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Biomedical subjects

F Ferchal

Publications and source records attributed to F Ferchal.

At least 37 records · Page 2Linked to original sources
PubMed1994

Human immunodeficiency virus (HIV) nef-specific cytotoxic T lymphocytes in noninfected heterosexual contact of HIV-infected patients.

We report on the detection of HIV-specific cytotoxic T lymphocytes (CTL) among 23 regular partners of HIV-infected individuals. 15 of the 46 individuals enrolled in the study were positive for HLA-A2.1 typing. Among the 23 contacts studied, 7 were seropositive and 16 were seronegative on repeated tests. None of the 16 seronegative contacts were positive for p24 antigenemia nor were they positive by the lymphocytes coculture assay, although, in two instances HIV-1 DNA could be detected by PCR (in one case using a gag SK 38/39 primer, and in the other using a primer for the pol P3/P4 primer). These two individuals remained seronegative for 18 and 36 mo, respectively. HIV-specific cytotoxicity was performed in the 15 HLA-A2.1 subjects (7 indexes, 2 seropositive contacts, and 6 seronegative contacts) and in 4 HLA-matched HIV negative donors. CTL specific for env, gag, or nef proteins could not be detected in unstimulated bulk cultures of peripheral blood lymphocytes in any of the six seronegative contacts. However, using a limiting dilution assay we found an usually high frequency of HIV nef-specific CTL precursors (CTLp) for HIV env and gag was very similar to that observed in seronegative HLA-matched healthy donors. Because no presence of HIV could be demonstrated in these individuals, these findings argue against the possibility of a silent HIV infection and suggest that a CTL response against nef may be involved in a rapid and effective clearance of the virus after sexual exposure.

Cytotoxicity, Immunologic↗
PubMed1994

Simultaneous progressive multifocal leukoencephalopathy, Epstein-Barr virus (EBV) latent infection and cerebral parenchymal infiltration during chronic lymphocytic leukemia.

We report a non-HIV patient who had B chronic lymphocytic leukemia (CLL) with progressive multifocal leukoencephalopathy (PML) and diffuse cerebral leukemic parenchymal infiltration in the presence of JC virus and Epstein-Barr virus (EBV) cerebral co-infection. Multiple subcortical hypodensities lining the cortico-subcortical junction were present within the white matter on computerized tomography (CT) scan, with large areas of high signal intensity on T2-weighted sequences on magnetic resonance imaging (MRI). JCV DNA was identified in peripheral blood nuclear cells and cerebrospinal fluid polymerase chain reaction (PCR) DNA/DNA hybridization plus Southern blot analysis. Frontal stereotactic biopsy confirmed the diagnosis of PML by immunocytochemistry, in situ hybridization (ISH) with JC Enzo probe and electron microscopy. Leukemic B cells with the same phenotype as leukemic blood cells were disseminated in the demyelinated areas. They were labeled by anti-latent membrane protein and by BamHl W EBV probe after ISH. Adhesion and activation molecules were positive for CD23. Autopsy showed diffuse visceral leukemic infiltration without acutization. EBV-transformed B lymphocytes would favour JCV penetration and/or intracerebral reactivation of previously latent JCV infection with further development of simultaneous PML and cerebral CLL infiltration in an immunosuppressed patient.

B-Lymphocytes↗
PubMed1993

Intestinal microsporidiosis in human immunodeficiency virus-infected patients with chronic unexplained diarrhea: prevalence and clinical and biologic features.

Eighteen patients infected with human immunodeficiency virus and with chronic unexplained diarrhea were prospectively studied to investigate the prevalence and clinical and biologic features of intestinal microsporidiosis. All patients underwent extensive evaluation for bacterial, viral, and parasitic pathogens. Enterocytozoon bieneusi was found in 9 patients (50%; 95% confidence interval, 27-73) in stools and duodenal and jejunal biopsies. In 8 patients, it was the sole pathogen found. Other pathogens were also isolated from the intestinal tracts of 4 patients, but diarrhea remained unexplained in 6. Patients with intestinal microsporidiosis had significantly lower mean Karnofsky scores (69.4 vs. 85.5, P = .009), CD4 cell counts (18.6 vs. 209.8/microL, P = .02), and D-xylose absorption tests (0.13 vs. 0.36 g/L, P < .001) than did patients without intestinal microsporidiosis. Intestinal microsporidiosis appears to be a frequent cause of unexplained chronic diarrhea in patients with AIDS and is associated with diminished D-xylose absorption.

