Statewide Asthma Learning Collaborative Participation and Asthma-Related Emergency Department Use.

BACKGROUND: Quality improvement (QI) efforts can improve guideline-recommended asthma care processes in the pediatric office setting. We sought to assess whether practice participation in an asthma QI collaborative was associated with decreased asthma-related emergency department (ED) visits. METHODS: A statewide network of practices participated in a pediatric asthma QI collaborative from 2015 to 2016. We evaluated asthma-related ED visit rates per 100 child-years for children ages 3 to 21 years with asthma, using the state's all-payer claims database. We used a difference-in-differences approach, with mixed-effects negative binomial regression models to control for practice and patient covariates. Our main analysis measured the outcome before (2014) and after (2017) the QI collaborative at fully participating and control practices. Additional analyses assessed (1) associations during the intervention period (2016) and (2) associations including practices partially participating in QI collaborative activities. RESULTS: In the postintervention year (2017), participating practices' (n = 20) asthma-related ED visit rate decreased by 5.8 per 100 child-years, compared to an increase of 1.8 per 100 child-years for control practices (n = 15; difference in differences = -7.3; P = .002). Within the intervention year (2016), we found no statistically significant differences in asthma-related ED visit rates compared to controls (difference in differences = -4.3; P = .17). The analysis including partially participating practices yielded similar results and inferences to our main analysis. CONCLUSIONS: Participation in an asthma-focused QI collaborative was associated with decreased asthma-related ED visit rates. For those considering implementing this type of QI collaborative, our findings indicate that it takes time to see measurable improvements in ED visit rates. Further study is warranted regarding QI elements contributing to success for partial participants.

PD-1 regulates T cell proliferation in a tissue and subset-specific manner during normal mouse pregnancy.

The regulation of T cell homeostasis during pregnancy has important implications for maternal tolerance and immunity. Evidence suggests that Programmed Death-1 (PD-1) participates in regulation of T cell homeostasis and peripheral tolerance. To examine the contribution of PD-1 signaling on T cell homeostasis during normal mouse pregnancy, we examined T cell number or proportion, PD-1 expression, proliferation, and apoptosis by flow cytometry, BrdU incorporation, and TUNEL assay in pregnant mice given anti-PD-1 blocking antibody or control on days 10, 12, and 14 of gestation. We observed tissue, treatment, and T cell-specific differences in PD-1 expression. Both pregnancy and PD-1 blockade increased T cell proliferation in the spleen, yet this effect was limited to CD4 T cells in the uterine- draining nodes. In the uterus, PD-1 blockade markedly altered the composition of the T cell pool. These studies support the idea that pregnancy is a state of dynamic T cell homeostasis and suggest that this state is partially supported by PD-1 signaling.

Transient modification within a pool of CD4 T cells in the maternal spleen.

Classic models suggest maternal tolerance is dependent on regulation of fetal antigen-specific T cell responses. We hypothesize that factors unique to a particular fetal antigen-specific T cell, rather than the state of pregnancy per se, are important determinants of T cell fate during pregnancy. To investigate the fate of fetal antigen-specific CD4 T cells in the systemic circulation, we examined spleen cells in a CD4 T cell receptor transgenic mouse specific for the male antigen H-Y. We observed a transient decrease in CD4(+) Vß6(+) cell numbers and, due to transient internalization of CD4, an increase in CD4(-) Vß6(+) T cells. Antigen-specific in vitro responsiveness was not depressed by pregnancy. These data suggest that pregnancy supports fluidity in this particular CD4 T cell pool that may, in turn, help to meet competing requirements of maternal immune responsiveness and fetal tolerance.