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

Introduction: Studies have shown reduced antiviral responses in kidney transplant recipients (KTRs) following SARS-CoV-2 mRNA vaccination, but data on post-vaccination alloimmune responses and antiviral responses against the Delta (B.1.617.2) variant are limited. Materials and methods: To address this issue, we conducted a prospective, multi-center study of 58 adult KTRs receiving mRNA-BNT162b2 or mRNA-1273 vaccines. We used multiple complementary non-invasive biomarkers for rejection monitoring including serum creatinine, proteinuria, donor-derived cell-free DNA, peripheral blood gene expression profile (PBGEP), urinary CXCL9 mRNA and de novo donor-specific antibodies (DSA). Secondary outcomes included development of anti-viral immune responses against the wild-type and Delta variant of SARS-CoV-2. Results: At a median of 85 days, no KTRs developed de novo DSAs and only one patient developed acute rejection following recent conversion to belatacept, which was associated with increased creatinine and urinary CXCL9 levels. During follow-up, there were no significant changes in proteinuria, donor-derived cell-free DNA levels or PBGEP. 36% of KTRs in our cohort developed anti-wild-type spike antibodies, 75% and 55% of whom had neutralizing responses against wild-type and Delta variants respectively. A cellular response against wild-type S1, measured by interferon-γ-ELISpot assay, developed in 38% of KTRs. Cellular responses did not differ in KTRs with or without antibody responses. Conclusions: SARS-CoV-2 mRNA vaccination in KTRs did not elicit a significant alloimmune response. About half of KTRs who develop anti-wild-type spike antibodies after two mRNA vaccine doses have neutralizing responses against the Delta variant. There was no association between anti-viral humoral and cellular responses.

Toddler With New Onset Diabetes and Atypical Hemolytic-Uremic Syndrome in the Setting of COVID-19.

This is a novel case of a 16-month-old boy with a history of prematurity with intrauterine growth restriction, severe failure to thrive, microcephaly, pachygyria, agenesis of the corpus callosum, and postnatal embolic stroke, who presented with new-onset diabetes mellitus with diabetic ketoacidosis in the setting of severe acute respiratory syndrome coronavirus 2 infection, with a course complicated by atypical hemolytic syndrome (aHUS). This patient demonstrated remarkable insulin resistance in the period before aHUS diagnosis, which resolved with the first dose of eculizumab therapy. There is increasing evidence that COVID-19 is associated with thrombotic disorders and that microangiopathic processes and complement-mediated inflammation may be implicated. In this case report, we describe a pediatric patient with COVID-19 and a new complement-mediated microangiopathic thrombotic disease. Because whole-exome sequencing and extensive workup returned without a clear etiology for aHUS, this is likely a COVID-19 triggered case of aHUS versus an idiopathic case that was unmasked by the infection.