Serum Levels Of Mannan-binding Lectin Research Articles

High MBL-expressing genotypes are associated with deterioration in renal function in type 2 diabetes.

Accumulating evidence support that mannan-binding lectin (MBL) is a promising prognostic biomarker for risk-stratification of diabetic micro- and macrovascular complications. Serum MBL levels are predominately genetically determined and depend on MBL genotype. However, Type 1 diabetes (T1D) is associated with higher MBL serum levels for a given MBL genotype, but it remains unknown if this is also the case for patients with T2D. In this study, we evaluated the impact of MBL genotypes on renal function trajectories serum MBL levels and compared MBL genotypes in newly diagnosed patients with T2D with age- and sex-matched healthy individuals. Furthermore, we evaluated differences in parameters of insulin resistance within MBL genotypes. In a cross-sectional study, we included 100 patients who were recently diagnosed with T2D and 100 age- and sex-matched individuals. We measured serum MBL levels, MBL genotype, standard biochemistry, and DEXA, in all participants. A 5-year clinical follow-up study was conducted, followed by 12-year data on follow-up biochemistry and clinical status for the progression to micro- or macroalbuminuria for the patients with T2D. We found similar serum MBL levels and distribution of MBL genotypes between T2D patients and healthy individuals. The serum MBL level for a given MBL genotype did not differ between the groups neither at study entry nor at 5-year follow-up. We found that plasma creatinine increased more rapidly in patients with T2D with the high MBL expression genotype than with the medium/low MBL expression genotype over the 12-year follow-up period (p = 0.029). Serum MBL levels did not correlate with diabetes duration nor with HbA1c. Interestingly, serum MBL was inversely correlated with body fat percentage in individuals with high MBL expression genotypes both at study entry (p=0.0005) and 5-years follow-up (p=0.002). Contrary to T1D, T2D is not per se associated with increased MBL serum level for a given MBL genotype or with diabetes duration. Serum MBL was inversely correlated with body fat percentage, and T2D patients with the high MBL expression genotype presented with deterioration of renal function.

MBL Binding with AhR Controls Th17 Immunity in Silicosis-Associated Lung Inflammation and Fibrosis.

ObjectiveMannan-binding lectin (MBL), a soluble pattern recognition molecule of the innate immune system, is primarily synthesized in the liver and secreted into the circulation. Low serum level of MBL has been reported to be related to an increased risk of lung diseases. Herein, we aimed to investigate the function of MBL in silicosis-associated pulmonary inflammation.MethodsSerum collected from silicosis patients was tested for correlation between serum MBL levels and Th17 immunity. In vitro studies were performed to further demonstrated the effect of MBL on Th17 polarization. Silica was intratracheally injected in wild type (WT) or MBL-deficient (MBL–/–) mice to induce silicosis-associated lung inflammation and fibrosis. Th17 response was evaluated to explore the effect of MBL on silicosis in vivo.ResultsSilicosis patients with high serum MBL levels displayed ameliorative lung function. We demonstrated that serum MBL levels negatively correlated to Th17 cell frequency in silicosis patients. MBL protein markedly reduced expression of IL-17 but enhanced expression of Foxp3 in CD4+ T cells in vitro when subjected to Th17 or Treg polarizing conditions, respectively. The presence of MBL during Th17 cell polarization significantly limited aryl hydrocarbon receptor (AhR) expression and suppressed the signal transducer and activator of transcription 3 (STAT3) phosphorylation. Treatment with the AhR antagonist abolished the effect of MBL on Th17 response. Strikingly, MBL directly bound to AhR and affected its nuclear translocation. Furthermore, MBL–/– mice displayed elevated Th17 cell levels compared with WT mice in response to the silica challenge. The CD4+ T lymphocytes from silica-administrated MBL–/– mice exhibited more AhR expression than the wild-type counterparts.ConclusionOur study suggested that MBL limited the Th17 immunity via controlling the AhR/STAT3 pathway, thus providing new insight into silicosis and other inflammatory diseases in patients with MBL deficiency.

