Association of Mannose-binding Lectin Polymorphisms with Tuberculosis Susceptibility among Chinese

Mannose-binding lectin gene sequence data in Kelantan population

The human mannose-binding lectin (MBL) gene encodes a polymorphic protein that plays a crucial role in the innate immune response. Human MBL deficiency is associated with immunodeficiencies, and its variants have been linked to autoimmune and infectious diseases. Despite this significance, gene studies concerning MBL sequencing are uncommon in Malaysia. Therefore, we aimed to preliminary described the human MBL sequencing dataset based on the Kelantan population. Blood samples were collected from 30 unrelated individuals and underwent DNA extraction, genotyping, and sequencing. The sequencing data generated 886 bp, which were deposited in GenBank (ON619541-ON619546). Allelic variants were identified and translated into six MBL haplotypes: HYPA, HYPB, LYPB, LXPB, HXPA, and LXPA. An evolutionary tree was constructed using the haplotype sequences. These findings contribute to the expansion of MBL information within the country, providing a valuable baseline for future research exploring the association between the gene and targeted diseases.

Association of mannose-binding lectin 2 gene polymorphisms with Guillain-Barré syndrome

Complement activation plays a critical role in the pathogenesis of Guillain-Barré syndrome (GBS), a debilitating immune-mediated neuropathy. Mannose-binding lectin (MBL) is a complement activation factor of lectin pathway which as genetic host factor may influence the susceptibility or severity of GBS. We investigated the frequency of MBL2 promoter (- 550H/L and - 221X/Y) and functional region (exon 1 A/O) polymorphisms and their association with disease susceptibility, clinical features and serum MBL among GBS patients (n = 300) and healthy controls (n = 300) in Bangladesh. The median patient age was 30 years (IQR: 18-42; males, 68%). MBL2 polymorphisms were not significantly associated with GBS susceptibility compared to healthy controls. HL heterozygosity in GBS patients was significantly associated with mild functional disability at enrolment (P = 0.0145, OR, 95% CI 2.1, 1.17-3.82). The HY, YA, HA and HYA heterozygous haplotypes were more common among mildly affected (P = 0.0067, P = 0.0086, P = 0.0075, P = 0.0032, respectively) than severely affected patients with GBS. Reduced serum MBL was significantly associated with the LL, OO and no HYA variants and GBS disease severity. No significant association was observed between MBL2 polymorphisms and electrophysiological variants, recent Campylobacter jejuni infection or anti-ganglioside (GM1) antibody responses in GBS. In conclusion, MBL2 gene polymorphisms are related to reduced serum MBL and associated with the severity of GBS.

Reversible Lectin Binding to Glycan-Functionalized Graphene

The monolayer character of two-dimensional materials predestines them for application as active layers of sensors. However, their inherent high sensitivity is always accompanied by a low selectivity. Chemical functionalization of two-dimensional materials has emerged as a promising way to overcome the selectivity issues. Here, we demonstrate efficient graphene functionalization with carbohydrate ligands—chitooligomers, which bind proteins of the lectin family with high selectivity. Successful grafting of a chitooligomer library was thoroughly characterized, and glycan binding to wheat germ agglutinin was studied by a series of methods. The results demonstrate that the protein quaternary structure remains intact after binding to the functionalized graphene, and that the lectin can be liberated from the surface by the addition of a binding competitor. The chemoenzymatic assay with a horseradish peroxidase conjugate also confirmed the intact catalytic properties of the enzyme. The present approach thus paves the way towards graphene-based sensors for carbohydrate–lectin binding.

Association Study of MBL2 Gene Polymorphisms and Risk of Tuberculosis in Southeast of Iran

