Mutações do gene do receptor de vitamina d e níveis séricos de vitamina d em crianças com asma / Vitamin d receptor gene mutations and vitamin d serum levels in asthmatic children

RESUMO Objetivo: Verificar a relação dos polimorfismos do gene do receptor de vitamina D (RVD) com sinais clínicos e níveis de vitamina D (VD) em asmáticos. Métodos: Estudo transversal com 77 crianças de 7 a 14 anos de um ambulatório especializado, divididas em 3 grupos: asmáticos, em uso de corticoide inalatório (ICS) por mais de um ano; asmáticos sem necessidade de ICS; não asmáticos e não alérgicos (de acordo com o International Study of Asthma and Allergies in Childhood - ISAAC. Foram avaliados: espirometria, testes alérgicos, presença do polimorfismo CDX2 do promotor do RVD por reação em cadeia da polimerase (PCR) e genotipagem de polimorfismos dos éxons 2 e 3 por PCR-SSCA (single-strand conformational analysis), imunoglobulina E (IgE) total e IgE específica para ácaros e gramíneas nos três grupos estudados. Níveis de 25-hidroxivitamina D foram dosados nos asmáticos. Resultados: A média de idade foi 10,8±2,2 anos, 57% masculinos, 38 asmáticos com ICS, 22 sem ICS e 17 não asmáticos. Rinite alérgica esteve presente em 90% dos asmáticos, polimorfismo CDX2 em 23% dos asmáticos e ausente nos controles (p=0,03). Menores níveis de volume expiratório forçado no primeiro segundo (VEF1%) foram observados nos asmáticos homozigotos para CDX2 (p=0,001). Variações nas sequências dos éxons 2 e 3 não foram relacionadas com a asma ou demais testes. Deficiência ou insuficiência de VD foi diagnosticada em 98% dos asmáticos. Não houve associação entre níveis de VD e polimorfismos genéticos dos éxons 2 e 3. Conclusões: Observou-se associação positiva entre polimorfismo CDX2 em homozigoze com asma e menores valores de VEF1%. O CDX2 pode modificar a interação celular do RVD com a vitamina, bem como pode estar associado com a asma e com a dificuldade de controle da doença.

ABSTRACT Objective: To verify the relationship between polymorphisms of the vitamin D receptor gene (VDR), clinical findings, and serum vitamin D (VD) levels in asthmatics. Methods: A cross sectional study of 77 children aged 7 to 14 years old, who were attended at a specialized clinic. The children were divided into 3 groups: asthmatics who had been using inhaled corticosteroids (ICS) for more than one year; asthmatics who had not been using ICS; non-asthmatics, and children without allergies (according to the International Study of Asthma and Allergies in Childhood ­- ISAAC). Spirometry, skin prick tests, the presence of a VDR promoter CDX2 polymorphism from an allele-specific polimerase chain reaction (PCR), exons 2 and 3 polymorphisms genotyping by PCR-SSCA (single-strand conformational analysis), total immunoglobulin E (IgE) and specific IgE to mites and grass were evaluated in these three groups. Levels of 25-hydroxyvitamin D were determined in asthmatics only. Results: The mean age of the children was 10.8±2.0 years old, 57% were male, 38 were asthmatic and using ICS, 22 were asthmatic and not using ICS, and 17 were non-asthmatic. Allergic rhinitis was present in 90% of asthmatics. Homozygous CDX2 was detected in 23% of the patients and absent in the control group (p=0.03). Lower forced expiratory volume in 1 second (FEV1%) values were observed in CDX2 homozygous asthmatics (p=0.001). Variations in the exon 2 and 3 sequences were not related to asthma or the other tests. VD deficiency or insufficiency was detected in 98% of asthmatics. There was no association between VD levels and genetic polymorphisms from exons 2 and 3. Conclusions: There was a positive association between homozygous CDX2 polymorphism, asthma and lower FEV1% values. CDX2 is capable of modifying cell interaction between VDR and VD, and it could be associated with the prevalence of asthma, and the difficulty in controlling the disease.

