Background: Secondary immune thrombocytopenic purpura (ITP) associated with coronavirus disease 2019 (COVID-19) is a rare but serious complication of the pandemic. Diagnostic criteria include clinical and laboratory findings. Early treatment is often effective, but rare severe bleeding and death can occur. An autoimmune mechanism is likely.

Objectives: To determine a role for molecular mimicry in producing disease.

Methods: Hexapeptide and heptapeptide matches between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and platelet N-glycosylated proteins and other human proteins were assessed.

Results: Shared viral and platelet glycoprotein peptides were found. Copy frequency of these peptides in the human proteome was low for many of the candidate molecular mimics.

Conclusions: The data support a contribution of molecular mimicry in COVID-19 ITP autoimmunity and offer avenues for in vitro diagnostic assay development. The continuation of the pandemic necessitates additional understanding of COVID-19 ITP as well as studies on diagnosis and mitigation.