Immune Profile Determines Response to Vaccination against COVID-19 in Kidney Transplant Recipients.

BACKGROUND AND AIM

Immune status profile can predict response to vaccination, while lymphocyte phenotypic alterations represent its effectiveness. We prospectively evaluated these parameters in kidney transplant recipients (KTRs) regarding Tozinameran (BNT162b2) vaccination.

METHOD

In this prospective monocenter observational study, 39 adult KTRs, on stable immunosuppression, naïve to COVID-19, with no protective humoral response after two Tozinameran doses, received the third vaccination dose, and, based on their immunity activation, they were classified as responders or non-responders. Humoral and cellular immunities were assessed at predefined time points (T: 48 h before the first, T: 48 h prior to the third and T: three weeks after the third dose).

RESULTS

Responders, compared to non-responders, had a higher total and transitional B-lymphocyte count at baseline (96.5 (93) vs. 51 (52)cells/μL, : 0.045 and 9 (17) vs. 1 (2)cells/μL, : 0.031, respectively). In the responder group, there was a significant increase, from T to T in the concentrations of activated CD4+ (from 6.5 (4) to 10.08 (11)cells/μL, 0.001) and CD8+ (from 8 (19) to 14.76 (16)cells/μL, : 0.004) and a drop in CD3+PD1+ T-cells (from 130 (121) to 30.44 (25)cells/μL, : 0.001), while naïve and transitional B-cells increased from T to T (from 57.55 (66) to 1149.3 (680)cells/μL, < 0.001 and from 1.4 (3) to 17.5 (21)cells/μL, : 0.003). The percentages of memory and marginal zone B-lymphocytes, and activated CD4+, CD8+ and natural killer (NK) T-cells significantly increased, while those of naïve B-cells and CD3+PD1+ T-cells reduced from T to T.

CONCLUSIONS

Responders and non-responders to the third BNT162b2 dose demonstrated distinct initial immune cell profiles and changes in cellular subpopulation composition following vaccination.