VITAMIN D RECEPTOR GENE MUTATIONS AND VITAMIN D SERUM LEVELS IN ASTHMATIC CHILDREN. / MUTAÇÕES DO GENE DO RECEPTOR DE VITAMINA D E NÍVEIS SÉRICOS DE VITAMINA D EM CRIANÇAS COM ASMA.

OBJECTIVE: To verify the relationship between polymorphisms of the vitamin D receptor gene (VDR), clinical findings, and serum vitamin D (VD) levels in asthmatics. METHODS: A cross sectional study of 77 children aged 7 to 14 years old, who were attended at a specialized clinic. The children were divided into 3 groups: asthmatics who had been using inhaled corticosteroids (ICS) for more than one year; asthmatics who had not been using ICS; non-asthmatics, and children without allergies (according to the International Study of Asthma and Allergies in Childhood -- ISAAC). Spirometry, skin prick tests, the presence of a VDR promoter CDX2 polymorphism from an allele-specific polimerase chain reaction (PCR), exons 2 and 3 polymorphisms genotyping by PCR-SSCA (single-strand conformational analysis), total immunoglobulin E (IgE) and specific IgE to mites and grass were evaluated in these three groups. Levels of 25-hydroxyvitamin D were determined in asthmatics only. RESULTS: The mean age of the children was 10.8±2.0 years old, 57% were male, 38 were asthmatic and using ICS, 22 were asthmatic and not using ICS, and 17 were non-asthmatic. Allergic rhinitis was present in 90% of asthmatics. Homozygous CDX2 was detected in 23% of the patients and absent in the control group (p=0.03). Lower forced expiratory volume in 1 second (FEV1%) values were observed in CDX2 homozygous asthmatics (p=0.001). Variations in the exon 2 and 3 sequences were not related to asthma or the other tests. VD deficiency or insufficiency was detected in 98% of asthmatics. There was no association between VD levels and genetic polymorphisms from exons 2 and 3. CONCLUSIONS: There was a positive association between homozygous CDX2 polymorphism, asthma and lower FEV1% values. CDX2 is capable of modifying cell interaction between VDR and VD, and it could be associated with the prevalence of asthma, and the difficulty in controlling the disease.

OBJETIVO: Verificar a relação dos polimorfismos do gene do receptor de vitamina D (RVD) com sinais clínicos e níveis de vitamina D (VD) em asmáticos. MÉTODOS: Estudo transversal com 77 crianças de 7 a 14 anos de um ambulatório especializado, divididas em 3 grupos: asmáticos, em uso de corticoide inalatório (ICS) por mais de um ano; asmáticos sem necessidade de ICS; não asmáticos e não alérgicos (de acordo com o International Study of Asthma and Allergies in Childhood - ISAAC. Foram avaliados: espirometria, testes alérgicos, presença do polimorfismo CDX2 do promotor do RVD por reação em cadeia da polimerase (PCR) e genotipagem de polimorfismos dos éxons 2 e 3 por PCR-SSCA (single-strand conformational analysis), imunoglobulina E (IgE) total e IgE específica para ácaros e gramíneas nos três grupos estudados. Níveis de 25-hidroxivitamina D foram dosados nos asmáticos. RESULTADOS: A média de idade foi 10,8±2,2 anos, 57% masculinos, 38 asmáticos com ICS, 22 sem ICS e 17 não asmáticos. Rinite alérgica esteve presente em 90% dos asmáticos, polimorfismo CDX2 em 23% dos asmáticos e ausente nos controles (p=0,03). Menores níveis de volume expiratório forçado no primeiro segundo (VEF1%) foram observados nos asmáticos homozigotos para CDX2 (p=0,001). Variações nas sequências dos éxons 2 e 3 não foram relacionadas com a asma ou demais testes. Deficiência ou insuficiência de VD foi diagnosticada em 98% dos asmáticos. Não houve associação entre níveis de VD e polimorfismos genéticos dos éxons 2 e 3. CONCLUSÕES: Observou-se associação positiva entre polimorfismo CDX2 em homozigoze com asma e menores valores de VEF1%. O CDX2 pode modificar a interação celular do RVD com a vitamina, bem como pode estar associado com a asma e com a dificuldade de controle da doença.

