Modern management of non-chemotherapy drug-induced agranulocytosis: a monocentric cohort study of 90 cases and review of the literature

BACKGROUND: The present study reports a monocentric experience of 90 drug-induced agranulocytosis cases and discusses their management, in particular the role of hematopoietic growth factors. METHODS: Data from 90 patients with drug-induced agranulocytosis who met the criteria of the IAAAS group and of Bénichou and Solal-Celigny [Nouv Rev Fr Hematol 1993; 33: 257.] were retrospectively reviewed. All cases were extracted from a cohort study of the Hopitaux Universitaires de Strasbourg, France. Data were specifically analyzed with regard to the use of hematopoietic growth factors (in 42 patients). RESULTS: Mean patient age was 63 (range 17-95) years and the sex ratio (M/F) was 0.39. An underlying disease was present in 37% of the patients. Antibiotics (25%), antithyroid drugs (23%), and antiaggregative platelet agents (16%) were the most frequent causative drugs. Main clinical features included isolated fever (41%), septicemia or septic shock (31%), and pneumonia (10%). Mean neutrophil count was 0.13 (range 0-0.46)x10(9)/l. Outcome was favorable in 98% of patients. The mean durations of hematological recovery (neutrophil count over 1.5x10(9)/l), antibiotic therapy, and hospitalization was 8.5 (range 2-21) days, 9.2 (range 2-21) days, and 10.5 (range 3-23) days, respectively. All patients were treated with broad-spectrum antibiotics and 42 patients with hematopoietic growth factors. In these 42 patients, the mean durations for hematological recovery, antibiotic therapy, and hospitalization were significantly reduced at: 6.3 (range 2-16) days, 7.1 (range 2-16) days, and 9.1 (range 3-23) days, respectively (all P<0.05). CONCLUSIONS: The present study shows that new causative drugs are emerging (antibiotics, antithyroid, and antiaggregative platelet agents), that drug-induced agranulocytosis remains typically a serious accident with severe sepsis, and that modern management with broad spectrum antibiotics and hematopoietic growth factors may reduce the mortality.     

Amplification of low-frequency antiviral CD8 T cell responses using autologous dendritic cells.

OBJECTIVE: To utilize the potent antigen-presenting capacity of mature dendritic cells (MDC) in order to develop a rapid, sensitive method for quantifying antigen-specific CD8 T cells present at low frequency in peripheral blood. DESIGN: Peripheral blood mononuclear cells (PBMC) were obtained from seven HIV-1-positive individuals with low to moderate CD8 T cell responses, including five on highly active antiretroviral therapy (HAART). IFN-gamma ELISPOT assays were performed using either monocytes or MDC to present antigens expressed by recombinant vaccinia viruses (r-VV). METHODS: Peripheral blood-derived monocytes were cultured for 5-6 days in the presence of IL-4 and granulocyte macrophage colony-stimulating factor, then matured in monocyte-conditioned medium. MDC were infected with r-VV and co-cultured in an ELISPOT assay with autologous monocyte-depleted PBMC. RESULTS: Relative to autologous monocytes, MDC amplified detection of antigen-specific CD8 T cells by 2-30-fold in response to antigens from HIV-1, Epstein-Barr virus and cytomegalovirus. Furthermore, antigenic specificities were revealed that had not been detected using standard ELISPOT of PBMC. CONCLUSION: This assay will prove useful for the detection of memory T cells present at low frequency, and may be of interest for identifying subdominant cytotoxic T lymphocyte epitopes. This method may have broad applications for the detection of antiviral CD8 T cell responses in patient populations in whom such responses have been difficult to detect, including HIV-1-seropositive individuals with advanced disease or undergoing HAART.     

Activation of HIV-1 specific CD4 and CD8 T cells by human dendritic cells: roles for cross-presentation and non-infectious HIV-1 virus