Mannan-Binding Lectin Reduces Epithelial-Mesenchymal Transition in Pulmonary Fibrosis via Inactivating the Store-Operated Calcium Entry Machinery

Idiopathic pulmonary fibrosis (IPF) is a type of idiopathic interstitial pneumonia with a poor clinical prognosis. Increasing evidence has demonstrated that epithelial-mesenchymal transition (EMT) contributes to the production of pathogenic myofibroblasts and plays a pivotal role in the development of pulmonary fibrosis. Mannan-binding lectin (MBL) is a soluble calcium-dependent complement molecule. Several studies have reported associations between serum MBL levels and lung diseases; however, the effect of MBL on IPF remains unknown. The present study observed aggravated pulmonary fibrosis in bleomycin-treated MBL−/− mice compared with their wild-type counterparts. Lung tissues from bleomycin-treated MBL−/− mice displayed a more severe EMT phenotype. In vitro studies determined that MBL inhibited the EMT process through attenuating store-operated calcium entry (SOCE) signaling. It was further demonstrated that MBL promoted the ubiquitination of Orai1, an essential component of SOCE, via pyruvate dehydrogenase kinase 1 (PDK1)-serum glucocorticoid-regulated kinase 1 signaling. PDK1 inhibition abolished the MBL-mediated regulation of SOCE activity and the EMT process. Notably, biochemical analysis showed that MBL interacted with PDK1 and contributed to PDK1 ubiquitination. In summary, the present findings suggested that MBL limited the EMT phenotype in human alveolar epithelial cells through regulation of SOCE, and MBL could be recognized as a potential therapeutic target for IPF.

Association of MBL2 polymorphism with Leg Ulcers Development in Sickle Cell Anemia Patients

Leg ulcers are the most common clinical manifestations of sickle cell anemia (SCA), a monogenic disease with huge clinical diversity among patients. They affect 8% to 10% of SCA patients, reaching a percentage greater than 50% in patients residing in tropical areas. These ulcers occur due to vascular occlusion, tissue hypoxia, hemolysis and genetic factors, presenting a slow healing, high recurrence rate and huge susceptibility to infection. Recently, some studies have shown a positive relationship between the complement system and the development of some vascular diseases and injuries such as leg ulcers in non-SCA patients. Mannan-binding lectin (MBL) is an important component of the humoral innate immune system, and MBL possesses several characteristics indicating that it may play an essential role in wound healing; modulating inflammation and contributing to the clearance of microorganisms and apoptotic cells. In a recent study of chronic leg and foot ulcer patients, serum MBL levels were significantly different between wounds of different etiologies, with chronic venous leg ulcers patients having a higher frequency of MBL deficiency. Polymorphisms in the MBL2 are associated with a reduction in the MBL protein serum levels, increasing risk of developing leg ulcers and also the maintenance of these wounds, compromising the integrity of the immune defence and its response to potential invading pathogens. Here, we aimed to determine the frequency of polymorphisms in the promoter region -221 (Y / X) and -550 (H / L) and exon 1 of the MBL2 and assess the clinical impact of these variants in a northeastern Brazilian SCA population who presented leg ulcers. Two-hundred seventy-five unrelated SCA patients were included. According the leg ulcers presence, the total cohort was classified in patients presenting current or prior history of leg ulcers (n=100) and SCA patients above 18 years with no history of leg ulcers (n=175). Molecular analysis was performed by qPCR. Our population was in Hardy-Weinberg equilibrium. The allelic frequency of haplotypes associated with high MBL production (HYA, LYA) was 54.5% for cases and 62.9% in controls. The genotypes related to low MBL production (HYO, LYO) in cases and controls was 27.5% and 18.6%, respectively. The frequency of genotype related to intermediate MBL production (LXA) was 18% in cases and 18.5% in controls. We had no statistically significant results when we analyzed only the polymorphisms (P>0.05). However, the phenotypic analysis between high and low MBL production revealed that patients with leg ulcers have lower MBL protein levels (P=0.019). We focused specifically on a possible role of MBL deficiency on healing complications, based on the facts that MBL deficiency is the most common immune disorder, and that a common causality for prolonged healing of these ulcers is infection or colonization by bacteria. In our study, MBL deficiency appears to increase the risk of developing leg ulcers in SCA patients. DisclosuresNo relevant conflicts of interest to declare.

