Severe Pandemic H1N1 2009 Infection Is Associated with Transient NK and T Deficiency and Aberrant CD8 Responses

BACKGROUND: It is unclear why the severity of influenza varies in healthy adults or why the burden of severe influenza shifts to young adults when pandemic strains emerge. One possibility is that cross-protective T cell responses wane in this age group in the absence of recent infection. We therefore compared the acute cellular immune response in previously healthy adults with severe versus mild pandemic H1N1 infection. METHODS AND PRINCIPAL FINDINGS: 49 previously healthy adults admitted to the National Hospital of Tropical Diseases, Viet Nam with RT-PCR-confirmed 2009 H1N1 infection were prospectively enrolled. 39 recovered quickly whereas 10 developed severe symptoms requiring supplemental oxygen and prolonged hospitalization. Peripheral blood lymphocyte subset counts and activation (HLADR, CD38) and differentiation (CD27, CD28) marker expression were determined on days 0, 2, 5, 10, 14 and 28 by flow cytometry. NK, CD4 and CD8 lymphopenia developed in 100%, 90% and 60% of severe cases versus 13% (p<0.001), 28%, (p = 0.001) and 18% (p = 0.014) of mild cases. CD4 and NK counts normalized following recovery. B cell counts were not significantly associated with severity. CD8 activation peaked 6-8 days after mild influenza onset, when 13% (6-22%) were HLADR+CD38+, and was accompanied by a significant loss of resting/CD27+CD28+ cells without accumulation of CD27+CD28- or CD27-CD28- cells. In severe influenza CD8 activation peaked more than 9 days post-onset, and/or was excessive (30-90% HLADR+CD38+) in association with accumulation of CD27+CD28- cells and maintenance of CD8 counts. CONCLUSION: Severe influenza is associated with transient T and NK cell deficiency. CD8 phenotype changes during mild influenza are consistent with a rapidly resolving memory response whereas in severe influenza activation is either delayed or excessive, and partially differentiated cells accumulate within blood indicating that recruitment of effector cells to the lung could be impaired

The Relevance of the Informational Content of Book-Tax Differences for Predicting Future Income: Evidence from Latin American Countries

This study aims to investigate whether the different types of book-tax differences are useful for predicting the future income of publicly traded companies in five Latin American countries. This is possible since these differences convey information about transitory components of income, which can be used by investors for predicting future income. However, little is known about the relationship between tax variables and companies' future results. The sample analyzed here is composed of 580 publicly traded companies from five Latin American countries (Argentina, Brazil, Chile, Mexico, and Peru) with information available in the Economatica(r) database covering 2002 to 2013. In terms of methodology, regressions are employed in order to find a connection between the different types (total, permanent, temporary, and the negative and positive variations) of book-tax differences and companies' current and future earnings per share, as well as some control variables suggested by previous literature. The model's coefficients were estimated through panel data techniques: fixed effects. The results obtained suggest that the information gathered in the different types of book-tax differences (total, permanent, temporary, positive and negative variations) is relevant in predicting future income. Total, permanent and temporary differences contribute to the uncertainty in future income prediction, given that results are more transitory and less persistent in years with higher book-tax differences. Positive and negative variations, on the other hand, attribute higher income in coming years to greater variations in book-tax differences, representing increased timeliness of results and a reduction in off balance sheet funding for the publicly traded companies from these countries