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Biomedical subjects

A Corell

Publications and source records attributed to A Corell.

At least 19 recordsLinked to original sources
PubMed2001

Cathepsin C gene: First compound heterozygous patient with Papillon-Lefèvre syndrome and a novel symptomless mutation.

Papillon-Lefèvre syndrome (PLS) has recently been shown to be caused by mutations in the cathepsin C gene resulting in periodontal disease and palmoplantar keratosis. Thirteen different homozygous mutations have been characterised in PLS patients of different ethnic origin. In the present paper, a PLS patient is described who carries two novel mutations (706G>T and 872G>A) in the paternal and maternal chromosomes, respectively. This is the first compound patient described so far. In addition, a novel symptomless mutation (458C>T) in the cathepsin C gene is described in three homozygous individuals. Thus, not all mutations should be considered as a cause of disease, whether case studies or general population screening is performed. Another already described mutation that provoked the Haim-Munk syndrome (HMS) in Indian Jews has also been found to give rise to PLS in a Spanish family from Madrid. On the other hand, PLS patients are ameliorated by retinoids, which indicates that retinoids may be used as therapeutic agents in this immune system deficiency.

Alleles↗
PubMed2001

A novel HLA-DRB1 sequence, DRB1*11272.

We describe the complete exon 2 sequence of a novel HLA-DRB1 allele, DRB1*11272. This allele differs from the DRB1*11271 allele by a synonymous mutation in codon 77 where an AAT is replaced with AAC, both encode for the amino acid asparagine. The same motif at codon 77 has also been found in DRB1*1107, DRB1*1333, DRB1*0422 and in most DRB1*03 alleles. A partial exon 2 sequence of this allele has previously been deposited in the EMBL Sequence Database under the accession number AF186407.

Alleles↗
PubMed2001

Novel mutations and defective protein kinase C activation of T-lymphocytes in ataxia telangiectasia.

Three ataxia telangiectasia (AT) patients have been characterized immunologically and molecularly. Patient 1 presents two nondescribed splicing mutations which affect exons 15 and 21 of the ATM gene. The maternal defect consists of a G > A transition in the first nucleotide of the intron 21 donor splicing site which results in a complete deletion of exon 21. The paternal mutation consists of an A > C transversion in the intron 14 acceptor splicing site which produces a partial skipping of exon 15. Two abnormal alternative transcripts were found, respectively, 17 and 41 nucleotides shorter. Patient 2 presents a homozygous genomic deletion of 28 nucleotides in the last exon of the gene. This deletion changes the normal reading frame after residue 3003 of the protein and introduces a premature stop codon at residue 3008 that could originate a truncated ATM protein. Patient 3, a compound heterozygote, presents a defect which consists of a G > A transition in the first nucleotide of intron 62 donor splicing site which results in a complete deletion of exon 62. The results obtained during a three year period in the proliferation assays show an impaired PMA (phorbol myristate acetate) activation in specific T lymphocyte activation pathways (CD69, CD26, CD28, CD3, PHA, PWM and Con A mediated) but not in others (CD2, ionomycin, and Ig surface receptor). The possible link among specific ATM mutations and abnormal immune responses is unknown.

Ataxia Telangiectasia↗
PubMed2001

A point mutation in a domain of gamma interferon receptor 1 provokes severe immunodeficiency.

Gamma interferon (IFN-gamma) and the cellular responses induced by it are essential for controlling mycobacterial infections. Most patients bearing an IFN-gamma receptor ligand-binding chain (IFN-gammaR1) deficiency present gross mutations that truncate the protein and prevent its expression, giving rise to severe mycobacterial infections and, frequently, a fatal outcome. In this report a new mutation that affects the IFN-gammaR1 ligand-binding domain in a Spanish patient with mycobacterial disseminated infection and multifocal osteomyelitis is characterized. The mutation generates an amino acid change that does not abrogate protein expression on the cellular surface but that severely impairs responses after the binding of IFN-gamma (CD64 and HLA class II induction and tumor necrosis factor alpha and interleukin-12 production). A patient's younger brother, who was also probably homozygous for the mutation, died from meningitis due to Mycobacterium bovis. These findings suggest that a point mutation may be fatal when it affects functionally important domains of the receptor and that the severity is not directly related to a lack of IFN-gamma receptor expression. Future research on these nontruncating mutations will make it possible to develop new therapeutical alternatives in this group of patients.

