The Immunology of SARS-CoV-2 Infection and Vaccines in Solid Organ Transplant Recipients

Abstract

Since its outbreak in December 2019, the coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), led to an enormous rise in scientific response with an excess of COVID-19-related studies on the pathogenesis and potential therapeutic approaches. Solid organ transplant (SOT) recipients are a heterogeneous population with long-lasting immunosuppression as a joining element. Immunocompromised patients are a vulnerable population with a high risk of severe infections and an increased infection-related mortality rate. It was postulated that the hyperinflammatory state due to cytokine release syndrome during severe COVID-19 could be alleviated by immunosuppressive therapy in SOT patients. On the other hand, it was previously established that T cell-mediated immunity, which is significantly weakened in SOT recipients, is the main component of antiviral immune responses. In this paper, we present the current state of science on COVID-19 immunology in relation to solid organ transplantation with prospective therapeutic and vaccination strategies in this population.

SARS-CoV-2 antibodies among people with cystic fibrosis prior to the vaccination campaign: A seroprevalence study in two specialized centres in Northern Italy

“…Although not statistically significant, the lower prevalence of SARS-CoV-2 antibodies in transplanted compared to non-transplanted pwCF is in line with the figures reported in non-CF transplanted patients [8] . This finding may be related to several factors, including a more cautious attitude towards the risk of infection, the recommendations for self-isolation provided by the CF centres, but also to a possible low seroconversion rate [ 9 , 10 ].…”

Comparing Humoral and Cellular Adaptive Immunity during Convalescent Phase of COVID-19 in Hemodialysis Patients and Kidney Transplant Recipients

“…Most studies on vaccination-induced anti-SARS-CoV-2 immunity showed an impaired response among kidney transplant recipients, whereas HD patients reached almost healthy-control levels [ 34 , 35 , 36 , 37 ]. A recent study showed that after two doses of mRNA vaccination, >95% of dialysis patients presented anti-S IgG antibodies, while only 63.3% of KTR seroconverted with substantially lower antibody levels.…”

Decline in Antibody Concentration 6 Months After Two Doses of SARS-CoV-2 BNT162b2 Vaccine in Solid Organ Transplant Recipients and Healthy Controls

“…Solid organ transplant (SOT) recipients receive immunosuppressive therapy to prevent allograft rejection, leaving them at higher risk of infections and infection-related morbidity and mortality (1). This may also be true for coronavirus disease 2019 (COVID-19) (2)(3)(4)(5)(6).…”

“…However, SOT recipients were not included in these trials (7)(8)(9). Reports on the short-term response to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) mRNA vaccines in SOT recipients indicate that the humoral response after two doses of vaccine (5,6,(10)(11)(12)(13)(14)(15)(16)(17)(18) is inferior to what was initially reported in immunocompetent populations (7,8).…”