MBL Levels Research Articles

Complement activation in Glioblastoma multiforme pathophysiology: evidence from serum levels and presence of complement activation products in tumor tissue.

Inflammation plays a key role in the pathophysiology of Glioblastoma Multiforme (GBM). Here we focus on the contribution of the so far largely ignored complement system. ELISA and immunohistochemistry were combined to assess levels and localization of critical components of the initiation- and effector pathways of the complement cascade in sera and tumor tissue from GBM patients and matched controls. Serum levels of factor-B were decreased in GBM patients whereas C1q levels were increased. C1q and factor-B deposited in the tumor tissue. Deposition of C3 and C5b-9 suggests local complement activation.MBL deficiency, based on serum levels, was significantly less frequent among GBM patients compared to controls (14% vs. 33%). Therefore low levels of MBL may protect against the initiation/progression of GBM.

Increased serum mannose binding lectin levels are associated with diabetic retinopathy

BackgroundMannose-binding lectin (MBL) may be implicated in the pathogenesis of diabetic retinopathy (DR) complications. We investigated serum MBL levels in type 2 diabetic patients with and without DR. MethodSerum MBL levels were determined in 184 type 2 diabetic patients with DR and 189 type 2 diabetic patients without DR matched for age, sex, and duration of diabetes. Multivariate analyses were performed using logistic regression models. The diagnostic value of MBL was compared with the HbA1c, Hs-CRP and with other known markers. ResultsWe found that serum MBL levels were significantly higher in diabetes with DR as compared to without-DR [3456 (IQR, 3128–3800) ug/l and 2432 (IQR, 2100–2670) ug/l, respectively; P<0.0001]. In multivariate logistic regression analysis, after adjusting for all other significant factors, MBL remained can be seen as an independent DR marker with an adjusted OR of 1.002 (95% CI, 1.001–1.003; P<0.0001). Based on the ROC curve, the optimal cutoff value of serum MBL levels as an indicator for diagnosis of DR was projected to be 3050 ug/L, which yielded a sensitivity of 82.5% and a specificity of 88.0%, with the area under the curve at 0.907 (95% CI, 0.876—0.938). ConclusionIn type 2 diabetic patients, evaluated serum levels of MBL can be seen as an independent marker of DR even after correcting for possible confounding factors.

Elevated MBL levels in type 1 diabetic patients are reversed after simultaneous pancreas–kidney transplantation

Elevated MBL levels in type 1 diabetic patients are reversed after simultaneous pancreas–kidney transplantation

CircRNA Biogenesis Competes with Pre-mRNA Splicing

Circular RNAs (circRNAs) are widely expressed noncoding RNAs. However, their biogenesis and possible functions are poorly understood. Here, by studying circRNAs that we identified in neuronal tissues, we provide evidence that animal circRNAs are generated cotranscriptionally and that their production rate is mainly determined by intronic sequences. We demonstrate that circularization and splicing compete against each other. These mechanisms are tissue specific and conserved in animals. Interestingly, we observed that the second exon of the splicing factor muscleblind (MBL/MBNL1) is circularized in flies and humans. This circRNA (circMbl) and its flanking introns contain conserved muscleblind binding sites, which are strongly and specifically bound by MBL. Modulation of MBL levels strongly affects circMbl biosynthesis, and this effect is dependent on the MBL binding sites. Together, our data suggest that circRNAs can function in gene regulation by competing with linear splicing. Furthermore, we identified muscleblind as a factor involved in circRNA biogenesis.

Low serum mannose-binding lectin levels are associated with inflammation and apoptosis in early surveillance allograft biopsies

