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S Giliani

Publications and source records attributed to S Giliani.

At least 37 records · Page 2Linked to original sources
PubMed1997

A boy with X-linked hyper-IgM syndrome and natural killer cell deficiency.

We present a boy with hyper-IgM syndrome with a previously not reported mutation in the CD40 ligand gene. He also had a concomitant natural killer (NK) cell deficiency. He had no CD56+ or CD16+ cells and no NK activity as determined in 4 h chromium release cytotoxicity assay. After 5 days in culture with IL-2-containing medium, however, his peripheral blood mononuclear cells lysed both NK-sensitive and NK-resistant targets, showing that he had lymphokine-activated killer cell precursors in the circulation. Due to the associated neutropenia, he was treated with granulocyte colony-stimulating factor (G-CSF) and responded well. In the same period we observed a transient increase in the number of NK cells. Isolated NK cell deficiencies are extremely rare. We suggest that the defect in our patient is part of the hyper-IgM syndrome, probably representing the phenotype of the new mutation described. Thus, it is possible that both the neutropenia and the NK cell deficiency are due to lack of growth-promoting signals normally delivered by the CD40 ligand.

CD40 Antigens↗
PubMed1996

In-utero transplantation of parental CD34 haematopoietic progenitor cells in a patient with X-linked severe combined immunodeficiency (SCIDXI).

BACKGROUND: X-linked severe combined immunodeficiency (SCIDXI) is an inherited immune defect which leads to death in infancy from severe infections. The defect is caused by mutations of the IL-2RG gene that encodes for the common gamma chain shared by several cytokine receptors. The disease is characterised by lack of T and NK cells with normal numbers of B cells. SCIDXI can be cured by bone marrow transplantation (BMT) or prevented by abortion after prenatal diagnosis. METHODS: A male fetus was diagnosed as having SCIDXI by molecular, immunophenotypic, and functional analyses. The fetus was injected intraperitoneally under ultrasound guidance with CD34 haematopoietic progenitor cells purified from paternal bone marrow and T-cell depleted by E rosetting. Chimerism analysis was by HLA-DQ alpha typing and gamma-chain staining on cord blood. FINDINGS: A healthy 3.6 kg boy was delivered by caesarean section at 38 weeks of gestation with no clinical or laboratory signs of graft-versus-host disease. Engraftment of donor-derived CD2 cells was found at birth. At 3.5 months of age the infant is well and his T-cell counts and function are normal. INTERPRETATION: In-utero transplantation of haematopoietic progenitor cells allowed immune reconstitution of a fetus with SCIDXI and may be an alternative to elective abortion. Our report should encourage applications of this method to other inherited disorders curable by BMT.

Antigens, CD34↗
PubMed1995

Mutations of Jak-3 gene in patients with autosomal severe combined immune deficiency (SCID).

Severe combined immune deficiency (SCID) represents a heterogenous group of hereditary diseases. Mutations in the common gamma-chain (gamma c), which is part of several cytokine receptors including those for interleukin (IL)-2, IL-4, IL-7, IL-9 and IL-15, are responsible for X-linked SCID, which is usually associated with a lack of circulating T cells and the presence of B lymphocytes (T- B+ SCID). The gene(s) responsible for autosomal recessive T- B+ SCID is still unknown. The Jak-3 protein kinase has been found to associate with the gamma c-chain-containing cytokine receptors. Therefore Jak-3 or other STAT proteins with which it interacts are candidate genes for autosomal recessive T- B+ SCID. Here we investigate two unrelated T- B+ SCID patients (both from consanguineous parents) who have homozygous mutations in the gene for Jak-3. One patient carries a mutation (Tyr100-->Cys) in a conserved tyrosine residue in the JH7 domain of Jak-3 which is absent in more than 150 investigated chromosomes. The other patient carries a homozygous 151-base-pair deletion in the kinase-like domain, leading to a frameshift and premature termination. Both mutations resulted in markedly reduced levels of Jak-3. These findings show that abnormalities in the Jak/STAT signalling pathway can account for SCID in humans.

B-Lymphocytes↗
PubMed1995

The genomic organization of the human transcription factor 3 (TFE3) gene.

