A. Aureli

Susceptibility to Guillain-Barré syndrome is associated to polymorphisms of CD1 genes.

Guillain-Barré syndrome (GBS) is the prototype of a postinfectious autoimmune neuropathy. Molecular mimicry between glycolipid antigens expressed by an infective antigen such as Campylobacter jejuni and the human peripheral nerve has been hypothesized to be the causative mechanism of GBS. However, only 1/1000 of C. jejuni enteritis develops GBS. This emphasizes the importance of host-related factors in the development of the disease. HLA studies in GBS failed to show an association or gave conflicting results but MHC class I and II process and present peptides to T lymphocytes making unlikely that the HLA system plays a role in GBS with autoantibodies against self-gangliosides. CD1 molecules are MCH-like glycoproteins specialized in capturing and presenting a variety of glycolipid to antigen-specific T cells. There are five closely linked CD1 genes in humans located in chromosome 1 (named CD1A, B, C, D, and E) all showing limited polymorphism in exon 2 which codifies for the alpha1 domain of CD1 molecules. The nucleotide substitutions in CD1B and CD1C are rare and reported to be silent. In 100 controls and 65 GBS patients (21 with a recent C. jejuni infection and 35 with anti-glycolipid antibodies) we used direct sequencing by polymerase chain reaction to genotype exon 2 of CD1A, CD1D and CD1E genes. CD1D is monomorphic in both controls and patients whereas CD1A and CD1E are biallelic in exon 2. Subjects with CD1E*01/01 genotype are 2.5 times more likely to develop GBS, whereas subjects with CD1A*01/02 or CD1E*01/02 have a reduced relative risk by 3.6 and 2.3 times respectively. The combination of CD1A*01/02 and CD1E*01/02 reduces by 5 times the risk of developing GBS. Although a correlation between CD1E*01/01 genotype and recent C. jejuni infection or presence of antiganglioside antibodies was not found the overall findings indicate that susceptibility to develop GBS is associated with polymorphisms of CD1E and CD1A genes.

Correlation between genetic HLA class I and II polymorphisms and anthropological aspects in the Chaouya population from Morocco (Arabic speaking)

The aim of this study was to provide genetic and anthropological information on the Chaouya (CH), an Arabic-speaking population living in West Morocco, Atlantic coast (Settat). In 98 unrelated healthy CH volunteers, we first investigated the human leukocyte antigen (HLA) class I and II allele polymorphisms using a sequence-based typing method and examined haplotypes and relatedness of this group to other African and Mediterranean populations. The study showed the close relatedness with Tunisian population and other North Africans, together with a strong influence of various immigrations, mainly Spaniards, French, and Portuguese, as expected. Nevertheless, analysis of class II allele frequencies (afs) showed that Oromo and Amhara Ethiopian groups cluster together with the Berbers and other North Africans, confirming the relationship between these populations (Afro-Asiatic linguistic group, Hamites). South and sub-Saharan Africans cluster separately at a great distance from CH, except the sub-Saharan Bantu population from Congo Kinshasa, which shows a relatively close genetic relationship ascribable to the effect of a diversifying selection. On the other hand, considering HLA class I afs analyses, it was noteworthy that CH grouped together with sub-Saharans, showing a close genetic distance mainly with Ugandas and Kenians Luo.

Sequence-Based analysis of the HLA-DRB1 polymorphism in Metalsa Berber and Chaouya Arabic-speaking groups from Morocco

To examine the genetic diversity in Morocco, the polymorphism at the HLA-DRB1 locus was investigated in two populations: the Metalsa group consisting of Berbers from north Morocco (who speak the Tarifit language and live in the Nador area), and the Chaouya group who are Arabic-speaking people from west Morocco (Atlantic coast) living in the Settat area. The DRB1 alleles of 197 healthy unrelated individuals were identified by direct DNA sequencing of exon 2 using fluorescently-labeled primers. A total of 28 and 29 alleles at DRB1 locus were identified in the Metalsa and Chaouya groups, respectively. The most frequent alleles in the Metalsa group are DRB1*03011 (20.2%), DRB1*0701 (12.12%), and DRB1*1302 (11.11%). In the Chaouya group, DRB1*0701 (16.33%), DRB1*15011 (12.76%), and DRB1*03011 (11.73%) are most common. Each population exhibits some specific variants and some uncommon alleles. The frequency of the DRB1*03011 allele differs significantly between the two populations (p = 0.0311). The DRB1 frequency distributions in the two groups suggest the effects of balancing selection. The interpopulation analysis highlighted a strong relatedness, based on genetic distances, between the two Moroccan groups and the other north Africans (the Moroccans from El Jadida area, Moroccan Souss Berbers, Algerians, and Tunisians), and to a lesser extent with the Iberians, French, and Ethiopians.

Attention-deficit hyperactivity disorder and intellectual disability: a study of association with brain-derived neurotrophic factor gene polymorphisms.

