The innate immune system represents the first line of host defense against pathogens. Genetics factors regulating the immune responses play a role in the susceptibility to infectious diseases, such as tuberculosis (TB). We analyzed MBL2 promoter and exon 1 functional single nucleotide polymorphisms (SNPs) in a group of 155TB patients and 148 healthy controls in order to evaluate their influence on the onset of infection and TB development. There was no association between MBL2 -550 HL promoter polymorphisms and susceptibility to develop TB, but heterozygous -221 Y/X genotype was significantly more frequent in pulmonary TB patients than controls. Moreover, MBL2 exon 1 O allele, was significantly associated with susceptibility to TB development in general (p=0.023, OR=1.61, 95% CI 1.05-2.49) and pulmonary TB (p=0.0008, OR=2.16, 95% CI 1.35-3.46); C allele at codon 57, as well as A/C genotype, were significantly more frequent in TB patients than in controls. Our results indicate that MBL2 polymorphisms, especially at codon 57, could be considered as risk factors for TB development.

Mannan-binding lectin (MBL) is an important factor of innate immunity contributing to the clearance of microorganisms. Recently, an antitumourigenic role of MBL has been suggested. We investigated mbl2 genotypes, MBL concentrations, and MBL-MASP-2 complex activity in patients with ovarian cancer. The expression of both mbl2 and masp-2 genes were investigated in ovarian tissue sections. Additionally, samples from patients with other malignant and benign tumours of the reproductive tract were tested. A significantly higher incidence of MBL deficiency/insufficiency-associated genotypes was found among patients with malignant disease compared to age-matched controls. Unexpectedly, no differences in median MBL level or MBL-MASP-2 complex activity were found between the groups. This was partly a reflection of higher MBL concentrations and MBL-MASP-2 activity in cancer patients compared with healthy women carrying corresponding genotypes. MBL-specific mRNA expression was detected in several normal and malignant ovarian tissues, as well as in ovarian epithelial cell lines. Intracellular staining with MBL-specific antibodies demonstrated the presence of MBL in ovarian cell lines, and in normal as well as malignant ovarian tissue sections. In contrast, MASP-2-specific mRNA expression was detected only in the ovary tissues of patients with malignant disease. No significant changes in MBL concentration during 3 months of chemotherapy were noticed. MBL was detected in ascites and in the fluid of benign ovarian cysts. Our findings may reflect anti-tumourigenic activity of MBL protein which might suggest potential therapeutic application. However, it cannot be excluded that mbl-2 mutant alleles may be in linkage disequilibrium with an unidentified tumour susceptibility gene(s).

Mannose-binding lectin (MBL) plays an important role in immunity to HIV-1 infection. The exon1 coding polymorphisms of the MBL2 gene have been implicated in the susceptibility to HIV-1 infection, but the results were controversial. In the present study, a case-control study in a Chinese population was conducted to replicate the association, and then a meta-analysis combing our new data and published data was performed to clarify these findings. In total, 15 studies consisting 2219 HIV-1 patients and 2744 controls were included. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were assessed in the main analyses. By dividing the controls into two groups, healthy controls and HIV-1 exposed but seronegative (HESN) controls, we explored different genetic models and allelic model to detect the association. By using the healthy controls, we found that the MBL2 exon 1 polymorphisms were associated with hosts' susceptibility to HIV-1 infection in dominant model (p=0.01, 95% CI 1.05-1.43), recessive model (p<0.0001, 95% CI 1.35-2.28), allelic model (p<0.0001, 95% CI 1.12-1.37) and O/O vs. A/A model (p<0.00001, 95% CI 1.40-2.38). In the subgroup analysis by ethnicity, significant elevated risks were found in Caucasians (recessive model: p<0.0001, 95% CI 1.36-2.51), but not in Asians (recessive model: p=0.10, 95% CI 0.91-2.77). Collectively, our findings from our case-control replication study and meta-analysis suggested that the MBL2 gene exon 1 coding variants were associated with hosts' susceptibility to HIV-1 infection, especially in Caucasians, but not in Asians.

