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Biomedical subjects

L Belec

Publications and source records attributed to L Belec.

At least 37 records · Page 2Linked to original sources
PubMed1998

The specificity patterns of human immunoglobulin G antibodies in serum differ from those in autologous secretions.

The specificity patterns of immunoglobulin G (IgG) antibodies to streptococcal antigens in serum and autologous secretions were compared in order to determine whether IgG found in human secretions is exclusively of serum origin or can also be locally produced irrespective of the systemic immune system. Surface antigens from a type 6 M-protein strain of Streptococcus pyogenes were extracted by cell wall digestion and subjected to sodium lauryl sulfate-polyacrylamide gel electrophoresis under reducing conditions. After being blotted onto nitrocellulose, the antigens were incubated with purified IgG from various body fluids: saliva, cervicovaginal secretions, seminal fluid, and colostrum. Binding was then revealed with labeled antibodies to human Fcgamma fragments. The antibody specificity patterns obtained by computer-assisted analysis were compared with those of paired sera. Major variations were observed between serum and secretions, as well as between different secretions from the same subject. These results are in favor of IgG-associated local immunity within different tissue compartments. This IgG response to mucosal antigens can complement that of secretory IgA in the defense against pathogens and should be taken into account during topical vaccinations.

Antibodies, Bacterial↗
PubMed1997

Peripheral neuropathy in human immunodeficiency virus-infected patients with the diffuse infiltrative lymphocytosis syndrome.

A subset of human immunodeficiency virus (HIV)-infected patients develop persistent CD8 hyperlymphocytosis and a Sjogren's syndrome-like syndrome associated with multivisceral CD8 T-cell infiltration, known as the diffuse infiltrative lymphocytosis syndrome (DILS). Patients with DILS tend to have higher CD4 cell counts, fewer opportunistic infections, and longer survival times than other HIV-infected patients. Peripheral nerve involvement in DILS has been poorly documented. We studied 12 HIV-infected patients with CD8 hyperlymphocytosis, DILS, and clinical signs of peripheral neuropathy. Two of 4 patients who were HLA typed were HLA-DR5 and 1 was HLA-DR6. All patients had the sicca syndrome and multivisceral involvement. The neuropathy was acute or subacute, always painful, and symmetrical in 8 cases. Electrophysiology was consistent with axonal neuropathy in 10 of 12 patients. Nerve biopsy showed marked angiocentric CD8 infiltrates without mural necrosis (12 of 12), and abundant expression of HIV p24 protein in macrophages (12 of 12). The HIV genome was detected by polymerase chain reaction in nerve homogenates. Zidovudine therapy was associated with improvement in 6 of 6 patients and steroid therapy was beneficial in 4 of 5 patients. No T-cell lymphoma was observed during follow-up, but 2 patients developed a primary B-cell lymphoma. We conclude that DILS neuropathy represents HIV-associated neuropathy, characterized by marked CD8 infiltration and abundant HIV in nerve, that improves with zidovudine or steroid therapy, and probably reflects a systemic host-determined and antigen-driven response to HIV.

Acquired Immunodeficiency Syndrome↗
PubMed1997

[Overproduction of tumor necrosis factor-alpha in African patients with HIV-1 infection, cachexia and low tri-iodothyronine syndrome].

Sick euthyroid syndrome characterized by low triiodothyronine (T3) levels is observed in advance stages of HIV infection. The purpose of this prospective study was to determine if proinflammatory cytokines play and role in the pathogenesis of this syndrome in HIV-1-infected patients. Serum levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1 beta were measured in 40 African patients presenting HIV-1 infection associated with low T3 levels in 20 cases (group I) and normal or elevated T3 levels in 20 cases (group II). Elevation of serum TNF-alpha levels was more common and mean serum TNF-alpha level was significantly higher in group I than group II (116 +/- 39 versus 3.05 +/- 0.04 pg/ml; p < 0.01). Serum IL-1 beta levels were not significantly different between the two groups. These findings are consistent with previous experimental data and suggest that sick euthyroid syndrome in cachectic HIV-1 infected patients may be due to overproduction of TNF-alpha.

