Persistence of episomal HIV-1 infection intermediates in patients on highly active anti-retroviral therapy.

Treatment of HIV-1-infected individuals with a combination of anti-retroviral agents results in sustained suppression of HIV-1 replication, as evidenced by a reduction in plasma viral RNA to levels below the limit of detection of available assays. However, even in patients whose plasma viral RNA levels have been suppressed to below detectable levels for up to 30 months, replication-competent virus can routinely be recovered from patient peripheral blood mononuclear cells and from semen. A reservoir of latently infected cells established early in infection may be involved in the maintenance of viral persistence despite highly active anti-retroviral therapy. However, whether virus replication persists in such patients is unknown. HIV-1 cDNA episomes are labile products of virus infection and indicative of recent infection events. Using episome-specific PCR, we demonstrate here ongoing virus replication in a large percentage of infected individuals on highly active anti-retroviral therapy, despite sustained undetectable levels of plasma viral RNA. The presence of a reservoir of 'covert' virus replication in patients on highly active anti-retroviral therapy has important implications for the clinical management of HIV-1-infected individuals and for the development of virus eradication strategies.

Measles infection of human mononuclear cells. I. Acute infection of peripheral blood lymphocytes and monocytes.

A study of the susceptibility of human peripheral blood mononuclear cells to measles virus infection and replication is reported. Resting lymphocytes obtained from adults showed very low levels of infection and virus replication while lymphocytes activated by plant mitogens or allogenic lymphocytes supported mononuclear cells obtained from the umbilical cord of healthy neonates were more susceptible to measles virus infection than those of adults; however, activated cord lymphocytes supported viral replication in the range observed with adult activated lymphocytes. Monocytes obtained from adults were relatively resistant to measles virus infection and replication while neonatal cord blood monocytes supported viral replication to the degree observed with activated lymphocytes. It is hypothesized that infection of acitivated lymphocytes may explain the depression of cell-mediated immunity seen during acute measles virus infection. The significance of the finding that neonatal monocytes are more susceptible to viral infection and replication than adult monocytes is discussed.

Early HIV-1 envelope-specific cytotoxic T lymphocyte responses in vertically infected infants.

High frequencies of cytotoxic T lymphocyte precursors (CTLp) recognizing HIV-1 laboratory strain gene products have been detected in adults within weeks of primary infection. In contrast, HIV-1-specific CTLp are uncommonly detected in infants younger than 6 mo. To address the hypothesis that the use of target cells expressing laboratory strain env gene products might limit the detection of HIV-1 env-specific CTLp in early infancy, recombinant vaccinia vectors (vv) expressing HIV-1 env genes from early isolates of four vertically infected infants were generated. The frequencies of CTLp recognizing target cells infected with vv-expressing env gene products from early isolates and HIV-1 IIIB were serially measured using limiting dilution followed by in vitro stimulation with mAb to CD3. In one infant, the detection of early isolate env-specific CTLp preceded the detection of IIIB-specific CTLp. CTLp recognizing HIV-1 IIIB and infant isolate env were detected by 6 mo of age in two infants. In a fourth infant, HIV-1 IIIB env and early isolate env-specific CTLp were simultaneously detected at 12 mo of age. These results provide evidence that young infants can generate HIV-1-specific CTL responses and provide support for the concept of neonatal vaccination to prevent HIV-1 transmission. However, the early predominance of type-specific CTL detected in some young infants suggests that the use of vaccines based on laboratory strains of HIV-1 may not protect against vertical infection.

Limiting dilution analysis of cytotoxic T lymphocytes to human immunodeficiency virus gag antigens in infected persons: in vitro quantitation of effector cell populations with p17 and p24 specificities.

The presence of cytotoxic T lymphocytes (CTL) to the gag antigens of human immunodeficiency virus (HIV) has been described in infected populations. We found that the majority of this immune response as measured in bulk CTL assays of unstimulated peripheral blood mononuclear cells (PBMC) is directed against the p24 component of the p55 gag precursor protein. Using limiting dilution analysis of this effector cell population we confirm that the majority of activated gag-specific CTL circulating in the PBMC of infected hemophilic patients are directed at p24 determinants and are present at frequencies of 1/36,000 to 1/86,000 lymphocytes. By performing in vitro stimulation after limiting dilution, the precursor population of gag-specific CTL are characterized and quantitated. HIV gag-specific CTL precursors are identified at frequencies of 1/1700 to 1/17,000 lymphocytes and are made up of cells with both p17 and p24 specificities. No HIV gag-specific CTL precursor cells are identified in the PBMC of HIV-uninfected individuals. These studies demonstrate that CTL directed at both p17 and p24 determinants make up the cellular immune repertoire in HIV-infected individuals but that only the p24-specific CTL are routinely found in an activated state in the circulation.

