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Biomedical subjects

I Theodorou

Publications and source records attributed to I Theodorou.

At least 19 recordsLinked to original sources
PubMed2006

Polymorphism in the proximal promoter region of the perforin gene and its impact on the course of HIV infection.

Cytotoxic T lymphocytes (CTLs) play an essential role in the control of viral replication during human immunodeficiency virus (HIV) infection. However, the efficacy of the CTL response varies between individuals. We tested the hypothesis that genetic polymorphisms in the lytic effector molecule perforin could influence the progression of HIV infection. The perforin gene was screened for single nucleotide polymorphisms (SNPs) by denaturing high-performance liquid chromatography (dHPLC). Correlations were sought between perforin genotype, perforin expression and lytic function of CD8+ T lymphocytes from HIV-positive patients. Association of perforin genotype with disease progression was investigated in 426 seroconverters enrolled in the French SEROCO cohort. AIDS-free survival curves were constructed using the Kaplan-Meier method and compared using the log-rank test. Three SNPs were found in the proximal promoter region of the perforin gene: 63G (allelic frequency 0.029), 112G (allelic frequency 0.071) and 1012T (allelic frequency 0.070). The presence of the 1012T genotype correlated with fewer perforin+ cells among circulating CD8+ CTL. However, CTL lines from HIV(-positive) individuals heterozygous for the perforin 1012T SNP displayed normal lysis of target cells, and within the SEROCO cohort, patients heterozygous for the 1012T SNP showed normal disease progression. However, 1012T/T homozygotes showed a tendency towards slower disease progression (P = 0.08). In conclusion, polymorphism in the perforin gene is limited, and although the 1012T genotype appears to influence perforin expression, it was not conclusively associated with disease progression in HIV infection.

Cytotoxicity, Immunologic↗
PubMed2000

Liver fibrosis in overweight patients.

BACKGROUND & AIMS: A common clinical issue is whether overweight patients with abnormal liver function test results should undergo liver biopsy. Although serious liver injury can occur, its prevalence and risk factors are not well known. METHODS: Ninety-three consecutive patients with abnormal liver function tests (but without overt liver disease), body mass index (BMI) > 25 kg/m(2), and no alcoholic, viral, autoimmune, drug-induced, or genetic liver disease were retrospectively studied. Clinical, biological, and histological variables were tested for association with septal fibrosis or cirrhosis. RESULTS: Septal fibrosis was present in 28 patients (30%) including cirrhosis in 10 (11%). Age >/= 50 years (odds ratio [OR], 14.1), BMI >/= 28 kg/m(2) (OR, 5.7), triglycerides >/= 1.7 mmol/L (OR, 5), and alanine aminotransferase (ALT) >/= 2N (OR, 4.6) were independently associated with septal fibrosis. Among histological features, septal fibrosis was strongly associated with necroinflammatory activity (OR, 44). A score combining age, BMI, triglycerides, and ALT had 100% negative predictive value for septal fibrosis when scoring 0 or 1 (100% sensitivity for a specificity of 47%). CONCLUSIONS: Septal fibrosis occurs frequently in overweight patients with abnormal liver function tests. A clinicobiological score combining BMI, age, ALT, and triglycerides could improve selection of patients for liver biopsy.

Adult↗
PubMed1999

Combined genotypes of CCR5, CCR2, SDF1, and HLA genes can predict the long-term nonprogressor status in human immunodeficiency virus-1-infected individuals.

Human immunodeficiency virus (HIV)-1-infected long-term nonprogressors (LT-NP) represent less than 5% of HIV-1-infected patients. In this work, we tried to understand whether combined genotypes of CCR5-triangle up32, CCR2-64I, SDF1-3'A and HLA alleles can predict the LT-NP status. Among the chemokine receptor genotypes, only the frequency of the CCR5-triangle up32 allele was significantly higher in LT-NP compared with the group of standard progressors. The predominant HLA alleles in LT-NP were HLA-A3, HLA-B14, HLA-B17, HLA-B27, HLA-DR6, and HLA-DR7. A combination of both HLA and chemokine receptor genotypes integrated in a multivariate logistic regression model showed that if a subject is heterozygous for CCR5-triangle up32 and homozygous for SDF1 wild type, his odds of being LT-NP are increased by 16-fold, by 47-fold when a HLA-B27 allele is present with HLA-DR6 absent, and by 47-fold also if at least three of the following alleles are present: HLA-A3, HLA-B14, HLA-B17, HLA-DR7. This model allowed a correct classification of 70% of LT-NPs and 81% of progressors, suggesting that the host's genetic background plays an important role in the evolution of HIV-1. The chemokine receptor and chemokine genes along with the HLA genotype can serve as predictors of HIV-1 outcome for classification of HIV-1-infected subjects as LT-NPs or progressors.