Base Sequence↗
PubMed2001

Role of Nijmegen breakage syndrome protein in specific T-lymphocyte activation pathways.

Nijmegen breakage syndrome (NBS) is a genetic disorder characterized by immunodeficiency, microcephaly, and "bird-like" facies. NBS shares some clinical features with ataxia telangiectasia (AT), including increased sensitivity to ionizing radiation, increased spontaneous and induced chromosome fragility, and strong predisposition to lymphoid cancers. The mutated gene that results in NBS codes for a novel double-stranded DNA break repair protein, named nibrin. In the present work, a Spanish NBS patient was extensively characterized at the immunological and the molecular DNA levels. He showed low CD3(+)-cell numbers and an abnormal low CD4(+) naive cell/CD4(+) memory cell ratio, previously described in AT patients and also described in the present report in the NBS patient. The proliferative response of peripheral blood lymphocytes in vitro to mitogens is deficient in NBS patients, but the possible link among NBS mutations and the abnormal immune response is still unknown.

B-Lymphocytes↗
PubMed2000

A new MICA allele with ten alanine residues in the exon 5 microsatellite.

The MICA and MICB genes code for protein products that have structural similarities to major histocompatibility complex (MHC) class I genes. These genes are upregulated by heat stress. They have been shown to interact with a common receptor (NKG2D/DAP10) on gammadelta T cells, CD8+ T cells and natural killer (NK) cells. The MICA gene has an expressed microsatellite, GCT, within the exon 5 which encodes for alanine. So far, four different repetitions of this short tandem have been reported. Also one non-synonymous, one synonymous substitution and a 1-bp insertion within this region have also been described. An association of Behcet's disease with the microsatellite A9 has been reported. Here we report a novel allele with 10 GCT repetitions (A10) which was detected by reference strand mediated conformation analysis and confirmed by DNA sequencing.

Alanine↗
PubMed2000

Reference strand mediated conformation analysis resolves HLA-DRB1 typing ambiguities when matching for unrelated bone marrow transplantation.

We show here the use of reference strand mediated conformation analysis (RSCA) to unambiguously resolve the HLA-DRB1 typing of two individuals which were selected as potential unrelated donors for bone marrow transplantation (BMT). In the first case, both sequence-specific primer (SSP) amplification and sequence-specific oligonucleotide probing (SSO), routinely used in different tissue typing laboratories gave, for the two unrelated donors, the same ambiguous typing of HLA-DRB1*04011+*0403 or DRB1*0407+*0413. In this case sequence-based typing (SBT) was not the method of choice to resolve the situation, due to the sequence ambiguities of these two given combinations. RSCA of both samples, using homozygous typing cells (HTCs) for DRB1*04011, *0403 and *0407 as internal controls, gave the unambiguous result that both donors were HLA-DRB1*04011+*0403. In the second case, a donor was typed as DRB1*1102+1103 by SSP, while SSO excluded the DRB1*1102 allele. The patient was unambiguously typed as DRB1*1101+1103 by both techniques. RSCA, using DNA from reference cell lines as internal controls, gave the unambiguous typing that the donor was DRB1*1103 homozygous.

Alleles↗
PubMed2000

A novel CD18 genomic deletion in a patient with severe leucocyte adhesion deficiency: a possible CD2/lymphocyte function-associated antigen-1 functional association in humans.

