Abstract 10035: COVID-19 and Cardiac Transplant Rejection - Coincidence or Not?

Overlap between the histopathologic changes of acute rejection and viral myocarditis presents a diagnostic dilemma. A 34 year-old female with a past medical history of postpartum cardiomyopathy and subsequent orthotopic heart transplant in December 2019, presented for routine surveillance heart biopsy seven months post-transplant. Her AlloMap was elevated and AlloSure was uptrending, concerning for rejection. Ten days prior to presentation, she tested positive for COVID-19 via polymerase chain reaction (PCR) testing. Her symptoms were fatigue and mild headache for two weeks prior to diagnosis. She did not seek medical attention for her symptoms and received no COVID-19 specific treatment. Endomyocardial biopsy showed grade 2R acute cellular rejection. Her echocardiogram was unchanged with normal left ventricular ejection fraction and right ventricular function. SARS-CoV-2 levels were measured by PCR of ribonucleic acid (RNA) isolated from the biopsy specimen and were undetectable. The patient was treated with two short courses of high dose prednisone which eventually abated her transplant rejection. The patient remained positive on PCR testing for COVID-19 for the next six months. Chest x-ray and computed tomography for follow up after COVID-19 infection showed no evidence of pulmonary fibrosis or superinfection considering ongoing immunosuppression for rejection. Our patient illustrates a case of concomitant COVID-19 infection and presumed transplant rejection, raising the question of whether the findings seen on immunohistochemistry were truly rejection or instead an elevated immune response due to COVID-19 infection. Given that our patient had a predominance of CD3+ T cells and less CD68+ macrophages (the former being more prominent in acute cellular rejection and the latter being more prominent in COVID-19 myocarditis), we are inclined to believe the former.