Adolescent↗
PubMed1999

CCR5 delta32 deletion and reduced risk of toxoplasmosis in persons infected with human immunodeficiency virus type 1. The SEROCO-HEMOCO-SEROGEST Study Groups.

This study attempted to determine whether the CCR5 Delta32 deletion affected progression to certain first AIDS-defining illnesses in human immunodeficiency virus type 1-infected patients enrolled in the French SEROCO/HEMOCO/SEROGEST cohorts. Toxoplasmosis onset as a first AIDS-defining illness was significantly delayed in 253 heterozygous patients, compared with 1404 wild type patients. The relative risk of toxoplasmosis associated with heterozygosity was 0. 39 (95% confidence interval, 0.16-0.96) after adjustment for age, CD4 cell count, and primary specific prophylaxis. A nonsignificant protective trend was observed with regard to the onset of mycobacterial, cytomegalovirus, and herpesvirus diseases, but these events were less frequent than toxoplasmosis. Progression to other conditions (e.g., wasting, non-Hodgkin's lymphoma, Kaposi's sarcoma) was similar in the 2 groups as was the frequency of toxoplasmosis as a subsequent AIDS-defining illness. As chemokines are involved in numerous infectious processes, the Delta32 deletion could delay progression to certain opportunistic infections such as toxoplasmosis.

AIDS-Related Opportunistic Infections↗
PubMed1999

Clinical and biological characteristics of human immunodeficiency virus-infected and uninfected intravascular drug users in Ho Chi Minh City, Vietnam.

To define the medical characteristics of intravascular drug users in Ho Chi Minh City, Vietnam, we examined 280 men, of whom 235 were infected with human immunodeficiency virus (HIV), being treated in a rehabilitation center. The patients used mainly opium, often in shooting galleries (50%). The prevalence of oral candidiasis (58%) and zoster infection (20%) was high in HIV-seropositive patients, whereas oral hairy leukoplasia and Kaposi's sarcoma were absent. The prevalence of acquired immunodeficiency syndrome was 24%. More than 80% of the patients had infections with hepatitis C virus, hepatitis B virus, cytomegalovirus, or human T cell lymphotropic virus type-1. The CD4+ cell counts correlated well with viral load. Only HIV-1 subtype E was detected in the 30 patients tested. A cohort study of HIV-infected subjects in this population seems feasible, and would permit introduction of anti-retroviral therapy The large number of HIV-seronegative subjects sharing the same at-risk practices as the HIV-infected subjects raises the possibility of natural protection in this population.

AIDS-Related Opportunistic Infections↗
PubMed1997

Expansion of CD4+CD7- T cells, a memory subset with preferential interleukin-4 production, after bone marrow transplantation.