AIDS-Related Opportunistic Infections↗
PubMed1996

Human T-lymphotropic virus type I excretion and specific antibody response in paired saliva and cervicovaginal secretions.

Paired sera, salivas, and cervicovaginal secretions from 17 HTLV-I-infected women (10-75 years) were evaluated for total IgA, IgG, IgM, for IgA and IgG to whole HTLV-I lysate, for albumin, and for tax-rex proviral HTLV-DNA. IgG to HTLV-I were constantly detected, with much higher titers in serum (mean titer: 97,800) than in saliva (53) or in cervicovaginal secretions (216). IgA to HTLV-I were detected in only 12 (70%) sera, 6 (35%) salivas, and 8 (53%) cervicovaginal secretions, with higher titers in serum (75) than in saliva (8). Using the relative coefficient of excretion by reference to albumin, as well as the comparison of specific activities, the HTLV-I-specific IgG appeared primarily originating from serum, whereas IgA to HTLV-I were primarily locally produced. Salivary synthesis of IgG to HTLV-I occurred in both patients with a sicca syndrome attesting salivary glands impairment. Local excretions of total IgA, IgG, and IgM evaluated in body fluids were normal. HTLV DNA was detected in 4 (24%) salivas and in 3 (20%) cervicovaginal secretions, always in patients demonstrating local synthesis of HTLV-I-specific IgA or IgG. HTLV-I excretion elicits a weak local immune response to HTLV-I in saliva as well as in cervicovaginal secretions, which could be relevant for HTLV-I transmission via body fluids.

Adolescent↗
PubMed1996

All-trans-retinoic acid in POEMS syndrome. Therapeutic effect associated with decreased circulating levels of proinflammatory cytokines.

Chronically elevated serum levels of proinflammatory cytokines is a feature of the syndrome known as POEMS (plasma cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy, monoclonal [M] protein, skin changes). A patient had a POEMS syndrome with thrombocytosis and biclonal gammopathy and was treated as follows: all-trans-retinoic acid (tretinoin) at 90 mg/day for 50 days, no treatment for 70 days, readministration of tretinoin at 75 mg/day for 180 days. Focal bone lesion irradiation was performed from day 26 to day 50. Serum levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF alpha), and IL-1 beta normalized within 7 days after the first administration of tretinoin, transiently increased at the time of radiotherapy, increased again after withdrawal of the tretinoin, and decreased again after its reintroduction. The platelet count and gammopathy paralleled the changes in the cytokine levels. This study documents in vivo the ability of all-trans-retinoic acid to down-regulate the release of IL-6, IL-1 beta, and TNF alpha, and illustrates its potential as a therapeutic agent in conditions associated with chronic overproduction of proinflammatory cytokines.

Cytokines↗
PubMed1996

Acute community-acquired bacterial pneumonia in Human Immunodeficiency Virus (HIV) infected and non-HIV-infected adult patients in Cameroon: aetiology and outcome.

SETTING: Yaounde Central Hospital, Jamot Hospital, Yaounde, and CEBEC Hospital in Douala. OBJECTIVE: To determine and compare the bacterial aetiology and outcome of acute community-acquired pneumonia in adult patients with and those without the Human Immunodeficiency Virus (HIV) infection. DESIGN: We studied 110 consecutive adult patients admitted for pneumonia into three hospitals in Cameroon, from November 1991 to December 1992. Blood cultures, sputum microscopy and cultures as well as pneumococcal antigen detection in sera and sputum were performed. Serological analysis for HIV, Mycoplasma pneumoniae, Coxiella burnetti and Chlamydia pneumoniae was also done. RESULTS: Twenty-eight (25.5%) of the 110 patients were HIV positive. Streptococcus pneumoniae was the most common single bacterial aetiology in the two groups. Bacteremia was observed in 12 (15.0%) of 80 patients on whom blood cultures were done and was significantly more common in HIV seropositive than seronegative patients. Mortality was the same in the two groups. CONCLUSION: There were no differences in aetiology and outcome between HIV seropositive and seronegative patients. However, bacteremia occurred more significantly in the HIV seropositive group.

