Background: We analyzed the impact of the anti-T-cell agents basiliximab and antithymocyte globu- lins (ATG) on antibody and cell-mediated immune responses after influenza vaccination in solid-organ transplant recipients.
Methods: 71 kidney and heart transplant recipients (basiliximab [n = 43] and ATG [n = 28]) received the trivalent influenza vaccine. Antibody responses were measured at baseline and 6 weeks post-vaccination by hemagglutination inhibition assay; T-cell responses were measured by IFN-)' ELISpot assays and intra- cellular cytokine staining (ICS); and influenza-specific memory B-cell (MBC) responses were evaluated using ELISpot.
Results: Median time of vaccination from transplantation was 29 months (IQR 8–73). Post-vaccination seroconversion rates were 26.8% for H1N1, 34.1% for H3N2 and 4.9% for influenza B in the basiliximab group and 35.7% for H1N1, 42.9% for H3N2 and 14.3% for influenza B in the ATG group (p = 0.44, p = 0.61, and p = 0.21, respectively). The number of influenza-specific IFN-)'-producing cells increased significantly after vaccination (from 35 to 67.5 SFC/106 PBMC, p = 0.0007), but no differences between treatment groups were observed (p = 0.88). Median number of IgG-MBC did not increase after vaccination (H1N1, p = 0.94; H3N2 p = 0.34; B, p = 0.79), irrespective of the type of anti-T-cell therapy.
Conclusions: After influenza vaccination, a significant increase in antibody and T-cell immune responses but not in MBC responses was observed in transplant recipients. Immune responses were not significantly different between groups that received basiliximab or ATG.