Leucocyte adhesion deficiency (LAD) is an autosomal-recessive genetic disease that is characterized clinically by severe bacterial infections and caused by mutations in the CD18 gene that codes for the beta2 integrin subunit. A patient with a severe LAD phenotype was studied and the molecular basis of the disease was identified as a single homozygous defect in a Herpes virus saimiri (HVS)-transformed T-cell line. The defect identified involves a deletion of 171 bp in the cDNA that encodes part of the proteic extracellular domain. This genetic abnormality was further studied at the genomic DNA level and found to consist of a deletion of 169 bp (from -37 of intron 4 to +132 of exon 5), which abolishes the normal splicing and results in the total skipping of exon 5. The 171-bp shortened 'in-frame' mRNA not only resulted in the absence of CD18 expression on the cell surface but also in its absence in the cytoplasm of HVS T-cell lines. Functionally, the LAD-derived HVS T-cell lines showed a severe, selective T-cell activation impairment in the CD2 (but not in the CD3) pathway. This defect was not reversible when exogenous interleukin-2 (IL-2) was added, suggesting that there is also a functional interaction of the lymphocyte function-associated antigen-1 (LFA-1) protein in the CD2 signal transduction pathway in human T cells, as has been previously reported in mice and in the human Papillon-Lefèvre syndrome. Thus, HVS transformation is not only a suitable model for T-cell immunodeficiency studies and characterization, but is also a good system for investigating the immune system in pathological conditions. It may also be used in the future in cellular models for in vitro gene-therapy trials.

Base Sequence↗
PubMed1999

Higher incidence of autoantibodies in X-linked chronic granulomatous disease carriers: random X-chromosome inactivation may be related to autoimmunity.

The presence of autoantibodies and autoimmune diseases was tested in all available members of five families with at least one member affected with X-linked chronic granulomatous disease. Patients and carriers relatives possess autoantibodies more frequently than non-carriers relatives (95% vs 10%, p < 1.0 x 10(-5), Fisher test). Further, a survey of the literature revealed that in X-linked immunodeficiencies with X-chromosome random inactivation, clear features of autoimmunity are observed, not found in those with non-random inactivation. It appears then as if random inactivation of the X-chromosome in these pathologies, may favor the expression of an autoimmune phenotype in patients and carriers.

Autoantibodies↗
PubMed1998

Immunodeficiency associated with anorexia nervosa is secondary and improves after refeeding.

Several studies have addressed the question of starvation effects on immune function by means of changes in lymphocyte subsets, cytokine induction or lymphocyte activation. Anorexia nervosa (AN) patients are severely malnourished and contradictory results have been obtained regarding the accompanying immunodeficiency, including its assignation as a part of the primary nervous disorder. In the present work, an extensive immunological function examination was carried out on 40 AN patients who were compared with a control group of 14 healthy girls. The AN patients were also classified according to their nutritional status (by the Body Mass Index: BMI), this being critical for a better understanding of these secondary immunodeficiency bases. Moreover, another immune system study was performed on five patients after refeeding. Lymphocyte subsets and function, cytokine induction and peripheral blood concentrations, and innate as well as humoral immunity were evaluated. Deregulation in the cytokine network, owing to the interaction of the central nervous (CNS) and immune systems, seems to be the initial immune alteration in AN immunodeficiency but it has not been disproved that the immunodeficiency is a direct consequence of the original psychiatric perturbation. Spontaneous high levels of circulating interleukin-1beta (IL-1beta) and tumour necrosis factor-alpha (TNF-alpha) have been observed; this is probably one of the causes of the anomalies found in the T-cell subpopulations (mainly the naive CD4+CD45RA+ reduction and the cytotoxic CD8+ increase) and T-cell activation status (mainly the down-regulation of the CD2 and CD69 activation pathways). This finally leads to an impairment, not only in T-cell function but also in T-cell to B-cell co-operation. The AN specificity of these results is confirmed by the fact that these immune alterations improve after refeeding and when nutritional status becomes less critical, which also suggests that AN immunodeficiency is indeed secondary to malnutrition.

Adolescent↗
PubMed1997

Retinol (vitamin A) is a cofactor in CD3-induced human T-lymphocyte activation.

Immunomodulatory effects of different retinoids have been demonstrated, both in vivo and in vitro, in different cellular lineages including human and murine thymocytes, human lung fibroblasts, Langerhans' cells, tumoral cells and natural killer (NK) cells; however, any attempt to demonstrate the effect of retinoids on human peripheral blood mononuclear cells (PBMC) resulted in negative results. In the present work, it is shown that retinol and retinoic acid induce a marked increase of proliferation on human PBMC from 32 unrelated healthy individuals, which had previously been stimulated with anti-CD3 antibodies 48 hr before. Serum-free medium, specific retinoid concentration (10(-7) M) and a particular timing of retinol addition to the cultures (48 hr after CD3 stimulation) was necessary clearly to detect this retinol-enhancing effect. The increased proliferative response is specifically mediated via the clonotipic T-cell receptor-CD3 complex and correlates with the up-regulation of certain adhesion/activation markers on the T-lymphocyte surface: CD18, CD45RO and CD25; also Th1-type of cytokines (interleukin-2 and interferon-gamma) are found concordantly increased after retinoid costimulation, both measured by a direct protein measurement and by a specific mRNA increase. In addition, it is shown that the in vitro retinol costimulation is only present in immunodeficient patients who have no defect on CD3 molecules and activation pathway. The fact that retinol costimulate lymphocytes only via CD3 (and not via CD2 or CD28) and the lack of response enhancement in immunodeficients with impaired CD3 activation pathway indicates that retinoids may be used as therapeutic agents in immune system deficiencies that do not affect the clonotypic T-cell receptor.

