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Biomedical subjects

L D Notarangelo

Publications and source records attributed to L D Notarangelo.

At least 73 records · Page 4Linked to original sources
PubMed1998

Characterization of a CD38-like 78-kilodalton soluble protein released from B cell lines derived from patients with X-linked agammaglobulinemia.

Studies on murine B lymphocytes showed that Bruton's tyrosine kinase mediates signal transduction induced via CD38, a nonlineage-restricted 45-kD ectoenzyme. This signaling is defective in B cells from X-linked immunodeficient mice affected with the analogue of human X-linked agammaglobulinemia (XLA). We performed a structural and functional analysis of CD38 in XLA and other immunodeficiencies, using EBV-immortalized B cells derived from such patients. Membrane CD38 was not significantly different from controls in structure, epitope density, enzymatic activity, and internalization upon binding of agonistic mAbs. Meanwhile, an increased release of soluble CD38 from XLA cells was observed: immunoprecipitation from XLA culture media yielded a protein of approximately 78 kD (p78), reacting also in Western blot and displaying both enzymatic activities and a peptide map similar to membrane CD38. Soluble forms and homotypic aggregations of CD38 were documented in different cell models and by crystallographic analysis of the Aplysia ADP-ribosyl cyclase, the ancestor of human CD38. p78 might represent the product of an altered turn-over of membrane CD38, a starting point for studying its association with Bruton's tyrosine kinase and its role in XLA and other B cell immunodeficiencies.

ADP-ribosyl Cyclase↗
PubMed1998

Partial V(D)J recombination activity leads to Omenn syndrome.

Genomic rearrangement of the antigen receptor loci is initiated by the two lymphoid-specific proteins Rag-1 and Rag-2. Null mutations in either of the two proteins abrogate initiation of V(D)J recombination and cause severe combined immunodeficiency with complete absence of mature B and T lymphocytes. We report here that patients with Omenn syndrome, a severe immunodeficiency characterized by the presence of activated, anergic, oligoclonal T cells, hypereosinophilia, and high IgE levels, bear missense mutations in either the Rag-1 or Rag-2 genes that result in partial activity of the two proteins. Two of the amino acid substitutions map within the Rag-1 homeodomain and decrease DNA binding activity, while three others lower the efficiency of Rag-1/Rag-2 interaction. These findings provide evidence to indicate that the immunodeficiency manifested in patients with Omenn syndrome arises from mutations that decrease the efficiency of V(D)J recombination.

Amino Acid Sequence↗
PubMed1998

Development of autologous, oligoclonal, poorly functioning T lymphocytes in a patient with autosomal recessive severe combined immunodeficiency caused by defects of the Jak3 tyrosine kinase.

Defects of the common gamma chain subunit of the cytokine receptors (gamma c) or of Jak3, a tyrosine kinase required for gamma c signal transduction, result in T-B+ severe combined immunodeficiency (SCID). However, atypical cases, characterized by progressive development of T lymphocytes, have been also reported. We describe a child with SCID caused by Jak3 gene defects, which strongly but not completely affect Jak3 protein expression and function, who developed a substantial number (> 3,000/microL) of autologous CD3+CD4+ T cells. These cells showed a primed/activated phenotype (CD45R0+ Fas+ HLA-DR+ CD62L(lo)), defective secretion of T-helper 1 and T-helper 2 cytokines, reduced proliferation to mitogens, and a high in vitro susceptibility to spontaneous (caused by downregulation of bcl-2 expression) as well as activation-induced cell death. A restricted T-cell receptor repertoire was observed, with oligoclonal expansion within each of the dominant segments. These features resemble those observed in gamma c-/y and in Jak3-/- mice, in which a population of activated, anergic T cells (predominantly CD4+) also develops with age. These results suggest that residual Jak3 expression and function or other Jak3-independent signals may also permit the generation of CD4+ T cells that undergo in vivo clonal expansion in humans; however, these mechanisms do not allow development of CD8+ T cells, nor do they fully restore the functional properties of CD4+ T lymphocytes.

Cell Death↗
PubMed1998

Defective actin polymerization in EBV-transformed B-cell lines from patients with the Wiskott-Aldrich syndrome.