IntroductionMannose-binding lectin (MBL) is a protein of the innate immune system that participates in host defense and the tissue injury/repair process, enhancing the clearance of apoptotic cells by macrophages. The aim is to characterize the relationship between pre-transplant MBL levels, histological lesions and number of apoptotic cells in early surveillance renal allograft biopsies. Patients and methodsConsecutive renal transplant recipients were recruited and MBL levels were classified into tertiles. The first tertile was considered the low MBL group. Surveillance biopsies were done during the first 6months and were evaluated according to Banff criteria. Renal inflammatory infiltrates were studied by immunohistochemical techniques. Apoptosis was studied using morphological methods in renal tubular cells and was expressed as the number of apoptotic cells/mm2. ResultsMBL was determined in 126 patients and a surveillance biopsy with sufficient tissue was obtained in 41 of them. Patients with low pre-transplant MBL levels showed a higher acute Banff index (3.14±1.96 vs. 1.88±1.56, p=0.044) and an increased proportion of biopsies with tubular cell apoptosis The proportion of biopsies with tubular cell apoptosis was higher in patients with low pre-transplant MBL levels in comparison with patients with high MBL levels (4.3±3.6 versus 0.2±0.9 p=0.012) and increased interstitial number of inflammatory cells and significantly the macrophages/mm2 (109±118 vs. 32±46; p=0.04). ConclusionLow pre-transplant serum MBL levels are associated with more severe inflammation and increased apoptosis in early surveillance renal allograft biopsies suggesting that MBL modulates renal inflammation after transplantation

Association of Mannose-Binding Lectin 2 (mbl2) gene heterogeneity and its serum concentration with osteoporosis in postmenopausal women

The aim of the study was to detect prevalence of MBL2 exon 1 (codons 52, 54 and 57) genetic polymorphism in postmenopausal women in Bosnia and Herzegovina and its possible role as genetic risk factor for susceptibility to occurrence of osteoporosis in this study group. Also, we investigated association between MBL serum concentrations and osteoporosis in postmenopausal women. Genetic codons' variations were determined by PCR-RFLP and MBL in serum was measured by ELISA method in 75 postmenopausal women (37 with osteoporosis and 38 apparently healthy, non-osteoporotic women serving as a control). Serum MBL levels were not significantly different between osteoporosis and control group (492 (37-565.1) and 522.6 (477-559.4) ng/mL respectively, p=0.206). Genotype frequencies were not significantly different (p=0.997) between the studied groups of postmenopausal women. Genotype frequencies A/A, A/0 and 0/0 in osteoporosis group were 0.576; 0.405; 0.018 and in control group 0.562; 0.412; 0.026, respectively. Frequencies of A and 0 allele were 0.78 and 0.22 in osteoporosis and 0.77 and 0.23 in control group. The results do not suggest association of functional polymorphism of MBL2 gene and MBL serum concentration with osteoporosis in postmenopausal females.

Bipolar and panic disorders may be associated with hereditary defects in the innate immune system

BackgroundMannan-binding lectin (MBL) and mannan-binding lectin-associated serine protease-2 (MASP-2) represent important arms of the innate immune system, and different deficiencies may result in infections or autoimmune diseases. Both bipolar and panic disorders are associated with increased inflammatory response, infections and mutual comorbidity. However, associations with MBL, MASP-2 or the gene, MBL2, coding for MBL, have not been investigated thoroughly. MethodsOne hundred patients with bipolar disorder, 100 with panic disorder and 349 controls were included. Serum concentrations of MBL and MASP-2 were measured and seven single nucleotide polymorphisms (SNPs) influencing these concentrations were genotyped. Disease association with genetic markers and serum levels were investigated. ResultsIn panic disorder, we observed a large proportion (30%) of MBL deficient (<100ng/ml) individuals and significantly lower levels of MBL and MASP-2 plus association with the MBL2 YA two-marker haplotype. Bipolar disorder was associated with the MBL2 LXPA haplotype and lower MASP-2 levels. LimitationsNo information on course or severity of disorders was included, and only MBL and MASP-2 were measured, excluding other components from the complement pathway. Restrictions defined by ethnical committees preclude information of control׳s ethnic origin. ConclusionsSignificant differences in MBL and MASP-2 concentrations were observed between cohorts, especially an intriguing finding associating panic disorder with MBL deficiency. These differences could not be fully explained by allele or haplotype frequency variations. Since MBL deficiency is highly heterogeneous and associated with both infectious and autoimmune states, more research is needed to identify which complement pathway components could be associated with bipolar respectively panic disorder.

