Factors associated with the humoral response after three doses of COVID-19 vaccination in kidney transplant recipients

Front Immunol. 2023 Feb 16:14:1099079. doi: 10.3389/fimmu.2023.1099079. eCollection 2023.

Abstract

Introduction: Kidney transplant recipients showed a weak humoral response to the mRNA COVID-19 vaccine despite receiving three cumulative doses of the vaccine. New approaches are still needed to raise protective immunity conferred by the vaccine administration within this group of high-risk patients.

Methods: To analyze the humoral response and identify any predictive factors within these patients, we designed a prospective monocentric longitudinal study of Kidney transplant recipients (KTR) who received three doses of mRNA-1273 COVID-19 vaccine. Specific antibody levels were measured by chemiluminescence. Parameters related to clinical status such as kidney function, immunosuppressive therapy, inflammatory status and thymic function were analyzed as potential predictors of the humoral response.

Results: Seventy-four KTR and sixteen healthy controls were included. One month after the administration of the third dose of the COVID-19 vaccine, 64.8% of KTR showed a positive humoral response. As predictive factors of seroconversion and specific antibody titer, we found that immunosuppressive therapy, worse kidney function, higher inflammatory status and age were related to a lower response in KTR while immune cell counts, thymosin-a1 plasma concentration and thymic output were related to a higher humoral response. Furthermore, baseline thymosin-a1 concentration was independently associated with the seroconversion after three vaccine doses.

Discussion: In addition to the immunosuppression therapy, condition of kidney function and age before vaccination, specific immune factors could also be relevant in light of optimization of the COVID-19 vaccination protocol in KTR. Therefore, thymosin-a1, an immunomodulatory hormone, deserves further research as a potential adjuvant for the next vaccine boosters.

Keywords: COVID-19; kidney transplant; mRNA vaccine; relative telomere length; sj/β-TREC ratio; thymic function; thymosin-α1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 2019-nCoV Vaccine mRNA-1273
  • COVID-19 Vaccines
  • COVID-19*
  • Humans
  • Kidney Transplantation*
  • Longitudinal Studies
  • Prospective Studies
  • Vaccination

Substances

  • COVID-19 Vaccines
  • 2019-nCoV Vaccine mRNA-1273

Grants and funding

This study was supported by a grant from the Fondo de Investigación Sanitaria (FIS/PI21/00357), which is co-founded by Fondos Europeos para el Desarrollo Regional (FEDER) “Una manera de hacer Europa”. VG-R, IO-M and AB-R were supported by Instituto de Salud Carlos III (CD19/00143, FI19/00298 and CM19/00051, respectively). MP-B was supported by the Consejería de Transformación Económica, Industria, Conocimiento y Universidades [DOC_01646 to MP-B] and YP was supported by the Consejería de Salud y Familias of Junta de Andalucía through the “Nicolás Monardes” [RC-0006-2021]. The funders had no role in the study design, data collection and interpretation, or the decision to submit the work for publication.