Evaluating Options and Ethics in Pediatric Dentistry due to Declining Access to Hospital Operating Rooms.

AbstractPediatric dentists rely on access to hospital operating rooms for safe, effective, and humane delivery of dental care. The children who benefit most from dental treatment in a hospital operating room are those who are very young, have dental anxieties or phobias, are precommunicative or noncommunicative, need extensive or invasive dental treatments, or have special healthcare needs. Diminishing access to hospital operating rooms for pediatric dental treatment has become an escalating problem in contemporary times. Financial barriers, hospital costs, reimbursement rates, health insurance policies and deductibles, out-of-network hospitals, socioeconomic factors, and the COVID-19 pandemic are prominent contributing factors. This problem in access to care has resulted in long waiting times for hospital operating rooms, deferral of medically necessary dental care, and pain and infection among this vulnerable patient population. Pediatric dentists have responded to the problem by utilizing alternative methods of care delivery, such as in-office deep sedation or in-office general anesthesia, and by implementing aggressive medical management of dental caries. However, the youngest of pediatric patients and children with special healthcare needs still remain at a disadvantage in receiving definitive dental treatment. This article aims to highlight the ethical challenges faced by pediatric dentists in contemporary practice in the face of limitations in hospital operating room access through four case scenarios.

Donor Genetic Predisposition to High Interleukin-10 Production Appears Protective against Acute Graft-Versus-Host Disease.

The persistence of graft-versus-host disease (GVHD) as the principal complication of allogeneic hematopoietic cell transplantation (HCT) demonstrates that HLA matching alone is insufficient to prevent alloreactivity. We performed molecular and functional characterization of 22 candidate cytokine genes for their potential to improve matching in 315 myeloablative, 10/10 HLA-matched donor−recipient pairs. Recipients of a graft carrying the -1082GG IL10 gene promoter region variant had a three-fold lower incidence of grade II−IV acute GVHD compared to IL10-1082AA graft recipients (SHR = 0.25, p = 0.005). This was most evident in matched unrelated donor (MUD) transplants, where the greatest alloreactivity is expected. IL10-1082GG transplants did not experience an increased incidence of relapse, and, consequently, overall survival was two-fold higher in IL10-1082GG MUD transplants (HR = 0.17, p = 0.023). Longitudinal post-transplant measurements demonstrated that -1082GG is a high-IL10-producing and -expressing genotype with attenuated CD8+ T-cell reconstitution. High post-transplant donor chimerism in T- and myeloid-cells (>95%) confirmed a predominant donor, rather than recipient, genotype effect on immune function and aGVHD. To date, this is the first study to report corroborating genome-to-cellular evidence for a non-HLA donor immunogenetic variant that appears to be protective against GVHD. The incorporation of IL10 variants in donor selection criteria and clinical-management decisions has the potential to improve patient outcomes.

Incomplete chimerism following myeloablative and anti-thymocyte globulin-conditioned hematopoietic cell transplantation is a risk factor for relapse and chronic graft-versus-host disease.

BACKGROUND AIMS: The value of routine chimerism determination after myeloablative hematopoietic cell transplantation (HCT) is unclear, particularly in the setting of anti-thymocyte globulin (ATG)-based graft-versus-host disease (GVHD) prophylaxis. METHODS: Blood samples were collected at 3 months post-HCT from 558 patients who received myeloablative conditioning and ATG-based GVHD prophylaxis. Chimerism was assessed using multiplex polymerase chain reaction of short tandem repeats in sorted T cells (CD3+) and leukemia lineage cells (CD13+CD33+ for myeloid malignancies and CD19+ for B-lymphoid malignancies). ATG exposure was determined using a flow cytometry-based assay. The primary outcomes of interest were relapse and chronic GVHD (cGVHD). RESULTS: Incomplete (<95%) T-cell chimerism and leukemia lineage chimerism were present in 17% and 4% of patients, respectively. Patients with incomplete T-cell chimerism had a significantly greater incidence of relapse (36% versus 22%, subhazard ratio [SHR] = 2.03, P = 0.001) and lower incidence of cGVHD (8% versus 25%, SHR = 0.29, P < 0.001) compared with patients with complete chimerism. In multivariate modeling, patients with high post-transplant ATG area under the curve and any cytomegalovirus (CMV) serostatus other than donor/recipient seropositivity (non-D+R+) had an increased likelihood of incomplete T-cell chimerism. Patients with incomplete leukemia lineage chimerism had a significantly greater incidence of relapse (50% versus 23%, SHR = 2.70, P = 0.011) and, surprisingly, a greater incidence of cGVHD (45% versus 20%, SHR = 2.64, P = 0.003). CONCLUSIONS: High post-transplant ATG exposure and non-D+R+ CMV serostatus predispose patients to incomplete T-cell chimerism, which is associated with an increased risk of relapse. The increased risk of cGVHD with incomplete B-cell/myeloid chimerism is a novel finding that suggests an important role for recipient antigen-presenting cells in cGVHD pathogenesis.

