSP and 73% of the healthy control group. These results suggest that codon 54 polymorphism in the MBL gene may hardly play a role in susceptibility to HSP in children, the first time this has been reported in the literature.

Mannose-binding lectin 2 (MBL2) gene polymorphisms do not influence frequency of infections in chronic lymphocytic leukemia patients

BackgroundInfectious complications represent the main cause of morbidity and mortality in chronic lymphocytic leukemia. It has been reported that polymorphisms of the mannose-binding lectin 2 (MBL2) genes are correlated with MBL protein serum levels and, consequently, are associated with the development of infectious diseases.ObjectiveThe purpose of this study was to investigate the possible association between MBL2 gene polymorphisms and risk of infection in chronic lymphocytic leukemia patients.MethodsPeripheral blood samples from 116 chronic lymphocytic leukemia patients were collected; after genomic DNA extraction, real time polymerase chain reaction was used to determine the polymorphisms of the promoter region and exon 1 of the MBL2 gene.ResultsA high frequency of Binet stage A (p-value = 0.005) and absence of splenomegaly (p-value = 0.002) were observed in patients with no infection; however, variant alleles/ genotypes and haplotypes of this gene had no impact on the risk of infection.ConclusionTo the authors’ knowledge, this is the first study describing the association between MBL2 polymorphisms and infectious disease in chronic lymphocytic leukemia. Although it was not possible to demonstrate any influence of MBL2 polymorphisms as a genetic modulator of infection in chronic lymphocytic leukemia, the authors believe that the present data are clinically relevant and provide the basis for future studies.© 2014 Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular. All rights reserved.

Vascular health late after Kawasaki disease: implications for accelerated atherosclerosis.

Kawasaki disease (KD), an acute vasculitis that primarily affects young children, is the most common acquired paediatric cardiovascular disease in developed countries. While sequelae of arterial inflammation in the acute phase of KD are well documented, its late effects on vascular health are increasingly unveiled. Late vascular dysfunction is characterized by structural alterations and functional impairment in term of arterial stiffening and endothelial dysfunction and shown to involve both coronary and systemic arteries. Further evidence suggests that continuous low grade inflammation and ongoing active remodeling of coronary arterial lesions occur late after acute illness and may play a role in structural and functional alterations of the arteries. Potential importance of genetic modulation on vascular health late after KD is implicated by associations between mannose binding lectin and inflammatory gene polymorphisms with severity of peripheral arterial stiffening and carotid intima-media thickening. The changes in cholesterol and lipoproteins levels late after KD further appear similar to those proposed to be atherogenic. While data on adverse vascular health are less controversial in patients with persistent or regressed coronary arterial aneurysms, data appear conflicting in individuals with no coronary arterial involvements or only transient coronary ectasia. Notwithstanding, concerns have been raised with regard to predisposition of KD in childhood to accelerated atherosclerosis in adulthood. Until further evidence-based data are available, however, it remains important to assess and monitor cardiovascular risk factors and to promote cardiovascular health in children with a history of KD in the long term.

Relation between mannose-binding lectin (MBL) gene codon 54 polymorphism (allele B) and susceptibility to HTLV-1 infection

Mannose-binding lectin (MBL) plays an important role in the innate immune defense against invading microorganisms. Deficiency of functional MBL is linked to polymorphisms in the MBL2 gene. The aim of the study was to determine the influence of MBL2 polymorphisms in susceptibility to HTLV-1 infection. A total of 43 HTLV-1 infected subjects and 127 healthy controls were evaluated for polymorphisms in the coding region of MBL2 gene. The point mutations in exon 1 at codon 54 (allele B) and codon 52 (allele D) and the wild type allele A were detected by PCR-RFLP. The frequency of the allele A, B and D was 66%, 29% and 5% among HTLV-1 infected subjects and 79%, 18% and 3% among healthy controls, respectively. Genotype and allele frequencies were statistically different between both groups, being the allele B more frequent among HTLV-1 infected subjects than in controls (29% and 18%, respectively; p=0.032). Moreover, the homozygous genotype BB was observed in 14% of HTLV-1 patients and only 3% of controls (p=0.016), and it was associated with an almost five-fold higher risk of HTLV-1 infection (p=0.016; OR=4.98, 95%CI=1,33-18,63). Our results suggest that carriers of the MBL2 allele B are more susceptible to HTLV-1 infection. Further studies with a large number of individuals are ongoing to confirm the impact of MBL polymorphisms as genetic determinant of HTLV-1 susceptibility.

