The perfect storm: Thrombotic thrombocytopenic purpura (TTP) associated with COVID‐19, a clinical case series and review

This is a case series of three patients in our hospital system who developed acquired thrombotic thrombocytopenic purpura (aTTP) after testing positive for COVID‐19 infection. Two patients had acute COVID‐19 infections, and one had COVID‐19 IgG antibodies consistent with prior COVID‐19 infection. Twelve additional cases of aTTP after COVID‐19 infection were found in the literature. COVID‐19 creates alterations in the vWF‐ADAMTS‐13 axis with reduced ADAMTS‐13 in acute illness that may lead those patients who are predisposed into fulminant aTTP. Further genetic studies are necessary to uncover why some patients with COVID‐19 can have concurrent aTTP. For those with a prior COVID‐19 infection, molecular mimicry with autoantibodies to ADAMTS‐13 is likely the predominant trigger, but having an underlying predisposition (prior episode of TTP, genetic predisposition to autoimmune conditions, or breast cancer history) creates an environment that could be a possible trigger for aTTP.