Human Herpesvirus 6 DNAemia Is Associated With Worse Survival After Ex Vivo T-Cell-Depleted Hematopoietic Cell Transplant

Background We examined the correlation between persistent human herpesvirus 6 (HHV-6) DNAemia (p-HHV-6) and absolute lymphocyte count (ALC), platelet count (PLT), and all-cause mortality by 1 year after ex vivo T-cell-depleted (TCD) hematopoietic cell transplant (HCT). Methods We analyzed a cohort of adult TCD HCT recipients during 2012-2016 prospectively monitored for plasma HHV-6 by quantitative polymerase chain reaction from day +14 post-HCT through day +100 (D+100). p-HHV-6 was defined as >= 2 consecutive values of >= 500 copies/mL by D+100. PLT and ALC were compared between patients with and without p-HHV-6 using generalized estimating equations (GEE). Multivariable Cox proportional hazard models (PH) were used to identify the impact of p-HHV-6 on 1 year mortality. Results Of 312 patients, 83 (27%) had p-HHV-6 by D+100. p-HHV-6 was associated with lower ALC and PLT in the first year post-HCT. In multivariable models, p-HHV-6 was associated with higher mortality by 1 year post-HCT (adjusted hazard ratio, 2.97 [95% confidence interval, 1.62-5.47]; P = .0005), after adjusting for age, antiviral treatment, and ALC at D+100. Conclusions p-HHV-6 was associated with lower ALC and PLT in the first year post-HCT. p-HHV-6 was an independent predictor of mortality in the first year after TCD HCT. Human herpesvirus 6 DNAemia was associated with lower CD4(+) and CD8(+) lymphocytes, absolute lymphocyte counts, and platelet counts, and was an independent predictor for increased all-cause mortality in the first year after ex vivo T-cell-depleted hematopoietic cell transplant.