We have determined the exon-intron structure of the human TFE3 gene located on Xp11.22-23. By designing PCR primers, we were able to amplify various segments of the TFE3 genomic region, thus establishing that this gene is composed of seven exons, the first six of which are small (from 56 to 159 nt). The 5' UT region is contained entirely in the first exon, while the 3' UT region is contained in the seventh exon. The comparison of the genomic and the published cDNA versions revealed that the deduced amino acid sequence of TFE3 in the C-terminus region is 125 amino acids shorter than previously reported. This eliminates most of the putative proline- and arginine-rich domain and makes the human sequence more similar to its mouse homolog. The activation domain at the N-terminus is contained in exon 2, as has been described for the mouse. The basic helix-loop-helix (BHLH) motif is spread over exons 4 to 6, while the leucine zipper (LZ) is almost all contained in the last portion of exon 6. This split BHLH is different from other BHLH-LZ genes whose genomic structures have been determined up to now.

Animals↗
PubMed1995

Characterization of nine novel mutations in the CD40 ligand gene in patients with X-linked hyper IgM syndrome of various ancestry.

X-linked immunodeficiency with hyper-IgM (HIGMX-1) is a rare disorder caused by defective expression of the CD40 ligand (CD40L) by activated T lymphocytes, resulting in inefficient T-B cell cooperation and failure of B cells to undergo immunoglobulin isotype switch. In the present work, we describe nine patients of various ancestry who bear different mutations in the X chromosome-specific CD40L gene. Two of the mutations were nonsense mutations, one each resulting in premature stop codons at amino acid residues 39 and 140. Three patients had single point missense mutations, one each at codons 126, 140, and 144. Another patient had a 4-bp genomic deletion in exon 2, resulting in a frameshift and premature termination. Three patients showed insertions, one each of 1, 2, and 4 nt, probably because of polymerase slippage, resulting in frameshift mutation and premature termination. Overall, these observations confirm the heterogeneity of mutations in HIGMX-1. However, the identification of two patients whose mutation involves codon 140 (previously shown to be altered in two other unrelated subjects) suggests that this may be a hotspot of mutation in HIGMX-1. In two additional patients with clinical and immunological features indistinguishable from canonical HIGMX-1, no mutation was detected in the coding sequence, in the 5' flanking region, or in the 3' UTR.

Base Sequence↗
PubMed1994

Organization of the human CD40L gene: implications for molecular defects in X chromosome-linked hyper-IgM syndrome and prenatal diagnosis.

Recently, CD40L has been identified as the gene responsible for X chromosome-linked hyper-IgM syndrome (HIGM1). CD40L on activated T cells from HIGM1 patients fails to bind B-cell CD40 molecules, and subsequent analysis of CD40L transcripts by reverse transcription PCR demonstrated coding region mutations in these patients. This approach, however, is of limited use for prenatal diagnosis of HIGM1 in the early-gestation fetus. In this report, we have defined the genomic structure of the CD40L gene, which is composed of five exons and four intervening introns. With this information, we have defined at the genomic level the CD40L gene abnormalities for three previously described HIGM1 patients who demonstrated clustered deletions in the CD40L coding region. These different deletions arose from three distinct mechanisms, including (i) a splice donor mutation with exon skipping, (ii) a splice acceptor mutation with utilization of a cryptic splice site, and (iii) a deletion/insertion event with the creation of a new splice acceptor site. In addition, we have performed prenatal evaluation of an 11-week-old fetus at risk for HIGM1. CD40L genomic clones provide a starting point for further studies of the genetic elements that control CD40L expression. Our knowledge of the CD40L gene structure will prove useful for the identification of additional mutations in HIGM1 and for performing genetic counseling about this disease.

Base Sequence↗
PubMed1994

Ineffective expression of CD40 ligand on cord blood T cells may contribute to poor immunoglobulin production in the newborn.

A major feature of the immature immune system in the newborn is its inability to produce significant levels of immunoglobulins other than IgM in response to antigens. It has recently been demonstrated that interaction of the CD40 molecule on B cells with the CD40 ligand (CD40L) on activated T cells is pivotal for immunoglobulin switching. In view of these findings, we have tested cord blood mononuclear cells (CBMC) for expression of CD40L. Our data clearly demonstrate that freshly isolated CBMC do not express significant levels of CD40L upon in vitro activation; this defect is intrinsic to CD4+ cord blood lymphocytes. In vitro priming of CBMC with phytohemagglutinin and interleukin-2 for several days induced a conversion from the "naive" to the "memory" phenotype (as assessed by expression of CD45 isoforms) and led to substantial CD40L expression upon appropriate restimulation. These data indicate that ineffective CD40L expression might represent a major factor for reduced immunoglobulin production in the neonate, and suggest that antigenic exposure in vivo leads to changes in the genetic program, enabling T cells to express CD40L.

