Patient HLA-DP–Specific CD4+ T Cells from HLA-DPB1–Mismatched Donor Lymphocyte Infusion Can Induce Graft-versus-Leukemia Reactivity in the Presence or Absence of Graft-versus-Host Disease  Caroline E. Rutten, Simone A.P. van Luxemburg-Heijs, Constantijn J.M. Halkes, Cornelis A.M. van Bergen, Erik W.A. Marijt, Machteld Oudshoorn, Marieke Griffioen, J.H. Frederik Falkenburg  Biology of Blood and Marrow Transplantation  Volume 19, Issue 1, Pages 40-48 (January 2013) DOI: 10.1016/j.bbmt.2012.07.020 Copyright © 2013 American Society for Blood and Marrow Transplantation Terms and Conditions

Figure 1 Kinetics of different activation markers for detecting patient HLA-DP–specific CD4+ T cells directly ex vivo. PBMNCs from a patient (HLA-DPB1*02:01,03:01) who underwent allo-SCT for chronic B cell leukemia with an HLA-DPB1–mismatched donor (HLA-DPB1*04:02,05:01) were analyzed for the presence of HLA-DPB1*03:01–specific CD4+ T cells. Purified CD4+ T cells obtained during the clinical response to DLI were stimulated with HeLa-II cells transduced with donor- or patient-specific HLA-DPB1 molecules. (A) After 6-18 hours of incubation, intacellular IFN-γ (upper panel) or CD154 (lower panel) staining was determined by flow cytometry. (B) After 16-44 hours of incubation, surface CD137 (upper panel) and CD154 (lower panel) expression was determined by flow cytometry. (C) Percentages of CD137-expressing CD4+ T cells after incubation with patient HLA-DPB1*03:01 (■), donor HLA-DPB1*04:02 (), or medium alone (□) was determined at different time points. Mean results ± SD of 2-4 individual experiments are shown. Biology of Blood and Marrow Transplantation 2013 19, 40-48DOI: (10.1016/j.bbmt.2012.07.020) Copyright © 2013 American Society for Blood and Marrow Transplantation Terms and Conditions

Figure 2 Emergence of patient HLA-DP–specific CD4+ T cells after HLA-DPB1–mismatched allo-SCT and DLI. (A) Percentage of donor chimerism in bone marrow after allo-SCT. The arrow indicates DLI. Conversion to 100% donor chimerism was observed 3 months after DLI. (B) CD4+ T cells purified from donor PBMNCs, patient PBMNCs obtained after allo-SCT before DLI, and 6 weeks after DLI were stimulated with HeLa-II cells, HeLa-II cells transduced with donor HLA-DPB1*05:01 or shared HLA-DPB1*04:01, HeLa-II cells transduced with patient HLA-DPB1*01:01, or left unstimulated. Percentages of CD137-expressing CD4+ T cells after 44 hours of incubation are shown. Biology of Blood and Marrow Transplantation 2013 19, 40-48DOI: (10.1016/j.bbmt.2012.07.020) Copyright © 2013 American Society for Blood and Marrow Transplantation Terms and Conditions

Figure 3 HLA-DP–specific CD137+/CD4+ T cells observed after HLA-DPB1–mismatched allo-SCT and DLI in 24 individuals. A total number of 24 patient–donor combinations were analyzed for the presence of patient HLA-DP–specific CD4+ T cells. In total, percentages of CD137+/CD4+ T cells in response to 39 donor or shared HLA-DPB1 molecules and 33 patient-specific HLA-DPB1 molecules are shown. For each patient–donor combination, CD4+ T cells purified from donor PBMNCs and patient PBMNCs obtained after allo-SCT before DLI and after DLI were stimulated with HeLa-II cells transduced with donor or shared HLA-DPB1 molecules (○) or HeLa-II cells transduced with patient-specific HLA-DPB1 molecules (●). Percentages of CD137+/CD4+ T cells are shown after 44 hours of coincubation with Hela-II cells. Results were corrected for background CD137 expression on unstimulated CD4+ T cells. For each patient–donor combination, representative results obtained after only 1 DLI are shown. HLA-DP–specific immune responses were defined as detection of >0.15% CD137+/CD4+ T cells after stimulation with Hela-II cells transduced with patient-specific HLA-DPB1 molecules based on <0.10% CD137+/CD4+ T cells in response to donor-specific or shared HLA-DPB1 molecules. The line represents the threshold of 0.15% for positive results. Results post-DLI represent the first DLI except for patients 14, 15, and 17. Results to the first DLI with a clinical response are shown for these patients. Biology of Blood and Marrow Transplantation 2013 19, 40-48DOI: (10.1016/j.bbmt.2012.07.020) Copyright © 2013 American Society for Blood and Marrow Transplantation Terms and Conditions

Figure 4 HLA-DP–specific CD137+/CD4+ T cells in patients with and without clinical responses to DLI. Percentages of CD137+/CD4+ T cells in response to stimulation with HeLa-II cells transduced with patient HLA-DPB1 molecules obtained after allo-SCT and DLI are shown. Results were corrected for background CD137 expression on unstimulated CD4+ T cells. For 9 patients who were screened for CD4+ T cells specific for 2 different patient-specific HLA-DPB1 molecules, results for only 1 HLA-DPB1 molecule with the highest percentage of CD137+/CD4+ T cells are depicted. (A) Patient HLA-DP–specific CD4+ T cells were found in 13 of 18 patients with clinical responses to DLI and in 1 of 6 patients without clinical responses to DLI. (B) CD137+/CD4+ T cells were found in all 8 patients with GVHD (in presence or absence of GVL), and in 5 of 10 patients who developed beneficial clinical responses without GVHD (selective GVL reactivity). CD137+/CD4+ T cells were detected in only 1 patient without clinical response to DLI. Biology of Blood and Marrow Transplantation 2013 19, 40-48DOI: (10.1016/j.bbmt.2012.07.020) Copyright © 2013 American Society for Blood and Marrow Transplantation Terms and Conditions

Figure 5 HLA-DP–specific CD137+/CD4+ T cells in response to permissive and nonpermissive mismatches. Percentages of CD137+/CD4+ T cells in response to stimulation with HeLa-II cells transduced with patient HLA-DPB1 molecules obtained after allo-SCT and DLI are shown. Results were corrected for background CD137 expression on unstimulated CD4+ T cells. CD137+/CD4+ T cell responses to each HLA-DPB1 allele are depicted separately. The modified algorithm classifying HLA-DPB1 alleles in 4 categories was used [19]. Results of nonpermissive and permissive HLA-DPB1 mismatch combinations are shown. The horizontal line represents median values. Biology of Blood and Marrow Transplantation 2013 19, 40-48DOI: (10.1016/j.bbmt.2012.07.020) Copyright © 2013 American Society for Blood and Marrow Transplantation Terms and Conditions