Association between Low Levels of Mannan-Binding Lectin and Markers of Autoimmune Thyroid Disease in Pregnancy

Functional deficiency of mannan-binding lectin (MBL) has been associated with adverse pregnancy outcome. Adverse events during pregnancy have also been described in women with autoimmune thyroid diseases (AITD), and thyroid hormones have been shown to influence serum levels of MBL. Therefore, the aim of this study was to analyse the impact of MBL-deficiency on the outcome of pregnancy in relation to the presence of AITD. Almost one year after delivery, we assessed serum MBL levels and MBL2-genotypes in 212 women positively screened for AITD in pregnancy. In 103 of these women, we could also measure MBL levels in frozen serum samples from the 9-12th gestational week, obtaining 96 pairs of MBL values (pregnancy vs. follow-up). As controls, 80 sera of pregnant women screened negatively for AITD were used. MBL2-genotyping was performed using multiplex PCR. Women with thyroid dysfunction and/or thyroid peroxidase antibodies (TPOAb) had lower MBL levels during pregnancy than controls, (3275 vs. 5000 ng/ml, p<0.05). The lowest levels were found in women with elevated thyroid-stimulating hormone (TSH) levels in the absence of TPOAb (2207 ng/ml; p<0.01 as compared to controls). MBL2 genotype distribution did not differ between subgroups. At a median follow-up period of 17 months (range: 3–78 months) after delivery, median MBL level had decreased further to 1923 ng/ml (p<0.0001) without significant changes in TSH. In an explorative survey, functional MBL-deficiency was neither linked to a history of spontaneous abortion, nor other obstetric complications, severe infections throughout life/pregnancy or antibiotics use in pregnancy. In conclusion, hypothyroidism during pregnancy is associated with decreased MBL levels, and the levels decreased further after delivery.

The lectin pathway of the complement system is downregulated in Crohn's disease patients who respond to anti-TNF-α therapy

Background and aimsThe lectin pathway of the complement system is initiated through the recognition of pathogens or altered self-structures by mannan-binding lectin (MBL) or ficolins and subsequent activation of MBL-associated serine proteases (MASPs). Altered ficolin levels may contribute to a dysregulated immune response in Crohn's disease (CD). A complete analysis of the lectin pathway has not been performed in patients with CD. We hypothesised that the lectin pathway proteins exacerbate inflammation in CD. MethodsWe assessed the lectin pathway proteins in 43 patients with active CD & 350 blood donors by measuring the serum levels of MBL; M-, H-, and L-ficolin; MASP-2; MASP-3; and MAp44. In patients with CD, the blood samples were obtained during induction treatment with infliximab or adalimumab. ResultsOf 43 patients with CD, 32 (74%) were classified as responders. We observed a nearly 50% decrease in median M-ficolin levels between day 0 and weeks 1/7 in the responders (p<0.001), whereas there was no decrease in the non-responders. MASP-2 levels decreased from baseline to week 1 in both the responders (37%, p<0.0001) and the non-responders (29%, p=0.02). In the responders only, the level of the inhibitory serine protease MASP-3 increased by 26% from baseline to week 1 (p<0.001) and remained high at week 7. ConclusionsOur findings indicated that M-ficolin, MASP-2, and MASP-3 may act in concert to reduce the activity of the lectin pathway, in patients with CD who respond to biological therapy.

Mannan-Binding Lectin Mediates Renal Ischemia/Reperfusion Injury Independent of Complement Activation

Ischemia/reperfusion injury (IRI) remains a major problem in renal transplantation. Clinical studies have identified that high serum levels of Mannan-binding lectin (MBL), the initiator of the lectin pathway of complement activation, are associated with inferior renal allograft survival. Using a rat model, we identified an entirely novel role for MBL in mediating renal IRI. Therapeutic inhibition of MBL was protective against kidney dysfunction, tubular damage, neutrophil and macrophage accumulation, and expression of proinflammatory cytokines and chemokines. Following reperfusion, exposure of tubular epithelial cells to circulation-derived MBL resulted in internalization of MBL followed by the rapid induction of tubular epithelial cell death. Interestingly, this MBL-mediated tubular injury was completely independent of complement activation since attenuation of complement activation was not protective against renal IRI. Our identification that MBL-mediated cell death precedes complement activation strongly suggests that exposure of epithelial cells to MBL immediately following reperfusion is the primary culprit of tubular injury. In addition, also human tubular epithelial cells in vitro were shown to be susceptible to the cytotoxic effect of human MBL. Taken together, these data reveal a crucial role for MBL in the early pathophysiology of renal IRI and identify MBL as a novel therapeutic target in kidney transplantation.

