T Cell Depleted Peripheral Blood Stem Cell Allotransplantation with T Cell Add Back for Patients with Hematological Malignancies: Effect of Chronic GVHD on Outcome

One hundred thirty-eight patients with hematologic malignancies received myeloablative T cell-depleted peripheral blood stem cell transplant (PBSCT) from an HLA-identical sibling donor. The T cell dose was adjusted to 0.2-1 × 105 CD3+ cells/kg. The CD34 dose was 2.7-16 × 106/kg. Patients with acute graft-versus-host disease (GVHD) grade <2 received 1 or 2 donor lymphocyte infusions of 107 CD3+ cells/kg between days 45 and 100. Patients were designated according to relapse probability as standard or high relapse risk (77 and 61, respectively). Overall survival (OS), relapse-free survival, relapse, and transplant-related mortality (TRM) were 58%, 46%, 40%, and 20%, respectively, after a median follow-up of 4 years. Fifty-three (39%) and 21 (15%) patients developed grade 2-4 and 3-4 acute GVHD. Forty-two (36%) had limited and 29 (25%) had extensive chronic GVHD. In multivariate analysis, disease risk was an independent factor for OS and relapse, day-30 lymphocyte count for OS and TRM, and chronic GVHD for OS and relapse. PBSCT with early T cell add back leads to comparable rates of chronic GVHD compared with T cell-replete PBSCT. However, this chronic GVHD after T cell add back is associated with less mortality and retains a protective effect in terms of relapse, at least in the standard-risk patients.