BACKGROUND: Inadequate reconstitution of CD4+ lymphocyte and interleukin (IL)-2 production defect are observed after bone marrow or peripheral blood stem cell transplantation (SCT). METHODS: We studied immune reconstitution after SCT in 33 consecutive patients who received allogeneic SCT (17 patients) or autologous SCT (16 patients). The aims were to assess the regeneration of the CD4+ T-cell subset with regard to helper cell differentiation. CD4+ T-cell subset regeneration and expansion of the CD4+CD7- subset were studied by immunofluorescence analysis. CD4+CD7- cell cytokine secretion was analyzed after cell sorting and costimulation of the CD3 and CD28 pathways, in enzyme-linked immunosorbent assay and reverse transcription-polymerase chain reaction assays. RESULTS: We report a relative expansion of the CD4+CD7- subset within CD4+ T cells, detected as early as 1 month after bone marrow transplantation and decreasing after day 60. CD4+CD7- T cells preferentially expressed CD45RO and activation markers such as CD57, CD25, and HLA-DR. No relationship was observed between the CD4+CD7- expansion and transplant-related complications. We observed no significant IL-2 production in supernatants from sorted CD4+CD7- T cells, whereas IL-4 levels were comparable to those produced by cells from normal individuals. Autologous CD4+CD7+ cells showed little, if any, IL-4 production, and IL-2 production was lower than that by normal CD4+CD7+ T cells. Reverse transcription-polymerase chain reaction assays showed similar amounts of interferon-gamma transcripts in the two subsets; tumor necrosis factor-alpha, IL-4, and IL-10 transcripts were detected in CD4+CD7- T cells but not in their CD4+CD7+ counterparts. CONCLUSIONS: These data confirm the IL-2 production defect after bone marrow transplantation and suggest that the CD4+CD7- T-cell subset might be preferentially involved in the enhanced production of IL-4 and low production of IL-2. These data show that the early immune reconstitution in CD4+ T cells after SCT preferentially involves memory T cells with a Th0/Th2 differentiation that might participate in the T-helper cell defect.

Adult↗
PubMed1997

Early protective effect of CCR-5 delta 32 heterozygosity on HIV-1 disease progression: relationship with viral load. The SEROCO Study Group.

OBJECTIVE: To determine the influence of heterozygosity for the delta 32 mutant CCR-5 allele on HIV-1 disease progression. DESIGN: HIV-1 disease progression and serum viral load were analysed according to the C-C chemokine receptor (CCR)-5 genotype in 412 Caucasian patients (319 men and 93 women) with a known date of seroconversion, who were enrolled in the SEROCO cohort (median follow-up, 74 months). RESULTS: The frequency of heterozygosity for the mutant allele was 17% and did not differ according to sex or risk factor of HIV infection. Heterozygotes were significantly less likely than patients with two functional alleles to have symptomatic primary infection. Their serum viral load was lower during the 6- to 24-month plateau phase after seroconversion. This difference persisted afterwards, although the rate of decline in CD4+ cells was similar. Kaplan-Meier survival curves showed slower progression to clinical AIDS in heterozygotes during the first 7 years following infection (P < 0.02), the two curves tending to join thereafter (overall log-rank test, P = 0.17). However, the interaction term with time did not reach significance in a Cox model. The overall relative risk of progression was 0.67 (95% confidence interval, 0.38-1.18) and was not influenced by adjustment for age at seroconversion or symptomatic primary infection. After adjustment for early viral load the relative risk was 0.83. Pneumocystis carinii pneumonia and toxoplasmosis were less likely to be the first AIDS-defining illness in heterozygotes than in the other patients (0 versus 24.7% of AIDS cases, P = 0.04), despite similar management. CONCLUSION: Deletion of one CCR-5 gene allele appears to protect against HIV-1 disease progression, mainly during the early years of the infection. Heterozygosity for the deletion leads to persistently lower viral load, and also seems to protect against some opportunistic infections.

AIDS-Related Opportunistic Infections↗
PubMed1996

VJ rearrangements of the TCR gamma locus in peripheral T-cell lymphomas: analysis by polymerase chain reaction and denaturing gradient gel electrophoresis.

Using Southern blotting for the diagnosis of clonality in peripheral T-cell lymphomas (PTCLs), analysis of the T-cell receptor (TCR) gamma gene rearrangement was shown to be more informative than that of the TCR beta gene rearrangement. In order to amplify every VJ gamma rearrangement, a polymerase chain reaction (PCR) procedure using newly designed GC-clamp primers has been developed. All primers can be mixed in a single multiplex PCR. PCR products are analysed by denaturing gradient gel electrophoresis (DGGE), providing tumour-specific imprints inasmuch as the procedure characterizes N sequence polymorphism at the VJ junctions. In a series of 30 PTCL cases, the PCR procedure demonstrated 27 cases to be clonally rearranged and failed in three cases. PCR was more accurate than Southern blotting, showing 47 rearranged gamma alleles, four of which were undetectable on the Southern blot. When lymphomas were studied at different sites and at relapse, the DGGE pattern remained unchanged. In PTCL, the proposed PCR is helpful for the diagnosis and staging of the disease and should improve the follow-up monitoring. The undetectability of clonal rearrangements in a few cases is discussed in the light of concepts of lymphomagenesis and T-cell differentiation.

