Markers of HIV infection in the Concorde trial. Concorde Co-ordinating Committee

The Concorde trial compared immediate (Imm) with deferred (Def) AZT monotherapy in asymptomatic HIV-positive participants. Haematological and immunological markers and weight were measured throughout, and correlated with clinical endpoints. Markers associated with disease progression (CD4 lymphocyte count and percentage, platelets, p24 antigen and beta 2 microglobulin favoured Imm: those associated with toxicity (haemoglobin, neutrophils and white cell count) favoured Def. CD8 and total lymphocyte count did not differ significantly between groups. In multivariate analysis, the combination of baseline CD4, p24 antigen and beta 2m was the best baseline predictor of disease. Including change in CD4 and beta 2m at 12 weeks, or changes over follow- up in these markers significantly improved the fit. Markers were also incorporated into the definition of 'clinical' endpoints. Hazard ratio estimates from end-points that included CD4 < 50 and CD4 < 25 were closest to those for AIDS or death alone, but added very few extra events. Use of other landmark CD4 counts (100 or greater) or relative decreases in counts (25% or more) increased the number of events, but overestimated the effect of immediate AZT. Although AZT had a beneficial effect on the surrogate markers of efficacy evaluated, these changes did not predict clinical outcome, nor could the markers be usefully incorporated into an endpoint definition.      

Tissue factor serum levels and the risk of future coronary artery disease in apparently healthy men and women: the EPIC-Norfolk prospective population study

INTRODUCTION: Tissue factor (TF) has been implicated in coronary artery disease (CAD). High levels of circulating TF are found in patients with acute atherothrombotic events. Whether high serum TF levels predict risk of future CAD independent of known risk factors remains unknown. METHODS: We conducted a prospective case-control study nested in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Norfolk population study. Cases (n=1037) were apparently healthy men and women, aged 45-79 years, who developed fatal or non-fatal CAD during follow-up. Controls (n=2005) were matched by age, sex, and enrolment time. Serum TF levels were measured using high-affinity antibodies. RESULTS: In men, median TF levels were not significant higher in cases than in controls (59.0 pg mL-1, range: 16.7-370.4 vs. 54.9 pg mL-1, range: 16.2-452.4). In women, median TF levels were not significant higher in controls than in cases (73.4 pg mL-1, range: 16.7-492.3 vs. 50.5 pg mL-1, range: 16.5-376.7). The incidence of smoking was about double in the lowest compared with the highest TF quartile. Correcting for sex, age, body mass index, smoking, diabetes, systolic blood pressure, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol and C-reactive protein levels, the risk of future CAD was 1.05 (95% CI: 0.81-1.36) for people in the highest TF quartile, compared with those in the lowest (P-value for linearity=0.8). CONCLUSION: High levels of serum TF were not independently associated with an increased risk of future CAD in apparently healthy individuals.     

Biocompatibility of white cell filters as evaluated by complement activation

The biocompatibility of nine different white cell filters was examined by analysis of complement activation in plasma specimens obtained from blood components before and after filtration. Filters for both red cell (RBC) concentrates and platelet concentrates (PCs) were tested. It was found in all of the filters tested that the postfiltration levels of complement activation products were not higher than the prefiltration levels in RBC concentrates and PCs. One exception was the filtration of multiple PCs with Imugard IG-500, in which case a rise in C3 activation products was seen. Moreover, there was a significant rise in C3 activation products, but not the terminal complement complex, when plasma was filtered through Imugard E, which contrasted with results with the other filters. High initial and storage time-dependent levels, especially of C3 activation products, were observed in the PCs, probably due to their processing at room temperature. It can be concluded that the majority of the filters tested do not activate complement.     