AIDS-Related Opportunistic Infections↗
PubMed1993

Interaction between human immunodeficiency virus and Toxoplasma gondii replication in dually infected monocytoid cells.

THP-1 monocytoid cells, either not infected or chronically infected with human immunodeficiency virus type 1 (HIV-1), were challenged with Toxoplasma gondii. Parasitic growth, as assessed by trophozoite counting and measurement of supernatant p30 membrane antigen, was similar in HIV-infected and noninfected THP-1 cells. Also, T. gondii did not affect HIV replication. These experiments therefore failed to demonstrate any interaction between HIV-1 and T. gondii replication in concurrently infected monocytoid cells.

Animals↗
PubMed1993

[Quantitative viremia and p24 antigenemia in short-term follow-up of the treatment with zidovudine in twenty HIV infected patients].

The authors emphasize the interest of detecting HIV p24 antigen after immune complexes dissociation as well as changes in cellular viremia titers in the therapeutic follow-up of HIV infected patients. A significant decline of cell virus titers was found in 4-8 weeks among 13 of 20 zidovudine treated patients. A significant decrease of immune complexes dissociated p24 antigenemia was noted in 11 out of 17 patients.

Acquired Immunodeficiency Syndrome↗
PubMed1992

HIV-1 sensitivity to zidovudine: a consensus culture technique validated by genotypic analysis of the reverse transcriptase.

In order to select and standardize a reliable assay for the analysis of sensitivity of HIV isolates to AZT, we have compared two culture methods. The first assay (Cell-Associated Isolate Sensitivity Assay: CAISA) quantified AZT-resistant HIV isolates by end-point dilution cultures of peripheral blood mononuclear cells (PBMCs) in the presence of various concentrations of AZT. In the second assay (Cell-Free Isolate Sensitivity Assay: CFISA), following a conventional isolation of HIV, dilutions of infected cell-free supernatants were cultivated with fresh normal donor PBMCs in the presence of increasing concentrations of AZT. Samples from 64 untreated and AZT-treated patients were studied by CAISA (41), CFISA (43) or both assays (20). The CFISA, which allows the determination of titration parameters with respect to various kinetics patterns of viral replication was selected, and some of the CFISA phenotypically characterized isolates were further studied by nucleotide sequence analysis of the reverse transcriptase gene. CFISA showed that isolates from untreated patients were susceptible to AZT while the frequency of resistance increased with the duration of therapy. Genotypic analysis of CFISA-resistant isolates exhibited mutations at crucial positions, particularly at residue 215. We consider CFISA as a consensus culture technique for longitudinal studies of isolates from patients receiving AZT or other analogs of nucleosides.

Cell-Free System↗
PubMed1992

Comparative assessment of quantitative HIV viraemia assays.

OBJECTIVE: To compare two published methods for determining plasma viraemia in HIV-seropositive patients, with reference to a cellular viraemia assay. PATIENTS, PARTICIPANTS: Three patient groups were defined according to CD4 cell count: group I, less than 200 x 10(6)/l (23 patients); group II, 200-500 x 10(6)/l (18 patients); and group III, greater than 500 x 10(6)/l (13 patients). METHODS: The two reported methodologies were applied to all fresh samples, simultaneously and on the same day. RESULTS: The two techniques did not differ significantly in the detection of plasma viraemia: 82.3% of group I patients and 55% of group II patients were positive, while all group III patients were negative. Cellular viraemia was positive for 96% of the overall population. CONCLUSIONS: These results, obtained in a network of seven French laboratories involved in clinical trials, confirm that both plasma viraemia and cellular viraemia are useful virological markers.

AIDS Serodiagnosis↗
PubMed1992

False-positive HIV antigens related to emergence of a 25-30 kD protein detected in organ recipients.