Adult↗
PubMed1994

Molecular analysis of the XP-D gene in Italian families with patients affected by trichothiodystrophy and xeroderma pigmentosum group D.

In several patients with the rare hereditary disorder trichothiodystrophy (TTD), a DNA repair defect has been shown to be in the same gene as in xeroderma pigmentosum complementation group D (XP-D). The ERCC-2 gene (excision repair cross-complementing rodent repair deficiency of group 2) has recently been identified as a strong candidate gene for XP-D, since it restores normal UV sensitivity to XP-D cells after transfection. Using Southern blotting, we have analysed the ERCC-2 gene in DNA samples from 28 members of nine Italian families with individuals affected by XP-D (three patients) or by TTD with photosensitivity due to the XP-D defect (eight patients). No major modifications of the ERCC-2 gene were detected with two cDNA probes in either XP-D or TTD patients indicating that the association between TTD and XP-D is not likely to result from a large deletion or rearrangement involving this gene. We found two RFLPs after digestion of the DNA samples with TaqI or MspI, but neither of them could be related to the molecular alteration determining the pathological phenotype. We also analysed a human homologue detected with the hamster sequence isolated by Arrand et al. (1989), which specifically, but partially, complements the DNA repair deficiency in XP-D cells. Our analysis demonstrated that this gene is not the primary gene defective in XP-D. In fact two RFLPs detected with a genomic probe do not co-segregate with the disease in an XP-D family.

DNA↗
PubMed1994

Defective expression of CD40 ligand on T cells causes "X-linked immunodeficiency with hyper-IgM (HIGM1)".

X-linked immunodeficiency with hyper-IgM (HIGM1) is a rare disorder, characterized by recurrent infections associated with very low or absent IgG and IgA, and normal to increased IgM serum levels. The disease has been earlier mapped to the q26-27 region of the X-chromosome. We have identified a novel molecule expressed on the surface of activated T cells, which was designated TRAP (Tumor necrosis factor Related Activation Protein), and could demonstrate that TRAP is a ligand for the CD40 receptor expressed on B cells. Our mapping of the TRAP gene to the Xq26.3-27.1 region suggested a causal relationship to HIGM1. Further work revealed that various mutations of the TRAP/CD40 ligand (CD40L) gene may lead to a defective expression of the TRAP/CD40L molecule on the T-cell surface in HIGM1 patients. A combination of structural and functional analyses finally demonstrated that the failure of TRAP/CD40L on T cells to interact with CD40 on B cells is responsible for the inefficient T-cell help for B cells observed in HIGM1. The observations made in HIGM1 allowed us to conclude that TRAP/CD40L is not required for IgM synthesis. In contrast, functional expression of TRAP is a prerequisite for effective immunoglobulin isotype switching and subsequent production of IgG, IgA and IgE by B cells in vivo. The interaction of TRAP/CD40L with CD40 thus provides a very critical link between the cellular and the humoral part of the immune system. The knowledge of TRAP/CD40L cDNA sequence, the availability of various reagents for the testing of expression and function of TRAP/CD40L, and our recent elucidation of the exon-intron structure of the TRAP/CD40L gene now provide all necessary tools for early diagnosis of affected patients and the detection of female carriers of HIGM1. The available information will also provide a basis for future attempts at gene therapy in this disease.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1993

Application of molecular analysis to genetic counseling in the Wiskott-Aldrich syndrome (WAS).

The Wiskott-Aldrich syndrome (WAS) is a severe X-linked, recessive disorder, with a high mortality rate at early age due to hemorrhages, infections, and lymphoid malignancies. The molecular pathogenesis of the disease is unknown. Carrier females of WAS are clinically and immunologically normal, thus precluding carrier detection by simple laboratory tests. Major advances in molecular genetics have allowed mapping of the WAS gene to the pericentromeric short arm of the X chromosome, and have made carrier detection and prenatal diagnosis feasible by segregation analysis with closely linked polymorphic DNA markers. Furthermore, the observation that carriers of WAS exhibit a unilateral inactivation of the X chromosome in hematopoietic cells has provided a new tool for carrier detection. However, critical interpretation of molecular analysis data is essential to provide accurate genetic counseling to WAS families.

