Association of the polymorphism Exon 1 (A/O) region of the mannose-binding lectin gene and periportal fibrosis regression in schistosomiasis after specific treatment

Abstract INTRODUCTION: We evaluated the association between genetic polymorphisms in exon 1 (A/O alleles) and promoter regions at positions -550 (H/L variant, rs11003125) and -221 (X/Y variant, rs7096206) MBL2 and periportal fibrosis regression. METHODS: This was a retrospective cohort study involving 114 Brazilians infected with Schistosoma mansoni, who were subjected to follow-up for three years after specific treatment for schistosomiasis to estimate the probability of periportal fibrosis regression. RESULTS: A risk association was observed between polymorphism at the exon 1 MBL2 and periportal fibrosis regression. CONCLUSIONS: This study suggests that the polymorphism of exon 1 MBL2 may potentially be used to predict periportal fibrosis regression in this population.

Mannose-binding lectin gene polymorphism and its effect on short term outcomes in preterm infants / Polimorfismo do gene da lectina ligante de manose e seu efeito em desfechos de curto prazo em bebês prematuros

Abstract Objective: Mannose-binding lectin, which belongs to the collectin family, is an acute-phase reactant that activates the complement system. This study aimed to investigate the effect of MBL2 gene polymorphism on short-term outcomes in preterm infants. Method: Infants of <37 gestational weeks who were admitted to the neonatal intensive care unit during a two-year period were enrolled in this prospective study. The neonates were categorized into two groups according to their MBL2 genotypes. Normal MBL2 genotype was defined as MBL2 wild-type (AA genotype), whereas mutant MBL2 genotype was defined as MBL2 variant-type (AO/OO genotype). The relationship between MBL2 genotype and short-term morbidity and mortality was evaluated. Results: During the two-year study period, 116 preterm infants were enrolled in this study. In MBL2 variant-type, mannose-binding lectin levels were significantly lower and incidences of mannose-binding lectin deficiency (MBL level < 700 ng/mL) were higher (p < 0.001). In this group, the prevalence of respiratory distress syndrome and mortality was significantly higher (p < 0.001, p = 0.03 respectively). In the MBL2 wild-type group, the prevalence of necrotizing enterocolitis (NEC) was higher (p = 0.01). Logistic regression analyses revealed that MBL2 variant-type had a significant effect on respiratory distress syndrome development (odds ratio, 5.1; 95% confidence interval, 2.2-11.9; p < 0.001). Conclusions: MBL2 variant-type and mannose-binding lectin deficiency are important risk factors for respiratory distress syndrome development in preterm infants. Additionally, there is an association between MBL2 wild-type and NEC. Further studies on this subject are needed.

Resumo Objetivo: A lectina ligante de manose (MBL, do inglês mannose-binding lectin), que pertence à família das colectinas, é um reagente de fase aguda que ativa o sistema complemento. Este estudo teve como objetivo investigar o efeito do polimorfismo do gene MBL2 em desfechos de curto prazo em prematuros. Método: Este estudo prospectivo incluiu crianças com menos de 37 semanas de gestação admitidas na unidade de terapia intensiva neonatal durante dois anos. Os neonatos foram categorizados em dois grupos de acordo com os genótipos do MBL2. O genótipo normal do gene MBL2 foi definido como MBL2 do tipo selvagem (genótipo AA), enquanto o genótipo mutante do gene MBL2 foi definido como o gene variante (genótipo AO/OO). Foi avaliada a relação entre o genótipo MBL2 e a morbidade e mortalidade em curto prazo. Resultados: Durante o período de dois anos, 116 bebês prematuros foram incluídos neste estudo. Os níveis de lectina ligante de manose foram significativamente menores nos variantes do MBL2 e as incidências de deficiência de lectina ligante de manose (nível de MBL < 700 ng/mL) foram maiores (p < 0,001). Nesse grupo, a prevalência de síndrome do desconforto respiratório (SDR) e a mortalidade foram significativamente maiores (p < 0,001, p = 0,03, respectivamente). No grupo MBL2 do tipo selvagem, a prevalência de enterocolite necrosante foi maior (p = 0,01). Análises de regressão logística revelaram que os genes variantes do MBL2 apresentaram um efeito significativo no desenvolvimento da síndrome do desconforto respiratório (odds ratio, 5,1; intervalo de confiança de 95%, 2,2-11,9; p < 0,001). Conclusões: As variantes do MBL2 e a deficiência de lectina ligante de manose são importantes fatores de risco para o desenvolvimento da síndrome do desconforto respiratório em neonatos prematuros. Além disso, existe uma associação entre MBL2 do tipo selvagem e a enterocolite necrosante. Mais estudos são necessários sobre esse assunto.