Cerebrospinal fluid complement activation in patients with pneumococcal and meningococcal meningitis

Recent research into the treatment of bacterial meningitis has examined the innate immune system, specifically the complement system, as a potential target for adjuvant therapy. However, the effects of blocking the complement system may be pathogen dependent. We measured cerebrospinal fluid (CSF) levels of complement components C1q, C3a, iC3b, C5a, sC5b-9, CFH and MBL in 310 patients with pneumococcal and meningococcal meningitis from a prospective nationwide cohort study. The CSF complement component levels were successfully determined for between 289 (93%) and 307 (99%) patients, depending on available volumes of stored CSF. Complement factors C1q and MBL as well as common complement pathway factors C3a, iC3b, C5a, sC5b-9 and complement regulator CFH were all elevated in patients with bacterial meningitis as compared to the controls. CSF levels of complement components C5a and sC5b-9 were higher in patients with pneumococcal meningitis compared to those with meningococcal meningitis. After correction for age, immunocompromised state and level of consciousness, the CSF concentrations of C5a and sC5b-9 remained different between causative microorganisms (P=0.006 and P=0.016 respectively). In pneumococcal meningitis high C5a and C5b-9 levels are associated with the occurrence of systemic complications, unfavorable outcome and death, whereas an inverse relationship between C5b-9 levels and mortality is observed in meningococcal meningitis. Our study shows striking variations in complement activation depending on the pathogen responsible for the bacterial meningitis. In pneumococcal meningitis, high CSF complement levels were a strong indicator of disease severity and mortality, however in meningococcal meningitis, an inverse relationship between sC5b-9 and mortality was observed.

Genetic Variation and Cerebrospinal Fluid Levels of Mannose Binding Lectin in Pneumococcal Meningitis Patients

It has been suggested that genetic variants in mannose binding lectin (MBL2) influence susceptibility and outcome of invasive pneumococcal disease. We assessed the influence of genetic variation in MBL2 on susceptibility, outcome and causative serotype of pneumococcal meningitis in a prospective nationwide cohort study including 299 white patients and 216 controls. We assessed functionality of the genetic polymorphisms by measuring levels of MBL, C3a, iC3b, C5a and sC5b-9 in cerebrospinal fluid. We also performed a meta-analysis of studies on MBL2 polymorphisms and susceptibility to invasive pneumococcal disease. The risk of contracting pneumococcal meningitis was substantially increased for white individuals homozygous with the defective MBL2 0/0 genotype (odds ratio [OR] 8.21, 95% confidence interval [CI] 1.05–64.1; p = 0.017). CSF MBL levels were significantly lower in patients with the A/0 and 0/0 genotype compared to homozygotes for the wild-type alleles (A/A; p<0.001). CSF MBL levels were positively correlated with C3a and iC3b levels, indicating complement activation by the lectin pathway. The effect of MBL2 genetic variants on susceptibility remained robust in a meta-analysis including 5 studies with 287 patients (OR 2.33, 99% CI 1.39–3.90). We conclude that MBL2 polymorphisms influence CSF MBL levels and substantially increase the risk of pneumococcal meningitis.

돌연변이 Mannose-binding Lectin 합성과 세포 병리적 연구

Innate immunity is the ability to differentiate infectious agents from self. The innate immune system is comprised of a complicated network of recognition and effector molecules that act together to protect the host in the early stage of an infectious challenge. Mannose-binding lectin (MBL or mannose-binding protein, MBP) belongs to the family of -dependent lectins (C-type lectin with a collagen-like domain), which are considered an important component of innate immunity. While it is associated with increased risk and severity of infections and autoimmunity, the most frequent immuno-deficiency syndrome was reported to be low MBL level in blood. Deficiency of human MBL is caused by mutations in the coding region of the MBL gene. Rat homologue gene of human MBL gene was used to study functions of wild type and mutant MBL proteins. Although extensive studies have yielded the structural information of MBL, the functions of MBL, especially mutant MBL, still require investigation. We previously reported the cloning of rat wild-type MBL gene and the production of a truncated form of MBL protein and its antibody. Here, we present the cloning of mutant MBL cDNA in collagen-like domain (R40C, G42D, and G45E) using site-directed mutagenesis and differential behaviors of wild type and mutant MBL in cells. The major difference between wild type and mutant MBL was that while wild type MBL was secreted, mutant MBL was inhibited for secretion, retained in endoplasmic reticulum, and still functioned as a lectin.

