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BackgroundAsthma is a heterogeneous disease. Clinical blood parameters differ by race/ethnicity and are used to distinguish asthma subtypes and inform therapies. Differences in subtypes may explain population-specific trends in asthma outcomes. However, these differences in racial/ethnic minority pediatric populations are unclear.ObjectiveWe investigated the association of blood parameters and asthma subtypes with asthma outcomes and examined population-specific eligibility for biologic therapies in minority pediatric populations.MethodsUsing data from 2 asthma case-control studies of pediatric minority populations, we performed case-control (N = 3738) and case-only (N = 2743) logistic regressions to quantify the association of blood parameters and asthma subtypes with asthma outcomes. Heterogeneity of these associations was tested using an interaction term between race/ethnicity and each exposure. Differences in therapeutic eligibility were investigated using chi-square tests.ResultsRace/ethnicity modified the association between total IgE and asthma exacerbations. Elevated IgE level was associated with worse asthma outcomes in Puerto Ricans. Allergic asthma was associated with worse outcomes in Mexican Americans, whereas eosinophilic asthma was associated with worse outcomes in Puerto Ricans. A lower proportion of Puerto Ricans met dosing criteria for allergic asthma-directed biologic therapy than other groups. A higher proportion of Puerto Ricans qualified for eosinophilic asthma-directed biologic therapy than African Americans.ConclusionsWe found population-specific associations between blood parameters and asthma subtypes with asthma outcomes. Our findings suggest that eligibility for asthma biologic therapies differs across pediatric racial/ethnic populations. These findings call for more studies in diverse populations for equitable treatment of minority patients with asthma.

Background: Clinical trials of allergen immunotherapy (AIT) may require up to 5 years to complete. These lengthy trials may be complicated by high and potentially differential dropouts, especially among participants who perceive that they are receiving placebo. We propose a three‐stage design in which the placebo group in Stage 1 crosses over to receive active treatment in Stage 2. In Stage 3, AIT is discontinued to determine whether benefit is maintained post‐treatment. We apply inferential statistics to support the three‐stage design for clinical trials to determine clinical efficacy, treatment response over time, and sustained response to AIT. Methods: The proposed framework constitutes a series of hypothesis tests for comparing treatment responses at the end of each stage. A simulation study was performed to illustrate the statistical properties under varying statistical missing mechanisms and effect sizes. Results: The statistical properties in terms of bias and statistical power were consistent with what are expected from conventional analyses. Specifically, the extent of bias depended on the missing mechanism and magnitude. The statistical powers were largely driven by effect and sample sizes as well as prespecified success margins. As an illustration, assuming relative treatment differences of 25% and stagewise dropout rate of 15%, a sample size of 200 per group may achieve 93% power to demonstrate a treatment effect and 60% power to demonstrate a maintained response post‐treatment. Conclusions: Inferential statistics support our proposed study design for evaluating benefits of AIT over time and inform clinical understanding and decisions. [ABSTRACT FROM AUTHOR]

The pathways for differentiation of human CD[4.sup.+] T cells into functionally distinct subsets of memory cells in vivo are unknown. The identification of these subsets and pathways has clear implications for the design of vaccines and immune-targeted therapies. Here, we show that populations of apparently naive CD[4.sup.+] T cells express the chemokine receptors CXCR3 or CCR4 and demonstrate patterns of gene expression and functional responses characteristic of memory cells. The proliferation history and T cell receptor repertoire of these chemokine-[receptor.sup.+] cells suggest that they are very early memory CD[4.sup.+] T cells that have 'rested down' before acquiring the phenotypes described for 'central' or 'effector' memory T cells. In addition, the chemokine-[receptor.sup.+] 'naive' populations contain Th1 and Th2 cells, respectively, demonstrating that Th1/Th2 differentiation can occur very early in vivo in the absence of markers conventionally associated with memory cells. We localized ligands for CXCR3 and CCR4 to separate foci in T cell zones of tonsil, suggesting that the chemokine-[receptor.sup.+] subsets may be recruited and contribute to segregated, polarized micro-environments within lymphoid organs. Importantly, our data suggest that CD[4.sup.+] T cells do not differentiate according to a simple schema from nalve [right arrow] CD45R[O.sup.+] noneffector/central memory effector/effector memory cells. Rather, developmental pathways branch early on to yield effector/memory populations that are highly heterogeneous and multifunctional and have the potential to become stable resting cells. chemokines | immunologic memory | Th1/Th2 cells

It is shown that recombinant envelope proteins from macrophage-tropic human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV), trigger a signal through CCR5 on CD4+ T cells, and that signal transduction induces chemotaxis of T cells. The response could contribute to HIV pathogenesis, by attracting CD4+ cells to viral replication sites.