Mannose-binding lectin 2 (Mbl2) gene polymorphisms are related to protein plasma levels, but not to heart disease and infection by Chlamydia

The presence of the single nucleotide polymorphisms in exon 1 of the mannose-binding lectin 2 (MBL2) gene was evaluated in a sample of 159 patients undergoing coronary artery bypass surgery (71 patients undergoing valve replacement surgery and 300 control subjects) to investigate a possible association between polymorphisms and heart disease with Chlamydia infection. The identification of the alleles B and D was performed using real time polymerase chain reaction (PCR) and of the allele C was accomplished through PCR assays followed by digestion with the restriction enzyme. The comparative analysis of allelic and genotypic frequencies between the three groups did not reveal any significant difference, even when related to previous Chlamydia infection. Variations in the MBL plasma levels were influenced by the presence of polymorphisms, being significantly higher in the group of cardiac patients, but without representing a risk for the disease. The results showed that despite MBL2 gene polymorphisms being associated with the protein plasma levels, the polymorphisms were not enough to predict the development of heart disease, regardless of infection with both species of Chlamydia.

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

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

Estudo do polimorfismo G54D do gene MBL2 no diabetes melito gestacional / Study of polymorphism G54D of MBL2 gene in gestational diabetes mellitus

Objetivo Analisar a influência da associação do polimorfismo G54D (rs1800450) do gene MBL2 no diabetes melito gestacional (DMG) quanto à necessidade de tratamento complementar e ocorrência de recém-nascidos grandes para a idade gestacional. Sujeitos e métodos Cento e cinco pacientes com DMG segundo parâmetro da OMS (Organização Mundial da Saúde) foram avaliadas no período de novembro de 2010 a outubro de 2012. As gestantes foram divididas em dois grupos correspondentes à presença (n = 37) ou à ausência (n = 68) do alelo mutante. As variantes do polimorfismo G54D foram identificadas por meio da técnica de polimorfismos de comprimentos de fragmentos de restrição (RFLP). Parâmetros antropométricos e bioquímicos da mãe e do recém-nascido (RN) e a necessidade de terapia complementar associada à dietoterapia foram avaliados como desfechos primários. Resultados Das pacientes analisadas, 35,2% carregavam pelo menos um alelo mutante do polimorfismo G54D. Os dois grupos não apresentaram diferença significativa quanto a ganho de peso, paridade, idade, índice de massa corporal e idade gestacional de chegada à maternidade. Os grupos de pacientes portadoras ou não do alelo mutante não diferiram quanto à necessidade de tratamento complementar à dietoterapia (16,2% vs. 26,7%) respectivamente e à ocorrência de recém-nascidos grandes para a idade gestacional (24,3% vs. 13,2%). Conclusão Nossos dados demonstraram que o polimorfismo G54D do gene MBL2 não teve efeito sobre a ...

Objective To assess the association of the G54D (rs1800450) polymorphism of the gene MBL2 in the gestational diabetes mellitus with the need for additional treatment and the occurrence of large newborns for the gestational age. Subjects and methods One hundred and five patients recruited in Joinville – Brazil were evaluated between November 2010 and October 2012. Pregnant women were divided in two groups correspondents to the presence (n = 37) or absence (n = 68) of the mutant allele. The variants of the polymorphism G54D were identified by restriction fragment lengths polymorphisms (RFLP). Anthropometric and biochemical parameters of the mother and the newborn, and the necessity of additional therapy associated with diet were assessed as the primary outcomes. Results Thirty-five point two percent of the evaluated patients carried at least one mutated allele of G54D polymorphism. There were no significant differences in weight gain, parity, age, body mass index and gestational age of arrival at maternity between the two groups. The groups of patients with or without the mutated allele did not differ in the need for additional treatment associated with diet (16.2% vs. 26.7%) respectively and with the occurrence of large newborns for gestational age (24.3% vs. 13.2%). Conclusion Our data showed that the polymorphism G54D of the gene MBL2 had no effect in the need for additional treatment associated with the diet-based therapy and in the occurrence of large newborns for gestational age in the studied population. Arq Bras Endocrinol Metab. 2014;58(9):900-5 .