We compared the prevalence of 8 polymorphisms in the tumor necrosis factor and mannose-binding lectin genes among 105 children and young adults with fatal influenza with US population estimates and determined in subanalyses whether these polymorphisms were associated with sudden death and bacterial co-infection among persons with fatal influenza. No differences were observed in genotype prevalence or minor allele frequencies between persons with fatal influenza and the reference sample. Fatal cases with low-producing MBL2 genotypes had a 7-fold increased risk for invasive methicillin-resistant Staphylococcus aureus (MRSA) co-infection compared with fatal cases with high- and intermediate-producing MBL2 genotypes (odds ratio 7.1, 95% confidence interval 1.6-32.1). Limited analysis of 2 genes important to the innate immune response found no association between genetic variants and fatal influenza infection. Among children and young adults who died of influenza, low-producing MBL2 genotypes may have increased risk for MRSA co-infection.

OBJECTIVE

The aim of the study was to examine whether the MBL2 C(-290)G and G161A, MASP2 A359G, AMELX C287T and C522T, and ENAM C2452T polymorphisms are associated with dental caries.

METHODS

Genomic DNA of 95 Polish children with 'higher caries experience' (HC) and 84 subjects with 'lower caries experience' (LC) belonging to two age-groups (5 and 13 years old) was extracted from the buccal mucosa. SNPs were genotyped with PCR-RFLP methods.

RESULTS

Among 5-year-old children, we found significantly higher percentage of subjects carrying MBL2 (-290)G allele in HC group compared with LC group (43.2%vs 17.6%, P = 0.023). MBL2 C(-290)G-G161A C-G haplotype was overrepresented in LC group in 5-year-olds (P = 0.01), while the opposite association was observed in 13-year-olds, where C-G was overrepresented in HC group (P = 0.028). In 5-year-old children, the frequency of MBL2 G-G haplotype was higher in HC group compared with LC subjects (P = 0.045), while the opposite association (with borderline significance) was observed in 13-year-old children (P = 0.057). SNPs in MASP2, AMELX, and ENAM were not associated with dental caries.

CONCLUSIONS

MBL2 gene polymorphism is associated with caries experience in Polish children, but the direction of this association seems to be opposite in primary and permanent dentition.

IgA nephropathy (IgAN) is characterized by infections followed by episodic gross hematuria. Deficiency of mannose-binding lectin (MBL) is associated with recurrent infection in many diseases, but controversy exists regarding the role of MBL in IgAN. Here, we measured MBL2 variants and MBL levels in 749 patients with IgAN and 489 healthy controls. Overall, 5.2% (39 of 749) of patients with IgAN had MBL deficiency (MBL levels <100 ng/ml), among whom LYPB/LYPB and LXPA/LYPB were the predominant MBL2 haplotypes (82%; 32 of 39). We found a nonlinear association between MBL levels and renal outcome in IgAN. Patients with IgAN and MBL deficiency had a higher incidence of prodromic infections and gross hematuria than those with sufficient MBL levels (100-3540 ng/ml). Moreover, MBL deficiency independently associated with poor renal outcome in IgAN after multiple adjustments (hazard ratio, 5.18; 95% confidence interval, 2.50 to 10.72; P<0.001). Patients with high MBL levels (>3540 ng/ml) had more severe proteinuria and a higher proportion of crescents, although the association with IgAN progression did not reach statistical significance after adjustments. In conclusion, MBL deficiency and MBL excess may both have deleterious effects on IgAN progression, which suggests that MBL contributes to IgAN pathogenesis through multiple mechanisms.

Infections after chemotherapy often cause significant morbidity in patients with acute myeloid leukaemia (AML). Chitotriosidase (CHIT) and mannose-binding lectin (MBL) are part of the innate immune system. Polymorphism in the CHIT-coding gene (CHIT1) may be associated with Gram-negative sepsis in children with AML, and polymorphism in the MBL-coding gene (MBL2) seems to modify the risk of infections in several patient groups. The purpose of this study was to investigate the possible associations between polymorphisms in CHIT1, MBL2 and sepsis in adult patients treated with high-dose chemotherapy for AML. We included 190 patients treated with 526 cycles of chemotherapy. The follow-up period was 6 months from the diagnosis of AML. Prophylactic antibiotics were not used. We identified 604 febrile episodes with 246 episodes of sepsis. Thirty-two patients (17%) either died from infection or infection was a major concomitant factor for death. No significant associations between CHIT1 polymorphism and sepsis (P = 0.85) or death caused by sepsis (P = 0.14) were found. Furthermore, no significant associations between MBL2 polymorphism and sepsis (P = 0.76) or death caused by sepsis (P = 0.24) were observed. The severe and long-lasting neutropenia and mucositis after chemotherapy may explain why the MBL system does not protect against sepsis in patients with AML. Replacement therapy with recombinant MBL is not likely to decrease the risk of sepsis in patients with AML.

