Biomedical subjects
Publications and source records attributed to S M Crowe.
Patients with herpes simplex or zoster infections are common in most medical practices. These infections are also very important in HIV medicine, often presenting in an otherwise well person. Knowledge of the effects of immune deficiency on herpes simplex and zoster infection assists in determining when to consider HIV.
Sera from 105 HIV-infected patients were tested for anti-neutrophil cytoplasm antibodies (ANCA) by indirect immunofluorescence (IIF), by specific ELISAs using target proteins of ANCA and by a neutrophil cytoplasm extract ELISA. Forty-four sera were positive. These included 18 positive by IIF, 7 with anti-neutrophil proteinase 3 antibodies, 26 with anti-myeloperoxidase antibodies and 2 with anti-elastase antibodies. Four sera were positive in the neutrophil cytoplasm extract ELISA but not in the specific ELISAs. None of these patients had clinical evidence of a cutaneous or systemic vasculitis. In addition there was no correlation between the presence of ANCA and the stage of disease, intercurrent bacterial or viral infection, anti-nuclear antibodies (ANA) and positive hepatitis B or syphilis serology.
Tuberculous meningitis remains an important illness that can be difficult to diagnose in a timely fashion and carries significant morbidity. We present a retrospective review of the cases of tuberculous meningitis diagnosed and treated at a single institution. Fifty-eight cases were identified and stratified according to stage of disease at presentation. Four patients (7%) died; three (5%) developed severe neurological sequelae. Poor outcomes were largely confined to cases presenting in an advanced stage and at the extremes of age. Corticosteroids were administered to 56 patients and may have contributed to the comparatively good outcome in these cases.
Monocyte-derived macrophages (MDM) infected in vitro with a macrophage-tropic strain of human immunodeficiency virus (HIV) fused with uninfected, CD4-expressing T lymphoblastoid cells, but not with a subclone of these cells lacking surface CD4. Infected MDM also fused with uninfected autologous and heterologous MDM. Recombinant soluble CD4 protein (rsCD4) (10 micrograms/ml) and full-length recombinant glycosylated gp120 (20 micrograms/ml) each inhibited fusion by 94-99%; the inhibition was dose-dependent. The N-terminal portion of gp120 did not inhibit syncytium formation. Fusion was also inhibited by a monoclonal antibody to an epitope which binds gp120 (S3.5), but not by antibody to an epitope not involved in gp120 binding (OKT4). HIV-infected MDM specifically bound fluorescein-conjugated rsCD4, and virus could be visualized budding from the surface of these cells. HIV-infected MDM express viral gp120 on their surface and fuse with CD4-bearing cells in a fashion similar to lymphoid cells. Macrophages may contribute to CD4 lymphocyte depletion in vivo by this fusion mechanism.
In this study we have looked at the effect of lipopolysaccharide (LPS) on the surface antigen expression of cultured monocytes. Monocytes were purified from peripheral blood mononuclear cells (PBMC) and cultured in the presence or absence of LPS. The cultured cells were then stained with anti-MO3, anti-IL-2R and anti-CD4 MoAbs. We have shown that freshly isolated monocytes are IL-2R- and MO3-negative and express CD4 in low density. After overnight culture, without LPS, the expression of these surface markers remained relatively unchanged. However, in the presence of LPS (1 microgram/ml) CD4 expression was reduced to undetectable levels while the expression of IL-2R and MO3 was induced to maximal density. This effect of LPS on monocyte surface antigen expression was demonstrated with LPS preparations from Escherichia coli, Salmonella typhi and Vibrio cholerae. Surface antigen expression after 7 days culture in medium supplemented with non-heat-inactivated serum was essentially as seen after overnight culture, with the exception that LPS-induced IL-2R expression was transient. The ability to prepare monocytes that maintained surface CD4 expression after overnight culture was donor dependent.
A homosexual man with histologically confirmed Kaposi's sarcoma remained seronegative for HIV-1, HIV-2, and HTLV-1 on conventional tests over a 4-year period. HIV cultures were also negative on thirteen separate occasions. However, serum antibodies to synthetic peptide analogues of the gp41 and nef regions of HIV-1 were consistently detected on an enzyme immunoassay. Tests with the polymerase chain reaction with primers directed to the gag and env regions were negative. The antigens to which the antibodies were produced might have come from a defective HIV mutant, another retrovirus, or a hitherto unknown "agent of Kaposi's sarcoma" with similar antigenic epitopes.