Genotyping of mannose-binding lectin [MBL2] codon 54 and promoter alleles in Egyptian infants with acute respiratory tract infections

MBL2 gene polymorphisms affect serum concentration of mannose-binding lectin and are associated with infectious conditions. Acute respiratory tract infections are among the most prevalent infections in childhood with the highest incidence among children younger than 2 years. This study aimed at correlation between the occurrence of acute respiratory tract infections and the prevalence of MBL2 gene codon [54] and promoter variants among the Egyptian infants in the study. This case-control study included 25 neonates [0.21 +/- 0.19 months], 25 infants [9.65 +/- 8.5 months] with acute respiratory tract infection and normal control group. CBC, CRP and chest X-ray were done. DNA was extracted from peripheral blood. Genotypes of MBL gene codon 54-exon 1[G54D] were identified by PCR-RFLP analysis. MBL2 promoter genotyping was performed by allele-specific polymorphisms at -550 [H/L] and - 221[X/Y]. Incidence of LX promoter haplotype among the patients was [58%] [p < 0.05]. Homo-zygosity for codon [54] allele A [high expression activity] among patients was [72%] [p > 0.05]. Heterozygote codon 54 A/B genotype appeared more in patients [18%] [p < 0.05]. Mutant genotype [too low expression activity] was more in patients but the difference was insignificant. Collectively the mutant allele [glycine to aspartic acid, allele B] appeared in 28% of patients compared to 20% in control [p > 0.05]. YA/XA heterozygote promoter genotype was more prevalent among patients group [44%] [p < 0.05]. Low-expression promoters [XA/B] and [B/B] appeared more in the patients [20%] compared to [12%] among control group [p > 0.05]. Among ICU neonates, LX promoter was the most prevalent among all grades of respiratory distress [39.13%] followed by LY allele [34.78%]. In the infants group, LY allele was [52.1%] with equal distribution of LY and HY [23.91% each]. Although there is a significantly increased incidence of LX promoter coding for low serum MBL concentrations among the ARTI patients; the YA/XA heterozygote promoter genotype was more prevalent over the homozygote mutant genotype. Also, the heterozygote codon 54 A/B genotype was more prevalent in the group of patients compared to the control. This may be an example of heterosis [heterozygote advantage] which may support the concept of balanced polymorphism

Variantes no gene MBL2 codificador da Lectina Ligante de Manose (MBL): implicações na leishmaniose visceral humana / Genetic variants of MBL2 encoding Mannose-binding lectin (MBL): implications in human visceral leishmaniasis

A leishmaniose visceral (LV) ou calazar é uma doença endêmica, crônica, grave e de alta letalidade se não tratada. Os estudos apontam a proteína Lectina Ligante de Manose (MBL), codificada pelo gene MBL2, como uma peça-chave na imunidade inata, dada a sua função no reconhecimento microbiano, na eliminação, inflamação e morte celular. Neste trabalho realizamos um estudo do tipo caso-controle que teve como objetivo investigar a associação entre variantes no gene MBL2 e a suscetibilidade à LV em indivíduos residentes em áreas endêmicas da Ilha de São Luís-MA. A amostra foi constituída por 322 indivíduos, sendo 161 casos com LV, não aparentados, de ambos os sexos, residentes em áreas endêmicas da doença na Ilha de São Luís e 161 controles saudáveis, não infectados e não aparentados da mesma região. A identificação dos casos de LV se deu por meio do contato constante com os principais hospitais e ambulatórios de referência para a doença na cidade. Também foram feitas buscas de pacientes com LV em ambiente domiciliar, a partir de registros da FUNASA-MA. A análise molecular consistiu na genotipagem de 6 variantes localizadas na região promotora [posições -550 (C>G), -221(G>C), +4(C>T)] e codificadora [códons 52 (C>T), 54 (G>A) e 57 (G>A)] do gene MBL2, através da reação em cadeia da polimerase e sequenciamento automático. A dosagem da proteína MBL no soro foi realizada pelo teste de ELISA. Verificamos que os fenótipos MBL dependem do conjunto de alelos presentes no gene MBL2, sendo nítido o efeito que as variantes defectivas causam nos níveis da proteína. Não encontramos diferença significativa entre casos e controles em relação à distribuição dos genótipos MBL2 e dos níveis séricos de MBL. As frequências alélicas das variantes exônicas na amostra total mostram que o alelo A é o mais comum (74,8%) e que os alelos defectivos (B, C e D) se encontram principalmente em heterozigose (36,6%), o que reforça a ideia de que alelos MBL2 defectivos são mantidos na população ...