CD3 Complex↗
PubMed1997

Cell surface phenotype and ultramicroscopic analysis of purified human enterocytes: a possible antigen-presenting cell in the intestine.

Epithelial cells of the intestine seem to act as antigen-presenting cells to surrounding lymphoid tissue and may be crucial to maintain the pool of peripheral T lymphocytes. The scope of this study was to carry out an immunophenotypic and ultramicroscopic analysis of purified human enterocytes to elucidate their role as antigen-presenting cells, in the immune responses in the gut-associated lymphoid tissue. A method has been developed to obtain purified and viable human enterocyte populations, later labeled with relevant monoclonal antibodies directed to leukocyte antigens and subjected to cytofluorometric analysis. Phenotypic analysis revealed the presence of markers common to "classical" antigen-presenting cells (CD14, CD35, CD39, CD43, CD63 and CD64), reinforcing the idea that enterocytes may act as such. Moreover, several integrins (CD11b, CD11c, CD18, CD41a, CD61 and CD29) were also found. CD25 (IL-2 receptor alpha chain) and CD28, characteristic of T cells, were detected on the surface of these cells; this latter finding rises the possibility that enterocytes could be activated by IL-2 and/or via CD28 through binding to its ligands CD80 or CD86. Finally, the presence of CD21, CD32, CD35 and CD64 that may bind immune complexes via Fc or C3, suggests their participation in the metabolism of immune complexes. Furthermore, the finding of a Birbeck's-like granule in the cytoplasm of the cells, shows that enterocytes contain an ultramicroscopic feature previously thought to be characteristic of Langerhans' cells, an antigen-presenting cell. The phenotype detected on the surface of enterocytes, along with their ultramicroscopic characteristics, suggests that they may play an important role in the immune responses elicited in the gut, presenting antigens to surrounding lymphoid cells, and establishing cognate interactions with them.

Antigen-Presenting Cells↗
PubMed1996

Herpes virus saimiri transformation of T cells in CD3 gamma immunodeficiency: phenotypic and functional characterization.

The characterization of T cell immunodeficiencies could in part be supported by using stable cell lines in which biochemical and molecular studies of the defect could be carried out thereby omitting frequent bleeding of patients. First attempts to obtain such cell lines included HTLV-I transformation and exogenous IL-2 administration, but both models have important disadvantages. Recently, a virus isolated from the squirrel monkey, Herpes virus saimiri (HVS), has been reported to have the ability to transform T cells. A stable IL-2-dependent HVS-transformed T cell line from a CD3 gamma deficient patient has been obtained; and this cell line displays both the phenotypic and the functional characteristics of the patient's lymphocytes. Moreover, the line down-modulates TCR/CD3 surface expression upon CD3 engagement, as do the patient's lymphocytes, showing that CD3 gamma and its phosphorylation are not necessary for TCR/CD3 internalization. In addition, the abnormal staining pattern of different anti-TCR/CD3 monoclonal antibodies is preserved in the HVS-patient line. Since HVS is capable of transforming CD3 gamma- T cells, the CD3 gamma chain does not seem to be involved in the HVS receptor process. The fact that it is not possible to obtain a CD8+ HVS line from the CD3 gamma- patient supports the existence of a functional anomaly in his scanty CD8+ peripheral lymphocytes. Thus, HVS transformation is a suitable model for T cell immunodeficiency studies and characterization. It may also be used in the future in cellular models for in vitro gene therapy trials.