Inflammatory changes in the gastric mucosa are commonly observed in Japanese patients with functional dyspepsia (FD). However, detailed data regarding the possible association between the genetic factors of inflammation related molecules and FD are not available. Toll like receptor 2 (TLR2) and mannan-binding lectin (MBL) protein play important roles in the innate immune activation. We aimed to clarify the association between common polymorphisms of TLR2 and MBL2 genes with FD in Japanese subjects. TLR2 -196 to -174 del and MBL2 codon54 G/A polymorphisms were genotyped in 111 FD patients according to Rome III criteria and 106 asymptomatic controls. Non-significant correlation was found between TLR2 and MBL2 polymorphisms with FD. However, in Helicobacter pylori (H. pylori) positives, we found significant inverse association between TLR2 -196 to -174 del carrier and FD among H. pylori positive subjects (Adjusted odds ratio (OR) = 0.48, 95% confidence interval (CI) = 0.23-0.996, p = 0.0488). We also found significant inverse association between the same genotype with postprandial distress syndrome (PDS) among H. pylori positive subjects (Adjusted OR = 0.22, 95% CI = 0.07-0.69, p = 0.0099). Our data suggest that TLR2 -196 to -174 del carriers's status but not MBL2 codon54 G/A is inversely related to the risk with FD in H. pylori-infected subjects.

Susceptibility to systemic lupus erythematosus (SLE) has been associated with immunologic, environmental, and genetic factors. To uncover a possible association between MBL2 gene polymorphisms and SLE, we analyzed functional polymorphisms in the promoter and first exon of the MBL2 gene in 134 Brazilian SLE patients and 101 healthy controls. Genotype and allele frequencies of MBL2 A/O polymorphism were significantly different between patients and controls, and the O allele was associated with an increased risk of SLE. An association between low mannose binding lectin (MBL) producer combined genotypes and increased risk for SLE was also reported. Furthermore, when stratifying SLE patients according to clinical and laboratory data, an association between the A/O genotype and nephritic disorders and between the X/Y genotype and antiphospholipid syndrome was evident. Combined genotypes responsible for low MBL production were more frequently observed in SLE patients with nephritis. Our results indicate MBL2 polymorphisms as possible risk factors for SLE development and disease-related clinical manifestations.

Most individual cystic fibrosis transmembrane conductance regulator (CFTR) mutations appear not to correlate directly with severity of lung damage in cystic fibrosis (CF). Components of innate immunity, namely, mannose-binding lectin (MBL2), and surfactant protein A1 and A2 genes (SFTPA1 and SFTPA2), were shown to be critical in pulmonary host defenses. A pilot association study was conducted to identify genetic modifiers of lung disease in adult patients with CF. The structural and promoter (-221x/y) variants of MBL2, variants at codons 19, 50, 62, and 219 of SFTPA1, and at codons 9, 91, and 223 for SFTPA2, were studied in 135 adults with CF and compared to their forced expired volume in 1 sec (FEV1), diffusion of CO (DLCO), and other pulmonary scores. Predicted FEV1 was significantly lower in adults with the SFTPA1 6A3 allele and SFTPA2 1A1) allele (P = 0.01 and 0.009, respectively). The extended haplotype 6A3/1A1, which includes SFTPA1 and SFTPA2, was associated with lower pulmonary function, using FEV1 (P = 0.005) and poor pulmonary scores which were determined by American Medical Association, American Thoracic Society, and modified Shwachman-Kulczycki scores. Lower FEV1 and DLCO values were associated with MBL2 coding variants in those who had the DeltaF508 CFTR mutation (P = 0.03 and 0.004, respectively). These results support the current hypothesis that variants in pulmonary host defense molecules are potentially genetic modifiers of pulmonary disease in CF. Further work in larger populations is required to provide important new insights into the pathogenesis of CF.

BACKGROUND

Lung transplantation is a well accepted therapy for end-stage lung disease, despite high mortality rates. Mortality after transplantation is mainly caused by allograft failure in the first years after transplantation. Mannose binding lectin (MBL), a recognition molecule of innate immunity, has been associated with transplant outcome in other solid organ transplantation. In this study, the effect of donor- and recipient-MBL genotype on lung transplant outcome was investigated.

