CMV after transplant: T-cell repertoire crooks

Human herpesvirus-6 reactivation and disease after allogeneic haematopoietic cell transplantation in the era of letermovir for cytomegalovirus prophylaxis

OBJECTIVES

Letermovir for cytomegalovirus (CMV) prophylaxis in allogeneic haematopoietic cell transplant (HCT) recipients has decreased anti-CMV therapy use. Contrary to letermovir, anti-CMV antivirals are also active against human herpesvirus-6 (HHV-6). We assessed changes in HHV-6 epidemiology in the post-letermovir era.

METHODS

We conducted a retrospective cohort study of CMV-seropositive allogeneic HCT recipients comparing time periods before and after routine use of prophylactic letermovir. HHV-6 testing was at the discretion of clinicians. We computed the cumulative incidence of broad-spectrum antiviral initiation (foscarnet, (val)ganciclovir, and/or cidofovir), HHV-6 testing, and HHV-6 detection in blood and cerebrospinal fluid within 100 days after HCT. We used Cox proportional-hazards models with stabilized inverse probability of treatment weights to compare outcomes between cohorts balanced for baseline factors.

RESULTS

We analysed 738 patients, 376 in the pre-letermovir and 362 in the post-letermovir cohort. Broad-spectrum antiviral initiation incidence decreased from 65% (95% CI, 60-70%) pre-letermovir to 21% (95% CI, 17-25%) post-letermovir. The cumulative incidence of HHV-6 testing (17% [95% CI, 13-21%] pre-letermovir versus 13% [95% CI, 10-16%] post-letermovir), detection (3% [95% CI, 1-5%] in both cohorts), and HHV-6 encephalitis (0.5% [95% CI, 0.1-1.8%] pre-letermovir and 0.6% [95% CI, 0.1-1.9%] post-letermovir) were similar between cohorts. First HHV-6 detection occurred at a median of 37 days (interquartile range, 18-58) in the pre-letermovir cohort and 27 (interquartile range, 25-34) in the post-letermovir cohort. In a weighted model, there was no association between the pre-versus post-letermovir cohort and HHV-6 detection (adjusted hazard ratio, 1.08; 95% CI, 0.44-2.62).

DISCUSSION

Despite a large decrease in broad-spectrum antivirals after the introduction of letermovir prophylaxis in CMV-seropositive allogeneic HCT recipients, there was no evidence for increased clinically detected HHV-6 reactivation and disease.

Effect of FOXP3 polymorphism on the clinical outcomes after allogeneic hematopoietic stem cell transplantation in pediatric acute leukemia patients

Forkhead BOX P3 (FOXP3) polymorphisms have recently been investigated as candidate risk factors in several tumors and autoimmune diseases. This study aims to evaluate the potential influence of FOXP3 rs3761548 polymorphism in the donor on the outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT). A total of 171 patients were enrolled for this study and genotyped using direct sequencing. Patients with rs3761548 CC genotype had higher incidence of hepatic veno-occlusive disease (HVOD) and cytomegalovirus (CMV) infection than that of the individuals with AA or AC genotype (P=0.011, P=0.023). Treatment-related mortality (TRM) rate of patients with AA or AC genotype was lower than that of the patients with CC genotype (P=0.044) resulting in a difference in overall survival (OS). However, there was no difference in graft-versus-host disease (GVHD) relapse or blood stream infection (BSI), depending on the genotype at rs3761548 locus. In multivariate analysis, CC genotype showed as a risk factor in the development of HVOD and CMV infection, with low OS. In conclusion, this is the first report on FOXP3 rs3761548 SNP in allo-HSCT and we suggest that this SNP be considered a candidate marker for predicting the development of HVOD and CMV infection after allo-HSCT.