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Biomedical subjects

M C Mazeron

Publications and source records attributed to M C Mazeron.

At least 19 recordsLinked to original sources
PubMed2004

Detection of ganciclovir resistance after valacyclovir-prophylaxis in renal transplant recipients with active cytomegalovirus infection.

Whether valaciclovir (VCV) prophylaxis could be responsible for ganciclovir (GCV)-resistance of Human cytomegalovirus (HCMV) in transplantation has never been documented. A multicentric retrospective pilot study was undertaken to detect GCV-resistance through mutations within the UL97 gene in renal transplant recipients who experienced active HCMV infection and received valacyclovir prophylaxis. Twenty-three patients who experienced HCMV antigenaemia or DNAemia during or at the end of prophylaxis were included. UL97 genotyping was carried out on peripheral blood samples, using a nested in-house PCR, which amplified the full-length UL97 gene. One patient has a resistance-related mutation (M460I); the major risk factor for emergence of resistance in this patient was the presence of early and persistent antigenaemia. GCV-resistance during VCV-prophylaxis was rare after renal transplantation. However, special attention must be paid to patients developing early active HCMV infection under prophylaxis.

Acyclovir↗
PubMed2003

Risk of cytomegalovirus transmission by cryopreserved semen: a study of 635 semen samples from 231 donors.

BACKGROUND: The hypothetical responsibility of sperm donation in cytomegalovirus (CMV) transmission to recipients and precautions to prevent this transmission are widely discussed. The aim of this French CECOS Federation study was to evaluate both the reality and the importance of the CMV risk due to donor sperm and the relevance of measures used to screen it. METHODS: We conducted a prospective multicentric study. CMV was detected by rapid and conventional cultures and by PCR in the frozen sperm of donors who met the normal criteria required of semen donors, irrespective of their CMV serological status. RESULTS: 635 samples from 231 donors (39.4% IgG(+)) were obtained and tested by culture; 551 samples from 197 donors were also tested by PCR. From those samples, 0.78% were culture(+), 1.57% culture(+) and/or PCR(+); 3.3% of seropositive donors and 0.72% of initially seronegative donors were culture(+), but in the latter seroconversion occurred during the quarantine period; of the 197 PCR-tested donors, 3.5% (6.2/1.7) were PCR(+), 3.3% (5.3/1.45) culture(+) and/or PCR(+). PCR(+) samples can be culture(-) and vice versa. The most strongly positive sample corresponded to an initially seronegative donor. CONCLUSION: The best strategy to prevent potential CMV risk is to test donors for CMV IgG and IgM antibody at the outset and after a 6 month period of quarantine and to reject initially IgM seropositive donors or donors who seroconvert during the quarantine period.

Antibodies, Viral↗
PubMed2000

Plasma cytomegalovirus DNA, pp65 antigenaemia and a low CD4 cell count remain risk factors for cytomegalovirus disease in patients receiving highly active antiretroviral therapy.