METHODS

All lung transplantations performed in our center, except from retransplantations and combined lung-liver or heart-lung transplantations, were included. Genotyping of the MBL2 variants (promoter: L/H, Y/X, and P/Q allele and exon 1: A/D, A/B, and A/C allele) was performed in donor and recipient DNA. Analyses on graft survival and the development of bronchiolitis obliterans syndrome were performed with Kaplan-Meier (log rank) survival analysis.

RESULTS

Of the 277 included cases, DNA was available from 189 donors and 200 recipients and genotyping of the promoter single nucleotide polymorphisms was successful in 184 donors and 198 recipients and of the exon 1 single nucleotide polymorphisms in 181 donors and 193 recipients. Patients who received a graft from a donor with an X-allele had better graft survival (P=0.007) and bronchiolitis obliterans syndrome free survival (P=0.007). Recipient MBL genotype was not associated with transplant outcome.

CONCLUSIONS

The donor X-allele, which corresponds to the LXPA haplotype is associated with superior lung transplant outcome. Our findings might prove to be important in finding ways to optimize outcome after lung transplantation.

BACKGROUND

Mannose binding lectin (MBL) has an important role in the activation of the complement system and opsonization of pathogenic microorganisms. Frequent polymorphisms found in the MBL2 gene affect the concentration and functionality of the protein and are associated with enhanced susceptibility to severe malaria in African children. Most MBL2 typing strategies were designed to the analysis of selected variants, the significance of whole haplotypes is poorly known. In this work, a new typing strategy was developed and validated in an association analysis of MBL2 with adult asymptomatic infection.

METHODS

MBL2 allele-specific fragments of 144 healthy Gabonese adults were amplified by using haplotype-specific sequencing (HSS), a new strategy that combines sequence-specific PCR and sequence-based typing. The Gabonese were investigated for the presence of Plasmodium falciparum parasitaemia by the amplification of parasite genes, immunochromatographic antigen detection and microscopic analysis. HSS results were also compared with a previously used real-time PCR (RT-PCR) method in 72 Euro-Brazilians.

RESULTS

Fourteen polymorphisms were identified beside the commonly investigated promoter (H, L; X, Y; P, Q) and exon 1 (A, O; O = B, C or D) variants. The MBL2*LYPA/LYPA genotype was associated with the absence of asymptomatic infection (P = 0.017), whereas the MBL2*LYQC haplotype and YA/YO + YO/YO genotypes were associated with positive parasite counts in asymptomatic adults (P = 0.033 and 0.018, respectively). The associations were specific to LYPA (identical to the reference sequence Y16577) and LYQC (Y16578) and would not have been revealed by standard genotyping, as there was no association with LYPA and LYQC haplotypes carrying new polymorphisms defined by sequence-based typing. In contrast, HSS and RT-PCR produced very similar results in the less diverse European-derived population.

CONCLUSIONS

In this work, a new typing strategy for a highly polymorphic gene was developed and validated focusing on the asymptomatic status of P. falciparum-infected adults. In populations with high nucleotide diversity, it allowed for the identification of associations with fine-scaled haplotypes that would not have been found using common typing techniques. In this preliminary study, MBL2 haplotypes or SNPs linked to them were found associated with susceptibility to infection and parasitaemia control of asymptomatic adults.

Mannan-binding lectin (MBL), a pattern recognizing serum protein, participates in the innate immune system of mammals as an opsonin. In humans, single-nucleotide polymorphisms (SNPs) in MBL2 gene were found to cause various innate immune dysfunctions. In the present study, we discovered three single-nucleotide polymorphisms of the MBL1 gene in Chinese native cattle and analyzed their associations with milk traits. By screening the genetic variation of MBL1 in 1053 individuals of three Chinese native cattle breeds including China Holstein, Luxi Yellow and Bohai Black using created restriction site-polymerase chain reaction (CRS-PCR), PCR-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing techniques, three new SNPs, g.855G>A, g.2651G>A and g.2686T>C, were found to have allele frequencies of 0-12.65%, 24.07-42.39% and 56.95-73.68%, respectively. While SNP g.855G>A is located within intron І, the other two SNPs reside in the exon II region with one mutation being non-synonymous (GTT (Val>>ATT (Ile)) and the other synonymous (GCT (Ala>>GCC (Ala)). Among the 596 Chinese Holstein cattle with at least 3 lactation Dairy Herd Improvement (DHI) records, eight different haplotypes and 19 genotype combinations were detected. Statistical analyses revealed no correlation between either g.855G>A or g.2686T>C and somatic cell score (SCS), however significant association was found between g.2651G>A and SCS, suggesting a possible role of this SNP in the host response against mastitis. Our data also suggested that the combined genotypes of GGC/AAC with the lowest SCS, AAT/AAT with the highest protein content and AGC/AGC with the highest 305-d milk yield were favorable combinations for mastitis resistance and milk production traits. Therefore, GGC/AAC, AAT/AAT and AGC/AGC can be used as possible candidates for marker-assisted selection in the dairy cattle breeding program.

