A longitudinal study of DNA and RNA viruses plasma detection in allogeneic hematopoietic stem cell transplant recipients

Background: Viral infections are among the most common complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and can be associated with transient or sustained viremia. Besides viruses that are common causes of infection, metagenomics revealed the presence of several novel viruses and variants that are overlooked in clinical routine and represent potential sources of unrecognized systemic infections. Our aim was to describe the prevalence and the dynamics of 17 DNA and 3 RNA viral infections using (r(RT-)PCR) assays on plasma samples of adult allo-HSCT recipients over a one-year period after HSCT. Methods: 109 adult patients that received a first allo-HSCT from 1st March 2017 to 31st January 2019 we included in this longitudinal observational monocentric cohort study. 17 DNA and 3 RNA viral species were screened with qualitative and/or quantitative r(RT)-PCR assays performed on plasma samples collected at five time-points (day 0 and 30 days, 3 months, 6 months and one year after HSCT). Results: TTV was the most prevalent with an increasing prevalence to 96% of patients at 3 months. HPgV-1 prevalence ranged from 26 to 36% of patients. TTV and HPgV-1 plasma viral load peaked at month 3 (TTV: median 3.29E5 copies/ml [range, 3.37E2 to 4.06E9 copies/ml]; HPgV-1: median 1.18E6 copies/ml [range, 2.61E3 to 4.49E7 copies/ml]). Among Polyomaviridae, BKPyV, JCPyV, MCPyV, HPyV6 and 7 were detected in ≥10% of patients at ≥1 time-point. HPyV6 and HPyV7 prevalence reached 27% and 12% of patients at month 3. Among those, 41% and 63% had quantifiable viral loads, with median viral loads above 1E3copies/ml and results may suggest HPyV6 sustained viremia. Co-detections were frequent, in particular at 3 months with ≥2 viruses detected in 72% of patients. Conclusion: Our study confirms that TTV and HPgV-1 infections are highly prevalent and that infection may be sustained up to one year after allo-HSCT. Our systematic and large strategy of screening also revealed diverse and numerous co-detections, and ...