Thomas G. Evans

The presence of a dehydroepiandrosterone-specific receptor binding complex in murine T cells

We have investigated the ability of dehydroepiandrosterone (DHEA) to alter the production of interleukin-2 (IL-2) and to bind to a specific binding complex in antiCD3 epsilon activated T cells. Binding activity correlated with the presence of a specific DHEA binding complex in the cytosol and nuclei of DHEA-responsive T-cell hybridomas, as well as in CD4+ and CD8+ cells isolated from peripheral lymph nodes of normal mice. Scatchard analysis determined that intact lymphocytes and cytosolic fractions contained high affinity binding for [3H]DHEA (approx. 2.6 nM) with 1000-7000 binding sites existing per cell. Five of the T-cell hybridomas tested both responded to DHEA treatment with increased production of IL-2 and also contained specific high affinity [3H]DHEA binding. Four additional T-cell hybridomas were found to contain no specific [3H]DHEA binding and were also unresponsive to DHEA influences on IL-2 production. Sucrose density gradients demonstrated a 3-4s [3H]DHEA binding complex in high salt and a 7-8s binding complex in low salt. Specific binding was inhibited by preincubation of the cytosol fractions with either trypsin or chymotrypsin, or by heating to 60 degrees C for 1 h (less than 15% of control). [3H]DHEA binding was unaffected by preincubation of the cytosol fractions with ribonuclease, deoxyribonuclease, or phospholipase A. The DHEA-protein complexes bound to DNA-cellulose with the amount of binding being slightly increased by preincubation at 25 degrees C as compared to 4 degrees C. As expected, [3H]DHEA binding was inhibited by the addition of unlabeled DHEA, but was also modestly inhibited by dihydrotestosterone and cortisol. Binding of DHEA was unaffected by progesterone, dexamethasone, estradiol, androsterone, DHEAS, and beta-etiocholanolone at all concentrations tested. DHEA was incapable of inhibiting the binding of [3H]DHT to the androgen receptor or [3H]dexamethasone to the glucocorticoid receptor. Collectively, these findings suggest that murine T cells contain a specific DHEA receptor. We believe that DHEA is a steroid hormone that is directly involved in the regulation of IL-2 production by both normal and some T-cell hybridomas.

The prophylactic use of low-dose amphotericin B in bone marrow transplant patients

PURPOSEnTo evaluate the efficacy of prophylactic low-dose amphotericin B (0.1 mg/kg per day) (LDA) in preventing fungal infections in patients who have had a bone marrow transplant (BMT).nnnMATERIALS AND METHODSnDouble-blind, randomized, controlled trial in which patients undergoing bone marrow transplantation received intravenous LDA or similar-appearing placebo from the onset of neutropenia until the absolute neutrophil count remained > 0.5 x 10(9)/L, or until high-dose amphotericin B was initiated. Weekly surveillance cultures were obtained from all patients.nnnRESULTSnFive of 18 patients (28%) randomized to placebo developed documented systemic fungal infections within the first 30 days after transplantation, compared to none of 17 patients who received LDA (P = 0.045). LDA recipients received fewer days of high-dose amphotericin B (P = 0.04) and fewer days of antibiotics (P = 0.008). There were trends towards fewer days of hospitalization (P = 0.14) and improved survival (P = 0.08); these differences were statistically significant among recipients of allogeneic BMT. No adverse effects occurred with LDA therapy.nnnCONCLUSIONSnLDA appears to be safe and to reduce early systemic fungal infections in BMT recipients. Improved survival was observed among LDA recipients, but this was not directly attributable to the prevention of fungal infection.

Effect of Dronabinol on Nutritional Status in HIV Infection

OBJECTIVE: To examine the effect of dronabinol (delta-9-tetrahydrocannabinol) on appetite and nutritional status in patients with symptomatic HIV infection and weight loss. DESIGN: Double-blind, randomized, placebo-controlled, crossover trial with two five-week treatment periods separated by a two-week washout period. Patients received dronabinol 5 mg twice daily before meals or placebo. SETTING: A university-based HIV/AIDS clinic and a large infectious disease private practice largely devoted to care of patients with HIV. PARTICIPANTS: Twelve HIV-infected patients who had had at least a 2.25-kg weight loss participated in the study. Five patients completed the protocol, and seven withdrew (two because of drug intolerance, two because of disease progression, two because of noncompliance, and one because of experimental antiretroviral therapy). MAIN OUTCOME MEASURES: Main outcome measures included caloric intake, weight, percent body fat, serum prealbumin, and symptom distress. RESULTS: During dronabinol treatment, subjects experienced increased percent body fat (one percent, p=0.04); decreased symptom distress (p=0.04); and trends toward weight gain (0.5 kg, p=0.13), increased prealbumin (29.0 mg/L, p=0.11), and improved appetite score (p=0.14). CONCLUSIONS: In a selected group of HIV-infected patients with weight loss, short-term treatment with dronabinol may result in improvement in nutritional status and symptom distress.

