Background: Heart failure (HF) patients are at risk for influenza despite widespread vaccination. Both humoral (antibody) and cytotoxic T-lymphocyte (CTL) responses are important for protection. We explored antibody- and CTL-mediated responses to the influenza vaccine in HF patients compared with healthy controls.
Methods and results: We studied 29 HF patients (9 ischemic, 20 nonischemic) stable on HF therapies and 17 healthy controls. Participants had phlebotomy before and after influenza vaccination. Antibody production was measured in serum by hemagglutination inhibition assay and CTL responses (via interferon [IFN]-gamma and interleukin [IL]-10 production) were measured in isolated peripheral blood mononuclear cells with enzyme-linked immunosorbent assay. CTL responses demonstrated increased IL-10 production in HF patients after vaccination (P = .002), but similar IFN-gamma responses to healthy controls. All participants demonstrated antibody seroprotection; groups had similar rates of seroconversion (P = NS). Antibody-mediated response to the newest vaccine antigen, H3N2, was reduced in HF (P = .009).
Conclusions: Patients with HF had higher vaccine induced IL-10 concentrations, suggesting a different CTL phenotype for vaccine responses. HF patients did not mount as vigorous of an antibody immune response to the newest vaccine viral strain compared with healthy individuals. These data suggest that immunologic memory may be important for vaccine protection in HF patients.