Abstract 4663

Introduction

Delayed immune reconstitution is a major cause of transplant-related mortality in allogeneic stem cell transplant setting. Reactivation of herpes viruses is a common post-transplant complication. In this study, we evaluate the recovery of cell-mediated immunity (CMI) to various herpes viruses by measuring lymphoproliferative response (LPR) to specific recall antigens.

Materials and Methods

Cell-mediated immunity was evaluated by the in-vitro lymphoproliferative response of peripheral blood mononuclear cells (PBMC) to specific purified HSV, VZV, CMV, EBV, HHV-6, 7, 8 antigens. Results were expressed as stimulation index (SI). SI≥a3 was regarded as positive lymphoproliferative response (LPR). Serial measurements were made at before transplant, and monthly during the initial 6 months post-transplant then quarterly till 12 months post-transplant.

Results

From 2001-2004, 36 patients (M=19; F=17) with median age 10.5 years old were recruited. Hematological malignancies accounted for 58.3% of cases. Most transplants were from matched siblings (MSD) with peripheral blood stem cells (PBSC) as the source of stem cells. Altogether 50% of subjects showed positive LPR to HSV, CMV and VZV antigens at 2-4 months post-transplant; A significant upsurge of LPR were observed at 4-6 months post-transplant. However, no positive LPR to HSV, HHV-6,7 and 8 antigens were observed. The antibody status of donor and recipient for HSV, CMV and VZV were associated with the timing of recovery of CMI. Donor choice and stem cell source were important determinants of eventual LPR at day 100 post-transplant.

Conclusion

More than half of transplant recipients developed satisfactory LPR to HSV, CMV and VZV at 2-4 months after transplant. Pre-transplant serostatus of donor and recipient, donor choice and stem cell are important determinants of LPR to herpes viruses.

Disclosures:

No relevant conflicts of interest to declare.

Author notes

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Asterisk with author names denotes non-ASH members.

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