Mannan-binding lectin deficiency — Good news, bad news, doesn't matter?

Mannan-binding lectin (MBL) deficiency has been classified as a commonly occurring immune disorder, affecting approximately 30% of the human population. MBL, being part of the innate immune system, supports the recognition of infectious pathogens by binding to carbohydrate moieties expressed on microorganisms and activates the lectin pathway of the complement system. MBL2 gene polymorphisms are associated with quantitative and qualitative MBL abnormalities in the serum. The clinical impact of MBL deficiency and its association to a wide variety of diseases has been extensively studied. The picture is puzzling as the studies suggest a detrimental or beneficial or no impact of low or high MBL serum levels on disease susceptibility. In this review we attempt to extract what is relevant from the literature and address controversial issues. We finally suggest that a comprehensive understanding of the role of MBL in human diseases requires considering its context-dependency.

Fibrosis severity and mannan-binding lectin (MBL)/MBL-associated serine protease 1 (MASP-1) complex in HCV-infected patients

Background and study aims Mannan-binding lectin (MBL) is a collectin synthesised in the liver and secreted into the bloodstream. It binds micro-organisms via interactions with glycans on the target surface. Bound MBL subsequently activates MBL-associated serine protease proenzymes (MASPs). Several studies have investigated the possible role for MBL in hepatitis C virus (HCV) infection by examining MBL levels and polymorphisms in relation to disease progression and in response to treatment. The aim of this study was to investigate the relation of the activity of MBL and MBL/MASP-1 complex in sera of patients with mild and severe chronic HCV infection and outcome of HCV infection. Patients and methods Serum level of MBL and functional assays for MBL/MASP-1 complex activity were assayed in sera of 80 patients with chronic HCV infection. Patients were divided into two groups according to the results of the liver biopsy, group I (40 HCV patients had mild hepatic fibrosis, Ishak fibrosis stages 0–1) and group II (40 HCV patients had severe hepatic fibrosis, Ishak fibrosis stages 5–6), in addition to 20 control subjects as group III. The analysis of the MBL/MASP-1 complex activity at 0, 3 and 6 months was performed in all patients. Results: Serum levels of MBL and MBL/MASP-1 complex activity were higher in sera of patients with chronic HCV liver disease compared to those in control subjects. There was a correlation between the activity of the MBL/MASP-1 complex and the severity of fibrosis ( P = 0.003). MBL/MASP-1 complex activity was associated more significantly with severe fibrosis in comparison to MBL concentration. Conclusion MBL and MBL/MASP-1 complex activities play a key role in first-line host defence mechanism against certain infectious agents including HCV infection. However, it is also likely that the role of MBL and MBL/MASP-1 complex activity extends beyond this restricted infection-related view in that it appears to be a key regulator of inflammation.

Mannan‐Binding Lectin (MBL) and MBL‐Associated Serine Protease 2 (MASP‐2) Genotypes in Colorectal Cancer

Mannan-binding lectin (MBL) and MBL-associated serine protease 2 (MASP-2) are key factors of the lectin pathway of complement activation. Polymorphisms of the MBL2 and MASP-2 genes affect serum levels of MBL and MASP-2. In patients with colorectal cancer (CRC), the MBL and MASP-2 serum levels are increased and high MASP-2 levels are associated with recurrence and poor survival, whereas low MBL levels predict post-operative pneumonia. It is not known whether these associations are genetically based. In this study, the MBL and MASP-2 genotypes are investigated in 593 patients with CRC and 348 healthy controls. The potential association between genetic profile and infections, recurrence and survival is evaluated. Four single-nucleotide polymorphisms (SNPs) of MBL2 were analysed using TaqMan assays, with characterization of MBL2 wildtype A, variants B, C and D and alleles H/L, Y/X and P/Q. The SNP D120G for MASP-2 was determined. Serum levels of MBL and MASP-2 were measured. The MBL2 and MASP-2 genotype distribution was similar among patients with CRC and healthy controls and MBL2 genotype significantly associated with MBL concentration in serum (P<0.0001). No significant association between MBL2/MASP-2 genotype and post-operative infectious complications (P=0.33 and 0.22), recurrent cancer or survival (P=0.74 and P=0.61 respectively) was found. Thus, the increased serum levels of MBL and MASP-2 found in patients with CRC are not explained for by genetic profiles. In contrast to what has been demonstrated for serum levels of MBL and MASP-2, the genotypes do not predict disease course of the CRC patients.