Visceral leishmaniasis (VL), also known as kalazar, is an endemic, chronic, severe and highly lethal disease when not treated. Studies have shown that the protein Mannose-biding lectin (MBL), encoded by the gene MBL2, is the major player in innate immune system due its role in microbial recognition, elimination and inflammation as well as in the cell death. In the current work, we conducted a case-control study which aimed to investigate the association between variants in the gene MBL2 and the susceptibility to VL in individuals living in endemic areas of the São Luís - MA. 322 individuals participated in this study. Of these, 161 were VL cases being unrelated individuals of both sexes, and inhabitants from endemic areas of the disease in São Luís. The other 161 individuals were uninfected healthy controls, being unrelated and from the same region. The identification of VL cases occurred by visiting reference hospitals and clinics in the city. VL patients were identified in the household environment through the records of FUNASA-MA. Molecular analysis consisted in genotyping six variants located in the promoter region [positions -550 (C> G), -221 (G> C), +4 (C> T)] and coding region [codons 52 (C> T), 54 (G> A) and 57 (G> A)] of the MBL2 gene by polymerase chain reaction and automated DNA sequencing. The concentrations of MBL protein in the serum was performed by ELISA. We found that MBL phenotypes depend on the number of alleles present in the gene MBL2, being clear the consequence of the defective variants in the protein levels. There was no significant difference between cases and controls regarding the distribution of MBL2 genotypes and MBL serum levels. The allele frequencies of exon variants in the overall sample showed that the A allele is the most common (74.8%) and that the defective alleles (B, C and D) are mainly heterozygous (36.6%). This highlights the idea that defective MBL2 alleles are maintained in the population to confer selective ...

The first report described as an important study: The association of mannose-binding lectin gene 2 polymorphisms in children with Down syndrome.

BACKGROUND: Mannose-binding lectin gene 2 (MBL2) plays a very important role in the first line of host immune response in Down syndrome (DS). The importance of MBL2 gene polymorphisms in children with DS is unclear, and no research has addressed MBL2 gene polymorphisms in patients with DS. This is the first report describing an important association between MBL2 gene polymorphisms and infections in children with DS. MATERIALS AND METHODS: We compared the frequency of single-nucleotide polymorphisms (SNPs) at two codons of the MBL2 gene in a cross sectional cohort of 166 children with DS and 229 controls. Polymorphisms at codons 54 (GGC→GAC) and 57 (GGA→GAA) in exon 1 of the MBL2 gene were typed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique using the restriction enzymes BshN1 (derivated from Bacillus sphaericus) and MboII (derivated from Moraxella bovis), respectively. RESULTS: MBL2 codon 54 GA genotype frequency was found to be lower in patients with DS (22.9%) than those of healthy controls (35.8%), differences were statistically significant (OR = 0.532, 95% CI = 0.339-0.836, P = 0.008). On the other hand, codon 57 polymorphism in the MBL2 gene was detected in none of the DS patients, but only one person in the control group showed codon 57 GA genotype (OR = 1.004, 95% CI = 0.996-1.013, P = 1.000). CONCLUSION: Our data provides an evidence for the first time that a homozygote or heterozygote for the variant, MBL2 alleles, is not associated with infections in patients with DS, and do not influence the incidence of infections.

Characterization of mannose-binding lectin plasma levels and genetic polymorphisms in HIV-1-infected individuals / Caracterização dos polimorfismos genéticos e dos níveis plasmáticos da lectina ligante de manose em indivíduos infectados pelo HIV-1

INTRODUCTION: The present study investigated the association between mannose-binding lectin (MBL) gene polymorphism and serum levels with infection by HIV-1. METHODS: Blood samples (5mL) were collected from 97 HIV-1-infected individuals resident in Belém, State of Pará, Brazil, who attended the Special Outpatient Unit for Infections and Parasitic Diseases (URE-DIPE). CD4+ T-lymphocyte count and plasma viral load were quantified. A 349bp fragment of exon 1 of the MBL was amplified via PCR, using genomic DNA extracted from controls and HIV-1-infected individuals, following established protocols. MBL plasma levels of the patients were quantified using an enzyme immunoassay kit. RESULTS: Two alleles were observed: MBL*O, with a frequency of 26.3 percent in HIV-1-infected individuals; and the wild allele MBL*A (73.7 percent). Similar frequencies were observed in the control group (p > 0.05). Genotype frequencies were distributed according to the Hardy-Weinberg equilibrium in both groups. Mean MBL plasma levels varied by genotype, with statistically significant differences between the AA and AO (p < 0.0001), and AA and OO (p < 0.001) genotypes, but not AO and OO (p = 0.17). Additionally, CD4+ T-lymphocytes and plasma viral load levels did not differ significantly by genotype (p > 0.05). CONCLUSIONS: The results of this study do not support the hypothesis that MBL gene polymorphism or low plasma MBL concentrations might have a direct influence on HIV-1 infection, although a broader study involving a large number of patients is needed.

