ELISPOT assay of interferon‐γ secretion for evaluating human cytomegalovirus reactivation risk in allo‐HSCT recipients

Abstract

Human cytomegalovirus (HCMV) is a common cause of significant morbidity and mortality in transplant recipients after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We evaluated interferon-γ (IFN-γ) secretion by HCMV NLVspecific CD8 + T cells in HCMV-reactivated allo-HSCT recipients using an enzymelinked immunospot (ELISPOT) assay at 3 months post-transplantation. Blood samples from 47 recipients were tested for HCMV DNAemia, HCMV pp65 antigenemia, and anti-HCMV immunoglobulins (IgG/IgM) over 3 months post-transplantation. Of the 47 transplant recipients, 26 were HLA-A*02 positive and 21 were HLA-A*02 negative. The results were essentially consistent between the 47 transplant recipients and the HLA-A*02-positive recipients. HCMV DNAemia was not linearly correlated with IFN-γ spot-forming cells (SFCs) counts; IFN-γ SFCs counts did not differ significantly between the HCMV DNAemia-positive and -negative groups, whereas the HCMV-DNA virus loads were inversely correlated with the IFN-γ SFCs counts. HCMV pp65 antigenemia was not linearly correlated with IFN-γ SFCs counts; IFN-γ SFCs counts in the HCMV pp65 antigenemia-positive and -negative groups were similar. More IFN-γ SFCs counts were detected in transplant recipients with high anti-HCMV-IgG antibody titers than in those with low anti-HCMV-IgG titers pre-transplantation in the 47 recipients. Anti-HCMV-IgG antibody titers were positively linearly correlated with IFN-γ SFCs counts in HLA-A*02-positive recipients. The HCMV infection indicators used to monitor HCMV reactivation had different values in transplant recipients. The use of the IFN-γ SFCs counts measured by ELISPOT to evaluate the risk of HCMV reactivation needs further study.

Cytomegalovirus Immune reconstitution in cord blood transplant recipients on letermovir prophylaxis

“…Seventy CBT recipients enrolled in this study had a mean (SD) age of 49 16 years; 51.4% were male, and 74.3% were white Caucasians (Table 1). The most common underlying hematological malignancy was acute myeloid leukemia ( n = 34, 48.6%), followed by acute lymphocytic leukemia ( n = 23, 32.9%); 36 participants (51.4%) underwent haplocord transplant; 38 (54.3%) CBT recipients developed Grade II‐IV acute graft versus host disease (GvHD), including 13 (18.6%) Grade III‐IV.…”

“…who detected CMV‐CMI reconstitution in HCT recipients more frequently than viremia 17 or Liang et al. and Gabanti et al., who also failed to find associations between viremia and CMV‐CMI reconstitution 16 . This finding suggests that CMV reactivations sufficient to prime the new immune system may not always result in levels of DNAemia above the limit of detection of the PCR assays commonly used or that the DNAemia does not last long enough to be detected through intermittent monitoring.…”

“…CMV-CMI reconstitution. 16 This finding suggests that CMV reactivations sufficient to prime the new immune system may not always result in levels of DNAemia above the limit of detection of the PCR assays commonly used or that the DNAemia does not last long enough to be detected through intermittent monitoring. This finding implies that CMV-CMI reconstitution may be more sensitive than viremia for the detection of CMV reactivation.…”

“…12,13 CMV-CMI reconstitution was shown in some studies to prevent CMV disease in HCT recipients, although study results have not been consistent. [14][15][16][17] Studies conducted with ganciclovir-or foscarnetbased prophylaxis showed that universal prophylaxis leads to delayed development of CMV-CMI compared to pre-emptive therapy because prophylaxis completely blocked viral replication and limited the antigenic exposure of the immune system. 18,19 However, letermovir does not entirely suppress the viral replication accompanying CMV reactivation.…”

Secretion of IFN-γ by specific T cells in HCMV infection

“…In our previous study [ 20 ], we analyzed the relationship between T cellular immune response specific to HCMV and HCMV infection indicators (HCMV-DNA, HCMV-IgG/M, HCMV-pp65) during the initial phases of transplantation. The findings demonstrated a strong relationship between the IFN-γ secretion of T cells and the indicators of HCMV infection.…”