Amyloidosis is one of the rare systemic illnesses characterized by the deposition of amyloid fibrils in various organs and tissues. There is a common point between COVID-19 and systemic amyloidosis regarding the multiorgan involvement in the pathological process which leads to a heightened risk for severe morbidity and mortality in amyloidosis patients who contracted COVID-19. We performed a pathomorphological analysis of the autopsy records of 22 patients who had COVID-19 and pre-existing systemic amyloidosis. The premortem diagnosis of systemic amyloidosis was established in 55% of patients, and in other 45% of cases, amyloidosis was found at autopsy. Based on the results of immunohistochemical amyloid typing, amyloid A (AA) amyloidosis was detected in 23%, amyloid light chain (AL) lambda in 32%, AL kappa-in 9%, and transthyretin (ATTR) amyloidosis-in 36% of observations. Immunohistochemical staining with an antibody against SARS-CoV-2 Spike (S) protein revealed positive immune reactions in type II alveolocytes in 59% of deceased persons. The analysis of autopsy findings indicates that patients with systemic amyloidosis are more likely to experience an aggressive clinical course of COVID-19 which leads to a multiorgan failure and a higher risk of fatal outcome.
Keywords: COVID-19; SARS-CoV-2; amyloidosis; comorbid pathology; immunohistochemistry.