Mannan-Binding Lectin Levels and Activity Are Not Altered in Atopic Dermatitis Patients with a History of Eczema Herpeticum

Background. Eczema herpeticum (EH) is a potentially serious, systemic complication in subjects with atopic dermatitis (AD) caused by herpes simplex virus (HSV). The innate immune dysregulation that predisposes these subjects to cutaneous viral infections is not well understood. We tested the hypothesis that defects in mannan-binding lectin (MBL) may be associated with an increased risk of EH. Methods. We evaluated serum MBL levels and functional activity in 13 AD subjects with a history of EH (EH+) and 21 AD subjects with no history of EH (EH−). MBL levels were detected by enzyme immunoassay. MBL pathway functional activity was evaluated by determining MBL C4b deposition capacity. Results. We found no statistical difference in MBL serum levels or function between EH+ and EH− groups. Conclusion. Considering the limitations of this study (e.g., small samples size) our findings suggest that MBL defects do not play a role in EH.

Mannan Binding Lectin (MBL) genotypes coding for high MBL serum levels are associated with rheumatoid factor negative rheumatoid arthritis in never smokers

IntroductionPrevious studies have provided inconsistent results on whether variants in the MBL2 gene, coding for the complement-activating mannan-binding lectin (MBL) protein, associate with rheumatoid arthritis (RA). We re-evaluated this in context of the main environmental and genetic risk factors (smoking, HLA-DRB1 'shared epitope' (SE), PTPN22*620W), which predispose to rheumatoid factor (RF) and/or anti-citrullinated-protein antibody (ACPA)-positive RA.MethodsIn this population-based EIRA study, rheumatoid factor (RF), ACPA, smoking, SE and PTPN22*620W status was determined in incident RA cases and matched controls. MBL-high (n = 1330) and MBL-low (n = 1257) genotypes predicting MBL levels were constructed from four promoter and exon-1 polymorphisms in the MBL2 gene. Odds ratios with 95% confidence interval (OR, 95% CI) were calculated by logistic regression. In extended families (n = 316), previously reported data were re-analyzed, considering RF and smoking.ResultsMBL-high genotypes tended to be associated with RF-negative (OR = 1.20, 95% CI 0.96-1.51) but not RF-positive (OR = 1.00, 95% CI 0.83-1.20) RA. Results divided by ACPA status did not differ. When stratified for smoking, MBL-high genotype was strongly associated with RF-negative RA in never smokers (OR = 1.82, 95% CI 1.24-2.69) but not in ever smokers (OR = 0.96, 95% CI 0.73-1.30). In never smokers, the association was observed in both the RF-negative/ACPA-negative (OR = 1.67, 95% CI 1.10-2.55) and RF-negative/ACPA-positive subgroups (OR = 3.07, 95% CI 1.37-6.89), and remained on an SE/PTPN22*620W negative background. In the extended families, the reported association between high MBL and RA was in fact confined to never smokers.ConclusionsHigh MBL may predispose to RF-negative RA but only in individuals who have never smoked. This illustrates the importance of phenotypic subgrouping in genetic studies.

