"Unusual" viral diseases after allogeneic hematopoietic stem cell transplantation: a multicenter, retrospective study

Objective: To observe the risk factors, clinical features, diagnosis and treatment, and prognosis of "unusual" viral diseases except "common" viruses such as cytomegalovirus (CMV) and Epstein-Barr virus (EBV) under the background of allogeneic hematopoietic stem cell transplantation dominated by haploidentical transplantation; to explore the optimal detection strategy for rare viruses. Method: From April 2018 to June 2023, the "uncommon" virus disease cases other than CMV and EBV diagnosed in 3 transplant centers in China: the First Affiliated Hospital of Soochow University, the Second People's Hospital of Huai'an and the Affiliated People's Hospital of Ningbo University were retrospectively observed and analyzed. Result: There were 10 cases of human adenovirus (HAdV) virus diseases, 7 cases of human herpesvirus 6 (HHV-6) virus diseases and 2 cases of human parvovirus B19 (HPV-B19) virus diseases. Up to the end of follow-up, 1 in 10 HAdV patients had survived and 9 had died, 8 of them died from viral infection and 1 died from recurrence of the primary disease. Of the 7 patients with HHV-6 virus, 6 survived and 1 died from recurrence of the primary disease. Of 2 patients with HPV-B19 virus, 1 survived and 1 died of HPV-B19 pneumonia. Conclusion: CD3+T cells < 300 /ul, GVHD, ATG, the use of CD25 monoclonal antibody, pre-transplant chimeric antigen receptor T-Cell immunotherapy (CAR-T) or blinatumomab treatment history: may increase the risk of "unusual" viral disease; Pathogenic metagenomic next-generation sequencing(mNGS) of organ-specific samples has the best detection efficiency and can provide information about virus subtypes. The prognosis of HAdV-C infection and HPV-B19 systemic infection is poor, which should be paid more attention to, and high-risk patients should be screened as early as possible.