DHEAS as an Effective Vaccine Adjuvant in Elderly Humans: Proof-of-Principle Studies

We have demonstrated that in aged mice, the titer of serum antibody induced against tetanus toxoid correlates with resistance to local paralysis caused by injection of tetanus toxin. Only mice immunized shortly after oral dosing with DHEAS demonstrated high serum antibody titers and complete protection from paralysis. These results became the basis for initiating proof-of-principle studies in human volunteers above age 65 using a licensed influenza vaccine and tetanus toxoid in two independent studies. The use of an oral delivery form of DHEAS before influenza vaccination was associated with a demonstrable increase in the number of individuals with a fourfold increase in HAI titers following vaccination. The overall mean increase in HAI titers was highest in the DHEAS-treated group. The use of DHEAS in the immunization of elderly subjects against tetanus toxoid, while unable to enhance the responses, was not a detriment to antibody response. We conclude that further studies will justify the use of DHEAS as an adjuvant for antigens that represent primary responses in the elderly.

The use of oral dehydroepiandrosterone sulfate as an adjuvant in tetanus and influenza vaccination of the elderly

Elderly individuals often exhibit a poorer immune response and shorter duration of immunity to vaccines than younger persons. Improvement in vaccine response has been demonstrated when administering the hormone dehydroepiandrosterone sulfate (DHEAS) as an adjuvant in animal trials. Two separate, randomized double-blinded vaccine trials were therefore conducted using DHEAS as an oral adjuvant in individuals age 65 or older. Sixty-six individuals were randomized to DHEAS, 50 mg po bid for 4 days, or a placebo capsule. Tetanus vaccination was given immediately before the fifth dose. At entry the level of protective antibody was age-dependent (P = 0.009), and by 28 days post-vaccination most individuals had protective levels of antibody, with no difference noted between treatment groups. In the second study, 67 individuals received placebo capsules or DHEAS immediately before and 24 h after influenza vaccination. The number of individuals who developed protective titers (> or = 1:40) was not different in the two groups. The mean log increase in HAI response was greater in the DHEAS group to all three vaccine components, although this did not achieve significance. Minimal side-effects of DHEAS administration were noted. Given the trend toward improved response in the elderly to influenza, larger trials using DHEA as an adjuvant in vaccines that are neoantigens may be indicated.

Th1Th2-like immunity and resistance to herpes simplex labialis

To investigate potential immunologic mechanisms of resistance to recurrent herpes simplex labialis, we assayed serum antibody titers and cultured peripheral blood mononuclear cell (PBMC) cytokine production among patients with a history of frequent episodes (H+S+), herpes simplex virus (HSV)-seropositive individuals without a history of herpes labialis (H-S+) and HSV-seronegative persons (H-S-). In addition, H+S+ patients were exposed to experimental ultraviolet radiation (UVR) on the lips and the immunologic assay results compared among those who developed experimental lesions and those who did not. H+S+ patients were found to have higher median serum titers of HSV antibody and trends to lower levels of HSV-specific PBMC IFN-gamma and IL-2 than H-S+ control patients (123 vs 66, P = 0.04; 424 vs 548 pg/ml, P = 0.08; 14 vs 26 pg/ml, P = 0.14, respectively). Correlation of the results with the occurrence of experimental lesions showed the inverse: the subgroup of H+S+ patients with UVR-induced lesions had lower titers of antibody and trends to higher levels of IFN-gamma and IL-2 than H+S+ patients who could not be induced (93 vs 149, P = 0.02; 501 vs 347 pg/ml, P = NS; 26 vs 11 pg/ml, P = NS, respectively). The size and duration of UVR-induced lesions showed positive correlations with IFN-gamma and IL-2 levels (r = 0.60-0.67, P = 0.02-0.04). Although the small number of patients limited the power of this study, the overall pattern of the findings suggests that a Th1-like cytokine response (IFN-gamma and IL-2 production) may be associated with resistance to naturally occurring episodes of herpes labialis. The development and severity of experimental UVR-induced herpes labialis appears to be regulated differently and may involve an immunopathologic mechanism.

