Immunohistochemistry analysis of pulmonary infiltrates in necropsy samples of children with non-pandemic lethal respiratory infections (RSV; ADV; PIV1; PIV2; PIV3; FLU A; FLU B).

Background: Acute viral respiratory infections represent a globally important cause of morbidity and mortality in childhood. An individual's cellular response appears to play a critical role in recovery from infections, given that individuals with impaired cellular immunity, congenital or acquired, have more severe diseases and secrete the virus for longer periods.

Objectives: The aim of this study was to immunohistochemically evaluate the expression of the cell surface antigens CD4, CD8, CD25, CD14 and CD74, in pneumonic infiltrates in the alveolar septa using paraffin-embedded lung samples from autopsies of immunocompetent children who died of lethal, non-pandemic, severe acute respiratory infections.