Evidence of Continued CD4+ and CD8+ T Cell Activity After SARS-COV-2 Clearance in a Late COVID-19 Pneumonia Heart Transplant Patient.

We have studied an unvaccinated heart transplant 64-year-old patient admitted for low-grade fever, dry cough, general malaise, and bilateral interstitial infiltrates, after two months of a diagnosis of coronavirus disease 2019 (COVID-19) bilateral pneumonia. A bronchoalveolar lavage and transbronchial biopsy were performed. Bacterial, mycotic and viral infections were ruled out including repeated reverse transcription polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Diffuse thickening of alveolar septa with fibrosis and infiltration of lymphocytes and macrophages into the alveolar septa with aggregates of CD4+ and CD8+ T cells with positive immunolabelling for granzyme B were observed, indicating a continuing cytotoxic process that might have induced proliferation and fibrosis. An intense ongoing immunopathological cellular reaction, potentially triggered by SARS-CoV-2 overcoming the anti-inflammatory and immunomodulatory effects of the immunosuppressive drugs is suggested by these findings, opening to debate the usual approach of minimizing immunosuppression after COVID-19 in transplant patients when presence of SARS-CoV-2 has been ruled out.