Localization of HIV RNA in mitochondria of infected cells: potential role in cytopathogenicity.

The intracellular distribution of HIV-1 RNA transcripts in infected cells was studied using in situ hybridization detected by electron microscopy and cellular fractionation. Although viral RNA and core protein could be detected throughout the cytoplasm and nucleus, viral RNA was found in significantly increased amounts in mitochondria relative to the cytoplasm and nucleus. In contrast, cellular poly(A) RNA or viral gag proteins were not increased in the mitochondria. A cell line containing an integrated latent genome that could be induced to express viral RNA after phorbol ester stimulation showed an increase in viral RNA accumulation in mitochondria parallel with the increase in HIV expression levels. Concomitant with HIV expression, there was a decrease in mitochondrial viability. Using immunofluorescent markers to detect probes to HIV RNA transcripts and antibodies to mitochondrial proteins simultaneously in single cells, there was an inverse relationship between the amount of viral RNA and mitochondrial integrity. High levels of viral RNA in mitochondria were found in acutely (but not chronically) infected cells. We propose that HIV RNA import into mitochondria can compromise mitochondrial function.

Effects of long-term reserpine treatment on brain tyrosine hydroxylase and behavioral activity.

Treatment of rats with reserpine (for 8 or 9 days) produced a temporally related increase in behavioral activity and in tyrosine hydroxylase activity in the midbrain. Weight loss resulting from such treatment was not sufficient, by itself, to account for either the behavioral or enzymatic changes. The results support the role of catecholamines in behavioral arousal.

Deficient natural killer cell activity in x-linked lymphoproliferative syndrome.

The activity of natural killer cells was found to be deficient in 10 of 12 males with X-linked lymphoproliferative syndrome, a life-threatening proliferation of lymphocytes after infection by Epstein-Barr virus. The activity levels of natural killer cells from affected males were increased after treatment with interferon in vitro, but normal levels of killing were not obtained. Deficient activity of killer cells in individuals with immunodeficiency and chronic infection by Epstein-Barr virus may contribute to the development of lymphoproliferative disorders.

X-linked lymphoproliferative syndrome. Natural history of the immunodeficiency.

The X-linked lymphoproliferative syndrome is characterized by immunodeficiency to Epstein-Barr virus (EBV) manifested by severe or fatal infectious mononucleosis and acquired immunodeficiency. We studied immune responses in six males of a well-characterized kindred with the X-linked lymphoproliferative syndrome. Two males were studied before and during acute fatal EBV infection. Both individuals demonstrated normal cellular and humoral immunity before EBV infection. During acute EBV infection, both individuals developed vigorous cytotoxic cellular responses against EBV-infected and -uninfected target cells. Anomalous killer and natural killer T cell activity was demonstrated against a variety of lymphoid cell lines, autologous fibroblasts and autologous hepatocytes. Effector cells responsible for anomalous killing reacted with a pan-T cell monoclonal antibody, and belonged to the OKT.8 T cell subset. Death in each case was caused by liver failure, but one patient developed extensive liver necrosis, whereas the other developed a massive infiltration of the liver with EBV-infected immunoblasts after aggressive immunosuppressive therapy. Immunological studies were performed on four males who had survived EBV infection years previously. They demonstrated global cellular immune defects with deficiencies of lymphocyte proliferative responses to mitogens and antigens, humoral immune deficiencies, abnormalities of regulatory T cell subsets and deficient natural killer cell activity. We propose that an aberrant immune response triggered by acute EBV infection results in unregulated anomalous killer and natural killer cell activity against EBV infected and uninfected cells. These studies suggest that global immune defects appearing in males with X-linked lymphoproliferative syndrome who survive EBV infection are epiphenomenon.

The abnormal gene in X-linked lymphoproliferative syndrome.

The gene defect responsible for X-linked lymphoproliferative syndrome, SH2D1A (SH2-domain-containing gene 1A), was recently cloned. This gene encodes a small protein of 128 amino acids containing a single SH2 domain, which is thought to play an important role in signal transduction in activated T cells. The definition of SH2D1A protein function will provide insight into the pathogenesis of fatal Epstein-Barr virus infection, lymphomas, Hodgkins disease, immunodeficiency, aplastic anemia and lymphohistiocytic disorders that characterize the syndrome.