Susceptibility to herpes labialis following multiple experimental exposures to ultraviolet radiation

We studied susceptibility to herpes labialis by exposing 20 volunteers to experimental ultraviolet radiation (UVR) on three occasions at 3- to 4-month intervals. The number of patients who developed lesions after each session was 9/20 (45%), 9/20 (45%) and 14/20 (70%). Herpes simplex virus (HSV) was isolated from 21/29 (72%) of lesions sampled. Three patients never developed a lesion, 13 developed lesions on one or two of the three occasions, and 4 patients had a lesion following all three sessions. Seven of 33 (21%) lesions were immediate lesions (developed within 48 h) and the others developed 3-7 days after UVR exposure (delayed lesions). Development of lesions correlated with historical susceptibility to sun-induced herpes labialis, but not with age, sex, years with herpes labialis, frequency of herpes labialis from all causes, or concurrent serum levels of cortisol, dehydroepiandrosterone, estradiol, progesterone or alpha 1-antitrypsin. Among normally menstruating females, a significant association was identified between the development of herpes labialis and the luteal phase of the menstrual cycle (8 cases of herpes labialis/11 attempts, RR = 14, P = 0.005). The lack of correlation between episodes of natural herpes labialis and susceptibility to experimental UVR-induced disease suggests that these events are controlled differently. The results of serial attempts to induce experimental herpes in each patient was most commonly inconsistent, indicating that individual patient susceptibility to UVR varies over time. While the explanation for this variation remains unclear, stages of the menstrual cycle may be important among women.

Preventive vaccines for tuberculosis

There are nearly ten million new cases and 1.4 million deaths from tuberculosis (TB) each year, and the 90-year old bacille calmette-guérin (BCG) vaccine in widespread use appears to have minimal impact on the worldwide incidence, despite demonstrating reasonable efficacy against complications of infant TB and death. Novel vaccine development has accelerated in the past ten years, with at least 16 candidates entering human trials, and a few vaccines have entered into Phase 2b efficacy studies. However, different vaccines may be needed due to the varying disease states (naïve, latently infected, or active), the ages affected (infants, adolescents and young adults, the elderly), and patient health status (HIV and immunocompromised patients especially). Modeling has shown that mass vaccination of latently infected populations, especially adolescents and young adults, will likely have the largest impact on new infection rates. At present, research and development of TB vaccines is hampered by the lack of validated animal models, the absence of correlates of immunity and a human challenge model, as well as by the size and cost of Proof-of-Concept clinical trials. Nonetheless, ongoing research and clinical studies should remove many of these barriers over the next five years, and lead to an increased understanding of the pathogenicity of Mycobacterium tuberculosis and what may constitute protective immunity during various stages of infection and disease.

Voluntary reporting of employee influenza vaccination rates by acute care hospitals in Iowa: The impact of a four year provider-based statewide performance improvement project

OBJECTIVEnIn 2006 a voluntary, provider-based project was initiated to improve influenza vaccination rates among healthcare workers (HCWs) employed by acute care hospitals in Iowa. The statewide vaccination target was 95% by 2010. Data from the first four influenza seasons (2006-2007, 2007-2008, 2008-2009 and 2009-2010) are presented.nnnMETHODSnA website was used to submit and circulate hospital-specific influenza vaccination rates. Rates were fed back to participating hospitals from the outset and hospital-specific rates made publicly available for the last two influenza seasons.nnnRESULTSnHospital participation rates ranged from 86% in season 1 to 100% in the subsequent three seasons. Statewide median hospital employee vaccination rates trended upward from 73% in season 1 to 93% in season 4. By season 4, 35% of participating hospitals had reached or exceeded a 95% vaccination rate. In season 4 the mean employee vaccination rate of 19 hospitals reporting use of a mandatory vaccination policy was 96% vs. 87% in the 64 hospitals not using such policies.nnnCONCLUSIONnOver a 4 year period, while participating in a provider-based, voluntary project, acute care hospitals in Iowa reported significantly improved seasonal influenza vaccination rates among their employees.

Status of vaccine research and development of vaccines for tuberculosis

TB is now the single pathogen that causes the greatest mortality in the world, at over 1.6 million deaths each year. The widely used the 90 year old BCG vaccine appears to have minimal impact on the worldwide incidence despite some efficacy in infants. Novel vaccine development has accelerated in the past 15 years, with 15 candidates entering human trials; two vaccines are now in large-scale efficacy studies. Modeling by three groups has consistently shown that mass vaccination that includes activity in the latently infected population, especially adolescents and young adults, will likely have the largest impact on new disease transmission. At present the field requires better validated animal models, better understanding of a correlate of immunity, new cost-effective approaches to Proof of Concept trials, and increased appreciation by the public health and scientific community for the size of the problem and the need for a vaccine. Such a vaccine is likely to also play a role in the era of increasing antibiotic resistance. Ongoing efforts and studies are working to implement these needs over the next 5 years, which will lead to an understanding that will increase the likelihood of a successful TB vaccine.