Antibody dynamics after tick-borne encephalitis and measles–mumps–rubella vaccination in children post early thymectomy

Thymectomized patients (TP) showed a delayed humoral immune response to tick-borne-encephalitis-virus (TBEV) vaccination, which served as a neo-antigen. From the previously published cohort, the TBEV-specific IgG concentrations and avidities were analyzed in 17 TP compared to 30 non-thymectomized healthy controls (HC) 220 weeks after the first TBE vaccination to identify patients with waning antibodies. Only in HC, increase of avidity was significant between 8 and 220 weeks (p < 0.001), whereas TP showed a lower avidity maturation at week 48 (p < 0.05). Cytomegalovirus (CMV) seropositivity at vaccination did not influence the humoral immune response. The ability of TP to maintain measles, mumps and rubella (MMR)-specific antibodies at least 8 years post (MMR) vaccination was evaluated in the serum samples of TP, retrospectively. Although all TP had MMR vaccination at least 6 months after thymectomy, TP showed no significant difference regarding MMR-specific IgG concentrations or avidities compared to HC. Regarding TBE vaccination, the data confirmed the previous observation of a delayed primary immune response in TP to TBE vaccine and also revealed an altered memory priming by paucity of high-avidity antibodies.