Mannose-Binding Lectin and Susceptibility to Schistosomiasis

Background. Human ficolin 2 (encoded by FCN2) and mannose-binding lectin (encoded by MBL2) bind to specific pathogen-associated molecular patterns, activate the complement lectin cascade in a similar manner, and are associated with several infectious diseases. Our recently published study established certain FCN2 promoter variants and ficolin-2 serum levels as protective factors against schistosomiasis. Methods. We used the Nigerian cohort from our recently published study, which included 163 Schistosoma haematobium–infected individuals and 183 matched healthy subjects, and investigated whether MBL deficiency and MBL2 polymorphisms are associated with schistosomiasis. Results. MBL serum levels were significantly higher in controls and were associated with protection (P < .0001). The −550H minor allele was significantly associated with protection (P = .03), and the heterozygous genotypes −550HL were observed to confer protection (P = .03). The MBL2*HYPA haplotype was significantly associated with protection (P = .03), with significantly higher serum MBL levels in controls (P = .00073). The heterozygous 6-bp deletion in the promoter was observed to be a susceptibility factor in schistosomiasis (P = .03). Conclusions. In agreement with findings from our recently published study, the findings reported here support the observation that MBL is also associated with protection in schistosomiasis.

Low functionality of plasma-derived MBL upon substitution in MBL-deficient patients possibly explained by interaction with C1-inh

s ingediend voor het Amsterdam Kindersymposium 2013 59 Low functionality of plasma-derived MBL upon substitution in MBL-deficient patients possibly explained by interaction with C1-inh Mischa Keizer (1,2), Nannette Brouwer (3), Angela Kamp (2), Gerard van Mierlo (2), Diana Wouters (2), Taco Kuijpers (1,3) (1) Department of Pediatric Hematology, Emma Kinderziekenhuis/AMC (2) Department of Immunopathology, Sanquin Research (3) Department of Blood Cell Research, Sanquin Research INTRODUCTION The risk of infection and infl ammation is increased in immunocompromised patients and this also holds true for pediatric oncology patients. Due to (chemo-)therapy-induced neutropaenia, these patients are more dependent on the non-cellular complement system as a defense against pathogens. Defi ciency of the complement component MBL is associated with an increased risk of infections in these patients. Previous work has shown that administration of plasma-derived MBL (pdMBL) to these patients leads to normal MBL plasma levels. However, despite high MBL levels, complement activation was not completely restored. METHODS C4-deposition on an activating surface is dependent on the MBL-MASP-2 complex. During purifi cation of pdMBL some (activated) MASP-2 is co-purifi ed. Depletion of MASP-2 was done using a known inhibitor, C1-inh, that forms covalent complexes with MASP-2. Depletion was confi rmed using diff erent immunoassays and mass-spectrometry. Due to the low recovery of MBL after depletion, a new immunoassay was developed to identify the presence of MBL-MASP-2 C1-inh (MMC)-complexes. RESULTS Although depletion of MASP-2 of pdMBL with C1-inh was complete, a low recovery of MBL was observed, indicating that most pdMBL molecules bear MASP-2 and the formation of MMC-complexes. These MMC-complexes can be identifi ed by ELISA upon incubation of plasma-derived MBL with MBL-defi cient serum. Moreover, we could detect these complexes in patients at several timepoints after receiving pdMBL. CONCLUSION Substitution of pdMBL in MBL-defi cient patients leads to the formation of MMC-complexes in vivo which would explain the reduced opsonophagocytosis and reduced restoration of C4-deposition as observed in the substitution trial.

The role of ficolins and MASPs in hereditary angioedema due to C1-inhibitor deficiency

