Immuno-epidemiologic Correlates of Pandemic H1N1 Surveillance Observations: Higher Antibody and Lower Cell-Mediated Immune Responses with Advanced Age

摘要: Background. Pandemic H1N1 (pH1N1) surveillance data showed lower attack rates but higher risk of severe outcomes with advanced age. We explored immuno-epidemiologic correlates findings including humoral and cell-mediated immunity (CMI). Methods. In an age-based design, ∼100 banked/residual sera per 10-year age stratum were assessed by hemagglutination inhibition (HI) microneutralization (MN) assays for preexisting antibody to pH1N1 recent seasonal H3N2 strains. a separate birth cohort design defined childhood influenza A/subtype priming (1919–1929: H1N1; 1945–1949: 1958–1960: H2N2; 1969–1970: H3N2; 1978–1989: H3N2/H1N1), whole blood was collected from up 50 volunteers cohort. The ratio Th1(IFN-γ):Th2(IL-10) cytokine responses evaluated in vitro. Results. Antibody viruses highest school-age children. Cross-reactive HI/MN low among participants <70 years (yoa; 6%/4% ≥ 40), seroprevalence increased at 70–79 yoa (27%/6%), even more 80–89 (65%/47%), ≥90 (88%/76%). CMI evident all 5 cohorts compared There little differentiation subtype priming, the Th1:Th2 dropped significantly 2 oldest cohorts. Conclusions. Preexisting may have protected very old infection, while diminished contributed greater severity once infected. young, cross-reactive mostly absent, intact against outcomes.