CD3/8 T-Cell Responses to CMV Reactivation and Association with Overall Survival in T-Cell Replete Haploidentical Transplants: A Retrospective Analysis Figure 3: Comparison of Th2+Th17 cTFH (Left) and (Th2+Th17)/Th1 cTFH ratio (Right) in patients without cGVHD (N¼38) and with cGVHD (N¼33). Figure 1. (Left) Recovery of tTFH and CD4+ T-cells/mL) after HSCT. (Right) Frequencies of cTFH in the CD4+ T-cell gate beginning 2 months after HSCT. Number of patients analyzed for each time point is indicated below the graph. Dashed lines represent the median values from 11 Healthy Donors (90% CI plotted in light red and light grey for the respective population). Figure 2. Assessment of B-tell helper function in cTFH subsets. cTFH (CD4+CD45RA-CXCR5+) and non-cTFH (CD4+CD45RA-CXCR5-) T cell subsets were purified by flow cytometric cell sorting. IgG (left) and IgM (Right) production was measured in supernatants? after 12-day co-culture of purified T-cell subsets with naive B-cells stimulated with Staphylococcal Enterotoxin B. Abstracts / Biol Blood Marrow Transplant 21 (2015) S147eS170 S165 cGVHD patients, we observed a selective decrease of the Th1 compartment in the cTFH subset (16.2% and 10.9% for No vs. cGVHD, p¼0.034), and relative increase of both Th2 and Th17 cTFH (Th2+Th17¼ 71.15 and 78.1% respectively, p¼0.07) leading to a greater (Th2+Th17)/Th1 ratio (p¼0.044) (Figure 3). We did not find any differences in cTFH subsets when comparing Mild vs. Moderate and Severe cGVHD. To further characterize cTFH, we analyzed BCL-2 and CD95 apoptosis pathways. Th2 and Th17 cTFH subsets appeared to express lower levels of CD95 and higher levels of BCL-2 compared to Th1 cTFH. Increased representation of Th2 and Th17 cTFH subsets that are relatively resistant to apoptosis may be a mechanism that promotes B-cell deregulation and pathologic antibody production in patients with cGVHD. Targeting Th2/Th17 cTFH or TFH-B cell interactions may provide novel therapies in patients with cGVHD. 204 CD3/8 T-Cell Responses to CMV Reactivation and Association with Overall Survival in T-Cell Replete Haploidentical Transplants: A Retrospective Analysis Mahasweta Gooptu 1, Benjamin Leiby 2, Onder Alpdogan 3, Matthew Carabasi 3, Joanne Filicko 4, Margaret Kasner 3, Thomas Klumpp 1, Ubaldo Martinez 5, Barbara Pro 3, Figure 1. Figure 2. Abstracts / Biol Blood Marrow Transplant 21 (2015) S147eS170S166 Manish Sharma 6, John L. Wagner 5, Mark Weiss 3, Neal Flomenberg 3, Dolores Grosso 3. 1 Medical Oncology, Thomas Jefferson University Hospital, Philadelphia, PA; 2 Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA; 3 Medical Oncology, Thomas Jefferson University, Philadelphia, PA; 4 Thomas Jefferson University Hospital, Philadelphia, PA; 5 Department of Medical Oncology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA; 6 Medical oncology, Thomas Jefferson University, Philadelphia, PA CMV reactivation has been associated with increased non- relapse mortality(NRM) and improved earlyrelapse incidence (RI) post HLA matched allogeneic hematopoietic stem cell transplant (HSCT), however, it’s effect has been less exten- sivelystudiedinTcell repletehaploidentical(HI)HSCT. Inthe2 step approach to HI HSCT developed at our institution, a large fixed dose of Tcells (2 x 108) is administered after conditioning ( Step 1), followed 2 days later bycyclophosphamide (CY) for T cell tolerization. In Step 2, a CD34-selected stem cell product is infused 1 day after completing CY. A significant increase in T cell numbers, especially in CD3/8 counts, was associated with CMV reactivation in many patients treated with this approach. We hypothesized that a CMV-associated increase in CD3/8 counts would impact HSCT outcomes. A retrospective outcomes analysis (OS, NRM and RI) using