Background and ObjectiveHereditary angioedema due to C1-inhibitor deficiency (HAE-C1-INH) causes disturbances in the complement system. However, the influence of HAE-C1-INH on the lectin pathway of complement is unresolved. Thus, we studied the main initiator molecules, enzymes and regulators in the lectin pathway in patients with HAE-C1-INH. MethodsThe serum concentrations of ficolin-2, ficolin-3, MBL, MASP-2, MASP-3, and MAP-1 were measured during symptom-free periods in 91 patients with HAE-C1-INH, and in 100 healthy controls using sandwich ELISAs. ResultsCompared with controls, the levels of ficolin-2 (p<0.0001) and MASP-2 (p=0.0238) were reduced, while the levels of MBL and MASP-3 were elevated (p=0.0028 and p<0.0001, respectively) in HAE-C1-INH patients. Ficolin-3 and MAP-1 levels did not differ significantly between the two groups. Ficolin-2 correlated with MASP-3 in patients (r=0.3443, p=0.0008), while these parameters showed an opposite relationship in controls (r=−0.4625, p<0.0001). In the patients, ficolin-3 correlated with MASP-2 (r=0.3698, p=0.001). Ficolin-2, -3, and MAP-1 correlated negatively with the annual requirement of plasma derived C1-INH concentrate (r=−0.2863, p=0.0059; r=−0.2654, p=0.0110 and r=−0.2501, p=0.0168, respectively). Ficolin-3 showed a negative correlation with the annual number of attacks (r=−0.2478, p=0.0179). ConclusionsWe found significant differences between patients and controls in the levels of some of the molecules belonging to the lectin complement pathway. Low concentrations of particularly ficolin-2 and -3 were inversely correlated with the severity of HAE-C1-INH, while this was not observed for MBL. This suggests a previously unrecognized involvement of the ficolin-dependent lectin complement pathway in the pathophysiology of HAE-C1-INH.

A study on anti-mannose binding lectin (anti-MBL) antibodies and serum MBL levels in Indian systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) is a prototype autoimmune disease characterized by systemic inflammation and autoantibody production. Anti-MBL autoantibodies have been studied in SLE for their possible effect on MBL levels and functional activity. This study aimed at detection of anti-MBL autoantibodies in Indian SLE patients and evaluates their relationship with related immunological parameters. Two hundred diagnosed SLE patients from Western India were included in the study where 87 patients were lupus nephritis (LN) (43.5 %) and remaining (56.5 %) were non-LN. Disease activity was assessed using the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). Anti-MBL autoantibodies to IgG and IgM isotypes, anti-C1q autoantibodies, MBL levels and circulating immune complex levels were detected by ELISA. C3, C4 and CRP levels were detected by nephelometer. Anti-MBL autoantibodies were detected in 52 % SLE patients, where 55 % had IgG-anti-MBL, 33.8 % had IgM-anti-MBL and 11.3 % had both subclasses. Low MBL levels were present in 64.4 % anti-MBL positives as compared with 61.5 % in anti-MBL negatives. Among anti-MBL positives, 74 % had anti-C1q antibodies, whereas 41.7 % of anti-MBL negatives had anti-C1q autoantibodies (p = 3.45E06). An inverse correlation was observed between serum MBL and CIC levels. A statistically significant difference was noted between anti-MBL positives and anti-MBL negative patients with hsCRP levels (p = 0.002). Occurrence of infections was higher among anti-MBL positives (65 %) as compared with anti-MBL negatives (35 %). The difference between SLEDAI scores among anti-MBL positive and negative groups was statistically insignificant. Anti-MBL autoantibodies in SLE patients can influence functional activity of MBL and have a significant role in SLE disease pathogenesis.

Low producer MBL genotypes are associated with susceptibility to systemic lupus erythematosus in Odisha, India

Variants of MBL gene have been associated with autoimmune disorders. The aim of this study was to explore whether common polymorphisms in MBL gene are associated with susceptibility to systemic lupus erythematosus (SLE) and its clinical manifestations in a cohort from eastern India. A total of 108 female SLE patients and 105 age, sex, and ethnically matched healthy controls were enrolled in the study. MBL2 codon and promoter polymorphisms were genotyped by AS-PCR and dARMS PCR, respectively. Plasma level of MBL was quantified by ELISA. Higher frequency of BB genotype and minor allele (B) was observed in patients of SLE compared to healthy controls (BB genotype: P = 0.0002; OR = 5.75, 95% CI = 2.09-15.76, B allele: P < 0.0001; OR = 2.78, 95% CI = 1.66-4.64). MBL codon 54, H-550L, Y-221X polymorphisms and combined MBL genotypes contributed to plasma MBL levels. Prevalence of MBL low producer genotype (LXA/LYB, LYB/LYB and LXB/LXB) was significantly higher in SLE patients compared to healthy control. (P = 0.005; OR = 3.09, 95% CI = 1.38-6.91). On analysis of clinical manifestations, MBL low producer genotype was significantly associated with autoimmune haemolytic anaemia (P = 0.006; OR = 13.06). Results of the present study indicate MBL2 variants as possible risk factors for development of SLE and clinical manifestation in eastern India.

