Structure and consistency of self-reported social contact networks in British secondary schools.

Self-reported social mixing patterns are commonly used in mathematical models of infectious diseases. It is particularly important to quantify patterns for school-age children given their disproportionate role in transmission, but it remains unclear how the structure of such social interactions changes over time. By integrating data collection into a public engagement programme, we examined self-reported contact networks in year 7 groups in four UK secondary schools. We collected data from 460 unique participants across four rounds of data collection conducted between January and June 2015, with 7,315 identifiable contacts reported in total. Although individual-level contacts varied over the study period, we were able to obtain out-of-sample accuracies of more than 90% and F-scores of 0.49-0.84 when predicting the presence or absence of social contacts between specific individuals across rounds of data collection. Network properties such as clustering and number of communities were broadly consistent within schools between survey rounds, but varied significantly between schools. Networks were assortative according to gender, and to a lesser extent school class, with the estimated clustering coefficient larger among males in all surveyed co-educational schools. Our results demonstrate that it is feasible to collect longitudinal self-reported social contact data from school children and that key properties of these data are consistent between rounds of data collection.

Increased eosinophil-lineage committed progenitors in the lung of allergen-challenged mice.

BACKGROUND: There is increasing evidence that hemopoietic progenitor cells may traffic from bone marrow to sites of allergen exposure in asthma and undergo in situ differentiation, contributing to ongoing airway inflammation. However, the isolation and detailed phenotyping of true CD34 + progenitors from lung tissue during an allergen-induced airway eosinophilia has not been performed. OBJECTIVE: We attempted to isolate and investigate the in vivo kinetics of hemopoietic progenitor cells and production of eosinophilopoietic mediators in the lung. METHODS: In a mouse model of allergic airway inflammation, cells were extracted from lung tissue by enzymatic digestion. Total (CD34 + 45 + ) and eosinophil lineage committed (CD34 + 45 + IL-5Ralpha + ) progenitors were enumerated by flow cytometry. Outcome measurements were made 2, 6, 12, 24, 48, and 72 hours and 7 and 14 days after allergen challenge. RESULTS: Compared with saline control, CD34 + 45 + progenitors were elevated between 6 and 48 hours ( P < .05), attenuated by 72 hours and subsequently increased by 14 days ( P > .05). CD34 + 45 + IL-5Ralpha + progenitors were transiently elevated at 6 hours ( P < .05) before a return to preallergen levels by 12 hours and a subsequent increase at 14 days ( P < .05). Bronchoalveolar lavage eosinophils were increased at 2 hours, peaking at 72 hours ( P < .00625) and declining by 14 days. Both IL-5 and eotaxin levels were increased by 2 hours, peaking at 12 hours ( P < .05) and 24 hours ( P < .05), respectively. CONCLUSION: We propose that the increase in CD34 + 45 + IL-5Ralpha + cells and the eosinophilopoietic mediators IL-5 and eotaxin in the lung after allergen exposure may promote in situ differentiation of eosinophils that contribute to ongoing allergic airway inflammation.