Mannose-binding lectin (MBL) is an acute phase protein which recognizes the pathogens through its carbohydrate recognition domain. It is an important part of human innate immunity. The aim of the current study was to evaluate the impact of MBL2 polymorphism on pulmonary tuberculosis in a number of patients from the southeast of Iran. In this case-control study, 2 MBL gene polymorphisms (rs1800450, rs7095891) were genotyped using PCR-RFLP method and polymerase chain reaction for detection of 34bp ins/del of MBL2 gene (rs777980157) polymorphism. The study included 170 patients with PTB (pulmonary tuberculosis) and 175 control subjects. The findings indicated that the GA (GA vs. GG: OR=0.172, 95% CI=0.107-0.275, P<0.001) (OR - odds ratio; CI - confidence interval) genotype as well as GA+AA (GA+AA vs. GG: OR=0.191, 95% CI=0.120-0.302, P<0.001) genotype of rs1800450 reduced the risk of PTB compared to GG genotype. The rs7095891 variant significantly decreased the risk of PTB in codominant (GA vs. GG: OR=0.118, 95% CI=0.054-0.258, P<0.001; and AA vs. GG: OR=0.029, 95% CI=0.01-0.082, P<0.001), dominant (GA+AA vs. GG: OR=0.095, 95% CI=0.044-0.207, P<0.001) and recessive (AA vs. GA+GG: OR=0.172, CI=0.081-0.365, P<0.001) inheritance models. No significant relationship was identified between the rs777980157 variant and PTB risk/protection. In conclusion, we found that the MBL2 rs1800450 and rs7095891 polymorphisms provide relative protection against PTB. Additional studies on larger populations with different ethnicities are required to verify our findings.

Selected factors of the innate immunity in Polish patients suffering from pulmonary tuberculosis

We conducted a prospective study of 453 Polish patients suffering from pulmonary tuberculosis and 267 healthy controls. Selected polymorphisms of the genes encoding for collectins, ficolins and MBL-associated serine protease 2 were investigated as were serum concentrations of mannose-binding lectin, surfactant protein D, ficolin-1 and ficolin-3. The number of MBL2 gene exon 1 variant allele carriers was significantly higher in patients, compared with controls. The homozygosity for SFTPA2 +26 C > A SNP variant allele occurred less commonly within TB, while homozygosity for the FCN1 -542 G > A major allele was less frequent within the control group. Two patients were found MASP-2-deficient. Serum concentrations of MBL, SP-D and ficolin-1 were higher amongst patients while the converse was found for ficolin-3. Ficolin-1 had high specificity to differentiate between individuals with tuberculosis and healthy persons and therefore may be considered potential disease marker.

Personalized Approach as a Basis for the Future Diagnosis of Tuberculosis (Literature Review)

The global spread of tuberculosis remains one of actual problems of public health despite of introduction of public health safety programs. Early, rapid and accurate identification of M. tuberculosis and determination of drug susceptibility are essential for treatment and management of this disease. Delay in delivering results prolongs potentially inappropriate antituberculosis therapy, contributing to emergence of drug resistance, reducing treatment options and increasing treatment duration and associated costs, resulting in increased mortality and morbidity. Faster, more comprehensive diagnostics will enable earlier use of the most appropriate drug regimen, thus improving patient outcomes and reducing overall healthcare costs. The treatment of infection based on the using of massive antimicrobial therapy with analysis of bacterial strains resistance to first line drugs (FLD) isoniazid (INH), rifampin (RIF), pyrazinamide (PZA), ethambutol (EMB) and streptomycin (SM). However, the public health practitioners pay no attention to functional activity of human immune system genes. The interaction of bacterial genomes and immune system genes plays the major role in infection progress. There is growing evidence that, together with human and environmental factors, Mycobacterium tuberculosis complex strain diversity contributes to the variable outcome of infection and disease in human TB. We suppose that the future of diagnosis and treatment of tuberculosis lies in the field of personal medicine with comprehensive analysis of host and pathogen genes.

Association between the mannose-binding lectin (MBL)-2 gene variants and serum MBL with pulmonary tuberculosis: An update meta-analysis and systematic review

In recent years, many studies have demonstrated that the MBL-2 gene polymorphisms may be associated with pulmonary tuberculosis (PTB) susceptibility. Moreover, some studies have shown that serum MBL levels were influenced by the MBL-2 gene polymorphisms and that it plays an important role in tuberculosis infection. However, the results of these studies were inconsistent and underpowered. The current meta-analysis and systematic review aimed to evaluate the association between the MBL-2 gene polymorphisms and serum MBL levels with PTB. Finally, 30 eligible articles were included in the study. The overall results indicated that the MBL-2 rs1800450 (54 A/B) and rs5030737 (52 A/D) polymorphisms were risk factors for PTB, but the MBL-2 rs1800451 (57 A/C) and rs7095891 (+4 P/Q) polymorphisms as protective factors against PTB. No associations were found in the other three polymorphisms (exon 1, rs7096206 (-221 X/Y), and rs11003125 (-550 H/L) of the MBL-2 gene. In addition, we could not detect any significant differences between haplotypes among PTB patients and healthy controls. More important, the meta-analysis results indicated that the serum MBL levels in patients with PTB were significantly lower than those in healthy controls (SMD = 0.43, 95% CI = 0.33-0.52). This study suggested that the MBL-2 gene polymorphisms may be involved in the pathogenesis of PTB, and serum MBL may be a biomarker for the diagnosis of PTB. More rigorous research is needed in the future to confirm these findings further.

