Association of MBL2 gene exon 1 variants with autoimmune thyroid disease in Brazilian patients.

We investigated the association between MBL2 gene exon 1 functional polymorphisms and autoimmune thyroid disease (AITD) in 163 Brazilian patients (87 with Hashimoto thyroiditis, HT; 76 with Graves' disease) and 214 healthy controls. Individuals carrying MBL2 O allele are at higher risk of developing AITD (OR = 1.58, 95% CI: 1.11-2.26; P-value = 0.009) and HT (OR = 1.67, 95% CI: 1.09-2.55; P-value = 0.013) as suggesting a possible role for mannose-binding lectin in influencing disease susceptibility.

Mannose-binding lectin (MBL2) polymorphisms and inflammation in hypertensive patients.

We investigated the possible role of Mannose binding lectin 2 (MBL2) functional polymorphisms in the prevalence of hypertension and hypertensive end-organ damage in 300 hypertensive patients and 313 normotensive individuals from Southern Brazil. Hypertensive subjects with MBL2 AO/OO genotypes presented lower C-reactive protein levels than AA individuals and consequently lower inflammatory status.

Functional polymorphisms of DEFB1 gene in type 1 diabetes Brazilian children.

We analyzed three functional 5' un-translated region beta-defensin 1 (DEFB1) single nucleotide polymorphism (SNPs) in a group of 170 type 1 diabetes (T1D) patients. In order to evaluate the SNPs influence on the disease onset and the development of other autoimmune disorder, such as celiac disease (CD) and autoimmune thyroid disease (AITD), patients were stratified according to the presence of AITD, CD, and both AITD and CD. As control group, we studied 191 healthy children and adolescent not presenting a familiar historic of T1D, CD or AITD. DEFB1 SNPs were in Hardy-Weinberg equilibrium both in healthy controls and T1D patients, as well in the T1D patients stratified according to the presence of other autoimmune disorder(s). Allele, genotype, and haplotype frequencies of T1D patients globally considered were comparable to healthy controls ones. No evidence of any association of DEFB1 SNPs with the onset of AIDT, CD, and both AITD and CD on T1D patients was evidenced. Only a minor trend was found for an increased frequency of the - 20 G allele in T1D patients only presenting AITD vs. T1D patients not presenting AITD or CD, as well as an increase of those haplotypes comprising the - 20 G allele when compared with the GCA haplotype. We also evaluated the influence of functional DEFB1 SNPs on the age of T1D onset: no significant statistical conclusion was achieved. Further studies are envisaged, in order to elucidate the possible role of functional DEFB1 polymorphisms in the onset of TD1 and other autoimmune-related disorders.

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%) and specific (100%) 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 degrees to 95 degrees C in 0.2 degrees 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.

CCR5 promoter polymorphisms and HIV-1 perinatal transmission in Brazilian children.

The frequencies of four CCR5 promoter polymorphisms, and of the Delta32 deletion, have been evaluated in Brazilian HIV-1 positive (HIV+) and HIV-1 negative (HIV-) children, both born from HIV-1 positive mothers and healthy controls (HC), with the aim of investigating whether CCR5 polymorphisms could be associated to vertical transmission of HIV-1. One hundred and six HIV-1 positive children and 70 HIV-1 negative children were enrolled from impoverished areas of Recife (Brazil). We recruited also as healthy controls 104 uninfected children from the same ethnic background, matched for age and known to be not at risk for HIV-1 infection. CCR5 polymorphisms were detected by PCR amplification and direct sequencing. Although no significative divergence was found for CCR5 Delta32, CCR5-59356-C/T and CCR5-59653 C/T polymorphisms, the frequency of CCR5-59353-T/C and CCR5-59402-A/G genotypes differed among HIV+, HIV- and HC children. The presence of the CCR5-59353-TT genotype indicated a trend for increased risk of vertical transmission of HIV-1 infection in Brazilian children, while the presence of the CCR5-59402-AA genotype is suggestive for a protective effect against HIV-1 vertical transmission.

Dietary Antioxidant Deficiency Facilitates Cortical Spreading Depression Induced by Photoactivated Riboflavin.

It is known that the photoactivation of riboflavin produces superoxide radicals. We investigated the ability of this process to elicit spreading depression (SD) in the cerebral cortex of adult rats receiving either a normal diet (control group; n = 9) or fed a diet free from vitamins C and E during 4-6 weeks prior to the experiment (deficient group; n = 15). SD was initially elicited, at 20 min intervals, by 2% KC1 topically applied for 1 min to a point (2-3 mm in diameter) on the dura mater at the frontal cortex and SD propagation was monitored by both EEG and DC-recordings at two points of the parietal region. After a 1-2 h "baseline" recording of KCl-elicited SD, tests were performed with 1.0 mM riboflavin applied to the same frontal region and illuminated by a white light bulb (40 W, 10-15 cm from the cortical surface, for 1-3 min). In the control group, 37 applications of riboflavin + light were performed (average: 4.1 applications per rat; range: 3-7) and 11 of these applications (29.7%) elicited SD in 7 out of the 9 rats. In the deficient group, the effectiveness of photoactivated riboflavin to elicit SD increased significantly to 62.8% (44 out of 70 applications; 15 out of 15 rats; average: 4.7 applications per rat; range: 3-6; P < 0.05). Elicitation of SD was not obtained, either by illumination of an equivalent volume of Ringer solution applied to the same region, or by riboflavin applied without illumination. The results demonstrate that photoactivated riboflavin is capable of eliciting SD in the rat cerebral cortex, and that dietary deficiency of the antioxidant vitamins C and E can enhance brain susceptibility to this process.