Non-Invasive Monitoring for Rejection in Kidney Transplant Recipients After SARS-CoV-2 mRNA Vaccination

Area of Science:

• Immunology
• Transplantation
• Virology

Background:

• Kidney transplant recipients (KTRs) exhibit reduced antiviral responses post-SARS-CoV-2 mRNA vaccination.
• Limited data exists on post-vaccination alloimmune responses and effectiveness against the Delta variant in KTRs.

Purpose of the Study:

• To evaluate SARS-CoV-2 mRNA vaccine safety and immunogenicity in KTRs.
• To assess vaccine-induced alloimmune and antiviral responses, including against the Delta variant.

Main Methods:

• Prospective, multi-center study of 58 adult KTRs receiving mRNA vaccines (BNT162b2 or mRNA-1273).
• Utilized non-invasive biomarkers for rejection monitoring (creatinine, proteinuria, cfDNA, PBGEP, urinary CXCL9, de novo DSA).
• Assessed anti-viral immune responses against wild-type and Delta SARS-CoV-2 variants.

Main Results:

• No significant de novo donor-specific antibodies (DSA) or widespread rejection observed.
• Minor changes in proteinuria, cfDNA, and PBGEP during follow-up.
• 36% developed anti-wild-type spike antibodies; 55% of these had neutralizing responses against the Delta variant.
• 38% developed cellular responses; no difference based on antibody response.

Conclusions:

• SARS-CoV-2 mRNA vaccination in KTRs is safe regarding alloimmune responses.
• A significant proportion of KTRs develop neutralizing antibodies against the Delta variant.
• No association found between anti-viral humoral and cellular responses.