Association Between Mannose‐binding Lectin Gene Polymorphisms and Necrotizing Enterocolitis in Preterm Infants

The aim of the present study was to evaluate whether polymorphisms of the mannose-binding lectin (MBL-2) gene and MBL serum levels on admission to neonatal intensive care unit are associated with necrotizing enterocolitis (NEC) in preterm infants and to verify MBL expression in NEC bowels. In this retrospective cohort study, 107 neonates (41 with NEC and 66 controls) were included. MBL-2 genotyping for the promoter polymorphism -221 and for the exon 1 variant alleles at codons 52, 54, and 57 was performed. MBL levels were determined by enzyme-linked immunosorbent assay in 55 infants. Immunohistochemical staining for MBL expression was performed on bowel specimens. The main study outcome was severe NEC (Bell stages II/III). The -221 Y allele and the MBL-2 YY genotype were more frequent in neonates with severe NEC than in controls (P = 0.04 and P = 0.004, respectively). In the multivariate analysis, the MBL-2 YA/YA genotype was associated with NEC (odds ratio = 3.03, 95% confidence interval 1.13%-8.13%, P = 0.024). Neonates with NEC had MBL level on admission >400 ng/mL more frequently than controls (P = 0.043). Among neonates with severe NEC, the deceased neonates were carriers of high or intermediate producing MBL-2 genotypes (P = 0.035). Finally, MBL was highly expressed in intestinal tissue from infants with NEC. MBL-2 genotypes associated with high MBL serum levels represent a risk factor for NEC. This finding, together with the MBL expression in bowel tissue, supports a role for MBL in the pathogenesis of NEC.

Pulmonary Innate Immunity in Children with Protracted Bacterial Bronchitis

To determine bronchoalveolar lavage (BAL) levels of 3 innate immunity components (human β-defensin-2 [hBD2], mannose-binding lectin [MBL], and surfactant protein-A [SP-A]), the relationship with airway neutrophilia and infection, and cytokine production of stimulated BAL cells in children with current protracted bacterial bronchitis (PBB), children with resolved PBB (PBB well), and controls. BAL of 102 children (mean age 2.8 years) fulfilling predefined criteria of current PBB (n = 61), PBB well (n = 20), and controls (n = 21) was cultured (quantitative bacteriology) and viruses examined by polymerase chain reaction. hBD2, MBL, and SP-A were measured, and cytokine production by lipopolysaccharide-stimulated BAL cells was determined. Median hBD2 and MBL levels were significantly higher in the current PBB group (hBD2 = 164.4, IQR 0-435.5 pg/mL; MBL = 1.7, 0.4-4 ng/mL) than in the PBB well group (hBD2 = 0, IQR 0-85.2; MBL = 0.6, IQR 0.03-2.9) and controls (hBD2 = 3.6, IQR 0-126; MBL = 0.4, IQR 0.02-79). hBD2 was significantly higher in children with airway infection (n = 54; median 76.9, IQR 0-397.3) compared with those without (n = 48; 0, IQR 0-236.3), P= .04. SP-A levels and cytokine production of stimulated BAL cells were similar between groups. In children's airways, hBD2, but not MBL and SP-A, relates to inflammation and infection. In children with PBB, mechanisms involving airway hBD2 and MBL are augmented. These pulmonary innate immunity components and the ability of BAL cells to respond to stimuli are unlikely to be deficient.

Association of the wild-type A/A genotype of MBL2 codon 54 with asthma in a North Indian population.

Background: High serumMBL level as well as polymorphisms in the mannose-binding lectin 2 (MBL2) gene resulting in MBL deficiency are involved in the mechanism of a number of non-infectious diseases such as asthma, conferring either risk or protection in different population studies. MBL being the first reactant of the MBL pathway is also a major determinant of the fate of the anaphylatoxins such as C3a and C5a, which are also pro-inflammatory mediators. The MBL2 gene polymorphisms thus control the serum levels of MBL as well as C3a and C5a. Objective: This is the first case-control study conducted in India, investigating the role of MBL2 codon 54 A/B polymorphism in asthma pathogenesis. Methods: A case-control study was performed with a total of 992 adult subjects, including 410 adult asthmatics and 582 healthy controls from regions of North India. The MBL2 codon 54 A/B polymorphism was genotyped by PCR-RFLP. Results: Statistical analysis for the codon 54 polymorphism revealed that the wild (A) allele was significantly associated with asthma with OR = 1.9, 95% CI (1.4–2.4), and p < 0.001. Conclusion: The MBL2 codon 54 A/B polymorphism is significantly associated with asthma and its phenotypic traits as the wild (A/A) genotype confers a significant risk towards the disease in the studied North Indian population.