The Wiskott-Aldrich syndrome (WAS) is a rare X-linked recessive disorder characterized by eczema, thrombocytopenia, and immunodeficiency. An allelic variant of the disease is characterized by isolated thrombocytopenia (XLT). The gene responsible for WAS/XLT (WASP) encodes for a 502 amino acid protein (WASP) that is possibly involved in actin binding and cytoskeleton organization. The expression of WASP and the distribution of F-actin and alpha-actinin (which binds to and stabilizes actin filaments) have been analysed in lymphoblastoid cell lines from six patients with WAS and one with XLT. Western blot and immunocytochemistry did not reveal WASP expression in four WAS patients, whereas two WAS patients (with a moderate clinical course) expressed trace amounts of mutant WASP. In contrast, the XLT patient expressed normal amounts of WASP. Furthermore, cell lines from WAS and XLT patients also markedly differed in F-actin polymerization and alpha-actinin distribution. In particular, severe defects of cytoplasmic F-actin expression and of F-actin-positive microvillus formation, and impaired capping of alpha-actinin, were observed in all patients who lacked WASP. As a whole, the degree of impairment of WASP protein expression in WAS/XLT seems to correlate with anomalies of cytoskeletal organization, strongly supporting a role for WASP in the regulation of F-actin polymerization.

Actinin↗
PubMed1998

Two novel mutations in exon 11 of the PAH gene (V1163del TG and P362T) associated with classic phenylketonuira and mild phenylketonuria. Mutations in brief no. 143. Online.

PKU is one of the commonest genetic disease in man, affecting 1/10,000 individuals. It presents a wide phenotypical spectrum, from classic PKU to moderate Hyperpheylalaninemia depending on the residual enzymatic activity. Two novel mutations 1163/1164delTG and P362T in exon 11 have been detected during the mutational screening of the PAH gene in 84 families. 1163/1164delTC can be confused with V388M if the mutational screening is performed with BsaAI restriction enzyme, this mutation in heterozigosis presents a moderate phenotype. P362T mutation in heterozigosis with V388M shows a classical PKU phenotype. We report here two new mutations in exon 11 of the PAH gene (GenBank U49897), V1163delTG and P362T (using cDNA sequence), detected during the analysis of 57 PKU and 36 HPA patients belonging to 84 unrelated families detected under a neonatal screening program performed in Catalonia.

DNA Mutational Analysis↗
PubMed1998

Mutation analysis by a non-radioactive single-strand conformation polymorphism assay in nine families with X-linked severe combined immunodeficiency (SCIDX1).

X-linked severe combined immunodeficiency (SCIDX1) is an inherited disease characterized by profound abnormalities of cell-mediated and humoral immunity. Patients with SCIDX1 have defects in the common cytokine receptor gamma chain gene (IL2RG) that encodes a shared, essential component of the receptors for interleukin-2 (IL-2), IL-4, IL-7, IL-9 and IL-15. We have characterized nine SCIDX1 families by using a DNA-based, non-radioactive screening method and DNA sequencing. Nine different mutations were found, scattered from exon 1 to exon 5 of the IL2RG gene. Two of these mutations have been previously identified in other unrelated patients; the other seven are novel mutations that differ from all of the 95 already reported in the IL2RG mutation data base. In addition to describing novel mutations in the IL2RG gene, this study shows that the knowledge of the genetic defect and the use of an efficient, non-radioactive, and rapid screening approach have important implications for prenatal and postnatal diagnosis, carrier female identification, and possibly prenatal therapy.

DNA Mutational Analysis↗
PubMed1998

Molecular and biochemical characterization of JAK3 deficiency in a patient with severe combined immunodeficiency over 20 years after bone marrow transplantation: implications for treatment.

Severe combined immunodeficiency (SCID) comprises a heterogenous group of disorders that are fatal unless treated by bone marrow transplantation (BMT). The most common form of SCID (T-B+ SCID) is due to mutations of either the common gamma chain (gammac) or of gammac-coupled JAK3 kinase. We report an unusual JAK3 defect in a female who was successfully treated > 20 years ago with a BMT using her HLA-identical father as the donor. Persistence of genetically and biochemically defective autologous B cells, associated with reconstitution of cellular and humoral immunity, suggests that integrity of the gammac-JAK3 signalling pathway is not strictly required for immunoglobulin production.

B-Lymphocytes↗
PubMed1997

Structural and functional basis for JAK3-deficient severe combined immunodeficiency.

Mutations of the Janus family kinase JAK3 have been found to be responsible for autosomal recessive severe combined immunodeficiency (SCID) in humans. We report here the analysis of four new unrelated patients affected by JAK3-deficient SCID. The genetic defects were heterogeneous and included a large intragenic deletion as well as different point mutations, leading to missense substitutions, early stop codons, or splicing defects. We performed a series of studies of the biochemical events induced by cytokines on lymphoblastoid B-cell lines obtained from these patients. Abnormalities in tyrosine phosphorylation of JAK3 in response to interleukin-2 (IL-2) and IL-4 were present in all patients. Accordingly, IL-2-mediated phosphorylation of STAT5 was also absent or barely detectable. On the contrary, in all cases, we could show reduced but clear phosphorylation of STAT6 upon IL-4 stimulation. In one patient carrying a single amino acid change (Glu481Gly) in the JH3 domain of JAK3, we observed partially conserved IL-2 responses resulting in reduced but detectable levels of JAK3 and STAT5 phosphorylation. Interestingly, the patient bearing this mutation developed a substantial number of circulating CD4(+)/CD45RO+ activated T lymphocytes that were functionally impaired. In two cases, patients' cells expressed JAK3 proteins with mutations in the JH2 pseudo-kinase domain. A single cysteine to arginine substitution (Cys759Arg) in this region resulted in high basal levels of constitutive JAK3 tyrosine phosphorylation unresponsive to either downregulation by serum starvation or cytokine-mediated upregulation. The characterization of the genetic defects and biochemical abnormalities in these JAK3-deficient patients will help define the role of JAK3 in the ontogeny of a competent immune system and may lead to a better understanding of the JAK3 functional domains.