Symptoms of attention-deficit hyperactivity disorder (ADHD) have been found in several studies of children with intellectual disabilities (ID) but the two diseases are not always associated. Several lines of evidence implicate the involvement of brain-derived neurotrophic factor (BDNF) in ADHD, and it may also be relevant in ID due to its known involvement in the development of the central nervous system (CNS) and in learning/memory functions. We genotyped paediatric patients with ADHD and ID for the Val66Met and 270 C/T polymorphisms in BDNF. Diagnosis of ADHD and ID was confirmed by the clinicians in accordance with DSM-IV criteria. The G/A genotype of the Val66Met SNP was associated with both ADHD and ID, and the G allele was significantly associated with ADHD. The C/C genotype of the C270T SNP was significantly overrepresented in both ADHD and ID groups compared with the controls. Data suggest that both BDNF polymorphisms could play a role in the etiology of ADHD. In addition, we present the first results suggesting that these BDNF SNPs are significantly associated with ID.

CD1A and CD1E gene polymorphisms are associated with susceptibility to multiple sclerosis.

Multiple sclerosis (MS) is thought to be an autoimmune T-cell-mediated disease directed at myelin antigens of the central nervous system. Besides myelin proteins, lipid components of CNS are supposed to play a role as antigens for T cells in MS. CD1 is a family of MHC-like glycoproteins specialized in capturing and presenting a variety of microbial and self lipids and glycolipids to antigen-specific T cells. CD1-restricted T cells specific for gangliosides and sulfatide have been isolated from subjects with MS and in mice with experimental allergic encephalopathy. We genotyped exon 2 of CD1A and CD1E in 205 MS patients and 223 unrelated healthy controls and determined their association with the presence of anti-ganglioside and anti-sulfatide antibodies. CD1E 01-01 is associated with a reduced risk of MS (OR 0.54, p=0.001); CD1A 02-02 (OR 1.99, p=0.012) or CD1E 02-02 (OR 2.45, p=0.000) with an increased risk. The combination of the genotypes CD1A 02-02 and CD1E 02-02 is present in 90.7% of patients but in only 9.4% controls (OR 94.16, p= 0.000). CD1A and CD1E polymorphisms contribute to the polygenic susceptibility to MS. The functional effects of CD1 polymorphisms are unknown, however changes in CD1 alleles may affect numerous immunological functions.

Involvement of IL-6 and IL-1 receptor antagonist on intellectual disability.

Imbalances in the regulation of pro-inflammatory cytokines have been increasingly correlated with several neurodevelopmental disorders and their role in neuronal development is being investigated. To assess the possible influence of cytokines on the onset of intellectual disability (ID), we studied the polymorphisms of thirteen proinflammatory cytokine genes in 81 patients and 61 healthy controls. We demonstrated a significant association of interleukin-6 (IL-6) single-nucleotide polymorphism (SNP) (-174 G/C and nt565 G/A), and interleukin-1 receptor antagonist (IL-1RA) (Mspa-I 11100) SNP with ID. Moreover, the IL-6 SNPs is an unfavorable genetic predisposition for females. The evaluation of circulating levels of IL-6 and IL-1RA showed that the serum concentrations of IL-6 were significantly higher in ID patients than in controls. These data suggest that functional cytokine gene polymorphisms may influence the development of ID.

A new HLA-A allele identified in a leukemic patient attending hematopoietic cell transplantation: A*2318.

Sequence-based typing procedure (SBT) procedure permitted us to identify a new human leukocyte antigen-A allele in a patient attending hematopoietic stem cell transplantation.

Chimerism in a child with severe combined immunodeficiency: A case report

Abstract:  Severe combined immunodeficiency (SCID) represents a group of rare, sometimes fatal, congenital disorders in which there is a combined absence of T‐lymphocyte and B‐lymphocyte function. Children with SCID die within two years of age, if untreated. The effective treatment for SCID is a hematopoietic stem cell transplantation (HSCT). It has been repeatedly described that in peripheral blood of infants with SCID maternal T cells can be found. Here we report a case of blood chimerism in a one‐year‐old boy with SCID.

CD1A, D and E gene polymorphisms in a North African population from Morocco

CD1 molecules are specialized in capturing and presenting lipids and glycolipids to distinct subsets of T and NKT cells. Glycolipid presentation could play a significant role in the immune response against microbial infections. There are five closely linked CD1 genes in humans, named CD1A, B, C, D, and E, which all show a limited polymorphism. In this study, exon 2 polymorphisms of CD1A, CD1D and CD1E were investigated and allele, genotype and haplotype frequencies of these loci were reported in a Moroccan population. A comparison with allele, genotype and haplotype frequencies observed in other geographic areas was also performed. Results confirmed the presence of ethnic differences in CD1 polymorphism, mainly in CD1D (in this population two additional CD1D variant alleles, CD1D(∗)03 and CD1D(∗)04, were described) and E genes. These data could be useful to evaluate a possible pathogenetic role of CD1 in diseases. Increasing the knowledge in this field may offer possibilities for the development of new immunotherapeutic approaches.

Increased CD1D polymorphism: identification of two novel alleles, CD1D*03 and *04, in individuals from Morocco.

Two novel CD1D alleles were identified in unrelated individuals from Morocco. They differ each from the common CD1D*01 allele by one nucleotide substitution in exon 2 resulting in one amino acid change in the G‐ALPHA1‐LIKE domain. According to the IMGT unique numbering for G domain, CD1D*03 has one nucleotide transition c136 > t in codon 46, with an arginine‐to‐cysteine amino acid change (R46 > C) in the D‐STRAND, whereas CD1D*04 has one transition c98 > t in codon 33, with a threonine‐to‐methionine amino acid change (T33 > M) in the C‐STRAND. This suggests that CD1D is more polymorphic than previously assumed.