StarGazer: A Hybrid Intelligence Platform for Drug Target Prioritization and Digital Drug Repositioning Using Streamlit.

Target prioritization is essential for drug discovery and repositioning. Applying computational methods to analyze and process multi-omics data to find new drug targets is a practical approach for achieving this. Despite an increasing number of methods for generating datasets such as genomics, phenomics, and proteomics, attempts to integrate and mine such datasets remain limited in scope. Developing hybrid intelligence solutions that combine human intelligence in the scientific domain and disease biology with the ability to mine multiple databases simultaneously may help augment drug target discovery and identify novel drug-indication associations. We believe that integrating different data sources using a singular numerical scoring system in a hybrid intelligent framework could help to bridge these different omics layers and facilitate rapid drug target prioritization for studies in drug discovery, development or repositioning. Herein, we describe our prototype of the StarGazer pipeline which combines multi-source, multi-omics data with a novel target prioritization scoring system in an interactive Python-based Streamlit dashboard. StarGazer displays target prioritization scores for genes associated with 1844 phenotypic traits, and is available via https://github.com/AstraZeneca/StarGazer.

Accurate Step Count with Generalized and Personalized Deep Learning on Accelerometer Data.

Physical activity (PA) is globally recognized as a pillar of general health. Step count, as one measure of PA, is a well known predictor of long-term morbidity and mortality. Despite its popularity in consumer devices, a lack of methodological standards and clinical validation remains a major impediment to step count being accepted as a valid clinical endpoint. Previous works have mainly focused on device-specific step-count algorithms and often employ sensor modalities that may not be widely available. This may limit step-count suitability in clinical scenarios. In this paper, we trained neural network models on publicly available data and tested on an independent cohort using two approaches: generalization and personalization. Specifically, we trained neural networks on accelerometer signals from one device and either directly applied them or adapted them individually to accelerometer data obtained from a separate subject cohort wearing multiple distinct devices. The best models exhibited highly accurate step-count estimates for both the generalization (96-99%) and personalization (98-99%) approaches. The results demonstrate that it is possible to develop device-agnostic, accelerometer-only algorithms that provide highly accurate step counts, positioning step count as a reliable mobility endpoint and a strong candidate for clinical validation.

OSPred Tool: A Digital Health Aid for Rapid Predictive Analysis of Correlations Between Early End Points and Overall Survival in Non-Small-Cell Lung Cancer Clinical Trials.

PURPOSE: Overall survival (OS) is the gold standard end point for establishing clinical benefits in phase III oncology trials. However, these trials are associated with low success rates, largely driven by failure to meet the primary end point. Surrogate end points such as progression-free survival (PFS) are increasingly being used as indicators of biologic drug activity and to inform early go/no-go decisions in oncology drug development. We developed OSPred, a digital health aid that combines actual clinical data and machine intelligence approaches to visualize correlation trends between early (PFS-based) and late (OS) end points and provide support for shared decision making in the drug development pipeline. METHODS: OSPred is based on a trial-level data set of 81 reports (35 anticancer drugs with various mechanisms of action; 156 observations) in non-small-cell lung cancer (NSCLC). OSPred was developed using R Shiny, with packages ggplot2, metafor, boot, dplyr, and mvtnorm, to analyze and visualize correlation results and predict OS hazard ratio (HR OS) on the basis of user-inputted PFS-based data, namely, HR PFS, or the odds ratio of PFS at 4 (OR PFS4) or 6 (OR PFS6) months. RESULTS: The three main features of the tool are as follows: prediction of HR OS on the basis of user-inputted early end point values; visualization of comparisons of the user's investigational drug with other drugs in the NSCLC setting, including by specific MoA; and creation of a probability density chart, providing point prediction and CIs for HR OS. A working version of the tool for download is linked. CONCLUSION: The OSPred tool offers interactive visualization of clinical trial end point correlations with reference to a large pool of historical NSCLC studies. Its focused capability has the potential to digitally transform and accelerate data-driven decision making as part of the drug development process.

