Impact of pretransplant asplenia vaccination on anti-A/B antibody titers in prospective ABO incompatible kidney transplant recipients

Background: Asplenia vaccination is employed before ABO-incompatible (ABOi) transplantation in case splenectomy is needed. Pneumococcal vaccines have been reported, in different patient groups, to increase anti-A/B titers, through cross-reactivity to shared polysaccharide epitopes. We investigated the impact of pretransplant asplenia vaccinations on anti-A/B antibody titers in prospective ABOi renal transplant recipients. Methods: Published asplenia vaccine microbial structures were reviewed to assess expression of A/B antigens. All patients who underwent ABOi transplantation at Monash Medical Centre with anti-A/B titers taken either side of asplenia vaccination were included in a retrospective cohort study between 2007 and 2021. Patients with paired titers without intervening vaccination were included as controls. Paired titers were compared within groups. Results: A and B antigens were found to be expressed by vaccine specific pneumococcal serotypes. Thirty-nine ABOi renal transplant recipients received vaccination including at least one pneumococcal vaccine. The most common donor to recipient combination was A1 to O. The median pre- and postvaccination anti-A/B titers were 1:32 and there was no significant change in titers following vaccination (median change in titer 0 dilutions, range -2 to 3, P=0.43). The same findings were apparent in the control group (n=20). There was no significant change in titer by donor blood group or vaccine type. No transplants were canceled or delayed by a rise in anti-A/B titers postvaccination. Conclusion: Pneumococcal vaccination had no clinically relevant impact on anti-A/B titers before ABOi transplantation in this cohort. These results provide reassurance regarding the safety of asplenia vaccination before ABOi transplantation.