Base Sequence↗
PubMed1996

Allelic repertoire of the human MHC class I MICA gene.

The hallmark of the classical major histocompatibility complex (MHC) class I molecules is their astonishing level of polymorphism, a characteristic not shared by the nonclassical MHC class I genes. A distinct family of MHC class I genes has been recently identified within the human MHC class I region. The MICA (MHC class I chain-related A) gene in this family is a highly divergent member of the MHC class I family and has a unique pattern of tissue expression. We have sequenced exons encoding the extracellular alpha1, alpha2, and alpha3 domains of the MICA gene from twenty HLA homozygous typing cell lines and four unrelated individuals. We report the identification of eleven new alleles defined by a total of twenty-two amino acid substitutions. Thus, the total number of MICA alleles is sixteen. Interestingly, a tentative superimposition of MICA variable residues on the HLA-A2 structure reveals a unique pattern of distribution, concentrated primarily on the outer edge of the MICA putative antigen binding cleft, apparently bordering an invariant ligand binding site.

Alleles↗
PubMed1996

Inflammatory neuromuscular disorders associated with chronic lymphoid leukemia: evidence for clonal B cells within muscle and nerve.

It is frequently difficult to determine whether a neuromuscular disorder (NMD) related to a lymphoproliferative disease is neoplastic, paraneoplastic, or incidental. This may explain why neuromuscular complications of chronic lymphoid leukemia (CLL), a frequent disorder, have been rarely reported. We describe 7 patients with CLL and neuromuscular involvement in whom phenotypic and genotypic characterization of infiltrating lymphoid cells was carried out by immunocytochemistry and PCR-amplification of immunoglobulin heavy chain locus. One patient had massive neoplastic infiltration of muscle, and six presented with inflammatory-like NMDs (dermatomyositis: 2, polymyositis: 1, vasculitic mononeuropathy: 2; inflammatory demyelinating neuropathy: 1). Immunocytochemistry on nerve and muscle frozen sections showed a monotypic lymphoid cell population in 3 cases and failed in 4 cases. The PCR analysis of immunoglobulin heavy chain gene (FR3-FR4) rearrangement detected clonal B-cells in all biopsy specimens. There are arguments suggesting that incidental or paraneoplastic inflammatory NMDs may progress to neoplastic infiltration in CLL patients, as a result of the traffic of tumor B-cells from circulation to nerve and muscle tissues. This may question the traditional distinction between inflammatory and neoplastic NMDs in patients with lymphoid cell proliferations.

Aged↗
PubMed1995

Cutaneous T-cell infiltrates: analysis of T-cell receptor gamma gene rearrangement by polymerase chain reaction and denaturing gradient gel electrophoresis.

In cutaneous T-cell infiltrates, the demonstration of a clonal T-cell receptor (TCR) gene rearrangement has been considered helpful to distinguish Cutaneous T-cell lymphomas from reactive lymphoproliferation. Hence, a polymerase chain reaction (PCR) method using GC-clamp primers and denaturing gradient gel electrophoresis has been developed in our laboratory to analyze the TCR gamma locus configuration. Two hundred eleven cutaneous samples from 155 patients were analyzed. A detectable clonal TCR gamma rearrangement was significantly associated with cutaneous T-cell lymphomas as defined by morphologic and immunologic criteria. A clonal TCR gamma rearrangement was also detected frequently in lymphomatoid papulosis, never in reactive lymphocytic infiltrates and B-cell lymphomas, and rarely in parapsoriasis en plaque and cutaneous lymphoid hyperplasia. Forty five patients had both a cutaneous and a peripheral blood sample. Fifteen had a detectable clonal rearrangement in the two samples and 22 were negative. Six patients had a positive skin sample and a negative blood sample, whereas two patients had a positive blood sample and a negative skin sample. Four lymph node samples were analyzed and the PCR results were the same as in the skin. Finally, 21 patients had sequential samples of recurrent skin lesions. The PCR results were concordant in all and, when detectable, the clonal TCR gamma rearrangement remained unchanged in a given patient. Because of its simplicity and accuracy, the newly designed PCR procedure improves the monitoring of diagnosis, staging, and follow-up in cutaneous T-cell infiltrates.

Base Sequence↗