AIDS-Related Opportunistic Infections↗
PubMed1996

[Pro-inflammatory cytokines: a pathogenic key of POEMS syndrome].

The Polyneuropathy, Organomegaly, Endocrinopathy, M protein, Skin changes (POMEMS) syndrome is a rare multisystem disorder of obscure pathogenesis, associated with osteosclerotic myeloma. Unlike multiple myeloma without neuropathy, circulating levels of proinflammatory cytokines (IL-1 beta, TNF-alpha IL-6) are increased in patients with POEMS syndrome. Sites of IL-1 beta production include lymph node and bone marrow tissues. These data support the view that pleiotropic effects of proinflammatory cytokines released secondary to a strong activation of the monocyte/macrophage system, take part in the multisystemic expression of the disease.

Cytokines↗
PubMed1995

Decreased cervicovaginal production of both IgA1 and IgA2 subclasses in women with AIDS.

Paired sera and cervicovaginal secretions from 35 HIV-1-infected women representing different CDC stages of HIV infection were evaluated for total IgA, IgA1 and IgA2, for IgA, IgA1 and IgA2 to gp160, and for albumin. Age-matched healthy women (n = 45) served as controls. The secretion rates of total IgA, IgA1 and IgA2 were evaluated by calculating their relative coefficients of excretion by reference to albumin. In HIV-infected women, total IgA1 and IgA2 in sera and in cervicovaginal secretions increased proportionately as early as stages II + III and more markedly at stage IV. By contrast, the secretion rates of total IgA IgA1 and IgA2 were markedly reduced in AIDS women, the IgA2 secretion rate decreasing significantly as early as stages II + III. This apparent discrepancy was probably the result of increased transudation of serum-borne immunoglobulins into the vaginal cavity, since albumin levels in cervicovaginal secretions increased significantly according to the stages of disease. HIV-reactive IgA antibodies in serum, as in cervicovaginal secretions, were principally found within the IgA1 subclass. In women at stage IV, a high local production of IgA1 to gp160 occurred in spite of the impairment of cervicovaginal IgA synthesis, probably because of marked genital HIV replication at advanced stages.

Acquired Immunodeficiency Syndrome↗
PubMed1995

[Seroprevalence of rickettsial infections of the Boutonneuse fever group or its apparent group in Bangui (Central African Republic)].

115 sera from African individuals, including 66 HIV-1-infected individuals and 49 HIV-seronegative age-matched healthy controls, living in Bangui, Central African Republic, were screened for Rickettsia conorii antibody by indirect immunofluorescent assay; 53 (46%) sera had significant IgG to R. conorii titer, and 5 (4.3%) had significant IgM to R. conorii titer, without significant difference between HIV-positive and negative individuals. These findings indicate a great exposure to spotted fever group rickettsial infections in Bangui.

Adult↗
PubMed1994

[Free dissociated and precipitated p24 antigenemia of HIV-1 in subjects of the black race].

P24/HIV-1 antigen in the sera from 41 HIV-1-infected Black individuals, living in the Central African Republic (n = 17) and in France (n = 24), and in 21 HIV-1-infected Caucasians patients, matched on the stages of the disease, has been detected and quantified by ELISA, without and with acid pretreatment of the sera by HC1 or by glycine, and after ultracentrifugation of serum. Free p24 antigenemia was detected less frequently in Black patients (9.7%), than in Caucasian controls (33%) (p < 0.05). Decomplexed p24 antigenemia was detected in 34% of patients after dissociation of circulating immune complexes (CIC) by HC1 (p < 0.01) and in 44% of patients after dissociation of CIC by glycine (p < 0.001). However, the mean concentration of decomplexed p24 antigenemia of positive sera was higher after pretreatment by HC1 (88 pg/ml) than by glycine (52 pg/ml), suggesting that a strong acid is more convenient than a weak one to disrupt the CIC in Black individuals. After ultracentrifugation of the serum, the detection of p24 antigen was not significantly increased. Acid dissociation of CIC is a usefull method to increase the sensitivity of detection of circulating p24 antigen in HIV-1-infected Black individuals.

AIDS Serodiagnosis↗
PubMed1993

The spectrum of vasculitis in human immunodeficiency virus-infected patients. A clinicopathologic evaluation.