Dosage Compensation, Genetic↗
PubMed1993

Genetic heterogeneity of the excision repair defect associated with trichothiodystrophy.

Trichothiodystrophy (TTD) is a rare autosomal recessive disease characterized by brittle hair with reduced sulfur content, mental and physical retardation, a peculiar face and ichthyosis. Photosensitivity has been reported in approximately 20% of the cases in the literature. DNA repair investigations demonstrated that clinical photosensitivity is usually associated with an enhancement of the cellular UV-sensitivity and that the repair defect is in the same gene as in patients from group D of xeroderma pigmentosum (XP). In this paper we describe the characterization of 13 further TTD patients; a defect in the nucleotide-excision repair was observed in fibroblast strains from 10 patients, confirming that TTD is frequently associated with DNA repair defects. Genetic analysis based on complementation studies demonstrated the presence of the XP-D defect in seven repair-defective TTD cases, indicating definitively that the concurrence of TTD with XP-D is not a sporadic or casual event. However, three further cell strains (TTD4VI and TTD6VI from two French siblings and TTD1BR from an English patient) showed restoration of normal UV-induced DNA repair synthesis after fusion with XP or TTD cells belonging to XP group D. These observations, which give the first indication that TTD is associated with repair defects behaving differently in the functional test of complementation, suggest some kind of causal connection between defective excision-repair factors and clinical features diagnostic for TTD. A peculiar aspect of TTD in which repair deficiencies are not related to an increased susceptibility to cancer is confirmed also in all the repair-defective TTD patients investigated in this paper.

Abnormalities, Multiple↗
PubMed1993

A new nucleotide-excision-repair gene associated with the disorder trichothiodystrophy.

The sun-sensitive, cancer-prone genetic disorder xeroderma pigmentosum (XP) is associated in most cases with a defect in the ability to carry out excision repair of UV damage. Seven genetically distinct complementation groups (i.e., A-G) have been identified. A large proportion of patients with the unrelated disorder trichothiodystrophy (TTD), which is characterized by hair-shaft abnormalities, as well as by physical and mental retardation, are also deficient in excision repair of UV damage. In most of these cases the repair deficiency is in the same complementation group as is XP group D. We report here on cells from a patient, TTD1BR, in which the repair defect complements all known XP groups (including XP-D). Furthermore, microinjection of various cloned human repair genes fails to correct the repair defect in this cell strain. The defect in TTD1BR cells is therefore in a new gene involved in excision repair in human cells. The finding of a second DNA repair gene that is associated with the clinical features of TTD argues strongly for an involvement of repair proteins in hair-shaft development.

Adolescent↗
PubMed1992

DNA repair investigations in nine Italian patients affected by trichothiodystrophy.

Trichothiodystrophy (TTD) is a rare autosomal recessive disorder characterized by brittle hair, mental and growth retardation, peculiar face, ichthyosis, and in 20% of the reported cases photosensitivity. Cellular photosensitivity due to the same genetic defect present in xeroderma pigmentosum group D (XP-D) has been described in several patients. Nine patients with clinical symptoms diagnostic for TTD have been identified in Italy to date. We report the results of DNA repair investigations performed in cultured fibroblasts from these patients and 8 TTD parents. Survival, DNA repair synthesis and RNA synthesis following UV irradiation were all normal in the 8 TTD heterozygous cell strains. Among the 9 TTD-affected individuals, normal cellular UV sensitivity was observed in the 2 patients without signs of clinical photosensitivity. In contrast, the other 7 TTD cell strains showed a notable reduction in UV-induced DNA repair synthesis (UDS) levels, ranging between 40% and 5-15% of normal values. Complementation analysis indicated that in the repair-deficient TTD cell strains the genetic defect is the same as that present in XP-D cells. The biochemical heterogeneity of the XP-D defect in TTD patients characterized by different degrees of defective UDS results in different patterns of response to the killing effect of UV light in non-proliferating cells.

Cells, Cultured↗