BACKGROUND: The CD4 T cells in mucosal subepithelia are the first cells to become infected during sexual transmission of HIV-1. Dendritic cells (DC) are located in the same area and are known to play a central role in antiviral immune responses. However, extensive viral replication, syncytia formation and cell death follows the interaction between T cells and DC previously exposed to HIV-1. Despite this, anti-HIV responses are generated that control viremia following acute infection. OBJECTIVE: The anti-HIV-1 cellular immune responses observed may be activated by sources other than productively infected DC. HIV-1 induces apoptosis both in cells it infects and in bystander cells. Furthermore, retroviral replication typically generates a predominance of defective particles. We tested whether DC exposed to antigen from either of these sources could elicit anti-HIV specific immune responses. DESIGN AND METHODS: Apoptotic or necrotic monocytes infected with vaccinia virus vectors encoding HIV antigens, a cell line with integrated HIV-1 and apoptotic CD4 T cells pulsed with non-infectious or infectious HIV-1 virus were used as sources of antigens to assess cross presentation by DC. Furthermore, direct DC presentation of antigen from non-infectious and infectious HIV-1 was examined. RESULTS: We find that dead cells expressing HIV-1 antigens as well as non-infectious HIV-1 particles can be acquired and processed by DC, leading to the activation, differentiation and expansion of viral antigen-specific CD4 and CD8 T cells from seropositive individuals. CONCLUSIONS: These sources of antigens may be critical for the generation and maintenance of anti-HIV-1 immunity by DC.     

The contribution of black carbon to global ice nucleating particle concentrations relevant to mixed-phase clouds

Black carbon (BC) aerosol plays an important role in the Earth’s climate system because it absorbs solar radiation and therefore potentially warms the climate; however, BC can also act as a seed for cloud particles, which may offset much of its warming potential. If BC acts as an ice nucleating particle (INP), BC could affect the lifetime, albedo, and radiative properties of clouds containing both supercooled liquid water droplets and ice particles (mixed-phase clouds). Over 40% of global BC emissions are from biomass burning; however, the ability of biomass burning BC to act as an INP in mixed-phase cloud conditions is almost entirely unconstrained. To provide these observational constraints, we measured the contribution of BC to INP concentrations ([INP]) in real-world prescribed burns and wildfires. We found that BC contributes, at most, 10% to [INP] during these burns. From this, we developed a parameterization for biomass burning BC and combined it with a BC parameterization previously used for fossil fuel emissions. Applying these parameterizations to global model output, we find that the contribution of BC to potential [INP] relevant to mixed-phase clouds is ∼5% on a global average.

