Immune Response to BNT162b2 in Solid Organ Transplant Recipients: Negative Impact of Mycophenolate and High Responsiveness of SARS-CoV-2 Recovered Subjects against Delta Variant.

Irene Cassaniti,Annalisa Turco,Antonella Sarasini,Eleonora Francesca Pattonieri,Daniele Lilleri,Carlo Pellegrini,Teresa Rampino,Irene Curti,Francesca Arena,Alessandro Ferrari,Elena Seminari,Federica Zavaglio,Fausto Baldanti,Federica Meloni,Marilena Gregorini,Federica Bergami,Laura Pandolfi,Jose Camilla Sammartino,Elena Percivalle

doi:10.3390/microorganisms9122622

Abstract

The immunogenicity of severe acute respiratory syndrome 2 virus (SARS-CoV-2) vaccines in immunocompromised patients remains to be further explored. Here, we evaluated the immunogenicity elicited by complete vaccination with BNT162b2 vaccine in solid organ transplant recipients (SOTRs). A cohort of 110 SOTRs from Northern Italy were vaccinated with two doses of BNT162b2 mRNA vaccine and prospectively monitored at baseline and after 42 days. Both SARS-CoV-2 naïve and recovered subjects were included. Humoral response elicited by vaccination, including SARS-CoV-2 neutralizing antibodies (SARS-CoV-2 NT Abs), was evaluated; additionally, ex-vivo ELISpot assay was performed for the quantification of Spike-specific T-cell response. Results were compared with those obtained in a cohort of healthy subjects. In a subset of patients, humoral and T-cell responses against delta variant were also evaluated. Less than 20% of transplanted subjects developed a positive humoral and cell-mediated response after complete vaccination schedule. Overall, median levels of immune response elicited by vaccination were significantly lower with respect to controls in SARS-CoV-2 naïve transplant, but not in SARS-CoV-2 recovered transplanted patients. Additionally, a significant impairment of both humoral and cell-mediated response was observed in mycophenolate-treated patients. Positive delta-SARS-CoV-2 NT Abs levels were detected in almost all the SARS-CoV-2 recovered subjects but not in previously uninfected patients. Our study supports previous observations of a low level of seroconversion after vaccination in transplanted patients.

Highlights

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome virus 2 (SARS-CoV-2) has severely impacted solid organ transplant recipients (SOTRs), for a substantial decrease of transplant care practice and for an increased risk of morbidity and mortality linked to SARS-CoV-2 infection [1]
In our prospective longitudinal study, we studied SOTRs vaccinated with BNT162b2 vaccine, analyzing both humoral and cell-mediated responses
Humoral and Cell-Mediated Response Elicited by mRNA BNT162b2 Was Suboptimal in SARS-CoV-2 Naïve Transplanted Patients

Summary

Introduction

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome virus 2 (SARS-CoV-2) has severely impacted solid organ transplant recipients (SOTRs), for a substantial decrease of transplant care practice and for an increased risk of morbidity and mortality linked to SARS-CoV-2 infection [1]. Prophylactic strategies are mandatory in order to avoid SARS-CoV-2 infection in SOTRs. So far, immunogenicity and efficacy of SARS-CoV-2 mRNA vaccines, including BNT162b2, has been widely documented in immunocompetent subjects [7,8]. The potential immunogenicity and efficacy of the SARS-CoV-2 vaccines in immunocompromised patients has been intensively studied. In the first 6 months after transplantation, patients receive the highest level of immunosuppression and it is recommended to avoid vaccinations because of a likely lack of response.

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