1. ¹Department of Medicine, Baylor College of Medicine and The Methodist Hospital, Houston, TX, USA
2. ²Center for Gene and Cell Therapy, Baylor College of Medicine and The Methodist Hospital, Houston, TX, USA
3. ³Department of Pediatrics, Baylor College of Medicine and The Methodist Hospital, Houston, TX, USA

Correspondence: Dr R Lamba, Center for Cell and Gene Therapy, Baylor College of Medicine, 6565 Fannin, M964, Houston, TX 77030, USA. E-mail: rlamba@tmh.tmc.edu

Received 7 February 2005; Accepted 23 June 2005; Published online 5 September 2005.

Abstract

We studied the incidence and recurrence of Cytomegalovirus (CMV) infection and reactivation in 38 recipients of Alemtuzumab reduced intensity conditioning-stem cell transplantation, and used CMV-HLA tetramer studies to discover if these events correlated with recovery of circulating CMV-specific CD8⁺ T cells (cytotoxic T lymphocyte (CTLs)). The cumulative incidence of CMV infection was 60% at 1 year (95% CI, 45–78%) with a median reactivation time of 24 days (range 5–95 days). All patients with CMV reactivation received Ganciclovir or Foscarnet, and only one developed CMV disease. More strikingly, only 8/21 patients had relapse of CMV antigenemia. Tetramer analysis in 13 patients showed that 11 reconstituted CMV CTLs (7/11 by day 30 and 10/11 by day 90). The development of CMV infection was accompanied by a >5-fold rise of CMV CTLs. Recurrence of CMV infection occurred only in the patients who failed to generate a CTL response to the virus. Hence, recipients of SCT using Alemtuzumab-RIC are initially profoundly immunosuppressed and have a high incidence of early CMV reactivation. However, in the majority of patients, infection is transient, and antiviral T cell reconstitution is rapid. Monitoring with CMV-specific CTLs may help identify the subset of patients at risk from recurrent infection or disease.