Black carbon (BC) is the primary light-absorbing aerosol in the atmosphere. Its short lifetime (days to weeks) relative to CO2 and methane makes it an intriguing target for near-term climate mitigation (1). Errors associated with BC climate forcing, however, obfuscate its efficacy as a climate mitigator. The largest contributions to BC’s forcing uncertainties are often attributed to its effects on clouds, in particular mixed-phase clouds [i.e., clouds containing supercooled cloud droplets and ice particles, (2)]. Efforts to reduce these uncertainties are hindered by the complexity of aerosol–cloud interactions (3). Particularly vexing is quantifying the abundance and identity of ice nucleating particles (INPs). INPs provide the only pathway for primary ice formation in mixed-phase clouds; however, they are rare [e.g., ∼1 in 106 particles are INPs at −20 °C (4)]. Despite their rarity, INPs influence mixed-phase cloud ice concentrations and precipitation and therefore alter cloud albedo and lifetime (5). Furthermore, the INP properties of aerosols, such as BC, will affect their own lifetime, vertical structure, and transport to climate-sensitive regions such as the Arctic (6). Despite its importance to the Earth’s climate and near-term climate mitigation strategies, the INP efficiency of BC relevant to mixed-phase clouds remains almost entirely unconstrained from direct observations, encumbering attempts to estimate BC’s impact on mixed-phase clouds in modeling studies (7).BC’s efficacy as an immersion-freezing INP (henceforth, INP will refer only to freezing by particles encapsulated within supercooled cloud droplets, termed immersion freezing and pertinent to mixed-phase cloud conditions) has been studied in the laboratory for decades, with starkly conflicting results. Early laboratory studies showed that acetylene and kerosene flame-generated soot can nucleate ice below −20 °C. (8, 9); after normalizing for surface area, these studies indicated that BC may be more ice active than the well-known INP mineral dust (10). Results from later laboratory studies were contradictory, suggesting that BC was not active as an INP above instrument limits of detection. These included soot aerosols from miniCAST soot generators, graphite spark generator soot, hydrocarbon flame-generated soot, and fullerene soot, as well as various lamp blacks and carbon blacks (11–15).Unfortunately, field study measurements of the contribution of BC to INP concentrations ([INP]) have also been inconclusive. For example, in-cloud measurements from the high-altitude observatory at Jungfraujoch, Switzerland saw that BC is enriched in ice-particle residuals and therefore may efficiently nucleate ice (16); later measurements at the same site, however, saw that BC is depleted in the ice phase, which suggests that BC does not play a significant role in mixed-phase cloud ice nucleation (17, 18).These contradictions in laboratory and field studies suggest that fuel type and combustion conditions determine the ice nucleation properties of BC. Such conditions prescribe BC’s physical and morphological properties as well as its coemitted and coagulated species. Major BC fuel types include fossil fuels and flammable biomass, and major combustion sources include diesel exhaust, residential fuel burning, prescribed burns, and wildfires (2). BC particles from fossil fuel combustion and anthropogenic pollution are not significant sources of INPs. For example, studies on diesel exhaust have shown that less than 1 in 109 BC particles are ice nucleation active at −30 °C (19). Furthermore, ambient [INP] in Beijing, China were relatively constant over several weeks despite BC concentrations varying by a factor of 30 and reaching values as high as 17.26 μg⋅m−3 (20).Elevated [INP] have been observed in biomass-burning smoke during laboratory and field studies (21–23); however, it is unclear from these studies if the INPs are actually BC. Some studies have shown that BC may be the dominant INP type in select biomass burning conditions. For example, soot particles were found to contribute up to 64% of the INPs in prescribed burns within a predominantly wiregrass understory (24). Furthermore, BC contributed up to 70% to [INP] in controlled laboratory burns of grasses (25). As biomass burning represents ∼40% of global BC emissions (2), BC from biomass burning could be a significant source of INP globally. In both of these studies, however, the overall ice-active fractions may be too low to influence [INP], even on the regional level (21). Thus, it remains unclear whether BC contributes to [INP] outside of thick plumes and on a global scale (26).Regional- and global-scale estimates of BC [INP] rely on models that can implement theory-based or empirical ice nucleation parameterizations. Using parameterizations based on BC INP activity from the acetylene and kerosene-burner soot studies, models have found that BC contributes ∼50% to [INP] in springtime low-level Arctic mixed-phase clouds (27), and 23 to 61% to global [INP] depending on dust loadings (28). Taking into account the aforementioned negative results, these modeling studies highlight that BC’s contribution to [INP] is poorly constrained and is estimated to vary from no contribution to being the most abundant INP globally.To assess the role of BC from biomass burning as an INP, we determined the contribution of refractory BC (rBC)-containing particles to [INP] from field measurements of both prescribed burns and wildfires using the single-particle soot photometer coupled to a continuous-flow diffusion chamber (SP2-CFDC) (29, 30). The SP2-CFDC selectively removes rBC from an aerosol stream and quantifies that effect on [INP]. From these burns, we found that rBC-containing particles contributed ≤10% to [INP]. From these results, we developed a surface-area normalized parameterization for BC INPs from biomass burning. The parameterization aligns well with other surface-area normalized parameterizations derived from laboratory proxies of BC and diesel exhaust BC (15, 19, 31). These parameterizations are over four orders of magnitude lower than the parameterization derived from acetylene and kerosene-burner soot studies and used in the aforementioned modeling studies. Assuming the INP characteristics of BC from the burns in this study can be extended to different biomass-burning fuel types and combustion conditions, this study strongly suggests that BC is not an efficient INP. Under this assumption, we assessed the global importance of BC as an INP by applying our parameterization to simulated biomass-burning aerosol from a global chemical transport model. A similar parameterization for diesel exhaust (19) was applied to simulated fossil fuel BC. From these treatments, we estimate that BC’s contribution to simulated, potential [INP] is only ∼5% on a global average.     

Determination of the lifetime and force dependence of interactions of single bonds between surface-attached CD2 and CD48 adhesion molecules

We studied single molecular interactions between surface-attached rat CD2, a T-lymphocyte adhesion receptor, and CD48, a CD2 ligand found on antigen-presenting cells. Spherical particles were coated with decreasing densities of CD48–CD4 chimeric molecules then driven along CD2-derivatized glass surfaces under a low hydrodynamic shear rate. Particles exhibited multiple arrests of varying duration. By analyzing the dependence of arrest frequency and duration on the surface density of CD48 sites, it was concluded that (i) arrests were generated by single molecular bonds and (ii) the initial bond dissociation rate was about 7.8 s⁻¹. The force exerted on bonds was increased from about 11 to 22 pN; the detachment rate exhibited a twofold increase. These results agree with and extend studies on the CD2–CD48 interaction by surface plasmon resonance technology, which yielded an affinity constant of ≈10⁴ M⁻¹ and a dissociation rate of ≥6 s⁻¹. It is concluded that the flow chamber technology can be an useful complement to atomic force microscopy for studying interactions between isolated biomolecules, with a resolution of about 20 ms and sensitivity of a few piconewtons. Further, this technology might be extended to actual cells.     