The type III secretion system is necessary for the development of a pathogenic and endophytic interaction between Herbaspirillum rubrisubalbicans and Poaceae.

BACKGROUND: Herbaspirillum rubrisubalbicans was first identified as a bacterial plant pathogen, causing the mottled stripe disease in sugarcane. H. rubrisubalbicans can also associate with various plants of economic interest in a non pathogenic manner. RESULTS: A 21 kb DNA region of the H. rubrisubalbicans genome contains a cluster of 26 hrp/hrc genes encoding for the type three secretion system (T3SS) proteins. To investigate the contribution of T3SS to the plant-bacterial interaction process we generated mutant strains of H. rubrisubalbicans M1 carrying a Tn5 insertion in both the hrcN and hrpE genes. H. rubrisulbalbicans hrpE and hrcN mutant strains of the T3SS system failed to cause the mottled stripe disease in the sugarcane susceptible variety B-4362. These mutant strains also did not produce lesions on Vigna unguiculata leaves. Oryza sativa and Zea mays colonization experiments showed that mutations in hrpE and hrcN genes reduced the capacity of H. rubrisulbalbicans to colonize these plants, suggesting that hrpE and hrcN genes are involved in the endophytic colonization. CONCLUSIONS: Our results indicate that the T3SS of H. rubrisubalbicans is necessary for the development of the mottled stripe disease and endophytic colonization of rice.

High-producing MBL2 genotypes increase the risk of acute and chronic carditis in patients with history of rheumatic fever.

Rheumatic fever (RF) and its most severe sequela, chronic rheumatic heart disease (CRHD), are mediated by an abnormal immunological host response following a Streptococcus pyogenes oropharyngeal infection. Mannan-binding lectin (MBL), a collectin that activates complement, binds to N-acetylglucosamine, a molecule present on the streptococcus cell wall and on human heart valves. As high levels of MBL and MBL2 associated genotypes have previously been seen to be associated with CRHD, we investigated the association between MBL2 polymorphisms and the presence of acute carditis and arthritis in patients with a history of RF. Polymorphisms in exon 1 and in the X/Y promoter region of the MBL2 gene were determined by PCR-SSP in 149 patients with a history of RF and 147 controls. Genotypes associated with the high production of MBL (YA/YA and YA/XA) were more frequent in the patients with acute (26/35, 74%) and chronic carditis (79/107, 74%) when compared to the controls (79/147, 54%; OR 2.48, 95% CI 1.09-5.67, p=0.035 and OR 2.42, 95% CI 1.41-4.16, p=0.001, respectively). Logistic regression analysis showed that MBL levels >2,800 ng/ml increased the risk of CRHD (OR 2.91, 95% CI 1.41-6.03, p=0.003). Among the RF patients without cardiac sequela, YA/YA and YA/XA genotypes were significantly associated with acute carditis when compared to the patients without this clinical manifestation (26/28, 93% vs. 9/14, 64%, OR 7.22, 95% CI 1.18-43.98, p=0.031); on the other hand, arthritis was more frequently observed in those patients presenting MBL2 genotypes related to the low production of MBL (10/14, 71% vs. 10/28, 36%; p=0.048, OR 0.22, 95% CI 0.05-0.89). We concluded that MBL2 genotypes associated with the high production of MBL seem to be involved in the pathogenesis of rheumatic carditis and its progression to CRHD.

Functional MASP2 gene polymorphism in patients with history of rheumatic fever.

