Rob Roy MacGregor

First Human Trial of a DNA-Based Vaccine for Treatment of Human Immunodeficiency Virus Type 1 Infection: Safety and Host Response

A DNA-based vaccine containing human immunodeficiency virus type 1 (HIV-1) env and rev genes was tested for safety and host immune response in 15 asymptomatic HIV-infected patients who were not using antiviral drugs and who had CD4+ lymphocyte counts of > or = 500 per microliter of blood. Successive groups received three doses of vaccine (30, 100, or 300 microg) at 10-week intervals in a dose-escalation trial. Vaccine administration induced no local or systemic reactions, and no laboratory abnormalities were detected. Specifically, no patient developed anti-DNA antibody or muscle enzyme elevations. No consistent change occurred in CD4 or CD8 lymphocyte counts or in plasma HIV concentration. Antibody against gp120 increased in individual patients in the 100- and 300-/microg groups. Some increases were noted in cytotoxic T lymphocyte activity against gp160-bearing targets and in lymphocyte proliferative activity. The safety and potential immunogenicity of an HIV-directed DNA-based vaccine was demonstrated, a finding that should encourage further studies.

Inhibition of Granulocyte Adherence by Ethanol, Prednisone, and Aspirin, Measured with an Assay System

Abstract A simple, rapid, in vitro assay was developed to study granulocyte adherence, an important component of the inflammatory reaction. Heparinized whole blood is filtered through nylon fiber packed in Pasteur pipettes, and the percentage of granulocytes adhering is calculated. Test variability from morning to evening, before and after meals, and on successive days is less than 10 per cent. In vitro exposure of whole blood to ethanol concentrations varying from 100 to 1000 mg per 100 ml caused a dose-dependent, significant inhibition of adherence (16–87 per cent, p<0.05), but incubation with sodium salicylate (5 to 50 mg per 100 ml) or hydrocortisone sodium succinate (500 to 3000 μg per 100 ml) had no effect. In all volunteers receiving 40 mg of prednisone or 1.2 g of aspirin, impaired adherence developed, suggesting that glucocorticoids and salicylates may affect adherence in vivo by inducing an inhibitor. The anti-inflammatory effect of salicylates, hydrocortisone and ethanol may be secondary to the...

A randomized clinical trial of granulocyte transfusions for infection in acute leukemia.

In a prospective, controlled, randomized study to evaluate the efficacy of filtration-leukapheresis granulocytes in granulocytopenic, febrile patients with leukemia, 19 patients received antibiotics alone, and 12 received antibiotics plus daily granulocyte transfusions from ABO-matched donors. In skin-chamber studies the granulocytes appeared at sites of inflammation for at least six hours after transfusion. Infected subjects survived longer if they received granulocytes. Differences between control and transfused patients were greatest in patients with persistent bone-marrow failure, the 21-day survival being 20 per cent in controls, and 75 per cent in transfused patients. Granulocytes appeared to have no effect on the outcome of febrile episodes in which infection was not documented, the 21-day survival being 79 per cent for controls and 88 per cent for transfused patients. The transfusion of granulocytes thus appears to offer a survival advantage to infected, persistently granulocytopenic patients.

Alternate-day prednisone therapy. Evaluation of delayed hypersensitivity responses, control of disease and steroid side effects.

Abstract Patients with a variety of febrile, inflammatory disorders were given an average dose of 62 mg of prednisone every other day for periods lasting from one to 16 months. In seven patients, a switch from daily to alternate-day therapy was followed by increased delayed hypersensitivity responses to appropriate antigens. In five patients started directly on an alternate-day schedule, pre-existing skin reactivity was not suppressed. In addition, six of seven patients could be sensitized to dinitrochlorobenzene while on alternate-day steroids. Patients on the alternate-day schedule had remarkably mild side effects.

Vaccination of Seronegative Volunteers with a Human Immunodeficiency Virus Type 1 envlrev DNA Vaccine Induces Antigen-Specific Proliferation and Lymphocyte Production of β-Chemokines

There is a pressing need to test novel vaccine concepts in an effort to develop an effective vaccine for human immunodeficiency virus (HIV) type 1. A phase I clinical study was done to test the immunogenicity of an HIV env/rev DNA vaccine, which was administered intramuscularly to HIV-1-seronegative persons. Subjects received 3 doses of vaccine at a single concentration (100 or 300 microgram) at 0, 4, 8, and 24 weeks. In at least 1 of multiple assays, the 6 subjects who received the 300-microgram dose had DNA vaccine-induced antigen-specific lymphocyte proliferative responses and antigen-specific production of both interferon-gamma and beta-chemokine. Furthermore, 4 of 5 subjects in the 300 microgram-dose group responded to both the rev and env components of the vaccine. The responses did not persist within inoculated individuals and scored in different individuals at different times in the trial. This study supports that HIV-1 DNA vaccine antigens can stimulate multiple immune responses in vaccine-naive individuals, and it warrants additional studies designed to enhance DNA vaccine immunogenicity.

Comparative adherence of granulocytes to endothelial monolayers and nylon fiber.

