Functional leukemia-associated antigen-specific memory CD8+ T cells exist in healthy individuals and in patients with chronic myelogenous leukemia before and …

K Rezvani, M Grube, JM Brenchley, G Sconocchia… - Blood, 2003 - ashpublications.org
K Rezvani, M Grube, JM Brenchley, G Sconocchia, H Fujiwara, DA Price, E Gostick…
Blood, 2003ashpublications.org
Antigens implicated in the graft-versus-leukemia (GVL) effect in chronic myeloid leukemia
(CML) include WT1, PR1, and BCR-ABL. To detect very low frequencies of these antigen-
specific CD8+ T cells, we used quantitative polymerase chain reaction (qPCR) to measure
interferon-γ (IFN-γ) mRNA production by peptide-pulsed CD8+ T cells from HLA-A* 0201+
healthy volunteers and from patients with CML before and after allogeneic stem cell
transplantation (SCT). Parallel assays using cytomegalovirus (CMV) pp65 tetramers …
Abstract
Antigens implicated in the graft-versus-leukemia (GVL) effect in chronic myeloid leukemia (CML) include WT1, PR1, and BCR-ABL. To detect very low frequencies of these antigen-specific CD8+ T cells, we used quantitative polymerase chain reaction (qPCR) to measure interferon-γ (IFN-γ) mRNA production by peptide-pulsed CD8+ T cells from HLA-A*0201+ healthy volunteers and from patients with CML before and after allogeneic stem cell transplantation (SCT). Parallel assays using cytomegalovirus (CMV) pp65 tetramers demonstrated the IFN-γ copy number to be linearly related to the frequency of tetramer-binding T cells, sensitive to frequencies of 1 responding CD8+ T cell/100 000 CD8+ T cells. Responses to WT1 and PR1 but not BCR-ABL were detected in 10 of 18 healthy donors. Responses to WT1, PR1, or BCR-ABL were observed in 9 of 14 patients with CML before SCT and 5 of 6 after SCT, often to multiple epitopes. Responses were higher in patients with CML compared with healthy donors and highest after SCT. These antigen-specific CD8+ T cells comprised central memory (CD45RO+CD27+CD57) and effector memory (CD45ROCD27CD57+) T cells. In conclusion, leukemia-reactive CD8+ T cells derive from memory T cells and occur at low frequencies in healthy individuals and at higher frequencies in patients with CML. The increased response in patients after SCT suggests a quantitative explanation for the greater effect of allogeneic SCT.
ashpublications.org