OBJECTIVE

To investigate the possible association between polymorphisms of the mannose-binding lectin gene (MBL2) and susceptibility to juvenile idiopathic arthritis (JIA).

METHODS

We performed a case-control association study including 118 Hungarian patients with JIA and 118 sex-matched healthy controls. MBL genotyping for the 3 mutant structural alleles at codons 54 (B), 57 (C), and 52 (D) in exon 1 and the promoter polymorphisms at position -550 (HL) and -221 (YX) were carried out by real-time PCR allelic discrimination. Serum level of MBL was determined by ELISA.

RESULTS

Variant allele frequencies of both codon 52 and 57 polymorphisms in the MBL2 gene were significantly overrepresented in JIA (p=0.001 and p=0.004, respectively). The frequency of low MBL genotypes (XA/XA, YA/YO, XA/YO, and YO/YO) in JIA was higher than that in healthy controls (p=0.001). Serum MBL concentrations were found to be significantly lower in JIA patients versus control subjects (p=0.001). The 2 promoter polymorphisms and codon 54 SNP of the MBL2 gene were not associated with JIA.

CONCLUSIONS

Our findings suggest that genetically determined low MBL levels may predispose children to JIA in a Hungarian population. These data warrant further research to investigate the role of the lectin-dependent complement system in the pathogenesis of JIA.

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.

OBJECTIVE

Rheumatoid arthritis (RA) is a disease with unknown etiology but it is probably multifactorial. RA susceptibility is related to genetic, hormonal, immunologic, and environmental factors. Mannose-binding lectin (MBL) is an important protein of the human innate immune system, encoded by the MBL2 gene. Polymorphisms in MBL2 were associated with several diseases, and may be an important factor in RA susceptibility. We analyzed 3 MBL2 gene polymorphisms in 322 Brazilian patients with RA and 345 ethnically matched healthy controls.

METHODS

MBL2 gene variants were analyzed through polymerase chain reaction sequencing.

RESULTS

Considering MBL2 B, C, and D alleles separately, a significant difference in both genotypic and allelic frequencies, particularly concerning frequency of the C allele, was observed comparing European-derived and African-derived individuals (European-derived patients 0.022 vs African-derived patients 0.205; European-derived controls 0.029 vs African-derived controls 0.144; both p < 0.001). We also analyzed MBL2 genotype in relation to extraarticular manifestations. Considering MBL2 variants together, we found an increased frequency of the OO genotype among patients with rheumatoid nodules (p = 0.031), although this association lost significance after Bonferroni correction.

CONCLUSIONS

Our findings suggest an association of MBL2 genotypes with some clinical manifestations of RA, but more studies are needed to clarify the actual role of MBL in RA.

Complement mannan-binding lectin (MBL) deficiency is associated with increased susceptibility to infections and autoimmune diseases. Previous studies suggested that the production of MBL is stimulated by thyroid hormones. The aim of our study was to investigate this association in patients with autoimmune thyroid diseases (AITD). Serum levels of MBL and parameters of the thyroid function were determined in 62 patients with Hashimoto's thyroiditis, 33 with Graves' disease and 47 blood donors. Follow-up measurements were performed after 6 to 24 months. MBL2 genotypes were determined using multiplex PCR and compared to 359 healthy Czech individuals. Serum levels of MBL tightly correlated with thyroid hormones, leading to strongly increased MBL levels in hyperthyroidism and decreased levels in hypothyroidism. With normalization of the thyroid function during follow-up, MBL levels decreased or increased respectively. The observed correlations were not due to MBL polymorphisms since the frequency of MBL2 polymorphisms in AITD patients was not different from the general population. We conclude that AITD are not associated with MBL polymorphisms. However, the MBL production is strongly dependent on thyroid function, regardless of the genotype.

