Loss of T Follicular Helper Cells in the Peripheral Blood of Patients with Chronic Graft-versus-Host Disease.

B cell antihost antibody production plays a central role in chronic graft-versus-host disease (cGVHD). T follicular helper (TFH) cells drive B cell responses and are implicated in this process. Given differences in cGVHD incidence between umbilical cord blood (UCB) and adult donor transplant recipients, we evaluated TFH cell reconstitution kinetics to define graft source differences and their potential pathogenic role in cGVHD. Although we observed significantly fewer TFH cells in the blood of UCB recipients (versus matched related donors [MRD]) early after transplantation, by 1 year the numbers of TFH cells were similar. Additionally, at both early (day 60) and late (1 year) time points, TFH cell phenotype was predominantly central memory cells in both cohorts. TFH cells were functional and able to produce multiple cytokines (INF-γ, TNF-α, IL-2, IL-17, and IL-21) after stimulation. In contrast to mouse models, where an enhanced frequency of splenic TFH cells contributes to cGVHD, patients with cGVHD showed significantly depleted circulating TFH cells after both UCB and MRD transplantation. Low numbers of TFH cells early after UCB transplantation could directly contribute to less cGVHD in this cohort. Additionally, systemic therapy (including steroids and calcineurin inhibitors) may contribute to decreases in TFH cells in patients with cGVHD. These data provide further evidence supporting the importance of TFH cells in cGVHD pathogenesis.

Reduced-intensity conditioning followed by related allografts in hematologic malignancies: long-term outcomes most successful in indolent and aggressive non-Hodgkin lymphomas.

Reduced-intensity conditioning (RIC) extends the curative potential of allogeneic hematopoietic cell transplantation (HCT) to patients with hematologic malignancies unable to withstand myeloablative conditioning. We prospectively analyzed the outcomes of 123 patients (median age, 57 years; range, 23-70 years) with hematologic malignancies treated with a uniform RIC regimen of cyclophosphamide, fludarabine, and total-body irradiation (200 cGy) with or without antithymocyte globulin followed by related donor allogeneic HCT at the University of Minnesota between 2002 and 2008. The cohort included 45 patients with acute myelogenous leukemia (AML) or myelodysplastic syndrome (MDS), 27 with aggressive non-Hodgkin lymphoma (NHL), 8 with indolent NHL, 10 with Hodgkin lymphoma (HL), 10 with myeloma, and 23 with acute lymphocytic leukemia, chronic myelogenous leukemia, other leukemias, or myeloproliferative disorders. The probability of 4-year overall survival was 73% for patients with indolent NHL, 58% for those with aggressive NHL, 67% for those with HL, 30% for those with AML/MDS, and only 10% for those with myeloma. Corresponding outcomes for relapse in these patients were 0%, 32%, 50%, 33%, and 38%, and those for progression-free survival were 73%, 45%, 27%, 27%, and 10%. The incidence of treatment-related mortality was 14% at day +100 and 22% at 1 year. The incidence of grade II-IV acute graft-versus-host disease was 38% at day +100, and that of chronic graft-versus-host disease was 50% at 2 years. Multivariate analysis revealed superior overall survival and progression-free survival in patients with both indolent and aggressive NHL compared with those with AML/MDS, HL, or myeloma. Worse 1-year treatment-related mortality was observed in patients with a Hematopoietic Cell Transplantation Comorbidity Index score ≥ 3 and in cytomegalovirus-seropositive recipients. These results suggest that (1) RIC conditioning was well tolerated by an older, heavily pretreated population; (2) patients with indolent and aggressive NHL respond well to RIC conditioning, highlighting the importance of the graft-versus-lymphoma effect; and (3) additional peri-transplantation manipulations are needed to improve outcomes for patients with AML/MDS or myeloma receiving RIC conditioning before HCT.