OBJECTIVE: To delineate the different types of inflammatory vascular diseases (IVD) occurring in patients with human immunodeficiency virus (HIV) infection. METHODS: Muscle, nerve, or skin biopsy specimens from 148 symptomatic HIV-infected individuals were reviewed, and subgroups of vasculitis were identified using the American College of Rheumatology (ACR) 1990 clinicopathologic criteria for the classification of vasculitis. RESULTS: IVD was documented in 34 patients (23%) and included necrotizing arteritis (3 patients), non-necrotizing arteritis (1 patient), neutrophilic IVD (7 patients), mononuclear IVD (17 patients), and other small vessel inflammatory changes (6 patients). According to the ACR criteria, 11 patients could be classified as having a distinct category of vasculitis, including polyarteritis nodosa (4 patients), Henoch-Schönlein purpura (1 patient), and drug-induced hypersensitivity vasculitis (6 patients), and 23 were classified in the group "other vasculitis, type unspecified." One patient had hepatitis B virus surface antigenemia, 2 had cryoglobulinemia, and 2 were coinfected by human T lymphotropic virus type I. Cytomegalovirus inclusions and antigens were found in endothelial cells in 1 patient. HIV antigens and genome were detected in perivascular cells of 2 of the 3 patients with necrotizing arteritis; in 1, HIV-like particles were seen by electron microscopy. Immune deposits were found in small vessel walls in 5 skin biopsy samples showing small vessel vasculitis and in the muscle of the 3 patients with necrotizing arteritis. CONCLUSION: A wide range of inflammatory vascular diseases may occur in HIV-infected individuals. Vascular inflammation appears multifactorial and may result from HIV-induced immunologic abnormalities and exposure to a variety of xenoantigens, such as HIV itself, other infectious agents, and drugs.

Adult↗
PubMed1993

Leishmaniasis: report of 33 cases and a review of the literature.

Leishmaniasis are parasitic diseases in extension. They appear in new foci, because of important displacements of populations, and they affect immunocompromised patients (under chemotherapy, transplanted, or HIV infected). Study of 33 cases of leishmaniasis, 22 visceral and 11 cutaneous, at the Hôpital du Kremlin-Bicêtre, France, showed predominant contamination in Maghreb and in the south of France. In the case of Kala-Azar, fever (18 cases) and hepatosplenomegaly (19 cases) are frequent, and the serodiagnosis and the search of parasites by myelogram are always positive. In HIV-infected individuals, clinical signs are similar, but the serodiagnosis is less reliable. Evolution is bad in transplanted patients who must remain under immunosuppressive drugs. In the case of cutaneous leishmaniasis, diagnosis is based on local sample, while the serodiagnosis remains negative. Treatment is sometimes long, necessitating repeated treatments.

Allopurinol↗
PubMed1993

Adult response to initial treatment with ampicillin in community acquired pneumonia in Yaoundé, Cameroon.

A prospective study was conducted to evaluate the efficacy of ampicillin as an initial therapy in 60 adult patients with community acquired pneumonia. Bacteriological etiology was obtained only in 24 (40pc) patients by microscopic examination, culture and antigen detection. Streptococcus pneumoniae was the leading causative agent identified in 15 cases. Other etiologies were Klebsiella pneumoniae (3), Streptococcus pyogenes (2) Staphylococcus aureus (2), Haemophilus influenzae (1) and Moraxella catarrhails (1). Patients were started on ampicillin one gram twice daily, empirically, and treated for 10 days. There were 52(86.7pc) patients cured, two(3.3pc) patients improved and six (10pc) were therapeutic failures. The causative agents in patients with failures were: Klebsiella pneumoniae (1), Staphylococcus aureus (1), Streptococcus pneumoniae (1) and unknown in three cases. Only six of 60 patients still febrile after three days were switched to amoxycillin/clavulanic acid or cefaclor according to culture results and susceptibilities or to roxythromycin because no organisms were isolated. Side effects were observed in only one (1.7pc) patient who developed a mild skin rash. Due to its low cost and its high efficacy, ampicillin still appears to be the drug of choice in adult community acquired pneumonia in our region.