Functional analysis of agalactosyl IgG in inflammatory bowel disease patients

Agalactosyl immunoglobulin (Ig) G is increased in inflammatory bowel disease (IBD) similarly to rheumatoid arthritis (RA). The lectin complement pathway is shown to be activated through association of agalactosyl IgG with mannan-binding lectin (MBL) in RA. Functional changes of IgG agalactosylation in IBD, however, have not yet been clarified. The ratio of the agalactosyl/non-agalactosyl fraction in fucosylated IgG oligosaccharides (G0F/G2F) and serum MBL levels were analyzed in 59 patients with Crohn's disease (CD), 64 ulcerative colitis (UC), and 39 healthy volunteers (HV). The MBL levels associated with serum IgG were analyzed by enzyme-linked immunosorbent assay. MBL expression in the intestinal mucosa was analyzed by immunohistochemistry. Phagocytosis of sheep red blood cells (SRBC) reacted with either an agalactosyl or non-agalactosyl SRBC-specific IgG antibody was determined by flow cytometry. The serum MBL levels were not significantly different among CD, UC, or HV. In patients with CD, the serum MBL levels were negatively correlated with the Crohn's Disease Activity Index (CDAI). The levels of MBL associated with agalactosyl IgG were not different from those associated with non-agalactosyl IgG. Immunoreactivity to MBL was less in the inflamed mucosa compared with the noninflamed mucosa. Phagocytic activity of SRBC was significantly higher in the presence of agalactosyl IgG compared to non-agalactosyl IgG. Agalactosyl IgG oligosaccharides enhanced antibody-dependent phagocytosis in vitro but did not activate the lectin complement pathway. Oligosaccharide alterations of IgG are not only a marker of IBD but also functionally modulate the immune function of IBD.

The production of mannan-binding lectin is dependent upon thyroid hormones regardless of the genotype: A cohort study of 95 patients with autoimmune thyroid disorders

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.

Serum Levels of Mannan-Binding Lectin in Patients with Crimean-Congo Hemorrhagic Fever

Mannan-binding lectin (MBL) is a central component of the innate immune response. Genetic variations in the MBL gene that reduce circulating levels and alter functional properties of the MBL are associated with susceptibility for many infectious diseases. Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne disease caused by an arbovirus in the family Bunyaviridae. We have investigated serum MBL levels in CCHF patients and a possible association between circulating MBL concentrations and the severity of CCHF. Forty-seven patients found to have CCHF in Cumhuriyet University Hospital and 29 healthy controls were recruited for this study. There were no differences in terms of age and sex between the patients and the healthy controls (p = 0.64 and p = 0.484, respectively). This study was conducted between July 1 and August 31, 2007, in Cumhuriyet University Hospital in Sivas, a city located in the central Anatolian region of Turkey. Patients with CCHF were matched with healthy controls, and serum MBL levels were measured. The median serum MBL level was significantly lower in the patient group than in the healthy control group (48.0 ng/mL [inter-quartile range (QR) 30.4-128.0] and 212.0 ng/mL [IQR: 115.8-524.0], respectively; p < 0.001). No significant difference was found between serum MBL levels in CCHF patients with severe and nonsevere form of the disease (p = 0.167). MBL levels were significantly lower in patients with CCHF than in healthy controls. There was no meaningful correlation between the serum MBL level and severity of CCHF disease. Low serum MBL level may be associated with the high consumption of MBL in CCHF infection and/or MBL gene polymorphism.

The production of mannan-binding lectin is dependent upon thyroid hormones regardless of the genotype: A cohort study of 95 patients with autoimmune thyroid disorders

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.

Mannan-binding lectin in women with a history of recurrent vulvovaginal candidiasis

Objectives To determine the serum concentration of mannan-binding lectin (MBL), a component of the innate immune system, in women with a history of recurrent vulvovaginal candidiasis (RVVC) and to correlate the result to candida-cultures, contraceptive use, if any, and to different antifungal therapies. Study design Twenty-nine women with a history of RVVC were investigated. Cultures of vulvar and vaginal samples were grown on chromogenic agar. Serum levels of MBL were determined by a sandwich time-resolved immunofluorometric assay, using anti-MBL coated microtiter wells containing samples, which were washed, incubated with biotinylated anti-MBL followed by europium-labeled streptavidin and measured by time-resolved flourometry. Results The median MBL level was higher in the RVVC cases than in 30 women with no history of genital candida infection who served as a comparison group ( p = 0.006). It was also higher in the candida-positive than in the culture-negative RVVC ( p = 0.02). The median concentration of MBL was also higher in hormonal contraceptive users as compared to condom-users and those using no contraceptive at all ( p = 0.03). Conclusion The result indicates a role of MBL in RVVC and the production may correlate to vulvar/vaginal colonization by Candida, hormonal contraceptive use, and antifungal therapies.