Epstein-Barr virus infections in hairy cell leukemia patients in the presence of complement-dependent neutralizing antibody.

Immune system status was characterized in patients with hairy cell leukemia (HCL) with respect to explaining their chronic or recurrent infections with Epstein-Barr virus. Measures of cellular immune responsiveness for a group of 11 HCL patients were, in general, decreased when expressed as the proportion of tested patients with values less than 2 S.D. below mean values for a group of 17 healthy adults: T-cell enumeration, seven of 13; mitogen responsiveness of phytohemagglutinin, 10 of 11; concanavalin A, 10 of 11; pokeweed mitogen, 10 of 11; B-cell responsiveness by anti-immunoglobulin immunobead stimulation, two of six; responsiveness to streptolysin O antigen, four of seven; mixed-lymphocyte reaction, six of seven; natural killer cell activity, six of eight. Specific immunity to Epstein-Barr virus was measured by complement-independent, antibody-mediated virus neutralization (mean index for HCL patients being 56% of control value) and complement-dependent virus neutralization (98% of control value). We concluded that, in spite of depressed levels of immune responses measured with general, cellular assays, functional levels of complement-dependent virus-neutralizing antibody were present in these HCL patients.

Documentation of Epstein-Barr virus infection in immunodeficient patients with life-threatening lymphoproliferative diseases by Epstein-Barr virus complementary RNA/DNA and viral DNA/DNA hybridization.

Tissues from patients thought to have Epstein-Barr virus (EBV)-induced lymphoproliferative diseases were probed for EBV genomes using 2 independent hybridization techniques. Tissues from six patients with the X-linked lymphoproliferative syndrome, all five renal allograft recipients with immunoblastic sarcoma, and eight patients with diverse types of immunodeficiency and lymphoproliferative diseases such as fatal infectious mononucleosis or malignant lymphoma associated with antecedent immunodeficiency contained significant numbers of EBV genome equivalents per cell. The use of 2 hybridization probes is recommended to confirm the presence of EBV genomes. The finding of significant numbers of EBV genomes in tissues from patients with immunodeficiency suggests that EBV is the etiological agent of the associated lymphoproliferative diseases.

Clinical spectrum of lymphoproliferative disorders in renal transplant recipients and evidence for the role of Epstein-Barr virus.

Six renal transplant recipients with abnormal lymphoproliferative disorders were studied in an attempt to define their clinical features and the role of Epstein-Barr virus (EBV) in their pathogenesis. Patients were either teenage (three) or in the sixth decade (three). The younger patients presented an average of 3 months after transplantation with fever, sore throat, and lymphadenopathy; had been markedly immunosuppressed; frequently had preceding or concomitant cytomegalovirus infections; and two of three had a rapidly fatal course. The older patients presented an average of 5 years after transplantation while on maintenance immunosuppressive drugs; in two of three cases with an oropharyngeal tumor; and had a more indolent, but frequently fatal, clinical course. The most frequent sites of biopsy-proven involvement in these patients were lymph nodes (three), the oropharynx (three), liver (three), bone marrow (three), transplanted kidney (three), colon (two), and central nervous system (two). EBV-specific antibody titers including anti-viral capsid antigen IgG, anti-viral capsid antigen IgM, anti-early antigen, and anti-Epstein-Barr nuclear antigen were serially measured in all patients. Four patients demonstrated serological evidence of a primary (one) or reactivation (three) EBV infection. No patient had significant changes in anti-early antigen or anti-Epstein-Barr nuclear antigen titers. All three patients tested for oropharyngeal shedding of EBV were positive. A touch imprint of one tumor was stained for the presence of Epstein-Barr nuclear antigen, and a majority of cells were positive. EBV complementary RNA/DNA filter hybridization and/or viral DNA/DNA reassociation analysis performed on tumor biopsy specimens in five patients demonstrated multiple EBV genome equivalents per cell in all eight specimens tested. Clinical, pathological, serological, and molecular hybridization studies provide substantial evidence that EBV was the cause of these lymphoproliferative disorders occurring after renal transplantation. Impaired host defenses allow the EBV-transformed B-lymphocytes to escape normal control mechanisms. This impairment is invariable and influenced by many factors resulting in the observed spectrum of disease. Cytogenetic changes, however, may also be important.

