Rapid reconstitution of cytomegalovirus-specific CD4⁺ T-cells following cord blood transplantation

Abstract

Cord blood transplantation (CBT) frequently can be complicated by cytomegalovirus (CMV) infection, which is required for administration of antiviral chemotherapy. Although the naïve feature of cord blood T-cells were suggested to increase the incidence of CMV infection, the underlying mechanism is not fully elucidated. CMVresponsive T-cells detected by intracellular interferon-gamma (IFN-γ) staining and CMV-specific CD8⁺ T- cells detected by MHC class I tetramers were analyzed in healthy adult blood and recipient blood post-CBT. CMV antigenemia was accompanied in thirty-two of thirty-nine recipients (82%) post-CBT. CMV-responsive CD4⁺ T-cells were detected in all recipients with CMV antigenemia within 120 days post CBT [first date of CMV- responsive CD4+ T-cell detection, median 41 days, (32-90 days); peak frequencies 18±21 cells/μl, n=22]. In contrast, CMV-responsive CD8⁺ T-cells were detected in only 38% of patients with CMV antigenemia with similar frequencies (peak frequencies 18±24 cells/μl, n=8). CMV-responsive CD4⁺ T-cells but not CMV responsive CD8⁺ T-cells were significantly induced in all recipients with CMV antigenemia. Rapid reconstitution of CMV-responsive CD4⁺ T-cells might suppress the progression of CMV disease from CMV antigenemia.