Donor CD3+ lymphocyte infusion after reduced intensity conditioning allogeneic stem cell transplantation: Single-center experience

Donor lymphocyte infusions (DLI) can induce remission in patients with hematologic malignancies who relapse after allogeneic stem cell transplantation. However, graft-vs-host disease (GVHD) remains a major complication of this strategy. We have used escalating doses of DLI for many years, and wanted to assess the risk factors for GVHD and transplant-related mortality as well as disease outcomes according to the reason for DLI. We analyzed 65 patients who received a total of 111 DLI for different reasons and at different intervals after transplantation. Median number of DLI was 2 (range, 1–4), median interval between transplantation and DLI was 9 months (range, 1–41 months) and median number of infused CD3+ cells/kg recipient body weight was 2.5 × 107 (range, 1 × 106–11.8 × 107). Reasons for DLI were relapse or progression in 37 patients (57%), residual disease in 15 patients (23%), and persistence of mixed chimerism in 13 patients (20%). Seven patients (11%) developed acute GVHD grade II to IV and 5 patients (8%) developed extensive chronic GVHD. In univariate analysis, we could identify a transplantation–DLI interval ≤6 months, the dose of DLI (≥1 × 107), and DLI number as predictive factors of GVHD. In multivariate analysis, these results were confirmed only for the transplantation–DLI interval (hazard ratio = 19.48; 2.23–170.34; p = 0.007). Our findings indicate that this form of adoptive immunotherapy is well tolerated and induces a low incidence of GVHD and transplant-related mortality, supporting further investigation as an upfront modality to enhance the graft-vs-tumor response in high-risk patients.