Genetic polymorphisms of exon 1 of MBL2 contribute to tuberculosis risk especially in Asian populations: an updated meta-analysis of 26 studies

Background

Evidence suggests that genetic variations of exon 1 of mannose-binding lectin 2 (MBL2) may contribute to tuberculosis (TB) risk. Many studies have investigated the association between MBL2 exon 1 polymorphisms (rs1800450, rs1800451, and rs5030737) and TB risk, but yielded inconclusive results.

Method

We conducted this meta-analysis of 26 eligible case–control studies that included 7952 cases and 9328 controls to identify the strength of association. Odds ratio (OR) and 95% CI were used to evaluate the strength of association. Statistical analyses were performed by using STATA 12.1.

Results

We found a statistically significant correlation between MBL2 exon 1 polymorphisms and increased TB risk among three models: allele model (O vs A: OR =1.18, 95% CI: 1.01–1.38, P_{heterogeneity}<0.0001, I²=85.8%), homozygote comparison (OO vs AA: OR =1.49, 95%CI: 1.02–2.18, P_{heterogeneity}<0.0001, I²=79.1%), dominant model (AO/OO vs AA: OR =1.20, 95% CI: 1.01–1.43, P_{heterogeneity}<0.0001, I²=83.5%), especially in studies based on Asian populations among five models: allele model (O vs A: OR =1.29, 95% CI: 1.11–1.51, P_{heterogeneity}<0.0001, I²=66.0%), homozygote comparison (OO vs AA: OR =1.67, 95% CI: 1.09–2.55, P_{heterogeneity}=0.008, I²=54.2%), heterozygote comparison (AO vs AA: OR =1.26, 95% CI: 1.05–1.50, P_{heterogeneity}=0.001, I²=62.9%), dominant model (AO/OO vs. AA: OR =1.31, 95% CI: 1.10–1.56, P_{heterogeneity}=0.001, I²=64.2%), and recessive model (OO vs AO/AA: OR =1.50, 95% CI: 1.01–2.22, P_{heterogeneity}=0.023, I²=48.0%). Meta-regression results revealed that source of controls (p=0.009), but not ethnicity (p=0.687), genotyping method (p=0.231), and sample size (p=0.451) contributed to the source of heterogeneity.

Conclusion

This meta-analysis suggests that MBL2 exon 1 polymorphisms may contribute to TB risk, especially in Asian populations.

Influence of Genetic Polymorphism Towards Pulmonary Tuberculosis Susceptibility

Tuberculosis (TB) is still remains the major threat for human health worldwide. Several case-control, candidate-gene, family studies and genome-wide association studies (GWAS) suggested the association of host genetic factors to TB susceptibility or resistance in various ethnic populations. Moreover, these factors modulate the host immune responses to tuberculosis. Studies have reported genetic markers to predict TB development in human leukocyte antigen (HLA) and non-HLA genes like killer immunoglobulin-like receptor (KIR), toll-like receptors (TLRs), cytokine/chemokines and their receptors, vitamin D receptor (VDR) and SLC11A1 etc. Highly polymorphic HLA loci may influence antigen presentation specificities by modifying peptide binding motifs. The recent meta-analysis studies revealed the association of several HLA alleles in particular class II HLA-DRB1 with TB susceptibility and valuable marker for disease development especially in Asian populations. Case-control studies have found the association of HLA-DR2 in some populations, but not in other populations, this could be due to an ethnic specific association of gene variants. Recently, GWAS conducted in case-control and family based studies in Russia, Chinese Han, Morocco, Uganda and Tanzania revealed the association of genes such as ASAP1, Alkylglycerol monooxygenase (AGMO), Forkhead BoxP1 (FOXP1), C-terminal domain phosphatase 1 (UBLCP1) and intergenic SNP rs932347C/T with TB. Whereas, SNP rs10956514A/G were not associated with TB in western Chinese Han and Tibetan population. In this review, we summarize the recent findings of genetic variants with susceptibility/resistance to TB.

