The Influence of Initial Immunosuppression on the Kinetics of Humoral Response after SARS-CoV-2 Vaccination in Patients Undergoing Kidney Transplantation

The effect of initial immunosuppressive therapy on the kinetics of the SARS-CoV-2 vaccine-induced humoral response is unknown. Here, we compared the kinetics of SARS-CoV-2 vaccine-induced humoral response in chronic kidney disease patients undergoing kidney transplantation (KTRs) and compared to patients remaining on dialysis during the Omicron circulation. This prospective, non-randomized, real-world study included 113 KTRs and 108 patients on dialysis. Those with previous COVID-19 or negative IgG at screening were excluded. Blood samples were collected to assess SARS-CoV-2 IgG titers and neutralizing antibodies at months (M) 1, 3, 6, and 12. Seroreversion occurred in 1 KTR and in 3 patients on dialysis. KTRs had lower IgG titers over time (M1: 10,809.3±12,621.7 vs. 15,267.8±16,096.2 IU/mL; M3: 12,215.5±12,885.8 vs. 15,016.2±15,346.1 IU/mL; M6: 12,540.4±13,010.7 vs. 18,503.5±14,581.0 IU/mL; p=0.005), but Neutralizing antibodies were similar (M1: 94.0 vs. 90.3%; M3: 92.9 vs. 90.5%; M6: 99.0 vs. 95.5%; M12: 98.9 vs. 97.5%; p=0.812). During follow-up, KTRs received more vaccine (141 vs. 73; p<0,001) and had more COVID-19 (32.7% vs. 14.8%; p=0.002). Compared to patients on dialysis, KTRs had lower SARS-CoV-2 IgG titers and similar rates of seroreversion and neutralizing antibodies over time. Although KTRs received more boosters, they had a higher incidence of COVID-19.