Adolescent↗
PubMed1993

[Alternative strategy for the diagnosis of HIV infection in sub-saharan Africa. Value of the sequential combination of the ELISA test and a 2nd generation rapid test].

The "conventional" algorithm for HIV testing based on the confirmation of all positive anti-HIV screening reactions by Western blot requires sufficient laboratory facilities and is expensive, that limits its use in developing countries, such as in subsaharian Africa. The apparition of second and third generation screening ELISA which are very sensitive and specific, as well as the development of rapid tests which are simple, visually read, and sufficiently sensitive and specific, has permitted the design of "alternative" strategy for HIV testing utilizing the association of 2 ELISA and/or rapid tests, in order to limit the use of a confirmatory assay. Alternative strategies are less expensive, yield generally very high sensitivity and specificity, and have proved to be valuable for African countries. In this study, 5 alternative strategies, using different associations of two second generation screening tests, one classical ELISA (Genelavia mixt) and one rapid test (Test PACK HIV-1/HIV-2 AB) have been retrospectively evaluated in the field in Bangui, Central African Republic, with a panel of 130 sera (prevalence of HIV infection: 42.7%). The strategy using two sequential screening tests (Test Pack HIV-1/HIV-2 AB following by Genelavia mixt) with the confirmation of discordant results by Western blot permitted to diagnose HIV-1 infection in Bangui with a sensitivity, a specificity and a positive predictive value of 100%, and to reduce the cost of more than 50% in comparison with the conventional strategy. Such an alternative strategy could be useful for the individual notification of HIV serology in Bangui.

Adult↗
PubMed1992

Varicella-zoster virus encephalitis in acquired immunodeficiency syndrome: report of four cases.

Four patients with acquired immunodeficiency syndrome, a 27-year-old female intravenous drug abuser and three males (two drug addicts aged 27 and 33 years and a 40-year-old homosexual) presented with a rapidly progressive encephalopathy. Two had generalized varicella-zoster virus skin infection, one had had a regressive thoracic zoster rash 7 months previously and one had no history of cutaneous eruption. Neuropathological examination revealed, in each case, multifocal necrotic changes with numerous, intranuclear Cowdry type A inclusion bodies in glial cells, endothelial cells, macrophages and neurons, within and around the lesions. These inclusion bodies were stained positively for varicella-zoster virus by immunocytochemistry and contained herpes virus nucleocapsids by electron microscopy. Molecular biology using the polymerase-chain-reaction method demonstrated viral genome. In one case, zoster-induced non-inflammatory vasculopathy involved medium sized leptomeningeal vessels and was associated with circumscribed areas of cortico-subcortical infarction. In another case, varicella-zoster virus encephalitis was associated with human immunodeficiency virus encephalitis and a secondary cerebral lymphoma. Multinucleated giant cells expressing human immunodeficiency virus proteins in their cytoplasm, were found in the lymphomatous deposits and in the varicella-zoster virus necrotic lesions. In these latter lesions, Cowdry type A inclusion bodies could be seen in the nuclei of some multinucleated giant cells confirming previous observations of MGCs co-infected by HIV and CMV, and supporting the hypothesis that DNA viruses interact with HIV, thus increasing its effect.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Quantitative and qualitative anomalies of sperm in African individuals infected with HIV].

Semen from 16 HIV1-infected african individuals (12 at stage II/CDC; 4 with pre-AIDS) has been analyzed both quantitatively (volume; number of spermatozoa) and qualitatively (motility). 12 healthy HIV1-seronegative individuals were recruited as controls. The HIV1-infected patients showed generally abnormalities of the semen: oligospermia (7 cases), azoospermia (3 cases), or asthenospermia (10 cases). These abnormalities were more marked in patients at advanced stages of the HIV infection. In comparison with the control group, the HIV1-infected individuals had more frequently a past history of sexually transmitted diseases. These abnormalities in the composition of the semen in HIV1-infected african individuals could affect the fertility of these men; that could indirectly restrict the risk of congenitally HIV contaminated child.

Acquired Immunodeficiency Syndrome↗