Patients’ perceptions of physicians’ recommendations for comfort care differ by patient age and gender

OBJECTIVE: To determine patient characteristics associated with patient and proxy perceptions of physicians’ recommendations for life-prolonging care versus comfort care, and with acceptance of such recommendations. DESIGN: Cross-sectional. SETTING: Five teaching hospitals in Denver, Colo. PATIENTS: We studied 239 hospitalized adults believed by physicians to have a high likelihood of dying within 6 months. MEASUREMENTS AND MAIN RESULTS: Interviews with patients or proxies were conducted to determine perceptions of physicians’ recommended goal of care and roles in decision making. RESULTS: Patients’ mean age was 66.6 years; 44% were women. In adjusted analysis, age greater than 70 years and female gender were associated with a higher likelihood of believing that comfort care had been recommended by the physician (odds ratio [OR], 3.70; 95% confidence interval [CI], 1.89 to 7.24; OR, 1.99; 95% CI, 1.04 to 3.84, respectively). Patients and proxies gave substantial decision-making authority to physicians: 29% responded that physicians dominate decision making, 55% that decision making is equally shared by physicians and patients, and only 16% that patients make decisions, Increasing age was associated with an increased likelihood of believing that physicians should dominate decision making (P<.005). CONCLUSIONS: Among patients with advanced illness, perceived comfort care recommendations were related to patient age and gender, raising concern about possible gender and age bias in physicians’ recommendations. Although all patients and proxies gave significant decision-making authority to physicians, older individuals were more likely to give physicians decision-making authority, making them more vulnerable to possible physician bias. Presented at the annual meeting of the American Geriatrics Society, May 19, 1999. Financial support for this work was received from the Hartford/Jahnigen Center of Excellence in Geriatrics at the University of Colorado and the Colorado Collective for Medical Decisions, a nonprofit organization to improve care of the dying in the state of Colorado.     

A vaccine manufacturer’s approach to address medical needs related to seasonal and pandemic influenza viruses

Abstract Vaccination is considered to be one of the most effective tools to decrease morbidity as well as mortality caused by influenza viruses.For the prevention of seasonal influenza, Fluarix ™ and FluLaval™ have been marketed since 1987 and 1992, respectively. Both vaccines have consistently been shown to meet or exceed the regulatory criteria for immunogenicity against the three strains H1N1, H3N2 and B, have a good safety profile, and are recommended for vaccinating children and adults of all ages.For the prevention of pandemic influenza, GlaxoSmithKline (GSK) has obtained licensure of a pre‐pandemic vaccine, Prepandrix ™. This split‐virus H5N1 adjuvanted with AS03, a proprietary oil‐in‐water emulsion‐based adjuvant system, has demonstrated broad immunity against drifted H5N1 strains and has been shown to be effective in preventing mortality and viral shedding in animal studies.The influenza vaccine portfolio of GSK addresses specific medical needs related to seasonal or pandemic influenza viruses, which remain an important public health threat worldwide.     

The current status of thalidomide in the management of multiple myeloma

Early anticancer research involving thalidomide was abandoned in the 1960s as the catastrophe surrounding the drug emerged, but research efforts were picked up in the 1990s when thalidomide's antiangiogenic and anti-tumour necrosis factor properties were explored. More than 50,000 patients with multiple myeloma are estimated to have been treated with thalidomide to date. Research with thalidomide provides clear and convincing evidence that thalidomide monotherapy is efficacious in relapsed and refractory patients with multiple myeloma. Results typically show a consistent 30% (95% confidence interval 27-32%) response rate (partial response + complete response, defined as a reduction of at least 50% in the monoclonal protein). Thalidomide treatment compares favourably with other typical treatments for multiple myeloma. In seven trials that included 332 patients, vincristine, adriamycin and dexamethasone (VAD) had a response rate of 39% (32-45%), while a trial in 193 patients showed a response rate with bortezomib of 27% (21-34%). The use of thalidomide in combination therapy could boost its efficacy further. More studies to look at the toxicity of the drug need to be carried out. Despite thalidomide's dark past, this drug is of major interest and could be brought back to clinical use in a controlled manner.