Platelet concentrates stored for 5 days in a reduced volume of plasma maintain hemostatic function and viability

BACKGROUND: Platelet concentrates prepared from whole blood are generally suspended in a standard volume of 50 to 60 mL of plasma and can be stored thus at 20 to 24 degrees C for up to 5 days. In vitro studies suggested that this plasma volume could be reduced to 30 to 35 mL without impairing platelet function. STUDY DESIGN AND METHODS: This study evaluated whether platelets stored for 5 days in a reduced volume (30-35 mL) of plasma maintained their in vivo viability, hemostatic function, and recovery in recipients. Paired autologous platelet survival studies were done in 20 adult volunteers to assess platelet viability. A rabbit ear bleeding-time model was used to compare the hemostatic effectiveness of human platelet concentrates stored for 5 days in the standard or reduced volume of plasma. Platelet recovery was compared in thrombocytopenic hospital patients. RESULTS: Paired platelet survival studies indicated no significant difference between the values in platelet concentrates stored for 5 days in the reduced volume of plasma and the values in those stored in the standard volume. In the animal model, there was no significant difference in the bleeding times achieved by either set of platelet concentrates. The platelet count increments in thrombocytopenic patients were measured. The platelet count increments in patients who received reduced-volume platelet concentrates were as good as the increments achieved in patients given standard-volume concentrates. CONCLUSION: The in vivo viability, recovery, and hemostatic function of platelets collected in polyvinylchloride plastic containers and stored in 30 to 35 mL of plasma for 5 days are maintained as well as those of platelets stored in 50 to 60 mL of plasma.     

Safety, tolerability, pharmacokinetics, and Abeta levels after short-term administration of R-flurbiprofen in healthy elderly individuals

To evaluate the safety and tolerability and pharmacokinetic properties of R-flurbiprofen (Tarenflurbil) in normal elderly individuals and to determine the effect of the drug on amyloid beta 42 (Abeta42) levels, we conducted a double-blind, placebo-controlled study of 48 healthy subjects aged 55 to 80. Three successive cohorts were randomized to doses of 400, 800, or 1600 mg/d, or placebo, given as 2 divided doses for 21 days. Blood and cerebrospinal fluid were collected for pharmacokinetic studies and measurement of Abeta levels at baseline and on day 21. R-flurbiprofen was well-tolerated at all 3 doses. The compound penetrated the blood-brain barrier in a dose-dependent manner. From baseline to 21 days, comparisons between study groups revealed no significant differences in changes of cerebrospinal fluid Abeta42 levels and no significant differences in changes of plasma Abeta42 levels at the time of trough drug level at 21 days of treatment. Further analysis of drug concentration-response for plasma samples showed that at the time of peak plasma concentration, higher plasma drug concentration was related to lower Abeta42 plasma levels (P=0.016). R-flurbiprofen had an excellent safety profile and showed dose-dependent central nervous system penetration. Exploratory analyses of plasma Abeta and peak drug levels suggested a short-term effect in plasma that warrants independent verification. The safety, tolerability, and pharmacokinetic profile of R-flurbiprofen in these older individuals support the ongoing studies of this compound in patients with Alzheimer disease.     

Accessory-Cell-Mediated Activation of Porcine NK Cells by Toll-Like Receptor 7 (TLR7) and TLR8 Agonists

