Cross-sectional study of the relationship of peripheral blood cell profiles with severity of infection by adenovirus type 55

BACKGROUND The immunologic profiles of patients with human adenovirus serotype 55 (HAdV-55) infections were characterized in subjects diagnosed with silent infections (n = 30), minor infections (n = 27), severe infections (n = 34), and healthy controls (n = 30) during a recent outbreak among Chinese military trainees. METHODS Blood was sampled at the disease peak and four weeks later, and samples were analyzed to measure changes in leukocyte and platelet profiles in patients with different severities of disease. Differential lymphocyte subsets and cytokine profiles were measured by flow cytometry and Luminex xMAP®, and serum antibodies were analyzed by ELISA and immunofluorescence staining. RESULTS Patients with severe HAdV infections had higher proportions of neutrophils and reduced levels of lymphocytes (p < 0.005 for both). Patients with minor and severe infections had significantly lower platelet counts (p < 0.005 for both) than those with silent infections. The silent and minor infection groups had higher levels of dendritic cells than the severe infection group. Relative to patients with silent infections, patients with severe infections had significantly higher levels of IL-17+CD4+ cells, decreased levels of IL-17+CD8+ cells, and higher levels of IFN-γ, IL-4, IL-10, and IFN-α2 (p < 0.001 for all comparisons). CONCLUSIONS Patients with different severities of disease due to HAdV-55 infection had significantly different immune responses. These data provide an initial step toward the identification of patients at risk for more severe disease and the development of treatments against HAdV-55 infection.