B-Lymphocytes↗
PubMed1997

Interleukin-15 (IL-15) induces IL-8 and monocyte chemotactic protein 1 production in human monocytes.

Interleukin-15 (IL-15) is a recently characterized cytokine that shares many biological activities with IL-2 and interacts with the beta and gamma components of the IL-2 receptor. Unlike IL-2, which is secreted only by T cells, IL-15 is expressed preferentially by nonlymphoid tissues, epithelial, and fibroblast cell lines and by activated monocytes/macrophages. High concentrations of IL-15 have been shown in inflamed joints of rheumatoid arthritis patients, suggesting a role for IL-15 in inflammatory diseases where there is recruitment of leukocytes. Although monocytes have been shown to bind IL-15, its effects on these cells are not defined. In this report we show that supernatants of monocytes treated with IL-15-contained chemotactic activity for neutrophils and monocytes which was neutralized by anti-IL-8 or by anti-monocyte chemotactic protein 1 (MCP-1) antibodies, respectively. Secretion of IL-8 and MCP-1 proteins is detectable by enzyme-linked immunosorbent assay as early as 6 hours after stimulation with IL-15. Production of the two chemokines is correlated with induction by IL-15 of mRNA expression in monocytes. In addition, IL-8 and MCP-1 induction by IL-15 is differently regulated by interferon-gamma (IFN-gamma) and IL-4. IFN-gamma inhibited IL-15-induced IL-8 secretion, but synergized with IL-15 in MCP-1 induction; whereas IL-4 inhibited both IL-8 and MCP-1 induction by IL-15. These results show that IL-15 can stimulate monocytes to produce chemokines that cause inflammatory cell accumulation. Thus, IL-15 locally produced at sites of inflammation may play a pivotal role in the regulation of the leukocyte infiltrate.

Cells, Cultured↗
PubMed1997

Missense mutations in the Fas gene resulting in autoimmune lymphoproliferative syndrome: a molecular and immunological analysis.

Programmed cell death (or apoptosis) is a physiological process essential to the normal development and homeostatic maintenance of the immune system. The Fas/Apo-1 receptor plays a crucial role in the regulation of apoptosis, as demonstrated by lymphoproliferation in MRL-lpr/lpr mice and by the recently described autoimmune lymphoproliferative syndrome (ALPS) in humans, both of which are due to mutations in the Fas gene. We describe a novel family with ALPS in which three affected siblings carry two distinct missense mutations on both the Fas gene alleles and show lack of Fas-induced apoptosis. The children share common clinical features including splenomegaly and lymphadenopathy, but only one developed severe autoimmune manifestations. In all three siblings, we demonstrated the presence of anergic CD3+CD4-CD8- (double negative, [DN]) T cells; moreover, a chronic lymphocyte activation was found, as demonstrated by the presence of high levels of HLA-DR expression on peripheral CD3+ cells and by the presence of high levels of serum activation markers such as soluble interleukin-2 receptor (slL-2R) and soluble CD30 (sCD30).

Adolescent↗
PubMed1997

A novel 4-kb interleukin-13 receptor alpha mRNA expressed in human B, T, and endothelial cells encoding an alternate type-II interleukin-4/interleukin-13 receptor.

A 4 kb human interleukin-13 receptor (IL-13R) chain cDNA was cloned from a B cell cDNA library using expressed sequence tags homologous to mouse IL-13R as probes. The deduced protein sequence shows a significant level of sequence identity with the IL-5R and the human IL-13R identified recently by expression cloning. The cytoplasmic region is very highly conserved between human and mouse homologs and contains a consensus binding motif for a signal transducer and activator of transcription. The cDNA encodes a protein binding IL-13 when expressed alone which participates in a receptor complex for both IL-4 and IL-13 when expressed in conjunction with the IL-4R alpha chain. Transcripts for this IL-13R chain could be detected in most tissues and organs studied and in T, B, endothelial cells, basophilic, immature mast cell, and monocytic cell lines. The pattern of expression is different from the other recently cloned IL-13R molecule, and correlates with sites where IL-4 and IL-13 signaling is known to occur. This novel receptor is therefore likely to be implicated in reactions involved in IgE responses, T helper 2 differentiation, adhesion of leukocytes to endothelium, and therefore in pathological phenomena such as allergy, atopy, and asthma.