BACKGROUND

Mannose-binding lectin (MBL) is an innate immune protein. The aim of our study was to determine whether genetically determined MBL deficiency is associated with susceptibility to juvenile rheumatoid arthritis (JRA) and whether MBL2 genotypes are associated with JRA severity.

METHODS

In a retrospective cohort study of 218 patients with polyarthritis (n = 67) and oligoarthritis (n = 151), clinical and laboratory disease variables were obtained by clinical examination and chart reviews. Healthy Caucasian adults (n = 194) served as control individuals. MBL2 gene mutations were determined by Taqman analysis to identify genotypes with high, medium and low expression of MBL. Functional MBL plasma concentrations were measured using enzyme-linked immunosorbent assay. Associations between clinical and laboratory variables and MBL2 genotypes were determined by Kruskal-Wallis and chi2 tests.

RESULTS

MBL2 genotype frequencies were similar in polyarthritis and oligoarthritis patients as compared with control individuals. MBL plasma concentrations were associated with the high, medium and low MBL genotype expression groups (P < 0.01). In polyarthritis patients, the presence of low-expressing (deficient) MBL2 genotypes was associated with early age at onset of disease (P = 0.03). In oligoarthritis patients, patients with low-expressing MBL2 genotypes were more often in remission (81%) than patients in the medium (54%) and high (56%) genotype groups (P = 0.02). The remaining clinical and laboratory variables, such as arthritis severity index, presence of radiographic erosions and antinuclear antibody positivity, were not associated with MBL2 genotypes.

CONCLUSIONS

Genetically determined MBL deficiency does not increase susceptibility to JRA, but MBL deficiency is associated with a younger age at onset of juvenile polyarthritis. On the other hand, MBL-deficient children with juvenile oligoarthritis are more often in remission. Therefore, MBL appears to play a dual role in JRA.

The vascular disease involves imbalanced function of the blood vessels. Risk factors playing a role in development of impaired vessel functions will be briefly discussed. In ischemia/reperfusion (I/R), ischemic hypoxia is one of the cardinal risk factors of restenosis. Various insults are shown to initiate the phenotype switch of VSMCs. The pathological process, leading to activated inflammatory process, complement activation, and release of growth factors, initiate the proliferation of VSMCs in the media and cause luminal narrowing and impaired vascular function. The review summarizes the alteration process and demonstrates some of the clinical genetic background showing the role of complement and the genotypes of mannose-binding lectin (MBL2). Those could be useful markers of carotid restenosis after stent implantation. Gene therapy and therapeutic angiogenesis is proposed for therapy in restenosis. We suggest a drug candidate (iroxanadine), which ensures a noninvasive treatment by reverse regulation of the highly proliferating VSMCs and the disturbed function of ECs.

OBJECTIVE

The lectin pathway of complement activation is a crucial effector cascade of the innate immune response to pathogens. Cytomegalovirus (CMV) infection occurs frequently in immunocompromised patients after orthotopic liver transplantation (OLT). Single-nucleotide polymorphisms (SNPs) in the lectin pathway genes determine their liver-derived protein level and functional activity. We examined the association between these SNPs and the risk for CMV infection in OLT.

METHODS

OLT patients (n = 295) were genotyped for recipient and donor SNPs in mannose-binding lectin (MBL2), Ficolin-2 (FCN2) and MBL-associated serine protease (MASP2) genes.

RESULTS

Combined analysis of independently associated variant MBL2 [HR 1.65, p<0.02] and wild-type FCN2 [1.85; p<0.02] SNPs in the donor liver showed an increased risk of CMV infection for either and both risk genotypes [HR 2.02 and HR 3.26, respectively, p = 0.004], especially in CMV Donor-/Recipient+ (D-/R+) patients [HR 4.7 and HR 10.0, respectively, p = 0.01]. A genetic donor-recipient mismatch for MBL2 and FCN2 increased the CMV risk independently, also combined [HR 5.35; p<0.001], particularly in CMV D-/R+ patients [HR 16.6; p = 0.009]. Multivariate Cox analysis showed a consistent stepwise increase in CMV infection risk with the gene profile of the donor [up to HR 2.77; p<0.005] and the combined MBL2 and FCN2 donor-recipient mismatch profile [up to HR 4.57; p<0.001], independent from donor-recipient CMV serostatus, also at higher CMV (re)infection cut-off values.