INTRODUÇÃO: O presente estudo investigou a associação entre o polimorfismo no gene da lectina ligante de manose (MBL) e os níveis séricos da proteína com a infecção pelo HIV-1. MÉTODOS: As amostras de sangue (5mL) foram coletadas de 97 indivíduos infectados pelo HIV-1 residentes em Belém, Estado do Pará, Brasil, que frequentavam a Unidade de Referência Especial para Doenças Infecciosas e Parasitárias Especiais (URE-DIPE). Os níveis de linfócitos T CD4+ e da carga viral plasmática foram quantificados. Um fragmento de 349pb do exon 1 da MBL foi amplificado via PCR, utilizando DNA genômico extraído das amostras controles e dos indivíduos portadores do HIV-1, seguindo protocolos previamente estabelecidos. O nível plasmático de MBL nos pacientes foi quantificado usando kit de ensaio imunoenzimático. RESULTADOS: Dois alelos foram observados - MBL*O, com uma frequência de 26,3 por cento em indivíduos infectados e o alelo selvagem MBL*A (73,7 por cento). Frequências similares foram observadas no grupo controle (p > 0,05). As frequências genotípicas estavam em equilíbrio de Hardy-Weinberg em ambos os grupos. A média dos níveis plasmáticos MBL variou por genótipo, com diferenças significativas entre os genótipos AA e AO (p < 0,0001), e AA e OO (p < 0,001), mas não entre AO e OO (p=0,17). Além disso, os linfócitos T CD4+ e os níveis plasmáticos de carga viral não diferiram significativamente de acordo com o genótipo (p>0,05). CONCLUSÕES: Os resultados deste estudo não apoiam a hipótese de que o polimorfismo no gene MBL ou baixa concentração plasmática de MBL poderia ter uma influência direta sobre a infecção pelo HIV-1, embora um estudo com número maior de pacientes seja necessário.

Molecular identification and sequencing of mannose binding protein [MBP] gene of acanthamoeba palestinensis

Acanthamoeba keratitis develops by pathogenic Acanthamoeba such as A. palestinensis. Indeed this species is one of the known causative agents of amoebic keratitis in Iran. Mannose Binding Protein [MBP] is the main pathogenicity factors for developing this sight threatening disease. We aimed to characterize MBP gene in pathogenic Acanthamoeba isolates such as A. palestinensis. This experimental research was performed in the School of Public Health, Tehran University of Medical Sciences, Tehran, Iran during 2007-2008. A. palestinensis was grown on 2% non-nutrient agar overlaid with Escherichia coli. DNA extraction was performed using phenol-chloroform method. PCR reaction and amplification were done using specific primer pairs of MBP. The amplified fragment were purified and sequenced. Finally, the obtained fragment was deposited in the gene data bank. A 900 bp PCR-product was recovered after PCR reaction. Sequence analysis of the purified PCR product revealed a gene with 943 nucleotides. Homology analysis of the obtained sequence showed 81% similarity with the available MBP gene in the gene data bank. The fragment was deposited in the gene data bank under accession number EU678895 MBP is known as the most important factor in Acanthamoeba pathogenesis cascade. Therefore, characterization of this gene can aid in developing better therapeutic agents and even immunization of high-risk people

Associação entre os polimorfismos dos genes MBL2, TGF-beta1 e CD14 com a gravidade da doença pulmonar na fibrose cística / Association of MBL2, TGF-beta1 and CD14 gene polymorphisms with lung disease severity in cystic fibrosis

