Evaluation of bloodsucking arthropod bite as possible risk co-factor in Human herpesvirus-8 transmission route.

Human herpesvirus-8 non-sexual transmission occurs primarily from mother-to-child. The viral load in saliva is higher than in other human fluids. Moreover, there is evidence that bloodsucking arthropod bites induce an inflammatory/immune response that facilitates viral replication. We aim to explore possible risk factors in mother-to-child HHV-8 transmission associated with traditional methods which involve the use of saliva to relieve the irritation and skin reaction caused by arthropod bites. We administered questionnaires to 2244 children from several African countries and Italy. Descriptive statistics and logistic regression were used in the analysis of the answers to evaluate the relationships between the use of traditional methods and other risk factors. The use of traditional methods is high in Cameroon (63.0%) and Uganda (39.9%), intermediate in Senegal (26.7%) and Italy (21.7%), low in Madagascar (6.7%). Statistical analyses show significant direct relationships between the use of traditional methods, skin reactions to the bite and their duration in Cameroon, Uganda and Senegal. The use of saliva and herbs applied by the mothers on the child's skin, is a common habit in Africa. If this practice plays a role in the HHV-8 transmission, then, it could provide the basis for interventions capable of reducing the health impact of the infection in children in tropical areas.

Restricted expression of retrovirus nucleic acids and proteins in primate type C virus (gibbon ape leukemia virus-simian sarcoma virus)-initiated human B-lymphoblast cultures.

Fresh human B-lymphoblasts established in culture following exposure of adult peripheral blood leukocytes to type C retroviruses of the simian sarcoma virus/simian sarcoma-associated virus-gibbon ape leukemia virus group were analyzed in detail for the presence of the infecting virus. Viral expression ranged from production of low levels of intact virus in a few cultures to the presence of viral RNA and protein in the absence of detectable of levels of complete virus in the majority of the cultures. In situ molecular hybridization assays using 3H-labeled complementary DNA and indirect immunofluorescence assays using antibody to purified viral protein indicated that the expression of viral RNA and proteins are preferentially expressed in only a fraction of the cells in some cultures. If expression of the infecting viral sequences is necessary for the sustained growth of these cells, then those cells detectably synthesizing viral RNA and proteins may be influencing the growth of the remaining virus-negative cells. The lack of virus production in cultures synthesizing viral RNA and protein indicate that these human B-lymphocytes restrict the life cycle of these viruses at some step(s) after transcription of viral RNA or translation of viral protein.

Cloning of a repeat sequence from human DNA which contains a BamHI site.

A human 1.5 kilobase BamHI repeated DNA fragment has been cloned from a genomic library and subcloned in pBR322. It is part of the human homogeneous main-band DNA, it has properties similar to those of long interspersed repetitive sequences (LINES), and differs from the families of human repeated DNA already described.

Acid sensitivity of cell-free and cell-associated HIV-1: clinical implications.

Infectivity of free and cell-associated human immunodeficiency virus type 1 (HIV-1) treated in vitro at pH 7.4 to 4.9 for 2 hours was assessed on susceptible CEM-ss cells. Viral activity was monitored by cytopathology and production of reverse transcriptase and p24 antigen. The infectivity of cell-free virus was gradually inactivated and at pH 5.4 was completely lost, with or without subsequent adjustment of pH to neutral. Virus-producing cells also gradually lost their ability to infect as the pH decreased; however, restoration of neutral pH resulted in regained infectivity. Since the pH values used in the study are similar to those found at various entry sites of the human body, the data may be relevant to the mode of transmittal of HIV.

Simple in vitro methods for titrating feline immunodeficiency virus (FIV) and FIV neutralizing antibodies.

The feline immunodeficiency virus (FIV) readily produced syncytia in Crandell feline kidney (CrFK) cells adapted to a medium containing 0.5% fetal calf serum, a variety of growth factors and other supplements. This finding has been exploited to develop simple and sensitive virus titration and neutralization assays. High titre neutralizing antibodies were detected in cats infected naturally and experimentally with FIV, but not in uninfected animals.

The risk of contracting an infectious disease from blood transfusion.

