Antigen-Specific T Lymphocyte Function Following Unrelated Cord Blood Transplantation (UCBT).

The T lymphocytes contained in cord blood are naïve and do not have antigen-specific function. Since the antigen-specific T lymphocytes contained in other hematopoietic stem cell (HSC) source may contribute to protective cellular immunity following transplantation, it has been hypothesized that the recipients of cord blood transplantation (CBT) might be at increased risk of opportunistic infections. The development of antigen-specific T lymphocyte function was measured in 153 recipients of unrelated cord blood transplants (UCBT) by determining antigen-specific T lymphocyte proliferation to the herpes viruses (CMV, HSC, VZV) for 3 years following UCBT. The first antigen-specific response was detected 29 days following transplantation to HSV. Positive T lymphocyte proliferative responses were detected in 66 recipients: 40 to VZV, 36 to HSV and 22 to CMV. Recipients with and without documented herpes infection/reactivation were equally likely to develop positive proliferative responses. The development of antigen-specific T lymphocyte function following UCBT documents successful immune reconstitution since the antigen-specific T lymphocytes are derived from naïve T lymphocytes or HSC, but not donor-derived antigen-specific T lymphocytes. The assessment of antigen-specific function following CBT is a model for the evaluation of post-transplant immune reconstitution without the compounding influence of donor derived antigen-specific function.