OBJETIVO: Verificar a correlação entre os polimorfismos dos genes MBL2, TGF-β1 e CD14 com a gravidade da doença pulmonar em pacientes com fibrose cística (FC), bem como correlacionar a presença dos alelos ΔF508 com a gravidade da doença naqueles pacientes. MÉTODOS: Estudo clínico-laboratorial, de corte transversal, com 105 pacientes fibrocísticos de um hospital universitário em 2005-2006. Foram analisados 202 doadores de sangue saudáveis como controles para a pesquisa dos polimorfismos no gene TGF-β1 e CD14. A análise de polimorfismos nos genes MBL2 e TGF-β1 no códon 10, posição +869, foi realizada pela técnica da PCR alelo-específica. A genotipagem do polimorfismo C-159T no gene CD14 foi realizada através de PCR e digestão enzimática. RESULTADOS: Dos 105 pacientes com FC avaliados, 67 apresentavam doença pulmonar grave segundo o escore de Shwachman. Os polimorfismos do gene MBL2 não foram associados com a gravidade da doença nos fibrocísticos. A análise do polimorfismo T869C no gene TGF-β1 mostrou somente uma associação entre o heterozigoto TC com doença pulmonar leve. Para o polimorfismo C-159T no gene CD14, obtivemos um predomínio de pacientes com o genótipo TT, mas não houve diferença significativa com relação à gravidade do quadro pulmonar. CONCLUSÕES: Houve associação entre o genótipo TC do polimorfismo T869C (TGF-β1) e o quadro pulmonar leve nos fibrocísticos. No gene CD14, o genótipo TT parece ser um fator de risco para o quadro pulmonar, mas não um fator modulador da gravidade. Não existiu associação entre pacientes homozigotos para a mutação ΔF508 e a gravidade do quadro pulmonar.

OBJECTIVE: To identify associations between genetic polymorphisms (in the MBL2, TGF-β1 and CD14 genes) and the severity of the lung disease in patients with cystic fibrosis (CF), as well as between the presence of ΔF508 alleles and lung disease severity in such patients. METHODS: This was a cross-sectional cohort study, based on clinical and laboratory data, involving 105 patients with CF treated at a university hospital in the 2005-2006 period. We included 202 healthy blood donors as controls for the determination of TGF-β1 and CD14 gene polymorphisms. Polymorphisms in the MBL2 and TGF-β1 genes at codon 10, position +869, were genotyped using the allele-specific PCR technique. The C-159T polymorphism in the CD14 gene was genotyped using PCR and enzymatic digestion. RESULTS: Of the 105 CF patients evaluated, 67 presented with severe lung disease according to the Shwachman score. The MBL2 gene polymorphisms were not associated with disease severity in the CF patients. Analysis of the T869C polymorphism in the TGF-β1 gene showed an association only between TC heterozygotes and mild pulmonary disease. Although patients presenting the TT genotype of the C159T polymorphism in the CD14 gene predominated, there was no significant difference regarding lung disease severity. CONCLUSIONS: There was an association between the TC genotype of the T869C polymorphism (TGF-β1) and mild pulmonary disease in CF patients. In the CD14 gene, the TT genotype seems to be a risk factor for pulmonary disease but is not a modulator of severity. We found no association between being a ΔF508 homozygote and presenting severe lung disease.

High frequency of clinically significant infections and cytomegalovirus disease in kidney transplant recipients with serum mannose-binding lectin deficiency

Mannose-binding lectin [MBL] constitutes defense against infections when adaptive immune response is compromised. Elevation in serum MBL levels has been shown in patients with kidney failure. We compared serum MBL levels before and after kidney transplant and evaluated association of MBL deficiency with infectious complications in kidney transplant recipients. This study was performed in 71 kidney transplant recipients and 48 healthy controls. In 36 recipients [group 1], serum MBL levels were tested before and on days 7 and 14 after transplantation. They were followed up for 6 months. In 35 recipients [group 2], serum MBL was measured during their posttransplant follow-up visits. In both groups, frequencies of clinically significant infections and acute rejection were compared between those with low MBL [< 500 ng/mL] and normal/high MBL [< 500 ng/mL]. Serum MBL levels [1744 +/- 905 ng/mL] were not higher in group 1 before transplantation than in controls. One and 2 weeks after transplantation, MBL levels decreased to 1699 +/- 1030 ng/mL and 1562 +/- 1020 ng/mL, respectively. Five patients who had low serum MBL levels experienced more frequent episodes of infections [P = .008] and CMV disease [P < .001]. Ten patients in group 2 with low MBL levels had more frequent episodes of CMV disease [P = .01]. These findings suggest a potential role for MBL in defense against developing posttransplant CMV disease and that low serum MBL levels in kidney transplant recipients be considered an indicator of the need for CMV prophylaxis

Characterization of polymorphisms in the mannose-binding lectin gene promoter among human immunodeficiency virus 1 infected subjects