The Interaction of Human Pathogenic Fungi With C-Type Lectin Receptors

Fungi, usually present as commensals, are a major cause of opportunistic infections in immunocompromised patients. Such infections, if not diagnosed or treated properly, can prove fatal. However, in most cases healthy individuals are able to avert the fungal attacks by mounting proper antifungal immune responses. Among the pattern recognition receptors (PRRs), C-type lectin receptors (CLRs) are the major players in antifungal immunity. CLRs can recognize carbohydrate ligands, such as β-glucans and mannans, which are mainly found on fungal cell surfaces. They induce proinflammatory immune reactions, including phagocytosis, oxidative burst, cytokine, and chemokine production from innate effector cells, as well as activation of adaptive immunity via Th17 responses. CLRs such as Dectin-1, Dectin-2, Mincle, mannose receptor (MR), and DC-SIGN can recognize many disease-causing fungi and also collaborate with each other as well as other PRRs in mounting a fungi-specific immune response. Mutations in these receptors affect the host response and have been linked to a higher risk in contracting fungal infections. This review focuses on how CLRs on various immune cells orchestrate the antifungal response and on the contribution of single nucleotide polymorphisms in these receptors toward the risk of developing such infections.

Mannose-binding lectin (MBL) deficiency and tuberculosis infection in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) patients may have higher prevalence of mannose-binding lectin (MBL) deficiency than normal individuals. MBL deficiency may influence susceptibility to infections. The aim of the study was to verify if MBL deficiency in patients with AS predisposes to infections. We studied 60 patients with AS diagnosed according to the Assessment of SpondyloArthritis international Society (ASAS) criteria. These patients had their MBL serum levels determinated. Twenty-five individuals were identified as MBL deficient (serum values 100 ng/mL). These patients were paired with 35 "sufficient" MBL producers (median serum level = 700 ng/mL; range 150-4100 ng/mL) for gender, age, use of medications, and tobacco exposure. Medical records of all patients were retrospectively investigated for the period of 5 years and the rate of infection occurrence was compared in the two groups. AS patients with MBL deficiency had higher number of urinary tract infections (p = 0.03; IRR = 2.33; 95% CI = 0.95-6.04) and tuberculosis (p = 0.008; IRR = 9.8; 95% CI = 1.2-441.6) than controls. Regarding tuberculosis infection, one patient (2.8%) in the MBL-sufficient group and six (24.0%) from the deficient group had this infection. The MBL-sufficient patient and five from the deficient group have had latent infections, detected in the screening tests done previous to anti-TNF drug use. The other, in the deficient group, had lung infection while not on anti-TNF treatment. Another patient, from the deficient group, has had tuberculosis skeletal infection in the past. We found a significant association between MBL deficiency and higher risk of tuberculosis and urinary tract infection in patients with AS. More studies with higher number of patients are needed to confirm this finding.

Evasion Mechanisms Used by Pathogens to Escape the Lectin Complement Pathway

The complement system is a crucial defensive network that protects the host against invading pathogens. It is part of the innate immune system and can be initiated via three pathways: the lectin, classical and alternative activation pathway. Overall the network compiles a group of recognition molecules that bind specific patterns on microbial surfaces, a group of associated proteases that initiates the complement cascade, and a group of proteins that interact in proteolytic complexes or the terminal pore-forming complex. In addition, various regulatory proteins are important for controlling the level of activity. The result is a pro-inflammatory response meant to combat foreign microbes. Microbial elimination is, however, not a straight forward procedure; pathogens have adapted to their environment by evolving a collection of evasion mechanisms that circumvent the human complement system. Complement evasion strategies features different ways of exploiting human complement proteins and moreover features different pathogen-derived proteins that interfere with the normal processes. Accumulated, these mechanisms target all three complement activation pathways as well as the final common part of the cascade. This review will cover the currently known lectin pathway evasion mechanisms and give examples of pathogens that operate these to increase their chance of invasion, survival and dissemination.