Identifying cytomegalovirus complications using the quantiferon-CMV assay after allogeneic hematopoietic stem cell transplantation

Background. A simple test to identify recovery of CMV-specific T-cell immunity following hematopoietic stem cell transplantation (HSCT) could assist clinicians in managing CMV-related complications. Methods. In an observational, multicenter, prospective study of 94 HSCT recipients we evaluated CMV-specific T-cell immunity at baseline, 3, 6, 9, and 12 months after transplant using the Quantiferon-CMV, an enzyme-linked immunosorbent spot assay (ELISpot), and intracellular cytokine staining. Results. At 3 months after HSCT, participants who developed CMV disease (n = 8) compared with CMV reactivation (n = 26) or spontaneous viral control (n = 25) had significantly lower CD8+ T-cell production of interferon-γ (IFN-γ) in response to CMV antigens measured by Quantiferon-CMV (P = .0008). An indeterminate Quantiferon-CMV result had a positive predictive value of 83% and a negative predictive value of 98% for identifying participants at risk of further CMV reactivation. Participants experiencing CMV reactivation compared with patients without CMV reactivation had a reduced proportion of polyfunctional (IFN-γ+/tumor necrosis factor a-positive) CD4+ and CD8+ T cells and a higher proportion of interleukin 2-secreting cells (P = .01 and P = .002, respectively). Conclusions. Quantifying CMV-specific T-cell immunity after HSCT can identify participants at increased risk of clinically relevant CMV-related outcomes.