In this study we investigated whether partial or total MASP-2 deficiencies resulting from Asp105Gly mutation are associated with rheumatic fever (RF) and chronic rheumatic heart disease (RHD). The Asp105Gly MASP2 mutation (D105G) was detected by polymerase chain reaction-restriction fragment length polymorphism in 148 patients (43 men and 105 women; mean age 39.1 +/- 14.4 years) with a history of RF, including 106 (73%) with RHD and 42 (27%) without cardiac sequelae, and 129 control subjects (52 men and 77 women, mean age 38.4 +/- 12.2 years). The D105G mutation was detected in four patients with RHD (3.77%) and in five control subjects (3.88%), all in the heterozygous state. None of the patients without cardiac sequelae had the mutation. No significant difference was found in the frequency of the mutant allele between the groups (p < 0.6). These results suggest that the D105G mutation in the MASP2 gene does not play a major role in the pathogenesis of RF. Whether D105G plays a role in the development of RHD should be ascertained in future studies.

Incidence of cystic fibrosis in five different states of Brazil as determined by screening of p.F508del, mutation at the CFTR gene in newborns and patients.

Cystic Fibrosis (CF) is one of the most common single-gene defects in European descent populations with an incidence of about 1 in every 2500 live births and carrier frequency of approximately 1 in 25. The most common mutation at the CF transmembrane conductance regulator (CFTR) gene is a deletion (p.F508del) of the phenylalanine codon 508; its frequency, however, is not the same throughout the world. The purpose of this paper is to document an application of a two-tier survey design in different states of Brazil, from which regional differences of the incidence of CF and frequency of CF-causing mutation(s) carriers can be for the first time estimated. We present data on genotype distributions in reference to p.F508del mutation in samples of newborns, adult controls and CF patients from five Brazilian states, in which a total of 2683 newborns born to Brazilian white parents and 500 African-Brazilians adult controls were screened, as well as 300 CF patients (262 European descents and 38 African descents) were genotyped. Our results suggest that the CF-incidence in different parts of Brazil may differ by almost 20-fold. For the five different states as a whole, nearly 48% of the CF-alleles carry the p.F508del mutation, which places the estimates of disease incidence and carrier frequencies for the Brazilian European descents as 1 in 7576 live births and 2.3%, respectively. The implications for prevention of CF and other rare Mendelian diseases through such surveys of mutation screening are discussed.

The association between mannan-binding lectin gene polymorphism and clinical leprosy: new insight into an old paradigm.

BACKGROUND: Mannan-binding lectin (MBL), a soluble protein of innate immunity, is known to play a role in pathogen recognition and clearance. For more than a decade, it has been proposed that MBL deficiency may be protective against intracellular pathogens, such as Mycobacterium leprae. METHODS: The polymorphisms at the promoter and exon 1 regions of the MBL2 gene were assessed by polymerase chain reaction and sequencing performed on 264 patients with leprosy and 214 matched healthy control subjects from southern Brazil. RESULTS. The distribution of MBL2-gene polymorphisms in patients was significantly different from that in controls, with a decreased frequency of haplotypes/genotypes associated with low expression of circulating MBL in lepromatous patients when compared with tuberculoid patients (odds ratio [OR] for haplotypes, 0.56 [95% confidence interval {CI}, 0.33-0.93] [P=.020]; OR for genotypes, 0.31 [95% CI, 0.13-0.71] [P=.004]). The LYPA haplotype was associated with susceptibility to leprosy per se (OR, 2.25 [95% CI, 1.31-3.88] [P=.003]) and to progression to the lepromatous (OR, 2.2 [95% CI, 1.21-4.05] [P=.008]) and borderline (OR, 2.98 [95% CI, 1.29-6.87] [P=.008]) forms of the disease. CONCLUSIONS: These results suggest that MBL2-gene polymorphisms play a role in susceptibility to leprosy per se and in the clinical progression of the disease.