{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T05:11:54Z","timestamp":1779340314867,"version":"3.51.4"},"reference-count":46,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T00:00:00Z","timestamp":1779321600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Immunol."],"abstract":"<jats:sec>\n                    <jats:title>Introduction<\/jats:title>\n                    <jats:p>Letermovir (LET) is an effective prophylaxis for human cytomegalovirus (HCMV) reactivations in HCMV-seropositive patients after allogeneic stem cell transplantation (allo-SCT). HCMV promotes polyfunctional T-cell responses, leading to HCMV-specific immune reconstitution (IR), thus contributing to polyclonal IR.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>We retrospectively analyzed HCMV-seropositive patients undergoing allo-SCT with ATG-based GvHD prophylaxis to assess the impact of LET on timing and quality of polyclonal IR. Two cohorts were identified: a pre-emptive treatment (PET) historical cohort transplanted without LET prophylaxis and a LET cohort receiving LET until at least day +100. All patients underwent weekly HCMV-DNA monitoring during the first 100 days post-allo-SCT. Immune monitoring was performed by flow cytometry, quantifying CD3+CD4+, CD3+CD8+ T-cells, CD19+ B-cells, and CD56+CD16+ NK-cells monthly during the first year after transplantation.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>A total of 276 HCMV-seropositive patients were analyzed, 99 (36%) in the LET cohort and 177 (64%) in the PET cohort. LET significantly reduced the incidence of clinically significant HCMV infections during the first 100 days [28.3% in the LET cohort vs. 68.4% in the PET cohort (p&amp;lt;0.001)]. The cumulative incidence of IR 18 months after allo-SCT was comparable in the two groups [24% in the LET cohort vs. 27% in the PET cohort (p=0.393)]. These data were supported by multivariable analysis (HR 1.2, 95% CI 0.74\u20131.95, p = 0.463). Distinct immune dynamics were observed in the LET cohort, including lower early CD8+ T-cell counts and earlier NK-cell expansion peak.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Discussion<\/jats:title>\n                    <jats:p>Despite these differences, LET does not appear to influence the long-term incidence and composition of IR.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fimmu.2026.1790563","type":"journal-article","created":{"date-parts":[[2026,5,21]],"date-time":"2026-05-21T04:45:26Z","timestamp":1779338726000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Letermovir does not affect long-term polyclonal immune reconstitution after allogeneic hematopoietic stem cell transplantation with ATG-based GvHD prophylaxis"],"prefix":"10.3389","volume":"17","author":[{"given":"Conrad","family":"Weidt","sequence":"first","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Adela Maria","family":"Neagoie","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Maral","family":"Saadati","sequence":"additional","affiliation":[{"name":"Division of Biostatistics, German Cancer Research Center","place":["Heidelberg, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Daniel","family":"F\u00fcrst","sequence":"additional","affiliation":[{"name":"Department of Transplantation Immunology, Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Transfusion Service, Baden Wuerttemberg - Hessen, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Verena","family":"Wais","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Christian","family":"Sinzger","sequence":"additional","affiliation":[{"name":"Institute for Virology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katrin","family":"Strauss","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katharina","family":"G\u00f6hring","sequence":"additional","affiliation":[{"name":"Institute for Virology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jacqueline","family":"Schnell","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Michaela","family":"Feuring","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Frank","family":"Stegelmann","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Axel","family":"Benner","sequence":"additional","affiliation":[{"name":"Division of Biostatistics, German Cancer Research Center","place":["Heidelberg, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Detlef","family":"Michel","sequence":"additional","affiliation":[{"name":"Institute for Virology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thomas","family":"Stamminger","sequence":"additional","affiliation":[{"name":"Institute for Virology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hartmut","family":"D\u00f6hner","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Donald","family":"Bunjes","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Elisa","family":"Sala","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine III, Hematology and Oncology, University Hospital Ulm","place":["Ulm, Germany"]}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1965","published-online":{"date-parts":[[2026,5,21]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1038\/s41409-025-02524-2","article-title":"The 2023 EBMT report on hematopoietic cell transplantation and cellular therapies. 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