Low Mannan-Binding Lectin Serum Levels Are Associated With Complicated Crohn's Disease and Reactivity to Oligomannan (ASCA)

Mannan-binding lectin (MBL) acts as a pattern-recognition molecule directed against oligomannan, which is part of the cell wall of yeasts and various bacteria. We have previously shown an association between MBL deficiency and anti-Saccharomyces cerevisiae mannan antibody (ASCA) positivity. This study aims at evaluating whether MBL deficiency is associated with distinct Crohn's disease (CD) phenotypes. Serum concentrations of MBL and ASCA were measured using ELISA (enzyme-linked immunosorbent assay) in 427 patients with CD, 70 with ulcerative colitis, and 76 healthy controls. CD phenotypes were grouped according to the Montreal Classification as follows: non-stricturing, non-penetrating (B1, n=182), stricturing (B2, n=113), penetrating (B3, n=67), and perianal disease (p, n=65). MBL was classified as deficient (<100 ng/ml), low (100-500 ng/ml), and normal (500 ng/ml). Mean MBL was lower in B2 and B3 CD patients (1,503+/-1,358 ng/ml) compared with that in B1 phenotypes (1,909+/-1,392 ng/ml, P=0.013). B2 and B3 patients more frequently had low or deficient MBL and ASCA positivity compared with B1 patients (P=0.004 and P<0.001). Mean MBL was lower in ASCA-positive CD patients (1,562+/-1,319 ng/ml) compared with that in ASCA-negative CD patients (1,871+/-1,320 ng/ml, P=0.038). In multivariate logistic regression modeling, low or deficient MBL was associated significantly with B1 (negative association), complicated disease (B2+B3), and ASCA. MBL levels did not correlate with disease duration. Low or deficient MBL serum levels are significantly associated with complicated (stricturing and penetrating) CD phenotypes but are negatively associated with the non-stricturing, non-penetrating group. Furthermore, CD patients with low or deficient MBL are significantly more often ASCA positive, possibly reflecting delayed clearance of oligomannan-containing microorganisms by the innate immune system in the absence of MBL.

Influence of mannose-binding lectin genotypes and serostatus in allo-SCT: analysis of 131 recipients and donors

Mannan-binding lectin (MBL) deficiency is determined by MBL gene polymorphisms and is associated with an increased infection risk. To clarify the role of MBL in Allo-SCT, 131 recipients-donors were analysed. MBL genotypes were determined by PCR and heteroduplex analyses, MBL serum levels by ELISA, and MBL oligomers by western blotting. MBL levels <400 ng/ml were associated with increased susceptibility to fungal pneumonia (7/12 vs 35/111; P=0.04, adjusted P=0.002), HSV/VZV (7/12 vs 26/111; P=0.03), CMV reactivation and acute GVHD. Donor genotypes had no influence. Pre-SCT MBL levels corresponded to recipients' genotypes (P<0.001), changed significantly post-SCT, but were not influenced by donors' genotypes. MBL oligomer profiles were similar pre-/post-SCT. Cultured CD34+ cells were found not to synthesise MBL. In conclusion, low MBL levels pre-transplant predisposed patients to sepsis, fungal and viral infection. Donors' MBL genotypes did not influence infection rates. Prospective studies should clarify the importance of MBL as a prelude for MBL replacement after SCT.

Epidemiology of Chronic Wound Patients and Relation to Serum Levels of Mannan-binding Lectin

The aim of this study was to describe the epidemiology of chronic wounds in a large cohort of patients from a tertiary hospital out-patient clinic, and examine the significance of serum mannan-binding lectin for the occurrence and clinical presentation of such wounds. The study comprised 489 consecutive patients with chronic foot and leg ulcers. A clinical classification of wound- aetiology was performed, and mannan-binding lectin was measured in the sera of patients and healthy controls. The patients presented with 639 wounds altogether; diabetic foot ulcers (309), venous leg ulcers (188), arterial ulcers (109), and vasculitis (33). The mannan-binding lectin levels of patients with venous leg ulcer, alone or in combination with other types of wounds, differed significantly from the control group, and the frequency of values < 100 ng/ml was significantly higher. In diabetic and arterial ulcer patients the frequency of values >or= 3000 ng/ml was significantly higher than that of the control group. This suggests a role for the innate immunity in the pathology of venous leg ulcers, and indicates different roles for mannan-binding lectin in the development of ulcers with different aetiologies; it further suggests that mannan-binding lectin substitution should be tested in a controlled clinical trial.