Antibody response to influenza immunization in kidney transplant recipients receiving either azathioprine or mycophenolate: A controlled trial

Aims: We aimed to assess humoral immune response to the influenza vaccine in adult kidney transplant recipients (KTRs) subjected to two immunosuppressive regimens containing either mycophenolate mofetil (MMF) or azathioprine (Aza). Methods: 40 eligible KTRs (24 treated with Aza [KTRs-Aza] and 16 treated with MMF [KTRs-MMF]) and 40 matched healthy controls (HCs) were administered the trivalent 2006-2007 anti-influenza vaccine. Antibody (Ab) titers were measured before (pre-vacc) and 1 month after (post-vacc) vaccination. The proportion of protective Ab titers (i.e. ≥1:40), the serological response (i.e. ≥4-fold rise in titers) rates, and the magnitudes of change in titers were evaluated. Results: KTRs and HCs were similar in serologic responses, magnitudes of change in Ab titers, and proportions of acquired protective titers against all antigens. Whereas KTRs-MMF and KTRs-Aza were identical in magnitude of rise in titers as well as in serologic responses, KTRs-MMF did poorer in developing post-vacc-protective titers against A/H1N1 (p < 0.05). The function of the transplanted kidney has not deteriorated after vaccination. Conclusions: Anti-influenza vaccination was safe in KTRs and evoked Ab responses comparable to those of HCs. KTRs-MMF and KTRs-Aza responded almost equally to the vaccine. Annual anti-influenza vaccination can be recommended to all stable KTRs.