CONCLUSIONS

MBL2 and FCN2 risk alleles of donor liver and recipient constitute independent risk factors for CMV infection after OLT. Patients with these risk genes probably need intensified CMV monitoring and anti-viral therapy.

Reliable analysis of single nucleotide polymorphisms (SNPs) in DNA derived from samples containing low numbers of cells or from suboptimal sources can be difficult. A new procedure to characterize multiple SNPs in traces of DNA from plasma and old dried blood samples was developed. Six SNPs in the Mannose Binding Lectin 2 (MBL2) gene were chosen as targets for analysis. DNA was extracted from plasma obtained from mothers (n=49) and their neonates (n=49) and from old dried blood samples (n=204). Multiple Real-Time SNP analyses in the MBL2 gene were carried out on all samples. Because of very low DNA concentrations in most of the samples, a pre-amplification step was utilized. It was possible to analyze all plasma samples (n=98), including those with very low cell numbers (n=21) and 93% of the old dried blood samples (n=189). Results obtained from pre-amplified samples were in full agreement with neat samples. All possible SNP alleles were present in our population. The frequencies of the different alleles from both plasma and dried blood samples (n=287) were in agreement with earlier studies of the Caucasian population. In conclusion, amplification prior to Real-Time PCR SNP analysis is a convenient, cost effective and useful method to significantly improve the reliable SNP detection in specimens containing very low concentrations or poor quality DNA from suboptimal sources.

Circulating mannan (or mannose)-binding lectin (MBL) is genetically determined. Low MBL concentrations are associated with certain point mutations in the human MBL2 gene. Here we report the full MBL2 genotypes of 1800 Polish neonates and relate individual genotypes to serum MBL and MBL-dependent activity of the lectin pathway of complement activation. The seven acknowledged common haplotypes were found, plus the uncommon LYPD haplotype, combining to form 33 genotypes in this population. As expected, a strong correlation existed between genotypes and serum MBL or lectin pathway activity, and the latter two entities correlated strongly with each other. However, serum MBL values varied up to greater than 90-fold within genotypes. Unexpectedly, higher lectin pathway activity was found in association with the P allele relative to the Q allele. These data from a large cohort of neonates, representing an ethnically homogenous population, suggest that the current knowledge of the genetics of MBL2 is inadequate to predict serum MBL concentration and MBL-dependent lectin pathway activity in individual subjects.

Both immunological and placental factors are involved in the pathogenesis of pre-eclampsia. The complement factor mannose-binding lectin (MBL) is associated with adverse pregnancy outcomes and has been suggested to play a role in abnormal placentation. We investigated whether MBL genotypes are associated with the systemic maternal syndrome pre-eclampsia. MBL2 gene polymorphisms were determined in a case-control study including 157 women with pre-eclampsia (case subjects) and 157 women with uncomplicated pregnancies (control subjects). Considering MBL polymorphisms, case and control subjects were categorized in groups of high (A), intermediate (B), and low (C) MBL production. No association was found between MBL genotypes and pre-eclampsia; adjusted odds ratios and 95% confidence intervals (95% CI) for group B were 0.97 (95% CI = 0.46-2.07) and for group C were 1.44 (95% CI = 0.52-3.94). A trend was found between MBL genotype groups B and C and severe pre-eclampsia or eclampsia. MBL genotypes were not found to be associated with pre-eclampsia; however low-MBL production genotypes might be considered as disease modifier. This suggests that MBL may play a role in modulating placental inflammation by facilitating clearance of apoptotic cells and cell debris.

Patients with hepatitis B virus (HBV) infection may develop severe chronic liver disease. Carriers of HBV have an increased risk of developing cirrhosis, hepatic decompensation, and hepatocellular carcinoma. Worldwide an estimated 350 million people are infected with HBV, and 15-40% will develop serious sequelae in their lifetime. In our study we investigated the association of single nucleotide polymorphisms (SNPs) in the first exon and promoter region of the mannose-binding lectin gene 2 (MBL2) situated on chromosome 10, with susceptibility to HBV infection. One-hundred and two patients infected with HBV were included in this study, and 232 uninfected individuals were used as healthy controls. Genotyping of the first exon (alleles A/O) was performed using a melting temperature assay. Genotyping of the promoter region (-550 H/L; -221 Y/X) was performed using the Taqman PCR technique. In the HBV-infected group we found a significantly increased frequency of haplotypes associated with low serum MBL. Our findings may indicate that MBL has a protective role against HBV infection in the studied population.