The cellular immunophenotype expression of influenza A virus and influenza B virus infection in children.

Background: The innate immune response is the primary defense against influenza virus infection.

Methods: This is a prospective study carried out in children <18 years of age who were diagnosed with influenza A or influenza B infection. Demographic and clinical data, laboratory findings and cell immunophenotypes on first presentation were compared.

Results: With respect to immunophenotype, influenza A infection resulted in a higher fraction of CD14 and CD4IL-17Acells compared to children infected with influenza B. By contrast, influenza B infection resulted in a comparatively higher percentage of double-negative CD4CD8 lymphocyte subsets. Influenza A infection was associated with comparatively higher percentages of CD4CD25Foxp3 and CD4CD25Foxp3 cells. By contrast, the percentage of CD8CD25 and CD8CD25 cells was similar among patients with influenza A infection and influenza B infection.

Conclusions: An improved understanding of the fraction of regulatory T cells with influenza virus infections may provide further understandings on immune responses.