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.

[Characterization of macrophages present in skin lesions of Hansen's disease: study by monoclonal antibodies]

As lesões cutâneas de 16 pacientes com hanseníase foram estudadas por imunofluorescência com anticorpos monoclonais anti-monócitos (OKM1 e anti-MO) e anti-Ia (OKIa). Foi avaliada a atividade de fosfatase ácida utilizando-se naftol AS-B1 fosfato como substrato. Os macrófagos parecem constituir uma população heterogênea em relação aos antigenos estudados neste trabalho e quanto a atividade enzimática. Em todas as formas estudadas um grande número de células eram OKIa positivas.