Documentation of Epstein-Barr virus infection in immunodeficient patients with life-threatening lymphoproliferative diseases by clinical, virological, and immunopathological studies.

Multiple methods, pedigree analysis, clinical evaluation, and Epstein-Barr virus (EBV)-specific serology, EBV DNA hybridization of tissues to probe for viral genome, staining of touch imprints for EBV nuclear-associated antigen, establishment of spontaneous infected B-cell lines from peripheral blood or tissues, examination of peripheral blood smears, and hematopathology studies, were used to study seven patients with the X-linked lymphoproliferative syndrome and seven additional patients with life-threatening EBV-associated diseases. These studies demonstrated EBV in the tissues of all 14 patients and immunodeficient antibody responses to EBV were documented. This virus can produce various life-threatening lymphoproliferative diseases in a variety of immunodeficient patients.

Transport of L-methionine in human diploid fibroblast strain WI38.

The transport of L-methionine in human diploid fibroblast strain WI38 was investigated. The uptake of L-methionine was measured in sparse cell cultures in a simple balanced salt solution buffered with either Tris.HCl of N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES). Similar results were obtained with these two buffers. Cultures were allowed to equilibrate with the buffered saline before transport was measured. The presence of glucose in the buffered saline results in a slight reduction in the initial rate of transport for the first 2 h of equilibration in buffered saline. L-Methionine is actively transported in WI38 by saturable, chemicallly specific mechanisms which are temperature, pH and, in part Na+ dependent, and are reactive with both L- and D-stereoisomers. Kinetic analysis of initial rates of transport at substrate concentrations from 0.0005 to 100 mM indicated the presence of two saturable transport systems. System 1 has an apparent KM of 21.7 micrometer and an apparent V of 3.57 nmol/mg per min. System 2 has an apparent KM of 547 micrometer and an apparent V of 22.6 nmol/mg per min. Kinetic analysis of initial rates of transport in Na+-free media or after treatment with ouabain suggested that system 1 is Na+ independent and that system 2 is Na+ dependent. Preloading of cells with unlabeled L-methionine greatly increases the initial rate of uptake. Efflux of transported methionine is temperature dependent, and is greatly increased in the presence of unlabeled L- or D-methionine or L-phenylalanine, but not in the presence of L-arginine. L-Methionine transport is strongly inhibited by other neutral amino acids, and is very weakly inhibited by dibasic amino acids, dicarboxylic amino acids, proline or glycine.

Platelet monoamine oxidase and serum dopamine-beta-hydroxylase activity in chronic alcoholics.

Previous independent reports suggest that low platelet monoamine oxidase (MAO) activity and high serum dopamine-beta-hydroxylase (DBH) activity may be associated with alcoholism or vulnerability toward alcoholism. However, there are also contradictory reports in the literature with regard to each of these two enzymes. We measured both platelet MAO and serum DBH activity in alcoholics followed up at periodic intervals for 12 months after hospitalization for acute alcoholism. Platelet MAO activity in the alcoholics was significantly lower compared to that of nonpsychiatric controls throughout the 12-month period, whereas serum DBH activity in the alcoholics was essentially the same as control values. Thus, low platelet MAO activity, previously reported in a spectrum of clinical psychiatric disorders, appears to be a relatively stable phenomenon in chronic alcoholics irrespective of acute intoxication or pathophysiological factors associated with acute decompensation in individuals vulnerable to alcoholism.

Atypical depression.

The term atypical depression generally indicates either depression accompanied by severe anxiety (type A) or by atypical vegetative symptoms, ie, increased appetite, weight, sleep, or libido (type V). Early age at onset, predominance in women, outpatient status, mild intensity, rarity of attempted suicide, nonbipolarity, nonendogenicity, and minimal psychomotor change are common to both types. Some types of bipolar depression may be considered as atypical if accompanied by reversed vegetative change. Monoamine oxidase inhibitors are more effective than placebo in treating atypical depression, but their reported superiority to tricyclic antidepressants awaits confirmation, for which the development of appropriate operational criteria would be helpful. Atypical depression is a term that covers several types of depressive disorder and can, for the most part, be better defined using the standard nomenclature.

Human immunodeficiency virus isolation studies and antibody testing. Household contacts and sexual partners of persons with hemophilia.