OBJECTIVE: To study the natural history and the current risk factors for cytomegalovirus (CMV) disease in the context of highly active antiretroviral therapy (HAART). SETTING: Prospective multicentre cohort in 15 university hospitals in France. METHODS: A group of 198 patients with CD4 cell count < 100 x 10(6) cells/l (or < 200 x 10(6) cells/l under HAART for at least 2 months), no previous CMV disease and CMV-positive serology were followed every 4 months clinically and for virological testing including HIV RNA and CMV blood markers (culture, pp65 antigenaemia, plasma CMV DNA and CMV late mRNA by the polymerase chain reaction). RESULTS: At inclusion, median CD4 was 77 x 10(6) cells/l (0-308) and 85% of the patients received protease inhibitors. The percentage of patients receiving HAART reached 99% at 12 months. After a follow-up of 23.6 months, the incidence of CMV disease was 3.2/100 patient-years [95% confidence interval (CI) 1.3-5.0]. In univariate Cox models, all the CMV markers, a CD4 cell count remaining < 75 x 10(6) cells/l and an HIV viral load > 100,000 copies/ml were predictive for CMV disease. The hazard ratios for CMV disease were 11 for blood culture; 14 and 70 for pp65 antigenaemia of > or = 1 and > or = 100 nuclei/200,000 cells, respectively; 35 for plasma CMV DNA; 6 for CMV mRNA; 29 for CD4 < 75 x 10(6) cells/l; and 12 for HIV RNA > 100,000 copies/ml. In a stepwise multivariate analysis, only three covariates were independently associated with the occurrence of a disease: plasma CMV DNA, pp65 antigenaemia > or = 100 nuclei/200,000 cells and a CD4 count < 75 x 10(6) cells/l. CONCLUSION: CMV blood markers and CD4 count < 75 x 10(6) cells/l remain risk factors for CMV disease in patients receiving HAART. Analysis of plasma CMV DNA by the polymerase chain reaction is a reproducible and standardized tool that could be used as a decision marker for initiating CMV pre-emptive therapy.

AIDS-Related Opportunistic Infections↗
PubMed2000

Development of cytomegalovirus resistance to ganciclovir after oral maintenance treatment in a renal transplant recipient.

The emergence of a resistant strain is a theoretical threat after extensive use of antiviral drugs. We report the emergence of a ganciclovir-resistant cytomegalovirus (CMV) strain in a kidney transplant recipient during oral ganciclovir maintenance treatment. The patient was treated by oral ganciclovir for 2 months after successful treatment of CMV primary infection by intravenous ganciclovir. He developed a new episode of CMV infection with no clinical response to intravenous ganciclovir. The CMV isolate exhibited both phenotypic and genotypic resistance to ganciclovir. The CMV isolate was constituted of a mixture of strains, with and without a mutation at codon 460 of the UL97 gene. The clinical condition improved when mycophenolate mofetil (MMF) was discontinued, and a short course of intravenous globulin was added to ganciclovir. The emergence of the CMV strain could be secondary to more potent immunosuppression provide by MMF or subtherapeutic level obtained during oral ganciclovir treatment. We believe that ganciclovir resistance must be part of the differential diagnosis when a patient relapses or fails to respond to ganciclovir treatment.

Administration, Oral↗
PubMed2000

[Leukocyte depletion and infection by cytomegalovirus].

Cytomegalovirus (CMV) can be transmitted by fresh blood components containing leukocytes. Consequences of CMV infection are serious in immunocompromised patients and in neonates. Thus, prevention of transfusion-transmitted CMV is of paramount importance. The use of blood products from CMV seronegative donors has been shown effective in preventing transmission. However, it does not completely eliminate the risk of transmission. Moreover, as CMV seroprevalence reaches 50 to 100% depending on the geographical and socioeconomic conditions, the availability of CMV seronegative products is limited. Leukodepletion of cellular blood products can be achieved by various filtration techniques. A method capable of achieving a residual leukocyte count < 5 x 10(6) per unit allows for the reduction of CMV transmission to a level at least equivalent to the transfusion of seronegative blood components. Moreover, leukodepletion may reduce endogenous virus reactivation. Administration of filtered blood products from CMV seronegative donors is usually recommended for those patients at major risk of severe CMV transfusion-associated disease. The ability of the most efficient methods for blood filtration in preventing CMV transmission has to be assessed. Such methods would make it possible to avoid serological screening of blood donors.

Antibodies, Viral↗
PubMed1999

[Cytomegalovirus (CMV)].

Human cytomegalovirus (CMV) is an ubiquitous agent. CMV infection is a common, usually subclinical world wide infection with a tendency for virulence in congenitally-infected infants and immunosuppressed patients including allograft recipients and patients with AIDS. Anti-CMV drugs are used for the treatment of severe infections in immunosuppressed patients. Developments of vaccine to protect pregnant women from primary infection are in progress.

