Antibody response to a third SARS-CoV-2 vaccine dose in recipients of an allogeneic haematopoietic cell transplantation.

Allogeneic haematopoietic cell transplantation (allo-HCT) recipients show impaired antibody (Ab) response to a standard two-dose vaccination against severe acute respiratory syndrome coronavirus-2 and currently a third dose is recommended as part of the primary vaccination regimen. By assessing Ab titres 1 month after a third mRNA vaccine dose in 74 allo-HCT recipients we show sufficient neutralisation activity in 77% of the patients. Discontinuation of immunosuppression before the third vaccine led to serological responses in 50% of low responders to two vaccinations. Identifying factors that might contribute to better vaccine responses in allo-HCT recipients is critical to optimise current vaccination strategies.

Antibody Response to SARS-CoV-2 Vaccination in Patients following Allogeneic Hematopoietic Cell Transplantation.

Vaccines against SARS-CoV-2 have been rapidly approved. Although pivotal studies were conducted in healthy volunteers, little information is available on the safety and efficacy of mRNA vaccines in immunocompromised patients, including recipients of allogeneic hematopoietic cell transplantation (allo-HCT). Here we used a novel assay to analyze patient- and transplantation-related factors and their influence on immune responses to SARS-CoV-2 vaccination over an extended period (up to 6 months) in a large and homogenous group of allo-HCT recipients at a single center in Switzerland. We examined longitudinal antibody responses to SARS-CoV-2 vaccination with BNT162b2 (BioNTech/Pfizer) and mRNA-1273 (Moderna) in 110 allo-HCT recipients and 86 healthy controls. Seroprofiling recording IgG, IgA, and IgM reactivity against SARS-CoV-2 antigens (receptor-binding domain, spike glycoprotein subunits S1 and S2, and nucleocapsid protein) was performed before vaccination, before the second dose, and at 1, 3, and 6 months after the second dose. Patients were stratified to 3 groups: 3 to 6 months post-allo-HCT, 6 to 12 months post-allo-HCT, and >12 months post-allo-HCT. Patients in the 3 to 6 months and 6 to 12 months post-allo-HCT groups developed significantly lower antibody titers after vaccination compared with patients in the >12 months post-allo-HCT group and healthy controls (P < .001). Within the cohort of allo-HCT recipients, patients age >65 years (P = .030), those receiving immunosuppression for prevention or treatment of graft-versus-host disease (GVHD) (P = .033), and patients with relapsed disease (P = .014) displayed low humoral immune responses to the vaccine. In contrast, the intensity of the conditioning regimen, underlying disease (myeloid/lymphoid/other), and presence of chronic GVHD had no impact on antibody levels. Antibody titers achieved the highest levels at 1 month after the second dose of the vaccine but waned substantially in all transplantation groups and healthy controls over time. This analysis of long-term vaccine antibody response is of critical importance to allo-HCT recipients and transplant physicians to guide treatment decisions regarding revaccination and social behavior during the SARS-CoV-2 pandemic.

Complement inhibition for the treatment of COVID-19 triggered thrombotic microangiopathy with cardiac failure: a case report.

BACKGROUND: Severe coronavirus disease 2019 (COVID-19) has been increasingly recognized as a multisystem disease. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can infect literally any cell type that expresses its target receptor angiotensin-converting enzyme 2. However, COVID-19-associated organ dysfunction is not only mediated by direct viral effects but also by the interaction between the host's immune response, endotheliopathy, and microvascular coagulopathy. It has been proposed that the activation of the complement system plays a central role in the pathophysiology of severe COVID-19 and the associated endotheliopathy. CASE SUMMARY: A 76-year-old male patient with indeterminate cardiogenic shock in the setting of confirmed SARS-CoV-2 infection was admitted to our intensive care unit. Coronary angiography did not reveal a plausible explanation for his symptoms. The patient developed renal failure, neurological symptoms, severe thrombocytopenia, and a Coombs-negative haemolytic anaemia with schistocytes. All together the clinical picture was highly suggestive of a thrombotic microangiopathy (TMA) with microvascular cardiac involvement. Conventional therapeutic strategies including high-dose steroids and seven sessions of therapeutic plasma exchange were all unsuccessful. Interestingly, complement inhibition with Eculizumab as rescue approach led to a rapid clinical and laboratory improvement and the patients were discharged with normalized organ functions at Day 36. CONCLUSION: The aetiology of cardiogenic shock observed in this patient cannot simply be explained by his focal and chronic coronary findings. Although viral myocarditis was not formally excluded, both the clinical features of TMA and the rapid resolution of all clinical signs and symptoms after pharmacological complement inhibition suggest a SARS-CoV-2-driven microangiopathic origin of heart failure.