The present study investigated the prevalence of mutations in the -550 (H/L) and -221 (X/Y) mannose-binding lectin (MBL) gene promoter regions and their impact on infection by human immunodeficiency virus 1 (HIV-1) in a population of 128 HIV-1 seropositive and 97 seronegative patients. The allele identification was performed through the sequence-specific primer polymerase chain reaction method, using primer sequences specific to each polymorphism. The evolution of the infection was evaluated through CD4+ T-lymphocyte counts and plasma viral load. The allele and haplotype frequencies among HIV-1-infected patients and seronegative healthy control patients did not show significant differences. CD4+ T-lymphocyte counts showed lower levels among seropositive patients carrying haplotypes LY, LX and HX, as compared to those carrying the HY haplotype. Mean plasma viral load was higher among seropositive patients with haplotypes LY, LX and HX than among those carrying the HY haplotype. When promoter and exon 1 mutations were matched, it was possible to identify a significantly higher viral load among HIV-1 infected individuals carrying haplotypes correlated to low serum levels of MBL. The current study shows that haplotypes related to medium and low MBL serum levels might directly influence the evolution of viral progression in patients. Therefore, it is suggested that the identification of haplotypes within the promoter region of the MBL gene among HIV-1 infected persons should be further evaluated as a prognostic tool for AIDS progression.

Polymorphism in the promoter region of the mannose-binding lectin gene among human T-cell lymphotropic virus infected subjects

The present study investigated the frequency of the mutations at positions -550 and -221 of the mannose-binding lectin (MBL) gene in a sample of 75 human T-cell lymphotropic virus (HTLV) infected patients and 96 HTLV seronegative controls, in order to evaluate the occurrence of a possible association between the polymorphism and HTLV infection. A sequence specific primer-polymerase chain reaction was used for discrimination of the polymorphism. The analysis of allele frequencies at position -550 did not show any significant differences between HTLV infected group and controls, but there was a significant difference at position -221. The comparative analysis of haplotypes frequencies were not significant, but the genotype frequencies between the two groups, revealed a higher prevalence of genotype LYLX (25.3 percent), associated with medium and low MBL serum levels among HTLV infected subjects. The odds ratio estimation demonstrated that the presence of genotype LYLX was associated with an increased risk of HTLV infection (p = 0.0096; 1.38 < IC95 percent < 7.7605). There was no association between proviral load and the promoter polymorphism, but when promoter and exon 1 mutations were matched, it was possible to identify a significant higher proviral load among HTLV infected individuals carrying haplotypes correlated to low serum levels of MBL. The present study shows that the polymorphism in the promoter region of the MBL gene may be a genetic marker associated with HTLV infection, and emphasizes the need for further studies to determinate if the present polymorphism have any impact on diseases linked to HTLV infection.

cDNA cloning and expression analysis of a mannose-binding lectin from Pinellia pedatisecta.

Pinellia pedatisecta agglutinin (PPA)is a very basic protein that accumulates in the tuber of P.pedatisecta .PPA is a hetero-tetramer protein of 40 kDa,composed of two polypeptide chains A (about 12 kDa)and two polypeptides chains B (about 12 kDa).The full-length cDNA of PPA was cloned from P.pedatisecta using SMART RACE-PCR technology; it was 1146 bp and contained a 771 bp open reading frame (ORF)encoding a lectin precursor of 256 amino acid residues with a 24 amino acid signal peptide.The PPA precursor contained 3 mannose-binding sites (QXDXNXVXY) and two conserved domains of 43% identity,PPA-DOM 1 (polypeptides A)and PPA-DOM 2 (polypeptides B).PPA shared varying identities,ranging from 40% to 85%,with mannose-binding lectins from other species of plant families such as Araceae, Alliaceae, Iridaceae, Liliaceae, Amaryllidaceae and Bromeliaceae. Southern blot analysis indicated that ppa belonged to a multi-copy gene family. Expression pattern analysis revealed that ppa expressed in most tested tissues, with high expression being found in spadix,spathe and tuber.Cloning of the ppa gene not only provides a basis for further investigation of its structure,expression and regulatory mechanism,but also enables us to test its potential role in controlling pests and fungal diseases by transferring the gene into plants in the future.