Adult↗
PubMed1998

Qualitative immunoglobulin abnormalities in HIV-positive patients: long-term follow-up.

We studied the immunoglobulins of a cohort of 212 HIV-positive patients followed-up for 13 years. The qualitative study of immunoglobulins by immunoelectrophoresis and immunofixation distinguished three groups of patients: those with monoclonal immunoglobulins, those with minor abnormalities of immunoglobulins and those with polyclonal immunoglobulins. We characterized these groups according to age, sex, immunoglobulin isotypes, and survival curves. The results show that this population of immunoglobulinopathies has distinctive characteristics. In particular, the presence of immunoglobulin abnormalities has no significant prognostic value.

Adult↗
PubMed1998

[Comparison of the in vitro sensitivity to cidofovir and ganciclovir of clinical cytomegalovirus isolates. Coordinated Action Group 11].

Cidofovir (CDF) or Vistid is a monophosphate nucleoside analogue that inhibits the DNA polymerase of herpes viruses including the cytomegalovirus (CMV). CDF is active on GCV-resistant strains with a mutation on the phosphotransferase gene (UL97). However, DNA polymerase gene mutations that induce resistance to GCV are responsible for cross-resistance to CDF. Resistance phenotypes to GCV and CDF were determined for 57 CMV strains isolated from blood and urine samples. Sixteen strains were recovered after CDF therapy. Of the remaining 41 CDF-naive strains, 34 were susceptible and seven resistant to GCV. Fifty percent inhibitory concentrations (IC50) for CDF were in the 0.2-2.6 microM range for CDF-naive strains susceptible to GCV. For GCV-resistant strains, IC50 values for CDF were < or = 3 microM for strains with a low level of resistance to GCV (GCV IC50 < 30 microM) and > or = 6 microM for three of the five strains with a high level of resistance to GCV (GCV IC50 > or = 30 microM).

Antiviral Agents↗
PubMed1997

Failure of ganciclovir treatment associated with selection of a ganciclovir-resistant cytomegalovirus strain in a lung transplant recipient.

We report the case of a lung transplant recipient with progressive cytomegalovirus (CMV) disease due to a resistant CMV strain emerging under ganciclovir (GCV) therapy. A discriminative polymerase chain reaction (PCR) assay, designed to detect the resistance-related V460 mutation within the viral enzyme UL97, revealed the presence of a mutated strain in a heterogeneous isolate 51 days after transplantation. The conventional antiviral susceptibility assay had failed to demonstrate resistance to GCV. Under prolonged GCV therapy, the mutated strain dominated the wild-type strain, as shown by the PCR assay. This domination led to laboratory resistance, associated with recurrent fever and progressively severe retinitis. As this discriminative PCR assay was shown to be effective in detecting mutated strains that constitute a minority in the virus load, it should allow better management of patients with CMV disease.

Adult↗
PubMed1996

[Value of anti-Epstein-Barr antibody detection in the diagnosis and management of undifferentiated carcinoma of the nasopharynx].

The Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC). Serological studies have shown that the clinical onset of NPC is preceded by the appearance of a high antibody titer of IgA to viral capsid antigens and early antigens. The titers increase with the total tumor burden and the antibodies decline with the response to therapy. In patients with confirmed clinical remission elevation of IgA serological titers is highly significant for prediction of relapse. This demonstrates the usefulness of EBV serology for the clinical management of NPC patients.

Antibodies, Viral↗
PubMed1996

[Resistance of cytomegalovirus to ganciclovir: rapid detection of the mutations 460 of the UL97 phosphotransferase].