Virus isolation studies and human immunodeficiency virus (HIV) antibody testing were performed on 87 household contacts of 68 HIV antibody-positive hemophilic patients to determine the extent that HIV could be transmitted through heterosexual or through nonsexual, but intimate contact. Human immunodeficiency virus seropositivity was established for the 68 hemophiliacs by immunofluorescence method or enzyme-linked immunosorbent assay and confirmed by Western blot testing (for 66 patients). Fifty-one nonsexual contacts and 36 sexual partners of these hemophiliacs were tested for HIV antibody by immunofluorescence or enzyme-linked immunosorbent assay and Western blot. All sexual partners and all nonsexual household contacts were HIV antibody-negative, including six partners and nine parents of hemophiliacs from whom the virus had been isolated and seven parents and six partners of patients with AIDS. This study further demonstrates lack of transmission of HIV in intimate, but nonsexual settings, and suggests that heterosexual transmission, although well known to occur, may be relatively uncommon in hemophilic couples when the male and female partner have no other risk factors. It is hoped that intensive education and counseling programs will reduce exposure and maintain a low risk of heterosexual transmission.

The role of Lin28b in myeloid and mast cell differentiation and mast cell malignancy.

Mast cells (MCs) are critical components of the innate immune system and important for host defense, allergy, autoimmunity, tissue regeneration and tumor progression. Dysregulated MC development leads to systemic mastocytosis (SM), a clinically variable but often devastating family of hematologic disorders. Here we report that induced expression of Lin28, a heterochronic gene and pluripotency factor implicated in driving a fetal hematopoietic program, caused MC accumulation in adult mice in target organs such as the skin and peritoneal cavity. In vitro assays revealed a skewing of myeloid commitment in LIN28B-expressing hematopoietic progenitors, with increased levels of LIN28B in common myeloid and basophil-MC progenitors altering gene expression patterns to favor cell fate choices that enhanced MC specification. In addition, LIN28B-induced MCs appeared phenotypically and functionally immature, and in vitro assays suggested a slowing of MC terminal differentiation in the context of LIN28B upregulation. Finally, interrogation of human MC leukemia samples revealed upregulation of LIN28B in abnormal MCs from patients with SM. This work identifies Lin28 as a novel regulator of innate immune function and a new protein of interest in MC disease.

Nevirapine synergistically inhibits HIV-1 replication in combination with zidovudine, interferon or CD4 immunoadhesin.

OBJECTIVE: To determine whether synergistic inhibition of HIV-1 replication would result from the in vitro use of nevirapine in combination with zidovudine, interferon (IFN)-alpha 2C, and CD4 immunoadhesin. DESIGN AND METHODS: The non-nucleoside reverse transcriptase inhibitor nevirapine (formerly BI-RG-587) was tested in combination with the other antiretrovial agents. Assays were performed on stimulated peripheral blood lymphocytes infected with HIV-1. Virus replication was assessed by the release of viral p24 antigen into culture supernatants. The median-effect principle was used to assess for synergistic interactions of the combined agents. RESULTS: Zidovudine, IFN-alpha 2C and CD4 immunoadhesin, when used in combination with nevirapine, synergistically inhibited HIV-1 replication in human peripheral blood lymphocytes compared with each agent used alone. Some analyses were also consistent with additive effects, but antagonism was not noted. CONCLUSION: These in vitro findings provide a scientific basis for future trials with similar drug combinations.

Quantitation of HIV-1 in whole blood of infected children.

OBJECTIVE: To validate the technique of HIV-1 culture from whole blood for the quantitation of viral load in infected children. PATIENTS: Forty-three HIV-1-infected children were followed in two paediatric centres. METHODS: Quantitative HIV-1 cultures from unfractionated whole blood using an end-point dilution technique were compared with simultaneous quantitative cultures of peripheral blood mononuclear cells (PBMC) and plasma. RESULTS: Good sensitivity (93%) of the methods used was confirmed. A close correlation (r = 0.80) was observed between HIV-1 titres measured directly from whole blood and those expected from PBMC and plasma titres. The mean whole blood viral load was higher in patients with more severe signs of disease, but the difference did not reach statistical significance. The whole blood viral titres measured sequentially at monthly intervals remained within one dilution of each other in 16 of the 22 patients studied. CONCLUSION: In this study, the quantitation of HIV-1 in unfractionated blood allowed for a reliable and sensitive measurement of the whole blood viral load in infected children.