In a large group of stem‑cell transplant patients, only a few got a serious adenovirus infection that was found using DNA sequencing. The infection hit multiple organs and was usually fatal, even with antiviral drugs and immune‑boosting treatments. One patient also received thymosin‑α1, but it didn’t clearly change the outcome.

This study aims to observe and analyze the clinical characteristics and prognosis of adenovirus (ADV) infection diagnosed by metagenomic next-generation sequencing (mNGS) after haploidentical hematopoietic stem cell transplantation (Haplo-HSCT), which was performed following Beijing Protocol. The clinical data of patients who developed ADV infection diagnosed by mNGS after Haplo-HSCT between January 2019 and March 2021, recorded in three transplantation centers, were retrospectively analyzed. Potential risk factors for infection and the clinical manifestations of ADV involvement in different end-organs were also studied. Additionally, the patient prognosis regarding the available treatment was observed. A total of seven patients were diagnosed with ADV infection by the mNGS technique after Haplo-HSCT of 976 patients enrolled. The risk factors for infection included antithymocyte globulin steroid-refractory graft-versus-host disease (GVHD) history, CD25 monoclonal antibody or ruxolitinib treatment history and <300 cells/μL of CD3+ T cells count in peripheral blood. The clinical manifestations of ADV infection included encephalitis, hepatitis, cystitis, and pneumonia. Six patients were treated with cidofovir (CDV) and intravenous immunoglobulin (IVIg), and one with CDV, ribavirin, IVIg, thymosin Alpha-1 for injection and low-dose donor lymphocyte infusion. One case showed negative ADV DNA results with improved conditions; however, the patient died of the relapse of the primary disease in the later stage. The remaining six died of ADV infection. mNGS can provide screening for ADV and information on ADV subtypes, helpful to understand tissue tropism. This technique could be useful in diagnosing patients at high risk for ADV infection. ADV infection can involve multiple organs, has difficulty in early diagnosis, and has a poor prognosis. Currently, effective treatments are inadequate.