Impact of FLT3 internal tandem duplication and NPM1 mutations in acute myeloid leukemia treated with allogeneic hematopoietic cell transplantation.

BACKGROUND AIMS: The internal tandem duplication of FLT3 (FLT3ITD) and NPM1 mutations (NPM1mut) are well-established prognostic factors in cytogenetically intermediate-risk acute myeloid leukemia (AML) when treated with chemotherapy alone. However, their prognostic value in the setting of allogeneic hematopoietic cell transplantation (HCT) is controversial. METHODS: FLT3 and NPM1 mutational status was determined at diagnosis using single-gene polymerase chain reaction or next-generation sequencing in 247 adult patients with cytogenetically intermediate-risk AML who underwent myeloablative HCT. Multivariate Fine-Gray and Cox regression was used to analyze the cumulative incidence of relapse (CIR), relapse-free survival (RFS) and overall survival (OS). RESULTS: FLT3ITD and NPM1mut were present in 74 of 247 (30%) and 79 of 247 (32%) patients, respectively. There was no significant difference between patients without a FLT3ITD or NPM1mut (FLT3NONITD/NPM1WT) and patients with a FLT3ITD mutation alone (FLT3ITD/NPM1WT) with regard to CIR (P = 0.60), RFS (P = 0.91) or OS (P = 0.66). Similarly, there was no significant difference between FLT3NONITD/NPM1WT and FLT3NONITD/NPM1mut patients with regard to CIR (P = 0.70), RFS (P = 0.75) or OS (P = 0.95). The presence of a concurrent mutation in NPM1 did not appear to modify the impact of having a FLT3ITD mutation. CONCLUSIONS: In contrast to chemotherapy-only treatment, FLT3 and NPM1 mutational status does not appear to predict outcomes in patients with cytogenetically intermediate-risk AML following HCT. These results suggest that HCT may ameliorate the poor prognostic effect of FLT3ITD mutation and that HCT should be considered over chemotherapy-only treatment in FLT3ITD-mutated AML.

Analysis of Use and Outcomes of the Balance Digital Disease Management Tool for Patients with Type 2 Diabetes.

Management of type 2 diabetes mellitus (T2DM) is a serious medical need for millions of patients and clinicians worldwide. Numerous smartphone apps for T2DM management are available. Due to their global accessibility, computing power and cellular connectivity, the pervasiveness of mobile phones now provide an opportunity for non-invasive Digital Therapeutics that have the potential to manage disease by modifying patient behavior as new modality for disease management and intervention. However, this novel approach has yet to be tested in large clinical studies. The BALANCE clinical study was designed to evaluate mobile phone App usage in a large multi-center clinical trial and its impact on T2DM outcomes. It included a digital aid for the management of, blood glucose, diet, physical activity, and medication adherence. Overall, patient use of the BALANCE-App was low (21% of significant patients users), and it diminished over time. BALANCE showed no effect on HbA1c or weight, what is consistent with other smartphone apps for T2DM which were tested on large clinical trials. Nevertheless, post-hoc subgroup analysis showed women using the App significantly achieved a significant reduction in HbA1c and weight.Clinical relevance Suitability of Digital Therapeutics, at least in the form of smartphone apps, for T2DM is under question. The low use indicates need for a strong focus in patient acceptability and patient engagement in the design process.

A biomarker-guided, prospective, phase 2 trial of pre-emptive graft-versus-host disease therapy using anti-thymocyte globulin.

