Low incidence of HHV‐6 reactivation in haploidentical hematopoietic stem cell transplantation with corticosteroid as graft‐vs‐host disease prophylaxis compared with cord blood transplantation

Abstract

Background Human leukocyte antigen (HLA) mismatch and the administration of immunosuppressive agents are considered risks for human herpesvirus 6 (HHV‐6) reactivation after stem cell transplantation (SCT). However, the incidence of HHV‐6 reactivation in HLA‐mismatched related SCT remains unknown. Methods We monitored plasma HHV‐6 DNA loads weekly using real‐time quantitative polymerase chain reaction for 5 weeks after SCT and compared serum IL‐6 levels in HLA‐mismatched SCT groups. Results Compared with detection in all 11 umbilical cord blood transplantation (CBT) patients (100%), plasma HHV‐6 DNA was detected in only 3 of 42 haplo‐SCT patients (7.1%) despite the use of methylprednisolone and antithymocyte globulin as graft‐vs‐host disease prophylaxis and a reduced‐intensity conditioning regimen, respectively. Correspondingly, serum IL‐6 levels in haplo‐SCT patients were significantly lower than those in CBT patients. No HHV‐6‐associated encephalitis developed in either groups. Conclusions Neither HLA disparity nor the use of methylprednisolone and antithymocyte globulin were risk factors for HHV‐6 reactivation in our haplo‐SCT patients. Rather than increasing risk, the administration of immunosuppressive agents potentially prevented HHV‐6 reactivation after haplo‐SCT by suppressing IL‐6 production.

Human herpesvirus 6 reactivation in unmanipulated haploidentical hematopoietic stem cell transplantation predicts the occurrence of grade II to IV acute graft‐versus‐host disease

“…16 A recent report from Japan showed a lower incidence of HHV-6 reactivation (7.1%) in haplo-HSCT than that in patients with CBT. 23 Regarding haplo-HSCT, several haploidentical SCT (haplo-SCT) TCD. 22 A retrospective study compared the incidence of virus infection in two different haploidentical HSCT settings.…”

“…21,22 A study from Japan showed a lower incidence of 7.1% in haplo-HSCT compared with CBT without description of the conditioning regimen. 23 However, the incidence of HHV-6 reactivation remains unknown in our novel granulocyte colony stimulating factor (G-CSF)-primed blood and marrow haploidentical transplantation system.…”

Hematopoietic stem cell transplantation and the noncytomegalovirus herpesviruses

“…92,93,97,98 The risk of HHV-6 reactivation in haploidentical HSCT is undefined and could be contingent on graft manipulation, the conditioning regimen used or the GVHD prophylaxis scheme, with higher rates seen with post-transplant cyclophosphamide (PTCy). [99][100][101][102] One report found an HHV-6 reactivation incidence rate of 42.7% in unmanipulated haploidentical HSCT with PTCy with 87% of HHV-6 reactivation followed by CMV reactivation at a median of 15 days. 103 In this patient population, HHV-6 reactivation was found to be an independent risk factor for the occurrence of grade II-IV GVHD.…”

“…HHV‐6 reactivation is typically seen in the setting of UCBT, allelic‐mismatched or unrelated donor, previous HSCT, use of a myeloablative conditioning regimen, administration of glucocorticoids, T‐cell depleting agents, and mycophenolate mofetil, acute GVHD grade II‐IV, engraftment syndrome, and male gender 92,93,97,98 . The risk of HHV‐6 reactivation in haploidentical HSCT is undefined and could be contingent on graft manipulation, the conditioning regimen used or the GVHD prophylaxis scheme, with higher rates seen with post‐transplant cyclophosphamide (PTCy) 99–102 . One report found an HHV‐6 reactivation incidence rate of 42.7% in unmanipulated haploidentical HSCT with PTCy with 87% of HHV‐6 reactivation followed by CMV reactivation at a median of 15 days 103 .…”