The induction of innate immune responses by toll-like receptor (TLR) agonists is the subject of intense investigation. In large part, this reflects the potential of such compounds to be effective vaccine adjuvants. For that reason, we analyzed the activation of innate cells in swine by TLR7 and TLR8 agonists. These agonists activated porcine NK cells by increasing gamma interferon (IFN-γ) expression and perforin storage. The activation of porcine NK cells was mediated by accessory cells, since their depletion resulted in reduced cytotoxicity toward target cells. Accessory cells were stimulated to produce interleukin 12 (IL-12), IL-15, IL-18, and IFN-α after treatment with TLR7 or TLR8 agonists. Neutralization of these cytokines reduced but did not completely inhibit the induction of NK cell cytotoxicity. Direct stimulation of NK cells with TLR7 or TLR8 agonists resulted in minimal cytotoxicity but levels of IFN-γ equivalent to those detected in the presence of accessory cells. Porcine NK cells express both TLR7 and TLR8 mRNAs, and treatment with these TLR agonists induced higher mRNA expression levels of TRAIL and IL-15Rα, which may contribute to the activity of NK cells. These data indicate that TLR7 and TLR8 agonists indirectly or directly activate porcine NK cells but that optimum levels of activation require cytokine secretion by accessory cells activated by these compounds. Interestingly, NK cells activated by TLR7 or TLR8 agonists were cytotoxic against foot-and-mouth disease virus (FMDV)-infected cells in vitro, indicating that these TLR agonists may be beneficial as adjuvants to stimulate the innate immunity against FMDV.Toll-like receptors (TLRs) are pathogen-associated molecular pattern recognition receptors responsible for signaling intrusion by pathogens. These receptors are expressed by cells mediating innate responses. Pathogens are recognized directly by the binding of pathogen-associated molecules. For example, TLR3 recognizes double-stranded RNA during virus replication; TLR5 binds bacterial flagellin; TLR9 detects nonmethylated, CG-rich prokaryotic DNA, i.e., CpG; and TLR7 and TLR8 recognize single-stranded RNA (44), although recognition by TLR8 may be species specific, as demonstrated recently by Forsbach et al. (11). The consequence of engaging TLRs is the induction of signals that lead to the expression of proinflammatory cytokines, antimicrobial and antiviral effector molecules, and costimulatory molecules on macrophages (Mφ) and dendritic cells (DCs) (25, 39). Overall, such events affect the activation and functional status of innate immune cells, such as natural killer (NK) cells and DCs, and further influence the organization of adaptive immune responses.NK cells perform a critical role in innate immunity, leading to protection against various pathogens well before the adaptive immune responses develop. NK cells are lymphocyte-derived cells that engage nonspecific target recognition mechanisms to eliminate malignant or virus-infected cells (10). However, it has recently been shown that some receptors on NK cells engage viral gene products. For example, Ly49H recognizes m157 of murine cytomegalovirus in mice, while NKp44 and NKp46 bind influenza virus hemagglutinin (4, 27). Moreover, NK cells express both inhibitory and activating receptors, which directly influence the outcome of NK cell activation. Besides the expression of such receptors (22), NK cells have other mechanisms that enhance their function as natural spontaneous effector cells (24). Such mechanisms include the expression of TLRs, which possibly allow NK cells to respond to the presence of pathogens by direct activation via these receptors.NK cells express TLR9 in mice (26) and TLR1 to TLR10 in humans (12, 17, 23). However, not much information is currently available on the expression of these receptors on immune cells of domestic livestock species, such as porcine or bovine species. Direct stimulation of human NK cells through TLR2, TLR3, TLR7, and TLR8 leads to the upregulation of gamma interferon (IFN-γ) secretion, although in some instances this response requires the presence of interleukin 12 (IL-12) (6, 12, 17). Furthermore, activation via TLR5 is reported to stimulate NK cell proliferation but not IFN-γ production (45). Additionally, stimulation via TLR2 or TLR7 induces chemokines such as CCL3, CCL4, and CCL5 (36). Although TLR9 is expressed in NK cells, it does not induce IFN-γ production directly unless the NK cells are presented with antibody-coated target cells or are cultured on plates with an immobilized antibody against immunoglobulin G (35). Therefore, TLR expression in NK cells may be involved in the differential regulation of these vital cells of the innate response. However, not much is known about the direct effect of TLR stimulation on the expression of NK cell effector molecules, such as perforin, granzymes, and cytokines.Using this class of molecules, it is now possible to formulate vaccine adjuvants that prime cell-mediated immunity. Engaging TLR receptors with specific synthetic agonists introduces a new way of inducing early innate responses as well as increasing the potency of adaptive immunity. The importance of such an approach is exemplified by several clinical studies currently under way. TLR9 and TLR4 agonist are being tested as vaccine adjuvants, and a TLR7 agonist is being tested in the treatment of genital warts caused by herpes simplex virus (28). In addition, TLR4 is being tested for the treatment of allergies, endotoxemia, and liver disease, TLR7 for cancer treatment, and TLR9 as a treatment for melanoma (reviewed by Ulevitch [46]).Foot-and-mouth disease virus (FMDV) infects cloven-hoofed animals, leading to devastating economic consequences (16). This is a highly contagious viral infection that causes a very acute disease. Clinical symptoms are detected within 1 or 2 days of exposure and resolve within a week to 10 days. Viral clearance may be mediated in part by antibodies, but under controlled experimental conditions, viremia is gone by day 3 or 4 after infection when anti-FMDV immunoglobulin M is barely detectable (2, 13). These results strongly suggest that other antiviral mechanisms contribute to the elimination of the virus in vivo. Innate responses, including the activation of DCs and NK cells, are likely involved.Therapeutic approaches involving TLR stimulation via synthetic agonists can augment innate responses, indicating that such therapeutics have the potential to induce early protection against foot-and-mouth disease (29, 30). Therefore, we have studied the effects of TLR agonists on porcine NK cells in vitro. We report that TLR7 and TLR8 agonists and a combined TLR7/8 agonist activate porcine CD2⁺ CD8⁺ CD3⁻ NK cells through accessory-cell-mediated mechanisms, such as the secretion of cytokines, including IFN-α, IL-12, IL-15, and IL-18. In addition, porcine NK cells are partially activated by the direct interaction of TLR7 and TLR8 agonists through these receptors expressed by NK cells. Activated cells show enhanced secretion of IFN-γ and storage of perforin granules and can effectively lyse tumor or FMDV-infected targets. These results are discussed in the context of rational approaches to antiviral measures against FMDV.     