BACKGROUND AIMS: Intensified immunosuppressive prophylaxis for graft-versus-host disease (GVHD) may be toxic and therefore warranted only in patients at high risk of developing GVHD. In patients who underwent allogeneic hematopoietic cell transplant at the authors' center, high serum soluble IL-2 receptor alpha (sIL-2Rα) and low IL-15 levels on day 7 post-transplant were found to predict a high risk of developing clinically significant GVHD (sGVHD), defined as grade 2-4 acute GVHD or moderate to severe chronic GVHD. METHODS: This was a prospective, phase 2 trial in which high-risk patients (serum sIL-2Rα >4500 ng/L or IL-15 <31 ng/L) received rabbit anti-thymocyte globulin (ATG) 3 mg/kg on day 8 post-transplant. Controls consisted of patients who had their sIL-2Rα/IL-15 levels measured but did not participate in the trial. A total of 68 trial patients and 143 controls were accrued to this study. The primary endpoint was incidence of sGVHD. RESULTS: There was a reduction in sGVHD in high-risk trial patients (received day 8 ATG) compared with high-risk controls (did not receive day 8 ATG) (sub-hazard ratio [SHR] = 0.48, P < 0.05). There was no significant difference between the groups in overall survival or relapse; however, there was a greater incidence of non-GVHD-associated non-relapse mortality in high-risk trial patients (SHR = 3.73, P < 0.05), mostly related to infections. This may be due in part to the biomarkers ineffectively stratifying GVHD risk. CONCLUSIONS: Pre-emptive ATG therapy is both feasible and effective at reducing sGVHD without increasing relapse. Further mitigation strategies are needed to reduce the risk of infection associated with intensified GVHD prophylaxis. This study was registered at ClinicalTrials.gov (NCT01994824).

Correlation Between Early Endpoints and Overall Survival in Non-Small-Cell Lung Cancer: A Trial-Level Meta-Analysis.

Early endpoints, such as progression-free survival (PFS), are increasingly used as surrogates for overall survival (OS) to accelerate approval of novel oncology agents. Compiling trial-level data from randomized controlled trials (RCTs) could help to develop a predictive framework to ascertain correlation trends between treatment effects for early and late endpoints. Through trial-level correlation and random-effects meta-regression analysis, we assessed the relationship between hazard ratio (HR) OS and (1) HR PFS and (2) odds ratio (OR) PFS at 4 and 6 months, stratified according to the mechanism of action of the investigational product. Using multiple source databases, we compiled a data set including 81 phase II-IV RCTs (35 drugs and 156 observations) of patients with non-small-cell lung cancer. Low-to-moderate correlations were generally observed between treatment effects for early endpoints (based on PFS) and HR OS across trials of agents with different mechanisms of action. Moderate correlations were seen between treatment effects for HR PFS and HR OS across all trials, and in the programmed cell death-1/programmed cell death ligand-1 and epidermal growth factor receptor trial subsets. Although these results constitute an important step, caution is advised, as there are some limitations to our evaluation, and an additional patient-level analysis would be needed to establish true surrogacy.

COVID-19 infection among international travellers: a prospective analysis.

OBJECTIVES: This report estimates the risk of COVID-19 importation and secondary transmission associated with a modified quarantine programme in Canada. DESIGN AND PARTICIPANTS: Prospective analysis of international asymptomatic travellers entering Alberta, Canada. INTERVENTIONS: All participants were required to receive a PCR COVID-19 test on arrival. If negative, participants could leave quarantine but were required to have a second test 6 or 7 days after arrival. If the arrival test was positive, participants were required to remain in quarantine for 14 days. MAIN OUTCOME MEASURES: Proportion and rate of participants testing positive for COVID-19; number of cases of secondary transmission. RESULTS: The analysis included 9535 international travellers entering Alberta by air (N=8398) or land (N=1137) that voluntarily enrolled in the Alberta Border Testing Pilot Programme (a subset of all travellers); most (83.1%) were Canadian citizens. Among the 9310 participants who received at least one test, 200 (21.5 per 1000, 95% CI 18.6 to 24.6) tested positive. Sixty-nine per cent (138/200) of positive tests were detected on arrival (14.8 per 1000 travellers, 95% CI 12.5 to 17.5). 62 cases (6.7 per 1000 travellers, 95% CI 5.1 to 8.5; 31.0% of positive cases) were identified among participants that had been released from quarantine following a negative test result on arrival. Of 192 participants who developed symptoms, 51 (26.6%) tested positive after arrival. Among participants with positive tests, four (2.0%) were hospitalised for COVID-19; none required critical care or died. Contact tracing among participants who tested positive identified 200 contacts; of 88 contacts tested, 22 were cases of secondary transmission (14 from those testing positive on arrival and 8 from those testing positive thereafter). SARS-CoV-2 B.1.1.7 lineage was not detected in any of the 200 positive cases. CONCLUSIONS: 21.5 per 1000 international travellers tested positive for COVID-19. Most (69%) tested positive on arrival and 31% tested positive during follow-up. These findings suggest the need for ongoing vigilance in travellers testing negative on arrival and highlight the value of follow-up testing and contact tracing to monitor and limit secondary transmission where possible.