Reports of human immunodeficiency virus (HIV) infection in seronegative individuals prompted the authors to investigate subjects who are at very high risk of acquisition of HIV in San Francisco. Nine HIV seronegative subjects were evaluated extensively, eight of whom were drawn from a well-characterized cohort of seropositive and seronegative homosexual men who have been followed prospectively since 1983-1984. These men have calculated probabilities of infection based on a fitted model of between 0.22 and 0.94. One additional subject is an intravenous drug user who has shared needles with HIV-infected individuals extensively. Peripheral blood lymphocytes and monocytes were separately cultured from each subject and evidence of HIV infection was sought by a reverse transcriptase assay, enzyme immunoassay, and immunocytofluorographic analysis for HIV antigens, in situ hybridization, RNA slot blot analysis, and polymerase chain reaction amplification of HIV cDNA. Uncultured monocytes and lymphocytes from each donor were also examined by these techniques. Evidence of HIV infection was not found in the peripheral blood mononuclear cells of these high risk individuals.
Infection with the human immunodeficiency virus (HIV) results in progressive depletion of the CD4 subset T-lymphocytes and the development of opportunistic infections and certain malignancies. Charts were reviewed for 185 HIV-infected individuals with 265 AIDS-defining illnesses (ADIs) who had T-lymphocyte subset analyses performed within 2 months prior to or 1 month following the diagnosis. Also included were 22 HIV-infected patients with oral candidiasis and 20 with asymptomatic infection. Significant differences in CD4 lymphocyte numbers were observed between the 12 ADIs, oral candidiasis, and asymptomatic infection, allowing them to be grouped into five general categories, based on mean CD4 count: (a) asymptomatic infection, CD4 greater than 500/mm3; (b) oral candidiasis and tuberculosis, range 250-500/mm3; (c) Kaposi's sarcoma, lymphoma, and cryptosporidiosis, range 150-200/mm3; (d) Pneumocystis carinii pneumonitis, disseminated Mycobacterium avium complex, herpes simplex ulceration, toxoplasmosis, cryptococcosis, and esophageal candidiasis, range 75-125/mm3; (e) cytomegalovirus retinitis, less than 50/mm3. Our data concur with clinical impressions and provide a basis for interim treatment and prophylaxis recommendations.
Monocyte--macrophages are important target cells and reservoirs for HIV. The existing methods for the quantification of infectious virus in HIV stocks are not totally satisfactory for use with macrophage cultures. We have developed an infectious focus assay for the direct quantification of virions infectious for human peripheral blood monocyte-derived macrophages adhering to plastic microtitre plates. The combination of an HIV-1 p24-antigen-specific monoclonal antibody and a beta-galactosidase-linked second antibody resulted in a sensitive and very specific assay. With 5-bromo-4-chloro-3-indolyl-beta-D-galactopyranoside as substrate, the assay proved to be as sensitive as p24 antigen quantification in culture supernatants.
Human immunodeficiency virus-(HIV) infected monocyte-macrophages may contribute to the pathogenesis of HIV-associated immune deficiency and dysfunction by acting as a target and potential reservoir for the virus in vivo, and by functioning abnormally following infection. We have shown that HIV-infected macrophages fuse with uninfected CD4-expressing lymphoid cells in vitro; this may provide an additional mechanism for CD4 lymphocyte depletion in vivo. We report here the inhibition of syncytium formation between HIV-infected macrophages and uninfected CD4-expressing T-lymphoid cells by monoclonal antibody S3.5, directed against an epitope of CD4 involved in binding HIV gp120, by a recombinant protein that comprises the full-length extracellular domain of the CD4 molecule, and by recombinant full-length HIV envelope glycoprotein, gp120. These results indicate that both molecules (gp120 and CD4) are critical to the fusion process, and suggest that gp120 is expressed on the surface of HIV-infected monocyte-macrophages.
We compared the efficacy of 3 antiretrovirals in cultured human peripheral blood monocyte-derived macrophages and lymphoid cells infected with the human immunodeficiency virus (HIV). Zidovudine (greater than 0.01 micrograms/ml) or foscarnet (greater than or equal to 100 micrograms/ml) consistently inhibited HIV replication (p24 antigen production) in acutely infected macrophages by more than 90%; alpha interferon (1,000 units/ml) inhibited HIV replication by 88-99%. Drug efficacy was equal in lymphoid cells and monocyte-derived macrophages. However, these antiretrovirals even in high concentration only minimally inhibited chronic, established HIV infection: while zidovudine (0.01 micrograms/ml) inhibited infection by over 90% in acutely infected macrophages and lymphoid cells, 50 micrograms/ml of this antiretroviral produced only 19-55% inhibition of HIV replication in chronically infected cells. Slot-blot analysis of HIV RNA was concordant with the p24 antigen data. Acutely infected macrophages are as susceptible to the inhibitory effects of antiretrovirals as lymphoid cells; however, chronically infected macrophages (which probably constitute the main in vivo reservoir for HIV) are several orders of magnitude more resistant.
