Tag-single nucleotide polymorphism-based human leukocyte antigen genotyping in celiac disease patients from northeastern Italy.

We genotyped celiac disease (CD)-associated haplotypes DQ2.5, DQ8, DQ2.2, and DQ7 in 1005 CD patients from North Eastern Italy using a Tag-single nucleotide polymorphism (SNPs) approach and real time PCR platform, checking the accuracy and reliability of the method and comparing it to traditional PCR-SSP. Only 14 of 2010 chromosomes analyzed (0.7%) showed discrepancies between the Tag-SNPs real-time polymerase chain reaction (PCR) method and the PCR-single-strand polymorphism (SSP) technique, indicating a high sensitivity and specificity (ranging from 0.987 to 1 and from 0.998 to 0.999, respectively) for tagging with respect to corresponding human leukocyte antigen (HLA) alleles identified by PCR-SSP. Moreover, the overall cost of the Tag-SNPs HLA typing method was low (3 to 4 €/sample instead of 35 to 70 €/sample with commercial kits), making it suitable for mass screenings. Hence, we believe that the Tag-SNPs HLA typing could be used to complement or replace classic HLA typing in at high-risk groups, for research purposes and eventually in population screening programs.

The missense variation Q705K in CIAS1/NALP3/NLRP3 gene and an NLRP1 haplotype are associated with celiac disease.

OBJECTIVES: Celiac disease (CD) is a multifactorial common disorder with several susceptibility loci. Variations in the NALP1/NLRP1 and NALP3/NLRP3 genes have been reported to confer risk for several autoimmune conditions. We hypothesized that polymorphisms in these genes, due to their role in innate immunity and inflammatory processes, may affect susceptibility to CD. METHODS: Two single-nucleotide polymorphisms (SNPs) in NLRP1 (rs12150220, rs2670660) and two SNPs (rs10754558, rs35829419) in NLRP3 genes were genotyped in 504 CD Italian patients and 256 healthy controls. RESULTS: The minor A allele of NLRP3 rs35829419 (Q705K) polymorphism appeared to exert a protective role against the development of CD (P=0.029; odds ratio (OR)=0.56). Moreover, a particular NLRP1 haplotype was associated with predisposition to CD (P=0.003; OR=1.38), even more when present in combination with the rs35829419 major C allele (P=0.002; OR=1.42). CONCLUSIONS: We hypothesized that the deregulation of CIAS1/NALP3/NLRP3 and NALP1/NLRP1 inflammasomes could have a role in CD pathogenesis.

HLA-G 14 bp deletion/insertion polymorphism in celiac disease.

OBJECTIVES: Nonclassical major histocompatibility class I HLA-G antigen is a tolerogenic molecule that inhibits lytic activity of natural killer (NK) cells and cytotoxic T lymphocytes. Because of its immunomodulatory and tolerogenic properties, HLA-G molecules may have a role in celiac disease (CD). We analyzed the HLA-G 14 bp deletion/insertion polymorphism, known to have a functional effect on mRNA stability, in a group of 522 CD patients, stratified for the presence of HLA-DQ2 genotype, and 400 healthy individuals to evaluate the possible effect of the polymorphism on the risk to develop the disease. METHODS: HLA-G 14 bp deletion/insertion polymorphism (rs1704) was detected by polymerase chain reaction and double-checked by direct sequencing. RESULTS: The 14 bp inserted (I) allele and the homozygous I/I genotype were significantly more frequent in CD patients than in healthy controls. The presence of I allele was associated with an increased risk of CD (OR 1.35) and the effect of I allele was consistent with a recessive genetic model (P<0.001). CONCLUSIONS: Our results also indicate that the effect of the HLA-G D/I polymorphism is restricted for HLA-DQ2, and not simply due to the presence of linkage disequilibrium with the major known risk factor; moreover we found that the presence of the I allele confers an increased risk of CD in addition to the risk conferred by HLA-DQ2 alone and that subjects that carry both DQ2 and HLA-G I alleles have an increased risk of CD than subjects that carry DQ2 but not the I allele.

HLA-G*0105N allele is associated with augmented risk for HIV infection in white female patients.

We analyzed HLA-G 3777G > C, HLA-G 14 bp deletion/insertion and HLA-G*0105N polymorphisms in HIV-positive white adult participants, infected through horizontal heterosexual transmission, and unexposed uninfected individuals, all from north eastern Italy. We report a new association between the HLA-G*0105N allele and HIV infection in adult white female participants, being HLA-G*0105N null allele correlated with an augmented risk (odds ratio = 4.35, 95% confidence interval = 1.38-18.07, P = 0.005) for HIV infection.

Five new OTOF gene mutations and auditory neuropathy.

OBJECTIVE: Purpose of this paper is to analyse OTOF gene in a series of subjects affected by auditory neuropathy. METHODS: Four children showing mild to profound prelingual deafness, confirmed by the absence of a clear and detectable responses at auditory brainstem responses (ABR), associated with the presence of bilateral OAE, were enrolled in the study. RESULTS AND CONCLUSIONS: Genetic analysis identified five new mutations (a nonsense, a small and a large deletion and two splicing site mutations), and one missense mutation (F1795C) previously described. These results further confirm the role of OTOF gene in auditory neuropathy. In the absence of a context of neurological syndrome, the combination of absent ABR and positive OAE responses should lead to an auditory neuropathy diagnosis and to a mutational screening in OTOF.