The use of hematopoietic hormones in HIV infection and AIDS-related malignancies

Three hematopoietic stimulants have been used in patients with HIV infection and a variety of AIDS-related complications. Both G-CSF and GM-CSF have demonstrated the ability to correct leukopenia related to HIV infection and ameliorate the drug-related myelosuppressive effects of zidovudine, trimethoprim/sulfamethoxazole, ganciclovir, and, in the case of GM-CSF, alpha-interferon, and cancer chemotherapies. Erythropoietin has been successfully used to ameliorate the anemia associated with HIV infection and zidovudine therapy. Treatment with these hematopoietic stimulants is very well tolerated with minimal toxicity. Of the granulocyte stimulants, G-CSF appears to induce fewer side effects than GM-CSF in trials conducted to date. Future trials demonstrating that the amelioration of hematopoietic suppression by the colony-stimulating factors results in increased clinical response rates and improved survival are necessary to fully assess the value of this approach in the care of HIV-infected patients.     

Early speech changes in children with multichannel cochlear implants

A number of studies have demonstrated that cochlear implants provide an improved auditory signal and enhance the development of speech-perception and production skills for profoundly deaf children. However, exactly when these early speech skills begin to develop remains unclear. To explore this issue, we observed, for a 1-year period, four prelingually deaf children who underwent implantation consecutively within 1 month of each other, and we paid particular attention to the first few months of rehabilitation. We found immediate speech scores as early as the first day of implant tune-up. Speech production continued to improve rapidly throughout the first 4 months but exhibited a generally slower rate of progress in some of the speech-production skills at 1 year. We also found vowel-production skills to be the easiest to achieve, with word-pattern recognition and consonant voicing of intermediate difficulty. Consonant placing and manner of consonant production were the hardest skills to achieve. Results of speech-perception tests 1 year after implantation were markedly improved over preimplantation levels in three of the four children. These early speech changes stress the need for maximization of the capability of the cochlear implant by institution of immediate and intensive speech rehabilitation efforts for prelingually deaf children. (Otolaryngol Head Neck Surg 1996;115:508-12.)     

Abdominal presentation of varicella-zoster infection in recipients of allogeneic bone marrow transplantation.

We report here three recipients of allogeneic bone marrow transplantation in whom visceral varicella-zoster virus infection preceded cutaneous dissemination producing life-threatening complications including hepatitis, pancreatitis and haemorrhage.