Gastrointestinal Kaposi's sarcoma is a well described and usually asymptomatic manifestation of the acquired immune deficiency syndrome. We report a patient who had extensive colonic Kaposi's sarcoma and presented with an ulcerative colitis like illness. Total colectomy was subsequently required as an emergency procedure for toxic megacolon. The patient remains well on maintenance interferon therapy 21 months after surgery.
This report documents an outbreak of hepatitis B (HB) and hepatitis D (HD) in a group of butcher shop employees. During the 13-month period from September 1983 to October 1984, 8 employees from 2 establishments developed acute HB. Epidemiological investigation suggested that the first case, who was also an intravenous drug user, was the source of infection for other employees. This person and 2 others were found to have concurrent HD. In November 1984 the wife of one of the infected butchers also developed HB.
In early 1984, five patients who were undergoing plasmapheresis at a Melbourne hospital developed a transient hepatitis B surface antigenaemia. A common batch of stabilized plasma-protein solution (SPPS) that was included in the replacement therapy for each patient was found to contain hepatitis B surface antigen (HBsAg). A follow-up study was undertaken of these patients and others who were known to have received SPPS from the same batch (in total, 10 patients were followed for a median of 46.5 weeks). No patient developed evidence of hepatitis, although one patient developed antibody to surface antigen. It was concluded that the manufacturing process was effective in destroying the infectivity of the HBsAg-positive plasma that was used in this batch of SPPS and that the final product was poorly immunogenic in these patients.
Cryopreservation and glycerol preservation are 2 successful methods for long-term preservation of human cadaver skin. Preservation is subjected to strict criteria to minimize the risk of disease transmission. This investigation compares the effects of glycerol preservation and cryopreservation on the inactivation of HIV-1. The effects of glycerol preservation and cryopreservation on inactivation of both extracellular and intracellular HIV-1Ba-L were investigated. After exposing HIV-1Ba-L-infected material to various concentrations of glycerol or to 10% dimethyl sulfoxide followed by cryopreservation, uninfected peripheral blood mononuclear cells were added to the treated material. At different time points during the culture, supernatants were taken to quantify HIV-1Ba-L and reverse transcriptase levels to determine HIV-1Ba-L infectivity. Cell-free HIV-1Ba-L was inactivated within 30 minutes in 70% and 85% glycerol. Also, intracellular HIV-1Ba-L in infected peripheral blood mononuclear cells or infected cadaver skin was completely inactivated by glycerol treatment in vitro. Cryopreservation did not show any extracellular or intracellular HIV-1Ba-L inactivation. Glycerol preservation--but not cryopreservation--of human cadaveric donor skin can inactivate both extracellular and intracellular HIV-1.
We have recently demonstrated that alteration of the human immunodeficiency virus type 1 (HIV-1) Gag/GagPol ratio in virus-producing cells reduces the infectivity of progeny viruses and hinders the formation of stable virion RNA dimers without impairing virion packaging of the viral genomic RNA. In addition, we have previously shown that the expression of GagPol mediates the selective packaging of tRNA(Lys3). In this study we report that overexpression of uncleaved GagPol in the virus-producing cell did not alter the packaging levels of tRNA(Lys3). Similarly, altering the virion-associated Gag/GagPol ratio did not affect the virion packaging of the HIV-1 envelope protein nor cyclophilin A. Thin section electron microscopy analysis of the cells overexpressing protease-defective [PR(-)] GagPol revealed immature virions but no mature virions. These immature virions were seen both extracellularly and in membrane-bound cytoplasmic vacuoles. Furthermore, an accumulation of electron-dense material was occasionally found at the plasma membrane and associated with intracytoplasmic membranous vacuoles in cells expressing excess PR(-) GagPol. No intracellular HIV was seen in the wild-type control. Density gradient analysis showed that the overall density of these mutant virions with excess PR(-) GagPol was identical to that of the wild-type HIV-1. The findings indicate that overexpression of PR(-) GagPol, in the presence of Gag synthesis, promotes intracellular budding of the mutant virions and inhibits virus maturation.