Association of the Wild-Type A/A Genotype of MBL2 Codon 54 with Asthma in a North Indian Population

Background: High serumMBL level as well as polymorphisms in the mannose-binding lectin 2 (MBL2) gene resulting in MBL deficiency are involved in the mechanism of a number of non-infectious diseases such as asthma, conferring either risk or protection in different population studies. MBL being the first reactant of the MBL pathway is also a major determinant of the fate of the anaphylatoxins such as C3a and C5a, which are also pro-inflammatory mediators. The MBL2 gene polymorphisms thus control the serum levels of MBL as well as C3a and C5a.Objective: This is the first case-control study conducted in India, investigating the role of MBL2 codon 54 A/B polymorphism in asthma pathogenesis.Methods: A case-control study was performed with a total of 992 adult subjects, including 410 adult asthmatics and 582 healthy controls from regions of North India. The MBL2 codon 54 A/B polymorphism was genotyped by PCR-RFLP.Results: Statistical analysis for the codon 54 polymorphism revealed that the wild (A) allele was significantly associated with asthma with OR = 1.9, 95% CI (1.4–2.4), and p &lt; 0.001.Conclusion: The MBL2 codon 54 A/B polymorphism is significantly associated with asthma and its phenotypic traits as the wild (A/A) genotype confers a significant risk towards the disease in the studied North Indian population.

Abstract B60: Hsa-miR-27a drives an association of MBL2 3′UTR haplotype with colon cancer risk in African Americans

Abstract Colon cancer (CC) is estimated to be the third most common cause of cancer deaths in the United States in 2010 and the incidence is higher among African Americans compared with Caucasians. Chronic intestinal inflammation is a risk factor for CC. Moreover, mediators of chronic inflammation have been implicated in CC development. MBL, a mannose-binding protein, is a critical component of the innate immune system, and it serves as a front-line protection against pathogens. MBL deficiency is common and present in approximately 5% of the population, predisposing individuals to bacterial and fungal infections. A previous resequencing analysis of the 10.0kbp region that includes the MBL2 gene showed a recombination hot-spot in the 3′ end of the gene, dividing MBL2 into two separate haplotype blocks: 5′UTR and 3′UTR haplotypes. In our previous work, we used a case-control study from the greater Baltimore, Maryland area (261 cases; 537 controls) and observed that haplotypes in both regions are associated with CC risk in African Americans, but not in Caucasians. Moreover, we showed that four single nucleotide polymorphisms (SNPs) comprising a 3′UTR region haplotype are individually associated with increased CC risk in African Americans: rs10082466, rs2120132, rs2099902, and rs10450310. In this study, we investigated whether the SNPs in this haplotype block fell within putative microRNA (miRNA) site due to the observed association of 3′UTR-region haplotypes and plasma MBL levels, using publicly available web-tools. We hypothesized that rs10082466 association with CC is driven by hsa-miR-27a binding to the C allele, resulting in decreased plasma MBL2 levels and activity. We tested the interaction of hsa-miR-27a with the 3′UTR region of MBL2 and its modulation by 3′UTR haplotypes in vitro using reporter constructs via luciferase activity. The increased binding affinity for the C allele of rs10082466 was reflected by a significant decrease in normalized luciferase activity, compared with the T allele. We also showed the C allele to be associated with lower plasma MBL2 levels and activity in cases and controls. Moreover, the fold increase of hsa-mir-27a precursor is significantly higher in African Americans compared to Caucasians in colon cancer. Therefore, 3′UTR haplotype association with CC may be driven by hsa-miR-27a binding to the C allele of rs10082466, which results in decreased plasma MBL2 levels and activity. In addition to the supporting evidence linking low levels of circulating MBL2 to increased susceptibility to infection, these results suggest that a genetic variant in MBL2 may increase colon cancer susceptibility in African Americans by creating a miRNA binding site. Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B60.