Antigen-specific Cytotoxic T Cells in the Treatment of Opportunistic Infections

Epstein Barr Virus (EBV) or Cytomegalovirus (CMV) infection results in significant morbidity and mortality in hematopoietic stem cell transplantation (HSCT) patients. HSCT patients often face opportunistic infections due to the immunosuppressive state during transplantation. Antimicrobial drugs are usually used for prophylactic purposes and for treatment after early detectable infections. Unfortunately, some patients develop resistance to such drug treatment. In addition to HSCT patient, immune compromised patient may also be victim to opportunistic infections. Many infections can be effectively managed by functional immune recovery. In this study, the safety and efficacy of microbial-specific cytotoxic T lymphocytes (CTLs) will be investigated.

Background:

Opportunistic infections are major causes of transplant-related morbidity and mortality in immunosuppressed patients, especially in the early post-transplant period. CMV, EBV, adenovirus (AdV), BK virus (BKV) and other viruses or non-viral pathogens may lead to life-threatening infections after transplantation.

Adoptive immunotherapy with cytotoxic T lymphocytes (CTLs) reactive with specific microbial antigens has proven to be effective without stimulating acute graft-versus-host disease (GVHD) owing to the significantly reduced nonspecific alloreactivity. This study aims to evaluate the safety and efficacy of treating opportunistic infections with microbial-specific CTLs in immune compromised patients.

Objective:

Primary study objectives: Infusion of autologous or allogenic pathogen-specific CTL to patients by I.V., to evaluate the safety.

Secondary study objectives: To evaluate the anti-microbial efficacy of IV-infused autologous or allogenic pathogen-specific CTLs.

Design:

Peripheral blood mononuclear cells (PBMC) will be obtained through apheresis. T cells from PBMC will be activated and enriched by dendritic cells with pathogen specific antigens. Cell preparation time is approximately 12-17 days. Subject will receive infusions of 1x105\~1x106 cells/kg body weight of CTLs via IV infusion. Patients are followed weekly for one month after the infusion, monthly for 3 months, and then every 3 months until the trial ends.