In our study we analysed three single nucleotide polymorphisms (SNPs) in the 5' untranslated region (UTR) of the DEFB1 gene, namely -52(G/A) -44(C/G) and -20(G/A), in three groups of northeastern Brazilian children in order to assess their role in HIV-1 infection. Our results allowed us to hypothesize that the SNPs located in the 5' UTR of the DEFB1 gene can be employed as a marker of risk for HIV-1 infection.

Human h-defensin-1 (hBD-1) has been shown to be a candidate tumor suppressor gene by Sun et al. (1) who reported that single nucleotide polymorphisms (SNP) in the DEFB1 gene are able to modify the transcriptional activity of hBD-1 promoter. In particular, the À44C/G SNP was described to enhance transcription up to 2.3 times more than the wild-type sequence in DU145 or TSU-Pr1 cell lines.Recently, we showed that significant correlation exists between SNPs in the 5 ¶ untranslated region (UTR) of the DEFB1 gene and the risk of being infected with HIV-1 in Italian and Brazilian children (2, 3).With the aim of verifying an eventual transcriptional functional effect of the SNPs in the 5 ¶UTR region of DEFB1 gene, we employed a dual luciferase assay, the same technique used by Sun et al. (1).Starting from the wild-type DEFB1 5 ¶UTR region, we generated three mutated inserts using primers designed to introduce the desired mutation into the wild-type sequence. The four different fragments (wild-type, À52A, À44G, and À20A) have been cloned into pGL3 promoter vector (Promega), and Caco2 cells were transfected for 48 h with 1 Ag of the reporter plasmids and 20 ng of control Renilla luciferase expression plasmid (phRG-TK, Promega) using 5 AL of GenePORTER transfection reagent; a dual luciferase assay (Promega) was done according to the manufacturer's instruction. To ensure the reproducibility of the results, all tests have been done in quadruplicate and repeated at a later time to confirm the obtained results.Our results show that the three SNPs do possess a functional activity, leading to an impaired production of the gene downstream to the mutated promoter.1 Both the À52A and the À20A alleles cause a 25% mean reduction of expression. Although quantitatively relevant, this reduction was not statistically significant. The À44G mutation, contrary to the data presented by Sun et al. (1), drag to a markedly reduced expression of about 53% in our experimental setup.Based on our results (2, 3) and because all the studied SNPs could hamper an effective production of hBD-1 in vivo, we hypothesized that they could be related to reduced response from the innate immune system.Despite the fact that DU145, TSU-Pr1, and Caco2 are all carcinoma-derived cell lines, their inherent differences could lead to variations in dual luciferase assay results: we believe that the functional effect of the DEFB1 5 ¶UTR SNPs is still controversial and deserves a more comprehensive study.

No abstract

Patients with an autoimmune condition are known to be at higher risk of developing other autoimmune disorders. Type 1 diabetes may be associated with additional autoimmune disorders including autoimmune thyroid disease. The aim of this study was to investigate the prevalence of thyroid autoantibodies in a group of children, adolescents, and young adults with type 1 diabetes from northeastern Brazil as well as their significance for the development of thyroid disorders. The study design was cross-sectional and descriptive, analyzing young people with a previous type 1 diabetes diagnosis. Two hundred and fourteen children and adolescents with prior diagnosis of type 1 diabetes were evaluated. Antibodies to thyroperoxidase (anti-TPO) were determined in all patients and thyroid-stimulating hormone (TSH) levels. The anti-TPO antibody test was positive in 54 out of the 214 patients studied, resulting in an overall prevalence of 25.2%. Among the anti-TPO-positive subjects, females were predominant (72%) over males (28%) (p < 0.001). A total of 55.5% patients with positive anti-TPO antibodies had abnormal TSH levels. Clinically significant hypothyroidism was found in 29.6% and subclinical hypothyroidism in 22.2% of patients with positive anti-TPO. Hyperthyroidism was present in only 3% of them. Our results demonstrate the high prevalence of autoimmune thyroiditis in patients with type 1 diabetes and the need for these patients of regular screening to make a precocious diagnosis of thyroid dysfunction.