Figure 5.

Antibody response to flu vaccination. (A) Hemagglutination-Inhibition assay was used to measure the titer of antibodies specific of each strains of influenza virus (Switzerland, California, and Phuket) present in the vaccine. The titer was measured just before and 21–28 days post-vaccination and results are expressed as a ratio of these two values for healthy volunteers (n = 9; controls, Ctl; open triangles), and transplant patients (n = 36, circles). The nature of induction immunosuppressive therapy received by transplant patient is indicated. Transplant patients were distributed into two groups according to the time elapsed since transplantation: (i) 6–12 months: early post-transplantation (Early Tx; n = 18), and (ii) >12–72 months: late post-transplantation (Late Tx; n = 18). Dotted line indicates the threshold of fold change in specific antibody titer above which the patient was considered as responder (≥4). (B) The Venn diagram summarizes the relations between the responses to the various virus strains.