Efficacy of Allogeneic Hematopoietic Cell Transplantation for Autoimmune Diseases.

Allogeneic hematopoietic cell transplantation (HCT) may be efficacious for autoimmune diseases (AIDs), but its efficacy for individual AIDs is unknown. Factors influencing the likelihood of relapse for each AID are also unknown. This study aimed to determine the likelihood of relapse for each common AID and to generate hypotheses about factors influencing the likelihood of relapse. We reviewed charts of adult patients with nonhematologic AIDs who had undergone HCT in Alberta (n = 21) and patients described in the literature (n = 67). We used stringent inclusion criteria to minimize the inclusion of patients whose AID may have been cured before transplantation. We also used stringent definitions of AID relapse and remission. AID relapsed in 2 of 9 patients (22%) with lupus, in 4 of 12 (33%) with rheumatoid arthritis (RA), in 0 of 4 (0%) with systemic sclerosis (SSc), in 3 of 16 (19%) with psoriasis, in 1 of 12 (8%) with Behçet's disease (BD), in 1 of 15 (7%) with Crohn's disease (CD), in 0 of 5 (0%) with ulcerative colitis (UC), in 4 of 8 (50%) with multiple sclerosis (MS), and in 3 of 3 (100%) with type 1 diabetes mellitus (T1DM). Among highly informative patients (followed for >1 year after discontinuation of immunosuppressive therapy if no relapse, or donor AID status known if relapse), relapse occurred in 0 of 3 patients with lupus, in 2 of 7 with RA, in 0 of 2 with SSc, in 3 of 6 with psoriasis, in 0 of 3 with BD, in 0 of 10 with CD, in 0 of 3 with UC, in 2 of 3 with MS, and in 2 of 2 with T1DM. There appeared to be no associations between AID relapse and low intensity of pretransplantation chemoradiotherapy, multiple lines of AID therapy (surrogate for AID refractoriness) except perhaps for lupus, absence of serotherapy for graft-versus-host disease (GVHD) prophylaxis, lack of GVHD except perhaps for lupus, or incomplete donor chimerism. Even though remission commonly occurs after HCT in lupus, RA, SSc, psoriasis, BD, CD, and UC, HCT is efficacious for only a subset of patients. The efficacy appears to be unrelated to pretransplantation therapy, GVHD, or chimerism. Large studies are needed to determine the characteristics of patients likely to benefit from HCT for each AID.

Impaired natural killer cell counts and cytolytic activity in patients with severe COVID-19.

The global pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-driven coronavirus disease 2019 (COVID-19) has caused unprecedented human death and has seriously threatened the global economy. Early data suggest a surge in proinflammatory cytokines in patients with severe COVID-19, which has been associated with poor outcomes. We recently postulated that the inflammatory response in patients with severe COVID-19 disease is not inhibited by natural killer (NK) cells, resulting in a "cytokine storm." Here, we assessed the NK-cell functional activity and the associated cytokines and soluble mediators in hospitalized COVID-19 patients. Significantly impaired NK-cell counts and cytolytic activity were observed in COVID-19 patients when compared with healthy controls. Also, cytokines like interleukin 12 (IL12), IL15, and IL21 that are important for NK-cell activity were not detected systematically. Serum concentrations of soluble CD25 (sCD25)/soluble IL2 receptor α (sIL2-Rα) were significantly elevated and were inversely correlated with the percentage of NK cells. Impaired NK-cell cytolytic activity together with other laboratory trends including elevated sCD25 were consistent with a hyperinflammatory state in keeping with macrophage-activation syndrome. Our findings suggest that impaired counts and cytolytic activity of NK cells are important characteristics of severe COVID-19 and can potentially facilitate strategies for immunomodulatory therapies.