CD3 Complex↗
PubMed1996

Diploid expression of human leukocyte antigen class I and class II molecules on spermatozoa and their cyclic inverse correlation with inhibin concentration.

A diploid expression of class I and class II human leukocyte antigens (HLA) has been found in purified spermatozoa by using double fluorescence labeling cytofluorometry and relevant monoclonal antibodies; this expression has been confirmed for the first time by the analysis of specific HLA mRNA and metabolic 35S labeling followed by immunoprecipitation, which demonstrates an active ongoing translation of HLA proteins in germinal cells. Long-living mRNA coming from diploid germinal cells may be translated to HLA molecules in spermatozoa. This translation is controlled (or at least inversely correlated) by a testicular hormone (inhibin) in a cyclic fashion. Remarkably, serum levels of inhibin, synthesized by Leydig and Sertoli cells, follow a 12- to 13-day cycle, with a peak level at Day 6; this is probably controlled by FSH (not cyclic in males) and other testicular and/or unknown hormones. Peak levels of inhibin concur with the lower density and percentage of spermatozoa expressing both HLA class I and II molecules (close to 3% by cytofluorometry); lowest levels of inhibin coincide with the highest numbers (35-40%) of spermatozoa positive for both HLA molecules and a higher surface density. These observations could put to an end a disconcerting and long-lasting controversy on the expression/non-expression of HLA antigens on spermatozoa. The possibility that HLA-bearing spermatozoa are more capacitated for fertilization than those that do not bear HLA, and the implications of our results on male fertility control are also discussed.

Antibodies, Monoclonal↗
PubMed1996

Primate DRB6 gene expression and evolution: a study in Macaca mulatta and Cercopithecus aethiops.

DRB6 has been found to be transcribed in human and apes. Promoter region and exon 1 come from a 5' LTR from a mammary tumour retrovirus. However, the putative protein structure would be very different to other DR molecules and it is doubtful that it may function as an antigen presenting molecule. Primate DRB6 alleles previously published together with the two new macaque sequences reported here support the existence of a strong selective pressure working on exon 2 to generate stop codons at the end of the exon (between codons 74 and 94) during at least 23 million years. The topology of dendrograms constructed with different primate DRB6 alleles supports the "trans-species" evolution proposed for MHC class I, class II and possibly C4 genes. Finally, DRB6, which is one of the oldest DRB genes, has been lost in the HLA-DRB3 (or DR52) group of haplotypes (DR3, DR5, DR6 and DR8) and a small DRB6 sequence is present at the exon 2 first hypervariable region of DRB4 (or DR53) gene, which is present in DR4, DR7 and DR9 haplotypes.

Animals↗
PubMed1996

Frequencies of HLA-A24 and HLA-DR4-DQ8 are increased and that of HLA-B blank is decreased in chronic toxic oil syndrome.

The cause of toxic oil syndrome (TOS) has not yet been definitively determined, but some genetic susceptibility factors (certain HLA antigens and female sex) have been identified in 236 patients. Similarities with genetic factors for scleroderma and hydralazine-induced lupus (i.e. in TOS female sex and HLA-A24, Pcorrected = 0.00001 and DR4, Pcorrected = 0.04, respectively) may provide a clue to the responsible xenobiotic and its pathogenesis, and may also help in understanding the basis of the related eosinophilia-myalgia syndrome associated with tryptophan ingestion. In this paper it is also established that a human class I antigen (HLA-A24) and, independently, an HLA class II haplotype (DR4-DQ8, Pcorrected = 0.04) and arginine 52 in the alpha-DQ chains (Pcorrected = 0.03) are associated with TOS susceptibility, similarly to insulin-dependent diabetes. This further supports the classification of TOS as an autoimmune disease. Also, the increased frequency of a particular set of low-frequency HLA class I antigens in chronic TOS patients (i.e. B27, B37, B38 and B49) and the probable decrease in the frequency of HLA-B homozygotes in surviving patients (Pcorrected = 0.008) may provide an objective model to explain the maintenance of the HLA polymorphism: less frequent HLA alleles may be more advantageous in the event of unexpected human contact with unusual xenobiotics (not only microbes); however, other mechanisms working together to preserve and generate HLA polymorphism may coexist.

Fatty Acids, Monounsaturated↗