Negative immune responses to two-dose mRNA COVID-19 vaccines in renal allograft recipients assessed with simple antibody and interferon gamma release assay cellular monitoring.

Crespo, Marta; Barrilado-Jackson, Antoni; Padilla, Eduardo; Eguía, Jorge; Echeverria-Esnal, Daniel; Cao, Higini; Faura, Anna; Folgueiras, Montserrat; Solà -Porta, Eulà lia; Pascual, Sergi; Barbosa, Francesc; Hurtado, Sara; Ribera, Laura; Río-No, Laura; Pérez-Sáez, María José; Redondo-Pachón, Dolores; Pascual, Julio

Studies are urgently needed to characterize immunogenicity, efficacy, and safety of SARS-CoV-2 mRNA vaccines in kidney transplant (KT) recipients, excluded from major clinical trials. Complex ELISPOT and other cellular response techniques have been applied, but simpler tools are needed. An easy-to-use real-world monitoring of SARS-CoV-2 IgG antibodies against the Spike protein and QuantiFERON® SARS-CoV-2 IFNγ release assay (IGRA) were performed at baseline and 28 days after the second dose in KT recipients and controls (dialysis patients and healthy ones). All healthy controls and >95% dialysis controls became positive for anti-S IgG antibodies, while only 63.3% of KT patients seroconverted with a very low antibody level. A positive IGRA was documented in 96.9% of controls, 89.3% peritoneal dialysis, 77.6% hemodialysis, 61.3% of KT patients transplanted more than one year ago and only 36% of those transplanted within the previous 12 months. Overall, 100% of healthy controls, 95.4% of dialysis patients and 78.8% KT recipients developed any immune response (humoral and/or cellular) against SARS-CoV-2. KT patients showed low rates of immune responses to mRNA COVID-19 vaccines, especially those with recent transplantations. Simple humoral and cellular monitoring is advisable, so that repeated doses may be scheduled according to the results.