Assessment of Objectively Measured Physical Activity as an Independent Estimator of Functional Status in Clinical Trials.

Functional status of patients is an important concept in clinical trials. It subsumes functional capacity, which is traditionally estimated by exercise tests, and functional performance, which is often estimated by questionnaires. Objectively measured physical activity by means of wearables devices containing accelerometers (PA) have recently been proposed as a novel and advantageous way to estimate physical status including capacity and performance. There is nonetheless insufficient evidence of the association between PA and traditional ways to estimate functional status. In the ACTIVATE clinical trial, cycle ergometry tests were performed multiple times in all 267 patients, PA was measured for a week prior to each cycle ergometry test, and questionnaires were answered daily during the same week. Pearson's correlation tests and clustering analysis revealed that PA, physical activity experience as assessed by questionnaires, and exercise endurance time as measured by the cycle ergometry test, are largely independent. Therefore, all three approaches together might achieve a complete assessment of the functional status of patients in clinical trials, as they each independently correlate with health-related quality of life and important clinical outcomes such as hospitalizations but are weakly associated among themselves.

Hematopoietic cell transplant outcomes after myeloablative conditioning with fludarabine, busulfan, low-dose total body irradiation, and rabbit antithymocyte globulin.

Optimal conditioning and graft-vs-host disease (GVHD) prophylaxis for hematopoietic cell transplantation (HCT) are unknown. Here, we report on outcomes after low toxicity, myeloablative conditioning consisting of fludarabine, busulfan, and 4 Gy total body irradiation, in combination with thymoglobulin and post-transplant methotrexate and cyclosporine. We retrospectively studied 700 patients with hematologic malignancies who received blood stem cells from 7 to 8/8 HLA-matched unrelated or related donors. Median follow-up of surviving patients was 5 years. At 5 years, overall survival (OS), relapse-free survival (RFS), and chronic GVHD/relapse-free survival (cGRFS) were 58%, 55%, and 40%. Risk factors for poor OS, RFS, and cGRFS were (1). high to very high disease risk index (DRI), (2). high recipient age, and (3). cytomegalovirus (CMV)-seropositive recipient with seronegative donor (D-R+). The latter risk factor applied particularly to patients with lymphoid malignancies. Neither donor other than HLA-matched sibling (7-8/8 unrelated) nor one HLA allele mismatch was risk factors for poor OS, RFS, or cGRFS. In conclusion, the above regimen results in excellent long-term outcomes. The outcomes are negatively impacted by older age, high or very high DRI, and CMV D-R+ serostatus, but not by donor unrelatedness or one HLA allele mismatch.

Curability and transferability of atopy with allogeneic hematopoietic cell transplantation.

Atopy is excessive production of IgE in response to allergens. We evaluated in patients undergoing allogeneic hematopoietic cell transplantation (HCT) the following hypotheses: (1) Atopy is "curable" in atopic patients receiving HCT from a nonatopic donor (D-R+), and (2) Atopy is transferable from atopic donors to nonatopic recipients (D+R-). Atopic patients with atopic donors (D+R+) and non-atopic patients with non-atopic donors (D-R-) served as controls. We measured levels of multiallergen-specific IgE (A-IgE, atopy defined as ≥0.35 kUA/L) in sera from 54 patients and their donors pre HCT and from the patients at ≥2 years post HCT. Only 7/12 (58%) D- R+ patients became nonatopic after HCT. Only 1/11 (9%) D+R- patients became atopic. Eleven of 13 (85%) D-R- patients remained nonatopic. Unexpectedly, 11/18 (61%) D+R+ patients became nonatopic. In conclusion, contrary to our hypothesis and previous reports, the "cure" of atopy may occur in only some D-R+ patients and the transfer of atopy may occur rarely. The "cure" may not be necessarily due to the exchange of atopic for nonatopic immune system, as the "cure" may also occur in D+R+ patients.

Comparison of abacavir-specific effector and proliferating functions of CD8 T cells in abacavir-treated HIV-1 patients.