In the general population, the likelihood of an individual receiving a transfusion has been calculated to be about 0.89% per year, increasing dramatically with age. Massive intraoperative hemorrhage from trauma, cardiopulmonary bypass, and orthotopic liver transplantation need substantial replacement therapy. In renal transplantation, blood transfusion is a debated induction tool for specific allograft tolerance, since it causes a nonspecific down-regulation of immune function. In transplantations, in humoral immune deficiencies, in hematological disorders, and in HIV infection, the intravenous immunoglobulin prophylaxis may alter the monocyte/macrophage system host immunity and immune surveillance against infection, tissue or cell damage, and malignancy. Some persons, like Jehovah's Witnesses, object to transfusion of blood products, posing ethical and practical issues concerning treatment of blood disorders, transplantation, and trauma. In this review we examined the actual risk of contracting an infectious disease from an allogeneic blood transfusion to contribute to an uneasy decision-making process. We have found that the procedure is presently considerably safe.

HIV-plasma viral load detection by branched DNA signal amplification.

To detect HIV-1 plasma viral load in seropositive patients, we applied a new molecular quantitation technique: branched DNA signal amplification (bDNA). We performed bDNA with 99 sera from HIV-1 seropositive patients undergoing antiretroviral therapy. We compared the results obtained with p24 antigenemia and CD4+ cell count. The bDNA proved quite sensitive and available for routine use in laboratories.

Detection of lymphotropic herpesvirus DNA by polymerase chain reaction in cerebrospinal fluid of AIDS patients with neurological disease.

Cerebrospinal fluid (CSF) samples from 49 acquired immunodefficiency disease syndrome (AIDS) patients with a central nervous system (CNS) disease were examined by polymerase chain reaction (PCR) to evaluate the association between the positivity for cytomegalovirus (CMV) and Epstein-Barr virus (EBV), and clinical diagnosis of a CNS disease. Frequency and clinical relevance of detection of DNA of human herpesviruses 6 (HHV-6), 7 (HHV-7) and 8 (HHV-8) were also determined. DNA of one or more of the following viruses was found in 26 of 49 patients (53%): CMV in 16 (33%), EBV in 13 (27%), human herpesvirus 6 (HHV-6) in 2 (4%), human herpesvirus 7 (HHV-7) in 1 (2%), and human herpesvirus 8 (HHV-8) in 1 (2%). The CMV detection was significantly associated with encephalitis and peripheral neuropathy (7/16 vs. 2/33, p = 0.003), while EBV with primary CNS lymphoma (P-CNSL) (8/13 vs. 0/36, p < 0.0001). HHV-6 DNA was found in CSF of two patients with neuroradiological features suggestive of cerebral lesions. HHV-8 or HHV-7 DNA was detected in the CSF of patients with unexplained neurological symptoms. This study confirms that the PCR analysis of CSF is a valid tool for the diagnosis of neurological diseases associated with CMV and EBV. On the other hand, HHV-6, HHV-7 and HHV-8, instead, were rarely detected in CSF of AIDS patients and have certainly no correlation with the CNS disease found.

[Different sensitivity to acid reaction of the AIDS virus and virus-producing cells: clinical conclusions]. / A szerzett immunhiány (AIDS) vírusának és a vírustermelö sejteknek eltérö érzékenysége savi vegyhatás iránt: klinikai következtetések.

Sensitivity of the cell-free human immundeficiency virus type 1 (HIV-1) and its producer cells was Studied in acidic media between pH 7.4 and 4.9 vitro. The cytopathic effect, reverse transcriptase activity and p24 antigen production by survived viruses were monitored in indicator cell cultures. It was established that, the cell-free HIV-1 particles are very sensitive to acidity. Between pH 7.4 and 6.0 they loose infectivity gradually, but this process is irreversible under pH 6.0 and subsequent neutralization cannot restore lost infectivity. However, viability, of virus producer cells is hardly affected between pH 7.4 and 4.9, but their ability to release infectious particles is lost gradually, similarly to the case of cell-free viruses. Neutralization of the media after treatment results in gradual restoration of releasing infectious viruses. These data explain that, cell-free HIV-1 looses infectivity in the acidic vagina or does on the skin, but infectivity is preserved in the blood, semen, rectum and breast milk being neutral or slightly alcalic. Virus carrier or producer lymphocytes by any route of infection can survive such protective mechanism of the body.

[Human herpesvirus 6 A enhances HIV-1 replication in vitro by soluble mediators, this effect is diminished by endotoxin]. / Az emberi 6-os herpeszvírus A változata szolubilis mediátorok által fokozza a HIV-1 szaporodását in vitro, mely hatást az endotoxin csökkenti.

