Acute cellular rejection (ACR) is a common complication after lung transplantation, which is mainly caused by the immune response of T lymphocytes recognizing the major histocompatibility complex on the cellular surface of grafts. It is currently considered as the main pattern of acute rejection. ACR is not only a direct cause of death of recipients, but also a high-risk factor for chronic rejection after lung transplantation. Nevertheless, it is a challenging task to deliver the diagnosis and treatment of ACR following lung transplantation. In this article, new progresses on the risk factors, pathogenesis, diagnosis and treatment of ACR in lung transplant recipients were summarized, aiming to improve the diagnostic and treatment efficiency of ACR and prolong the survival of recipients.

Objective:To explore the clinical manifestations and imaging features of nocardia infection (NI) after lung transplantation and boost the diagnosis and treatment of NI.Methods:From January 2018 to December 2019, basic profiles, clinical manifestations, laboratory examinations, imaging features and treatment outcomes of 5 lung transplant recipients with a diagnosis of NF were retrospectively analyzed and summarized with the relevant literatures. There were 4 males and 1 female with a median age of 66(26-69) years. 3 patients were single-lung transplantation, 2 patients were bilateral-lung transplantation. The median time from an initial diagnosis of NI to lung transplant surgery was 6(5-19) months. Common symptoms included fever, cough with yellow phlegm and shortness of breath. Laboratory findings showed lymphopenia, significantly high C-reactive protein levels, a slight elevation of procalcitonin, hypoproteinemia and anemia. The major manifestations of high-resolution computed tomography (CT) included multiple nodules, consolidation, cavitation and pleural effusion.Results:Five strains of N. farcinica were identified from bloodstream infection ( n=2) and pulmonary infection ( n=3). After with a combined therapy of two sensitive agents, all patients improved and were discharged from hospital. During follow-ups, one patient died and the remainders were cured. Conclusions:Nocardia infection occurs in lung transplant recipients mostly within 1 year post-operation. There are non-specific symptoms and imaging features of multiple nodules and consolidation. Combination therapy of sensitive agents is indicated for lung transplant recipients with NI.