Human megakaryocytes possess intrinsic antiviral immunity through regulated induction of IFITM3.

Evolving evidence indicates that platelets and megakaryocytes (MKs) have unexpected activities in inflammation and infection; whether viral infections upregulate biologically active, antiviral immune genes in platelets and MKs is unknown, however. We examined antiviral immune genes in these cells in dengue and influenza infections, viruses that are global public health threats. Using complementary biochemical, pharmacological, and genetic approaches, we examined the regulation and function of interferon-induced transmembrane protein 3 (IFITM3), an antiviral immune effector gene not previously studied in human platelets and MKs. IFITM3 was markedly upregulated in platelets isolated from patients during clinical influenza and dengue virus (DENV) infections. Lower IFITM3 expression in platelets correlated with increased illness severity and mortality in patients. Administering a live, attenuated DENV vaccine to healthy subjects significantly increased platelet IFITM3 expression. Infecting human MKs with DENV selectively increased type I interferons and IFITM3. Overexpression of IFITM3 in MKs was sufficient to prevent DENV infection. In naturally occurring, genetic loss-of-function studies, MKs from healthy subjects harboring a homozygous mutation in IFITM3 (rs12252-C, a common single-nucleotide polymorphism in areas of the world where DENV is endemic) were significantly more susceptible to DENV infection. DENV-induced MK secretion of interferons prevented infection of bystander MKs and hematopoietic stem cells. Thus, viral infections upregulate IFITM3 in human platelets and MKs, and IFITM3 expression is associated with adverse clinical outcomes. These observations establish, for the first time, that human MKs possess antiviral functions, preventing DENV infection of MKs and hematopoietic stem cells after local immune signaling.

Lymph Node Ratio in Pancreatic Adenocarcinoma After Preoperative Chemotherapy vs. Preoperative Chemoradiation and Its Utility in Decisions About Postoperative Chemotherapy.

BACKGROUND: Single-center studies in pancreatic adenocarcinoma have suggested that preoperative chemotherapy (PCT) is associated with higher lymph node ratio (LNR) than preoperative chemoradiation (PCRT). The association of postoperative chemotherapy with overall survival (OS) in patients treated with PCT and PCRT remains unclear. Our objectives were to investigate whether (1) PCT is associated with higher LNR than PCRT and (2) postoperative chemotherapy is associated with longer OS after PCT and PCRT in LNR-stratified cohorts. METHODS: A retrospective cohort study was performed of patients with pancreatic adenocarcinoma treated with PCT or PCRT followed by resection between 2006 and 2014 in the National Cancer Database. Temporal trends were evaluated with Cuzick's test. OS was evaluated with multivariable Cox regression and inverse probability weighted (IPW) Cox regression. RESULTS: Of 4187 patients, 1993 (47.6%) received PCT. PCT rates were stable at approximately 30% in 2006-2010 (p = 0.33) but increased to 64.9% by 2014 (p < 0.001). Node positivity rates were higher after PCT than PCRT (62.7 vs. 41.8%, P < 0.001) and mean LNR was higher (0.10 [95% CI 0.096, 0.11] vs. 0.058 [95% CI 0.052, 0.063], P < 0.001). Postoperative chemotherapy was associated with longer OS in patients with LNR 0.01-0.149 after PCT by univariate analysis (median OS 34.5 vs. 26.5 months, P = 0.002), multivariable Cox regression (HR 0.64, 95% CI 0.48, 0.84), and IPW Cox regression (HR 0.72, 95% CI 0.55, 0.94). Postoperative chemotherapy was not associated with longer OS for patients who were node-negative or who had LNR ≥ 0.15 after PCT or for any patient subgroups after PCRT. CONCLUSIONS: PCT is associated with a higher LNR and higher rates of node positivity than PCRT. Postoperative chemotherapy is associated with longer OS than observation in patients with a LNR of 0.01-0.149 after PCT.

Outcomes After Pediatric Out-of-Hospital Cardiopulmonary Interventions.

OBJECTIVE: The aim of the study was to evaluate outcomes after pediatric out-of-hospital cardiopulmonary interventions (CPIs) by emergency medical services (EMS). METHODS: Children (age, ≤18 years) who received CPI by EMS from 2001 to 2008 were identified from the Utah Department of Health. Cardiopulmonary intervention was defined as oxygenation, ventilation or CPR, and transport to a hospital by EMS. Univariate and multivariable regression analyses evaluated associations between potential predictors and outcomes (death and new neurologic dysfunction). RESULTS: A total of 464 patients (58% male) received EMS attention. For the 71% patients (327) who were alive on EMS arrival, 63% (205) received CPI without CPR. Of note, 6% (12) of these patients died after arrival to the hospital and new neurologic dysfunction was diagnosed in 6% (13). Among the 12 patients who died, 50% (6) were younger than 1 year.On multivariable regression analysis, factors associated with increased risk of death before and in-hospital are the following: age younger than 1 year (odds ratio [OR], 0.26; 95% confidence interval [CI], 0.17-0.39), shorter EMS transport time (OR, 0.94; 95% CI, 0.89-0.99), and longer EMS dispatch time (OR, 1.23; 95% CI, 1.08-1.40). Factors associated with increased risk of new neurologic dysfunction are the following: lack of pulse (OR, 0.14; 95% CI, 0.04-0.53), requiring CPR (OR, 6.15; 95% CI, 1.48-25.6), and CPR duration (OR, 1.20; 95% CI, 1.05-1.37). CONCLUSIONS: Age younger than 1 year, shorter transport time, and longer dispatch time were associated with increased risk of death. Being pulseless upon discovery and receiving CPR were associated with new neurologic dysfunction. Maximizing EMS transport interventions for patients younger than 1 year requiring CPI may improve patient outcomes.

Stereological analysis of bacterial load and lung lesions in nonhuman primates (rhesus macaques) experimentally infected with Mycobacterium tuberculosis.

Infection with Mycobacterium tuberculosis primarily produces a multifocal distribution of pulmonary granulomas in which the pathogen resides. Accordingly, quantitative assessment of the bacterial load and pathology is a substantial challenge in tuberculosis. Such assessments are critical for studies of the pathogenesis and for the development of vaccines and drugs in animal models of experimental M. tuberculosis infection. Stereology enables unbiased quantitation of three-dimensional objects from two-dimensional sections and thus is suited to quantify histological lesions. We have developed a protocol for stereological analysis of the lung in rhesus macaques inoculated with a pathogenic clinical strain of M. tuberculosis (Erdman strain). These animals exhibit a pattern of infection and tuberculosis similar to that of naturally infected humans. Conditions were optimized for collecting lung samples in a nonbiased, random manner. Bacterial load in these samples was assessed by a standard plating assay, and granulomas were graded and enumerated microscopically. Stereological analysis provided quantitative data that supported a significant correlation between bacterial load and lung granulomas. Thus this stereological approach enables a quantitative, statistically valid analysis of the impact of M. tuberculosis infection in the lung and will serve as an essential tool for objectively comparing the efficacy of drugs and vaccines.