OBJECTIVE: The routine screening of organ donors for HIV-1 since 1985 has markedly reduced the risk of acquiring infection in organ recipients. However, commercial HIV-1 p24-antigen assays reveal false-positive reactivity in certain recipients. This observation will be discussed here. METHODS: Post-transplantation sera collected sequentially from different organ recipients were tested for HIV antigen: 79 samples were from 14 kidney recipients, 57 from seven bone-marrow allografts and 18 from two heart recipients. Neutralization assays to determine specificity were performed on reactive samples. Immunoblots prepared from sera containing high levels of antigens were tested by Western blot using polyclonal anti-HIV sera. RESULTS: Abbott HIV-1-EIA kits detected non-neutralizable antigens in early post-transplantation sera from 12 kidney, five bone-marrow and two heart recipients. Using in-house immunoblots prepared from positive non-neutralizing antigen sera, a 25-30 kD protein was detected and shown to be the cause of the false HIV antigen cross-reactivity. CONCLUSION: False-positive HIV antigens related to the emergence of a 25-30 kD protein in early post-transplantation sera are detectable in transplant recipients.

Adolescent↗
PubMed1991

Use of PCR amplification for diagnosis of HTLV-I infection after blood transfusion.

We studied the seroconversion to human T-cell leukemia virus type-1 (HTLV-I) in two immunocompromised patients after transfusions of cellular blood components. One patient produced IgM antibodies against the viral p19 protein 149 days post-transfusion (a serum on day 43 was negative). Both patients showed indeterminate Western-blots (IgG anti-p19 and anti-gp46 but no anti-p24). Using the polymerase chain reaction (PCR) with two primer pairs (SK43/44 and SK54/56), we demonstrated HTLV-I infection prior to seroconversion. This infection was confirmed by Southern blot.

Aged↗
PubMed1990

[Prevalence of HIV-1, HIV-2 and HTLV-1 infections. Experience in a Parisian center for sexually transmitted diseases].

Human immunodeficiency virus (HIV) infection is, to a great extent, a sexually transmitted disease (STD). Its diffusion among the heterosexual population is still limited. STD treatment centres are particularly well organized to watch this diffusion. At the STD centre of the Saint-Louis hospital, Paris, we conducted a 6-week prospective study concerning the systematic detection of HIV-1 infection in 240 consecutive female out-patients in 1988, and in 504 male out-patients in 1989. The results obtained were as follow: 5/240 women (2.1 percent) and 19/504 men (3.8 percent) were seropositive for HIV-1. Out of these 24 subjects, 15 did not know they were seropositive. Predictive factors for seropositivity were male homosexuality, addiction to heroin and, in women, drug addicts as sex partners. Altogether, 23 of the 24 seropositive subjects had the classical risk factors for HIV-1 infection. None of the 744 subjects in this study were HIV-2 seropositive, and only 1 out of 504 men was HTLV-1 seropositive. We conclude that the prevalence of HIV-1 infection was high in our centre, and this prompts us to suggest that the serological test should be proposed to all out-patients and that patient's education and preventive measures should be organized by STD centres, even though the infection is still limited to patients at a particularly high risk (drug addicts, homosexuals, country of origin).

Adult↗
PubMed1990

[Microbiological study of male genital ulcers. Apropos of 75 cases].

Between November 1986 and June 1987, the microbial aetiology of genital ulcers was assessed in 75 male patients attending the Sexually Transmitted Disease (STD) clinic in Hôpital Saint-Louis, Paris. Evidence of Haemophilus ducreyi was found in 18 patients (24%), Herpes simplex virus in 19 (25.3%). Syphilis was diagnosed on the basis of dark field microscopy and/or positive serology test in 19 patients (25.3%). Lymphogranuloma venereum was not diagnosed in any patient. Primary pathogens were not identified from the remaining 19 (25.3%) men. Neisseria gonorrhoea was isolated in five patients, from the ulcer in three cases, from the urethra in two. Asymptomatic urethral carriage of Chlamydia trachomatis was culture proven in seven cases. The presence of IgM antibodies to C. trachomatis at a titre greater than 40 found in 17 patients was a indication of a current chlamydial infection. Three patients (4%) were discovered to be HIV-1 positive.

Adolescent↗