Amino Acid Sequence↗
PubMed1997

In vitro cell death of activated lymphocytes in Omenn's syndrome.

Omenn's syndrome (OS) is characterized by erythrodermia, hepatosplenomegaly, lymphadenopathy, hypereosinophilia and elevated IgE levels associated with increased susceptibility to severe infections. Peripheral blood T cells, though usually present in normal number, show an activated phenotype (including an increased expression of CD95/Fas), a Th2 pattern of cytokine secretion and defective proliferative response to mitogens. In this report, we demonstrate that T cells from patients with OS undergo an excessive cell death in vitro resulting from two mechanisms. First, a substantial number of peripheral blood lymphocytes from OS patients die in unstimulated cultures (p = 0.009 vs. healthy controls). This spontaneous apoptosis is associated with reduced expression of bcl-2 gene product (p < 0.05) and can be prevented by addition of interleukin (IL)-2 (which also prevents down-modulation of bcl-2), while is independent from CD95 signaling. Second, lymphocytes from OS patients are highly susceptible to activation-induced cell death (AICD) induced with mitogens. This mechanism is largely independent from IL-2, while it can be significantly inhibited blocking CD95 with an IgG2b monoclonal antibody (mAb). The dependence of AICD from signals transduced via CD95 was confirmed showing that cross-linking CD95 with an IgM mAb induces a higher cell death in purified CD4+ CD45R0+ cells from OS patients than in controls (comparable for CD95 expression). Both mechanisms of cell death observed in this study result from lymphocyte hyperactivation occurring in vivo in these patients and may contribute to functional T cell defects of OS.

Apoptosis↗
PubMed1997

Clinical spectrum of X-linked hyper-IgM syndrome.

We report the clinical and immunologic features and outcome in 56 patients with X-linked hyper-IgM syndrome, a disorder caused by mutations in the CD40 ligand gene. Upper and lower respiratory tract infections (the latter frequently caused by Pneumocystis carinii), chronic diarrhea, and liver involvement (both often associated with Cryptosporidium infection) were common. Many patients had chronic neutropenia associated with oral and rectal ulcers. The marked prevalence of infections caused by intracellular pathogens suggests some degree of impairment of cell-mediated immunity. Although lymphocyte counts and in vitro proliferation to mitogens were normal, a defective in vitro proliferative response to antigens was observed in some patients, and additional defects of cell-mediated immunity may be presumed on the basis of current knowledge of CD40-ligand function. All patients received regular infusions of immunoglobulins. Four patients underwent liver transplantation because of sclerosing cholangitis, which relapsed in there. Three patients underwent bone marrow transplantation. Thirteen patients (23%) died of infection and/or liver disease. X-linked hyper-IgM syndrome, once considered a clinical variant of hypogammaglobulinemia, is a severe immunodeficiency with significant cellular involvement and a high mortality rate.

Bone Marrow Transplantation↗
PubMed1997

A PCR-based non-radioactive X-chromosome inactivation assay for genetic counseling in X-linked primary immunodeficiencies.

The Wiskott-Aldrich syndrome (WAS), X-linked severe combined immunodeficiency (SCIDX1), and X-linked agammaglobulinemia (XLA) are severe congenital immunodeficiencies with X-linked inheritance. Although rare, they are all associated with severe infections from early in life, and high morbidity and mortality. Female carriers of these diseases can be identified by a non-random pattern of X-chromosomal inactivation in cell lineages targeted by each gene defect. For patients with WAS, SCIDX1 or XLA, the demonstration of non random X-Chromosome inactivation in their mothers can be used to confirm clinical diagnosis. Furthermore, analysis of X-Chromosome inactivation in at risk females allows preconceptional carrier detection, thus representing an important aid in genetic counseling. For each disease we established a PCR-based, non radioactive assay at the human androgen receptor (HUMARA) locus, that allows analysis of X-Chromosome inactivation in the affected cell types and in tissue specific controls to exclude the issue of skewed X-chromosomal inactivation. In our study, 50 females with a known family history of XLA [19], WAS [18], and SCIDX1 [13],were examined. A carrier status was established in 19 females (7 XLA, 6 WAS, 6 SCIDX1) and excluded in 29 ( 11 XLA, 11 WAS, 7 SCIDX1). Only in 2 cases (4%) the assay was not informative.

Cell Lineage↗