Lectina de unión a manosa: actividad biológica y significado / Manosse-binding lectin: biological activity and significance

La lectina de unión a la manosa (MBL) es una colectina que se sintetiza en el hígado y es secretada al torrente sanguíneo, la cual es capaz de unirse con estructuras repetidas de azúcares presentes en una amplia variedad de bacterias y otros microorganismos promoviendo su eliminación mediante la activación del complemento a través de serín proteasas asociadas. A las deficiencias de MBL se les considera como un importante factor de riesgo de infecciones en niños y en individuos inmunosuprimidos. Se discute la evidencia de que la MBL contribuye de forma importante a la inmunidad innata con el incremento de la susceptibilidad a determinadas enfermedades o la incidencia en el curso de estas. Estudios preliminares del empleo de terapias sustitutivas con MBL han arrojado resultados prometedores, los que deben ofrecer evidencias acerca del significado fisiológico de esta proteína

A cost-effective melting temperature assay for the detection of single-nucleotide polymorphism in the MBL2 gene of HIV-1-infected children

We report a fast (less than 3 h) and cost-effective melting temperature assay method for the detection of single-nucleotide polymorphisms in the MBL2 gene. The protocol, which is based on the Corbett Rotor Gene real time PCR platform and SYBR Green I chemistry, yielded, in the cohorts studied, sensitive (100 percent) and specific (100 percent) PCR amplification without the use of costly fluorophore-labeled probes or post-PCR manipulation. At the end of the PCR, the dissociation protocol included a slow heating from 60° to 95°C in 0.2°C steps, with an 8-s interval between steps. Melting curve profiles were obtained using the dissociation software of the Rotor Gene-3000 apparatus. Samples were analyzed in duplicate and in different PCR runs to test the reproducibility of this technique. No supplementary data handling is required to determine the MBL2 genotype. MBL2 genotyping performed on a cohort of 164 HIV-1-positive Brazilian children and 150 healthy controls, matched for age and sex and ethnic origin, yielded reproducible results confirmed by direct sequencing of the amplicon performed in blind. The three MBL2 variants (Arg52Cys, Gly54Asp, Gly57Glu) were grouped together and called allele 0, while the combination of three wild-type alleles was called allele A. The frequency of the A/A homozygotes was significantly higher among healthy controls (0.68) than in HIV-infected children (0.55; P = 0.0234) and the frequency of MBL2 0/0 homozygotes was higher among HIV-1-infected children than healthy controls (P = 0.0296). The 0 allele was significantly more frequent among the 164 HIV-1-infected children (0.29) than among the 150 healthy controls (0.18; P = 0.0032). Our data confirm the association between the presence of the mutated MBL2 allele (allele 0) and HIV-1 infection in perinatally exposed children. Our results are in agreement with the literature data which indicate that the presence of the allele 0 confers a relative risk of 1.37 for HIV-1 infection through vertical transmission.

Variantes del gen Mannose Binding Lectin (MBL) en pobladores amazónicos de Andoas - Loreto y su posible implicancia en la salud / Variants of gene MBL in native amazonians from Andoas - Loreto, and its possible implications in health

El gen MBL (Mannose Binding Lectin) codifica una proteína de la inmunidad innata que activa el sistema del complemento, así como recluta macrófagos y quimioquinas proinflamatorias. Estudios realizados en otras latitudes han asociado susceptibilidad o resistencia a enfermedades infecciosas, autoinmunes y cardiovasculares con alelos deficientes de MBL. Sin embargo, muchos estudios no son concluyentes debido a la rareza de estos alelos en las poblaciones estudiadas. Previamente hemos demostrado que en las islas del Lago Titicaca, el alelo deficiente B tiene la más alta prevalencia del mundo. Por ello, queremos corroborar su presencia en zonas más cálidas que son más propicias a enfermedades infecciosas. Para ello se analizó el genotipo de 94 individuos procedentes de la región amazónica de Andoas-Loreto. Aunque en menor proporción que en las islas del Lago Titicaca, la frecuencia de la variante deficiente B en Andoas es más alta que en otras poblaciones del mundo. Esta frecuencia y su gran exposición a enfermedades tropicales, hacen de Andoas una población interesante para estudiar el rol de las variantes de MBL en el desarrollo de las mismas.

The gene MBL codifies for a protein that has a role in innate immunity by activating the complement system as well as recruiting macrophages and proinflammatory chemokines. Studies performed around the world have associated susceptibility/resistance to infectious, autoimmune and cardiovascular diseases, with deficient alleles of MBL. However, many of these studies remain inconclusive because of the rarity of these alleles. We have previously shown that the frequency of defective allele B in the islands of Lake Titicaca is the highest in the world. Now, we want to evaluate the frequency of this allele in Amazonian areas that are more prone to infectious diseases. We have genotyped 94 individuals from Andoas-Loreto and found a higher frequency of the defective allele B compared to other populations (but lower than that from Lake Titicaca). This frequency and the high exposure to tropical diseases make the population of Andoas interesting to study the role of the MBL variants in the development these diseases.