HLA-G 3' UTR haplotypes and HIV vertical transmission.

We evaluated the possible association of human leukocyte antigen-G (HLA-G) 3777G>C and 14-bp deletion/insertion (D/I) polymorphisms haplotypes and combined genotypes with perinatal HIV transmission in Brazilian children. The 3777G>C polymorphism alone has no effect on HIV vertical transmission but, when linked with the D allele, exerts a positive role in the protection. Indeed, we identified the DC HLA-G haplotype as significantly associated with a protective effect towards HIV vertical transmission.

Genetic factors in mother-to-child transmission of HCV infection.

HCV infection transmission rate in infants born to HCV-positive mothers is about 5%. HIV co-infection and high maternal RNA viral load are associated with increased transmission. The only genetic factor previously evaluated is HLA. We investigated the role of genetic factors already associated in adults with HCV infection evolution (HLA-DRB1, MBL2, TNF-alpha, IFN-gamma and IL-10), or liver disease progression (HFE and TGF-beta1). 384 Italian subjects were recruited, including 38 HCV-positive mother/child pairs; 104 infected, non-transmitting mothers with their 114 children; 21 vertically infected children and 69 HCV-exposed, uninfected children. Samples were analysed for previously described gene polymorphisms. Maternal HLA-DRB104 correlated with protection from vertical transmission (p=0.023), while HLA-DRB110 in children was a risk factor (p=0.036). Investigation of concordance degree in HLA-DRB1 locus revealed that a HLA mismatch between mother and child was a protective factor (p=0.017) indicating that alloreactive immune responses are involved in preventing HCV vertical transmission.

MBL2 gene polymorphisms are correlated with high-risk human papillomavirus infection but not with human papillomavirus-related cervical cancer.

We investigated whether there is a correlation between MBL2 polymorphisms and the host susceptibility to human papillomavirus (HPV) infection and cancer development. Toward this end, we analyzed MBL2 exon 1 polymorphisms in 172 women infected by strains of HPV that are associated with high-risk of cervical cancer development (or "high-risk" HPV infection), 105 of whom had HPV-related squamous cell carcinoma of the cervix (SCC), as well as 105 women not infected by HPV. We demonstrated an association of MBL2 polymorphisms with high-risk HPV infection in women without SCC who showed increased presence of the mutant MBL2 0 allele and 0/0 genotype as compared with women with SCC and healthy controls. No correlation with MBL2 polymorphisms was found in women who developed cancer. Therefore we propose that MBL2 polymorphisms responsible for defective production of mannose binding lectin (MBL) protein play a role in the increased susceptibility to high-risk HPV infection but not to cervical cancer onset and development.

Association between HLA-G 3'UTR 14-bp polymorphism and HIV vertical transmission in Brazilian children.

OBJECTIVES: The aim of our study was to verify the possible association between an HLA-G 14-bp deletion/insertion polymorphism and perinatal HIV transmission in Brazilian children. DESIGN: We analyzed the 14-bp deletion/insertion polymorphisms in seronegative (i.e., exposed uninfected, N = 71) and seropositive (exposed infected, N = 175) Brazilian children born from HIV-positive mothers and in healthy controls (n = 175). METHODS: HLA-G 14-bp deletion/insertion polymorphism (rs16375) was detected by PCR amplification of the target sequence followed by agarose gel electrophoresis. All the samples were also analyzed by direct sequencing in order to validate the genotyping results. RESULTS: HIV-exposed uninfected children showed significant differences in their allele and genotype frequencies of the HLA-G 14-bp polymorphism when compared to both seropositive children and healthy controls. The 14-bp-deleted (D) allele was more frequent in exposed uninfected children (79%) than in healthy controls (60%) and HIV-positive children (58%); the higher percentage of the D allele found in the exposed uninfected children with respect to HIV-positive individuals was significantly associated with a reduced risk of vertical transmission. This effect was ascribable to the presence of the D/D homozygous genotype. CONCLUSION: Our findings support the possible role for the HLA-G 14-bp deletion/insertion polymorphism in the HIV vertical transmission in Brazilian children. The presence of the D allele and D/D genotype is associated with a protective effect toward HIV perinatal infection.

MBL2 genetic screening in patients with recurrent vaginal infections.

PROBLEM: Mannose-binding lectin (MBL) is an important component of the innate immunity, present at the mucosal level in vagina: a common pathogen's entry point. METHOD OF STUDY: We used a rapid genotyping method based on melting temperature assay to search for three single nucleotide polymorphisms (SNPs) located in the first exon of the MBL2 gene and we also measured MBL serum levels in patients with recurrent bacterial vaginosis (rBV) and recurrent vulvovaginal candidiasis (rVVC). RESULTS: Detected frequencies of MBL2 SNPs were comparable to the ones already reported for the Italian population and no significant differences were found between rVVC, rBV and controls. MBL serum levels did not show significant differences between the studied groups. CONCLUSION: No correlation for the screened mutations has been found neither in protecting nor in favoring the infection in rVVC and rBV patients. Our data demonstrate a lack of association between functional polymorphisms in the first exon of MBL2 gene, MBL deficiency, VVC and rBV.