High Ferritin, but Not Hepcidin, Is Associated with a Poor Immune Response to an Influenza Vaccine in Hemodialysis Patients

Abstract

Background: The immune response to vaccination in hemodialysis (HD) patients can be influenced by disorders of iron metabolism, iron overload or chronic inflammatory state. Elevated levels of hepcidin are considered a new marker of iron metabolism impairment and anemia of inflammation in HD patients. Methods: We studied the effects of hepcidin, other markers of iron status and intravenous iron (Fe_iv) on the response to an influenza vaccine (Influvac® subunit 2008/2009) in 40 HD patients. The immune response of HD patients was compared with that of 46 controls without renal disease according to serum antihemagglutinin antibody titer (anti-HA). Results: A total of 31 HD patients (responders) attained seroconversion (at least a 4-fold increase in anti-HA) to at least 1 of 3 vaccine strains; 9 patients (nonresponders) did not respond to any strain. Responders did not differ from nonresponders in hepcidin [99 µg/l (36–200) vs. 97 µg/l (23–216), p = 0.97]. Responders had lower ferritin (571 ± 291 vs. 821 ± 309 µg/l, p = 0.031) and were administered higher doses of Fe_iv within the last 12 weeks prior to vaccination [625 mg (312–625) vs. 312 mg (0–625), p = 0.029]. The seroconversion to A(H1N1), A(H3N2) and B strains was noted in 20, 52 and 40% of HD and in 11, 39 and 48% of controls, respectively (HD vs. controls, p = nonsignificant). The rates of seroprotection (anti-HA ≧40) to vaccine strains in HD (27, 85 and 95%) and controls (24, 96 and 98%) were also comparable. Conclusion: Antibody production following influenza vaccination in HD patients may be suppressed by very high ferritin levels. Hepcidin does not correlate with immune response and high levels of hepcidin may reflect its retention in HD patients. Fe_iv administration was not associated with a poorer immune response. The immunogenicity of the A(H1N1) strain was inadequate in HD patients and controls alike.