Adherence of granulocytes to tissue culture monolayers of endothelium averaged 26.2 +/- 1.3% SEM, which was similar to their adherence on 50-mg nylon fiber columns (27.7 +/- 3.6%). In contrast, adherence to epithelial cells, fibroblasts, kidney cells, and plastic Petri dishes without monolayers was only 12.4, 9.9, 11.1, and 4.3%, respectively. Cyclic nucleotides and adherence-modifying plasma factors induced changes of adherence to endothelium similar to those in nylon fiber columns. Adherence of granulocytes in whole blood was the same as for purified granulocytes in Hanks balanced salt solution. Exposure of endothelial monolayers to 0.18% trypsin for 10 min reduced subsequent granulocyte adherence to 25.2% of control values. Incubation of trypsin-treated monolayers with nutrient medium for 4 h did not improve adherence, but values returned to normal or above by 24 h, with or without serum proteins present in the nutrient medium. The similarity of granulocyte adherence to nylon fiber and to endothelial monolayers in vitro suggests that results with the nylon fiber assay reflect in vivo granulocyte-endothelium interaction. Furthermore, the endothelial monolayer offers a new model for studying this cell-cell relationship in vitro.

Clindamycin Compared with Penicillin for the Treatment of Anaerobic Lung Abscess

The clinical efficacy of clindamycin was compared with that of penicillin in a randomized study of the treatment of community-acquired putrid lung abscess. After starting therapy, patients treated with clindamycin had a shorter febrile period and fewer days of fetid sputum than patients treated with penicillin (mean 4.4 versus 7.6 days and 4.2 versus 8.0 days, respectively, p less than 0.05). Four of 20 patients treated with penicillin had clinically significant pulmonary or pleural extension of their infection within 10 days after starting therapy; this was not found in any of 19 patients treated with clindamycin (p less than 0.05). Penicillin treatment failed in two additional patients after 20 days of therapy. Within 1 month after treatment, 1 of 4 patients given penicillin for 3 weeks had relapse, but none of the 13 patients given clindamycin for 3 or 6 weeks, and none of the 5 patients given penicillin for 6 weeks had relapse. Overall, only 8 of 15 patients treated with penicillin who could be followed to the end of the study were cured, whereas all 13 patients treated with clindamycin who could be followed were cured (p less than 0.01). These results suggest that penicillin may not be optimal therapy for anaerobic lung abscess.

A Randomized, Double-Blind Trial of Valaciclovir Prophylaxis for Cytomegalovirus Disease in Patients with Advanced Human Immunodeficiency Virus Infection

Cytomegalovirus (CMV) disease is a common complication of advanced human immunodeficiency virus (HIV) infection. Administration of oral valaciclovir, a valine ester of acyclovir, achieves sufficient plasma acyclovir levels to inhibit many clinical isolates. Acyclovir has been associated with enhanced survival in AIDS but not with CMV disease prevention. CMV-seropositive patients (1227) with CD4 cell counts <100/mm3 were enrolled in a randomized, double-blind trial. Valaciclovir, 8 g/day, was compared with acyclovir, 3.2 or 0.8 g/day, for CMV prevention; all three arms were compared for survival. The confirmed CMV disease rate was 11.7% among valaciclovir recipients and 17.5% in the pooled acyclovir arms, a 33% reduction in risk. Time to confirmed CMV disease was significantly longer for the valaciclovir group (P = .03). A trend toward earlier mortality for valaciclovir recipients was seen (P = .06). Toxicity and earlier medication discontinuation were more common in this group. Valaciclovir significantly reduces the risk of CMV disease. Further exploration of a better-tolerated dose is warranted.

DNA vaccination with HIV-1 expressing constructs elicits immune responses in humans

Humoral and cellular immune responses have been produced by intramuscular vaccination with DNA plasmids expressing HIV-1 genes, suggesting possible immunotherapeutic and prophylactic value for these constructs. Vaccination with these constructs has decreased HIV-1 viral load in HIV-1-infected chimpanzees. In addition, naive (i.e. non-HIV-1-infected) chimpanzees were protected against a heterologous challenge with HIV-1. Ongoing phase I clinical trials show that therapeutic vaccinations indeed boost anti-HIV-1 immune responses in humans. A therapeutic phase I trial on humans with these constructs induced a good safety profile and also demonstrated an immunological potentiation. These findings indicate that further studies with these constructs in humans are warranted.

Vancomycin concentrations in infected and noninfected human bone.

Concentrations of vancomycin in bones of 14 patients undergoing total hip arthroplasty (group 1) and 5 patients with osteomyelitis (group 2) were studied. Group 1 received vancomycin, 15 mg/kg intravenously, 1 h prior to anesthesia. Group 2 received doses adjusted to achieve peak levels in serum of 20 to 30 micrograms/ml and trough levels of less than 12 micrograms/ml; bone specimens were collected during surgical debridement. The specimens were pulverized and eluted into phosphate buffer, and the supernatants were analyzed for vancomycin content by fluorescence polarization immunoassay. In group 1, vancomycin was detectable in all cancellous specimens with a mean concentration of 2.3 +/- 4.0 micrograms/g (range, 0.5 to 16 micrograms/g); 10 of 14 cortical specimens had detectable vancomycin; the mean cortical concentration was 1.1 +/- 0.8 micrograms/g (range, not detectable to 2.6 micrograms/g). In group 2, vancomycin was detectable in only two of five cortical bone specimens (mean concentration, 5.9 +/- 3.5 micrograms/g). Cancellous bone was obtained in one patient; the vancomycin concentration was 3.6 micrograms/g. In most patients the vancomycin levels in bones were higher than the MIC for susceptible staphylococci following single prophylactic doses. In the few infected patients studied, penetration was variable and deserves further study.