The substitution of methionine by either isoleucine or valine at residue 460 in the UL97 phosphotransferase has been shown to be responsible for resistance to ganciclovir (GCV) in 30% of resistant cytomegalovirus (CMV) isolates [4]. These substitutions require one nucleotide change in the gene (G- > T 1 380 and A- > G 1378 respectively). The aim of this study was to develop a discriminative PCR assay for rapid detection of these DNA changes. A PCR assay was duplicated in parallel for each mutation; to detect G- > T 1380 each reaction mixture contained primer VSUL14 and either primer LNW to distinguish wild type residues or LNM to distinguish mutant residues, and for A- > G 1378 primers were VSUL8 and either MCMW to detect wild type sequences or MCMM to detect mutated residues. For optimal discrimination, primers MCMW and MCMM were designed with a mismatch at position 3'-1. The reference strains AD169, Davis and Towne, a laboratory GCV-resistant mutant RCL1.7, and 33 CMV isolates (10 resistant, 2 indetermined and 21 sensitive) were tested by PCR. AD169, Davis and Towne, and 30 isolates were amplified only with non modified primers, and the absence of 460 mutations was confirmed by sequencing. Two isolates P1 and P2, from a transplanted patient were amplified with both MCMM and MCMW: sequencing analysis shown the presence of a mixture of strain, one of them harbouring A- > G 1378 mutation. One resistant strain was amplified neither with MCMM nor with MCMW: a C- > T silent mutation at nt 1368 was present. As sequencing analysis confirmed PCR results, discriminative PCR enables isolates to be rapidly assessed for the presence or absence of 460 mutations. Moreover, it can distinguish Met to Val from Met to Ile mutations, and allows the analysis of mixtures of sensitive ad resistant strains.

AIDS-Related Opportunistic Infections↗
PubMed1995

Value of a new rapid non-radioactive sequencing method for analysis of the cytomegalovirus UL97 gene in ganciclovir-resistant strains.

Various DNA changes located within a restricted region of the UL97 open reading frame were shown to be associated with the resistance of cytomegalovirus strains to ganciclovir (GCV). In order to analyse this UL97 region in sensitive and GCV-resistant strains, a non-radioactive sequencing assay (Promega, Madison, WI, USA) which combines the dideoxy visualisation by silver-staining of the gel was used. Using this assay, polymerase chain reaction products from results were obtained within 1 day. Point mutations modifying the amino acid sequence of the putative UL97 catalytic site were detected in three isolates. These led to an alanine to valine substitution in residue 594 in one strain with reduced GCV sensitivity, and to a cysteine to glycine substitution in residue 592 in two GCV-resistant isolates. These mutations were different from the DNA changes previously mapped in GCV-resistant laboratory or field strains. No amino acid substitution in the UL97 catalytic site was found in GCV-sensitive isolates. Transfer marker experiments are in progress in order to test the significance of these DNA changes for GCV resistance. This rapid non-radioactive sequencing protocol could be a useful tool for analysing the UL97 region encoding the putative UL97 catalytic site of clinical isolates.

Amino Acid Sequence↗
PubMed1994

Prevalence of HIV infections among patients attending a Parisian anonymous testing center between 1988 and 1993.

The prevalence of HIV infection was assessed among 15,611 consecutive patients attending a Parisian anonymous testing center from April 1988 to June 1993. Sera (17,910) were tested for the presence of anti-HIV antibodies using two different enzyme-linked immunosorbent assays. Seropositivity was verified by Western blotting. The sera were also assayed for HIV antigenemia detection in 2,493 cases. Six hundred and seventy-seven patients were found to be anti-HIV antibody positive: among them 666 were infected by HIV-1 and only 11 by HIV-2. Antigenemia was detected in 108 samples (4.3%). In all cases but 5, antigenemia was associated with the presence of specific antibodies. Risk factors for HIV infection could be determined for 5,735 patients. The HIV prevalence rates were 5.2% in 1988-89, 4.9% in 1990, 3.4% in 1991, 2.8% in 1992 and 1.8% for the 6 first months of 1993 (p < 0.01). Only one patient was coinfected with HTLV-1. This study shows a trend of decreasing seropositivity rates among the patients attending the anonymous testing center since 1990. By contrast, the percentage of seropositive patients with antigenemia was stable between 1988 and 1993.

Acquired Immunodeficiency Syndrome↗