Simultaneous HHV-6A infection can activate HIV-1 latency and promote AIDS progression, but in this process the effects of HHV-6A induced soluble mediators on HIV-1 have not been studied yet. Recently, supernatants of HSB-2 cultures infected with HHV-6A and/or treated with endotoxin have been filtered virus free at time intervals until the cytopathic effect developed. Biological activity of some cytokines which might participate in HIV-1 activation was quantitated. Filtered supernatants were mixed into CEM-ss cultures, which had been HIV-1 infected at 1:1 cell:virus ratio, subsequently HIV-1 replication was quantitated and compared to controls. Supernatants filtered during the first 96 hours of HHV-6A replication without visible cytopathic effect augmented HIV-1 syncytium formation by tenfold, reverse transcriptase activity by threefold, p24 antigen production by 6-fold. Filtered supernatants obtained at onset of HHV-6A cytopathic effect did not modify HIV-1 replication. HSB-2 cultures produced no IL-2, and IFN-gamma induced by endotoxin diminished HIV-1 replication. HHV-6A delayed IFN-gamma release. An increase in the tumour necrosis factor activity upon the effect of HHV-6A and endotoxin was not parallel to HIV-1 activation. The putative mediator, different from those above which characterisation is in progress, might transmit similar transactivating effects between immune cells of lymph nodes and circulation.

[Studying the course of HIV-1 infection in cell culture]. / A HIV-1 fertözés lefolyásának tanulmányozása sejtkultúrákban.

The hallmark of AIDS is the gradual loss of CD4+ T-lymphocytes, in spite of their infection in low ratio. The pathomechanism is hardly known, therefore, the production of HIV-1 and certain aspects of cell death were studied. Infectivity was decreased by the acidification of culture media. C8166 cells transformed by HTLV-I and exhibiting features of both immature T lymphocytes and myeloid cells, produced transient protoplasmic surface extrusions, similar to the hairy cell leukemia. These can have a role in the direct cell-to-cell spread of HIV-1. Polarization of nuclei and cell organelles as well as sites of virus budding during syncytium formation resembled the directed lymphokine secretion. Both cell membrane and intravacuolar buddings were characteristic. Abnormal virus particles also were seen. Certain morphological signs resembled apoptosis. Fibroblast cultures in the presence of HIV-1 infected lymphoid cells were arrested in growth and underwent cell death without syncytium formation. The results draw attention to the faster development of AIDS in the case of HIV-1 infection of precursor immune cells. Double infection by HTLV and HIV-1 can result in atypical leukemias.

Hepatitis C virus seroprevalence in Italian haemophiliacs injected with virus-inactivated concentrates: five year follow-up and correlation with antibodies to other viruses.

The overall prevalence of anti-HCV antibody in a group of 125 haemophiliacs was 62%. Four patients who had never received replacement therapy were anti-HCV negative. Of the 121 patients injected regularly with commercial concentrates, 76 were already anti-HCV seropositive in 1985 and remained so throughout the follow-up. Two patients seroconverted in 1987 without obvious signs or symptoms of hepatitis. Our patients were treated with dry heat-treated concentrates since 1985 and with wet heat- or solvent/detergent-treated concentrates since 1988. The absence of further seroconversions and of symptoms of acute post-transfusion non-A, non-B hepatitis since 1988 suggest that present virucidal treatments of concentrates are effective in preventing HCV transmission. Anti-HCV positivity appeared to be unrelated to the type and degree of haemophilia as well as to the presence of antibodies to hepatitis B virus, human immunodeficiency virus type 1, and human herpesvirus type 6.

Correlation between plasma HIV-1 RNA levels and the rate of immunologic decline.

To determine the influence of HIV-1 replication on immunologic decline and clinical outcome, we quantified the HIV-1 plasma viral load in 20 patients at different times over a mean period of 10.8 months. Quantitation was performed by branched DNA signal amplification (bDNA) and p24 antigenemia. Immunologic status was assessed through beta 2-microglobulin and CD4+ cell count determinations. CD4+ cell decline was expressed as a slope of the regression line constructed by the logarithms of CD4+ cell count observations. Mean values of plasma viral load were correlated with CD4+ cell decline and mean beta 2-microglobulin levels. Significant correlation was observed between plasma viral load quantified by the bDNA technique and CD4+ cell decline. No significant correlation was observed between plasma viral load quantified by p24 antigenemia and CD4+ cell decline. A significant correlation was observed between plasma viral load and beta 2-microglobulin levels. Immunologic decline was better predicted from HIV-1 RNA levels than from the CD4+ cell count. Significantly higher plasma viral load was observed in patients who had clinical progression of HIV-1 infection. Thus, HIV-1 plasma viral load quantified by a highly reliable technique such as bDNA showed that the immunologic decline is closely related to HIV-1 RNA replication.