Monitoring cytomegalovirus T-cell immunity in small bowel/multivisceral transplant recipients

Background: Cytomegalovirus (CMV) is a major cause of graft failure and posttransplantation mortality in intestinal/multivisceral transplantation. CMV infection exhibits a wide range of clinical manifestations from asymptomatic infection to severe CMV disease. STUDY'S PURPOSE: The purposes of this study were to assess the utility of measuring CMV-specific cellular immunity in bowel/multivisceral transplant recipients and to provide additional information on the risk of infection and development of CMV disease. Methods: We studied 10 bowel/multivisceral transplant recipients to investigate the kinetics of CMV infection using real-time polymerase chain reaction (on blood and biopsy tissue samples) and CMV-specific T-cell reconstitution by Enzyme-linked ImmunoSPOT Assay (ELISPOT) that enumerates Interferon-gamma-secreting CMV-specific T cells upon in vitro stimulation with viral antigens (pp65 and IE-1). Results: All patients were seropositive for CMV. According to the pattern of T-cell reconstitution occurring either within the first month after transplantation or later, patients were classified as early (n = 7) or late responders (n = 3). Clinically, early responder patients (3/7; 43%) experienced asymptomatic or mild CMV infections, whereas all late responders (3/3; 100%) developed moderate or severe CMV disease. A reduction in mean and peak CMV viral load was observed in early responders, whereas the onset time of infection did not differ significantly between early and late CMV responders. Conclusions: A good and early reconstitution of CMV-specific T-cell immune responses after transplantation is a critical determinant in controlling CMV infections. Simultaneous monitoring of CMV infection and CMV-specific T-cell immunity predicts T-cell-mediated control of CMV infection.