Mannose-binding lectin genetic analysis: possible protective role of the HYPA haplotype in the development of recurrent urinary tract infections in men

Factors related to bacterial virulence and/or to the host have been implicated in the pathogenesis of recurrent urinary tract infections (rUTI), but in most cases the cause is unknown. Mannose binding lectin (MBL) is an acute phase glycoprotein that exerts immunological functions by binding to the surface of a variety of pathogens. Some human gene variants reduce MBL activity thereby predisposing the host to bacterial and viral infections. The aim of this study was to investigate MBL2 gene variants in relation to rUTI risk. Six MBL gene variants and seven haplotypes were analyzed by PCR and direct sequencing in rUTI patients (n = 83) and in healthy subjects from southern Italy (n = 642). The frequencies of the L allele (-550) and the HYPA haplotype were higher in controls than in patients stratified according to sex (p < 0.05). Our data indicate that the HYPA haplotype in the MBL2 gene could be associated with a minor risk of developing rUTI in males.

Innate immunity in renal transplantation: The role of mannose-binding lectin

Innate immune system plays an important role in the modulation of the inflammatory response during infection and tissue injury/repair. Mannose-binding lectin (MBL) is a component of the innate immune system that activates complement via the lectin pathway. Different polymorphisms of the MBL gene are associated with MBL levels and MBL function. The relationship between MBL and disease is rather complex because MBL behaves as a double-edged sword. In the general population, low serum MBL levels are associated with higher risk of infection, type 2 diabetes, autoimmune and cardiovascular disease. However, in patients with diabetes or autoimmune disease, high MBL levels are associated with more severe renal and cardiovascular comorbidities. In renal transplantation, low MBL serum levels constitute a risk factor for infection, low grade inflammation, new onset diabetes after transplantation and subclinical rejection. Despite these associations suggest that low MBL levels should be associated with poorer renal allograft outcome, epidemiological studies evaluating the predictive value of MBL levels on graft survival are controversial. Taken together, these observations suggest that low MBL serum levels modulate chronic inflammatory response that may influence transplant outcome.

Association between Mannose-Binding Lectin Gene Polymorphisms and Hepatitis B Virus Infection: A Meta-Analysis

ObjectiveThe results of studies on the relation between Mannose-binding lectin gene (mbl2) polymorphism and HBV infection were contradictory and inconclusive. In order to shed a light on these inconsistent findings and to clarify the role of mbl2 polymorphisms in susceptibility or progression of chronic hepatitis B (CHB), a meta-analysis was performed.MethodsPubMed and Embase were searched for available articles. A meta-analysis was performed to examine the association between mbl2 polymorphisms and chronicity or progression of hepatitis B infection. Odds ratio (OR) and its 95% confidence interval (CI) served as indexes.ResultsA total of 17 eligible studies were involved, including 2151 healthy controls (HC), 1293 spontaneous recovered (SR) patients with acute infection, 2337cases with chronic hepatitis B (CHB) and 554 cases with progressive hepatitis B. There was no evidence of significant association between mbl2 exon1 polymorphisms and CHB risk in any genetic model or pairwise comparisons when compared with HC group or SR group. In the stratified analysis of ethnic groups, also no obvious relation between mbl2 polymorphism and CHB risk was identified. There was still no significant association between the complete mbl2 genotypic profile (including both the exon1 and the promoter gene) polymorphisms and CHB risk, as compared with SR group. However, it was found that there was an association between the mbl2 AO/OO genotype and severe hepatitis B (SHB) or liver cirrhosis (LC) (LC vs. HC:OR=3.66, 95%CI, 2.38-5.63; SHB vs. HC, OR=3.88, 95%CI, 2.26–6.64), but there was no relationship between the mbl2 AO/OO genotype and hepatocellular carcinoma (HCC) (OR=1.26, 95%CI, 0.82-1.94).ConclusionThe present meta-analysis indicated that mbl2 exon1 polymorphisms might not significantly associate with chronicity of HBV infection, but might be significantly related to the progressive HBV such as SHB and LC.