Citations

Abstract The objective of this study was to test the hypothesis that the increasing global incidence of allergy and atopy are due in part to improved hygiene and decreased microbial exposure. We have adopted a novel mouse model of normalized microbial exposure to test the impact of immune experience on subsequent responses to airway allergens. In this model, specific pathogen free (SPF) B6 mice are cohoused with mice from pet stores and become “dirty” – many commensals and pathogens are transmitted through cohousing and influence the immune cell populations systemically and in the lungs. We treated mice intranasally with a single dose of A. alternata fungal extract (Alt) and assessed production of type 2 cytokines. IL5 and IL13 levels in the lungs and bronchoalveolar lavage fluid were dramatically elevated by Alt in SPF mice but were not significantly increased by Alt in dirty mice. Type 2 innate lymphoid cells (ILC2) are the cells responsible for IL5 and IL13 after acute Alt treatment, and interestingly the number of lung ILC2 was unaltered by cohousing and their activation status appeared similar in both housing conditions. We treated mice with recombinant IL33, the alarmin released by lung epithelial cells in response to allergens, and the results suggest an impaired response to IL33 by dirty lung ILC2. In a repeated Alt exposure model, ILC2 cells expanded in SPF lungs and recruited eosinophils, neutrophils, and T cells. Most dirty mouse lungs contained these cell populations at steady state but were only modestly recruited with repeated Alt exposure. Lung function experiments are in progress. This study suggests that increased microbial exposure leads to more type-2 associated immune cells in the lungs, however responses to airway allergens are dampened.

Abstract The impact of microbes on restraining the immune response to allergens has been extensively studied and is a key element of the hygiene hypothesis. Lung type 2 innate lymphoid cell responses to airway allergens can be inhibited by administration of a number of microbial products; however, it is unclear whether such an effect would be observed with natural infections and how sustained any observed inhibitory effects would be. To answer these questions, we used a murine model of physiological microbial exposures through cohousing SPF laboratory mice with pet store mice and examined the acute type 2 response to intranasally delivered fungal allergen extract Alternaria alternata. We found laboratory mice cohoused with pet store mice for two weeks display a suppressed ILC2 response to A. alternata which resulted in reduced eosinophilia. By comparison, mice cohoused for at least two months had ILC2 and eosinophil responses similar to SPF mice despite dramatic changes to the composition of the immune cell populations in the lungs. Lung ILC2 in two-month cohoused mice were still sensitive to subsequent inflammatory cues, as administration of poly(I:C) was able to suppress ILC2 activation and eosinophilia equally well in SPF and two-month cohoused animals. These findings suggest ILC2 dynamically respond to their environment and are not easily desensitized long-term.

Background Temsirolimus (CCI-779) is a small-molecule inhibitor of the mammalian target of rapamycin (mTOR) and represents a rational therapeutic target against glioblastoma multiforme (GBM). Methods Recurrent GBM patients with ≤ 1 chemotherapy regimen for progressive disease were eligible. Temsirolimus was administered in a 250-mg intravenous dose weekly. Results Sixty-five patients were treated. The incidence of grade 3 or higher nonhematologic toxicity was 51%, and consisted mostly of hypercholesterolemia (11%), hypertriglyceridemia (8%), and hyperglycemia (8%). Grade 3 hematologic toxicity was observed in 11% of patients. Temsirolimus peak concentration (Cmax), and sirolimus Cmax and area under the concentration-time curve were decreased in patients receiving p450 enzyme–inducing anticonvulsants (EIACs) by 73%, 47%, and 50%, respectively, but were still within the therapeutic range of preclinical models. Twenty patients (36%) had evidence of improvement in neuroimaging, consisting of decrease in T2 signal abnormality +/− decrease in T1 gadolinium enhancement, on stable or reduced steroid doses. Progression-free survival at 6 months was 7.8% and median overall survival was 4.4 months. Median time to progression (TTP) for all patients was 2.3 months and was significantly longer for responders (5.4 months) versus nonresponders (1.9 months). Development of grade 2 or higher hyperlipidemia in the first two treatment cycles was associated with a higher percentage of radiographic response (71% v 31%; P = .04). Significant correlation was observed between radiographic improvement and high levels of phosphorylated p70s6 kinase in baseline tumor samples (P = .04). Conclusion Temsirolimus is well tolerated in recurrent GBM patients. Despite the effect of EIACs on temsirolimus metabolism, therapeutic levels were achieved. Radiographic improvement was observed in 36% of temsirolimus–treated patients, and was associated with significantly longer TTP. High levels of phosphorylated p70s6 kinase in baseline tumor samples appear to predict a patient population more likely to derive benefit from treatment. These findings should be validated in other studies of mTOR inhibitors.