Susceptibility to abacavir hypersensitivity (ABH) in HIV-1-positive patients is strongly linked to the carriage of HLA-B*57:01 and the potential mechanism includes drug-specific activation of cytokine producing CD8 T cells exclusively in individuals carrying HLA-B*57:01. Here, we report a detailed characterization of abacavir-induced functional response of CD8 T cells in HLA-B*57:01pos individuals. Peripheral blood mononuclear cells (PBMNCs) from HLA-B*57:01pos ABHpos and HLA-B*57:01neg ABHneg individuals were stimulated with abacavir. Multicolor flow cytometry was performed to assess the cytokine (IFNγ) production and degranulation (CD107a expression) after 6-18 hr culture and to enumerate proliferating CD4/CD8 T cells by culturing carboxyfluorescein diacetate succinimidyl ester-loaded PBMNCs for 7 days. CD8 T cells from HLA-B*57:01pos ABHpos individuals were multifunctional: proliferating, IFNγ producing, degranulating (CD107apos ), and both degranulating and IFNγ producing (CD107apos IFNγpos ). Degranulating CD8 T cells in general and both degranulating and IFNγ producing CD8 T cells in particular dominated abacavir-specific immune response. All functional responses were partially blocked by addition of HLA-B*57:01-reactive Bw4 mAb, but not by non-HLA-B*57:01-reactive Bw6 mAb. In conclusion, the study demonstrates that abacavir-specific CD8 T-cell-restricted immune response in HLA-B*57:01pos ABHpos HIV-1 patients has multiple effector and proliferating functions, where the primary effector response appears to be the release of cytolytic granules. The findings have implications for immunotherapy of HLA-related drug hypersensitivities.

More acute lymphoid leukemia than acute myeloid leukemia blasts are killed by rabbit antithymocyte globulin.

Rabbit antithymocyte globulin (ATG, thymoglobulin), a polyclonal antibody, is used to prevent graft-versus-host disease (GVHD) and graft failure in the setting of allogeneic hematopoietic cell transplantation (HCT). Recent in vitro studies suggest that ATG also has anti-leukemic activity. Whether acute lymphoid leukemia (ALL) or acute myeloid leukemia (AML) is more sensitive to ATG is not known. We used primary cells from 12 B-ALL and 38 AML patients and measured ATG-induced complement-dependent cytotoxicity (CDC) and complement-independent cytotoxicity (CIC) at clinically relevant ATG concentrations (10 and 50 mg/L). At 50 mg/L, ALL blasts were killed to a greater degree than AML blasts by CDC (median 96% vs 50% dead cells, P = 0.001) as well as CIC (median 23% vs 11% apoptotic cells, P = 0.049). At 10 mg/L, the difference was significant for CDC but not CIC. In conclusion, the anti-leukemic activity of ATG, particularly CDC, is more potent for ALL than AML in vitro. If this applies in vivo, ATG-based GVHD prophylaxis may be particularly advantageous for ALL.

High incidence of hematologic malignancy relapse after allogeneic transplantation in patients with low Epstein-Barr virus-specific T-cell counts.

BACKGROUND: Association between low counts of herpesvirus-specific T cells and subsequent relapse of hematologic malignancy has been shown in two retrospective studies. METHODS: Here we present results of a prospective validation study. Multiple subsets of Epstein-Barr virus (EBV)-specific T cells were measured in 69 patients on day 56 and 84, using intracellular flow cytometry after incubation of blood mononuclear cells (MNCs) with EBV peptides or lysate. RESULTS: All EBV T-cell subsets measured, both on day 56 and 84, were lower in patients who did versus did not subsequently relapse. This was most significant for day 56 EBV lysate-stimulated CD8 T cells producing interferon-gamma. Patients with day 56 counts of this subset >5/µL had a significantly lower likelihood of relapse compared with those with ≤5/µL (subhazard ratio, 5.7; P = 0.007). Similar significant associations were shown for a total of seven EBV T-cell subsets on day 56 and nine subsets on day 84. However, sensitivity and specificity of relapse prediction using the count of any subset was low (area under the curve of receiver-operator characteristic curve was <0.8). DISCUSSION: In conclusion, the association between EBV T-cell counts and subsequent relapse is valid. However, its clinical utility appears to be limited.