multivariable proportional hazards regression was per- formed on all patients enrolled on a 2 step clinical trial since 2006, who were alive and disease free at D90 (n¼106). High v low CD3/8 count at D90, a history of GVHD treated with steroids and CMV reactivation (defined by > 100 copies/ml by PCR) both by D90, were the factors of interest. Known predictors of outcomes including disease at HSCT and he- matopoietic comorbidity index (HCT CI) were included in the analysis. The median CD3/8 count for the group, 125 cells/ul, was used to differentiate CD8H v CD8L levels. 43% patients reactivated CMV prior to D90. The median CD3/8 count for CMV-R (reactivators) v CMV-NR (non- reactivators) was 308.4 v 53.7 cells/ul (p<0.0001). For the whole group, CD8H had a significant protective effect for OS and NRM. CMV reactivation, disease at HSCT and higher HCT CI score had a significant negative impact. Table 1. No var- iables were significantly associated with RI. In a subset analysis, patients with acute GVHD/CD8H had superior OS in both CMV-R and CMV-NR groups. CMV-NR patients with CD8L/no acute GVHD had the poorest OS. Fig 1. CMV-R patients with CD8L had equally poor OS with or without acute GVHD. Fig 2. Higher CD3/8 counts were significantly associated with improved OS and lower NRM in all patients irrespective of CMV reactivation. Higher CD3/8 counts in CMV-R patients may mitigate the effects of CMV reactivation while preser- ving the beneficial effects of GVHD on OS, a finding that re- quires further investigation. Prospective analyses of CD3/8 and CD3/4 numbers and strategies to increase them such as early withdrawal of immunosuppression are warranted. Table 1 Multivariable model for OS Variable Comparison Hazard Ratio (95% CI) p-value CMV D90 R v NR 3.28 (1.19,9.05) 0.022 CD8 D90 CD8L v CD8H 3.87 (1.39,10.8) 0.0096 GVHD/Steroid D90 Y v N 0.71 (0.32,1.57) 0.40 Dz at HSCT N v Y 0.27 (0.11,0.65) 0.0036 HCTCI 1 unit increase 1.43 (1.08,1.90) 0.013 Age 1 year increase 0.99 (0.97,1.02) 0.60 Conditioning Myelo v RIC 1.36 (0.63,2.94) 0.44 205 Second Allogeneic Hematopoietic Cell Transplantation for Graft Failure: Poorer Outcomes for Neutropenic Graft Failure Troy Christopher Lund 1, Jessica Liegel 2, Paul Orchard 3, Qing Cao 4, Jakub Tolar 2, Claudio Brunstein 5, John E. Wagner 6, Michael R. Verneris 7, Daniel J. Weisdorf 5. 1 Pediatric Blood and Marrow Transplant, University of Minnesota, Minneapolis, MN; 2 University of Minnesota, Minneapolis, MN; 3 Pediatrics Blood and Marrow Transplantation, University of Minnesota Masonic Cancer Research Building, Minneapolis, MN; 4 Biostatistics and Bioinformatics, University of Minnesota, Minneapolis, MN; 5 University of Minnesota Medical Center, Minneapolis, MN; 6 Pediatric Blood and Marrow Transplantation, University of Minnesota, Minneapolis, MN; 7 Pediatric Hematology and Oncology, University of Minnesota Medical Center, Fairview, Minneapolis, MN Graft failure (GF) after hematopoietic cell transplant (HCT) occurs in 5-30[DW1] % of patients. GF can be accompanied by neutropenia(NGF)orcan result withadequate neutrophils, but loss ofdonorchimerism (non-neutropenic graft failure, NNGF). We analyzed the outcomes of 61 patients (pediatric and adult) treated with a second HCT for GF at the University of Minne- sota; 27 withNGFand 34withNNGF. The cumulative incidence of neutrophil engraftment at 42 days after second HCT was 88% for NNGF, and 68% for NGF (p¼0.03). The incidence of grade III- IV acute graft versus host disease (GVHD) was 15% (95% con- fidence interval (CI), 2 e 28%) and 6% (95% CI, 2 - 17%) for NGF and NNGF, respectively (p ¼ 0.17). From the 2ndHCT, 1-year CD3/8 T-Cell Responses to CMV Reactivation and Association with Overall Survival in T-Cell Replete Haploidentical Transplan ...