Association of acute myeloid leukemias most immature phenotype with risk groups and outcomes

The precise phenotype and biology of acute myeloid leukemia stem cells remain controversial, in part because the “gold standard” immunodeficient mouse engraftment assay fails in a significant fraction of patients and identifies multiple cell-types in others. We sought to analyze the clinical utility of a novel assay for putative leukemia stem cells in a large prospective cohort. The leukemic clone’s most primitive hematopoietic cellular phenotype was prospectively identified in 109 newly-diagnosed acute myeloid leukemia patients, and analyzed against clinical risk groups and outcomes. Most (80/109) patients harbored CD34+CD38− leukemia cells. The CD34+CD38− leukemia cells in 47 of the 80 patients displayed intermediate aldehyde dehydrogenase expression, while normal CD34+CD38− hematopoietic stem cells expressed high levels of aldehyde dehydrogenase. In the other 33/80 patients, the CD34+CD38− leukemia cells exhibited high aldehyde dehydrogenase activity, and most (28/33, 85%) harbored poor-risk cytogenetics or FMS-like tyrosine kinase 3 internal tandem translocations. No CD34+ leukemia cells could be detected in 28/109 patients, including 14/21 patients with nucleophosmin-1 mutations and 6/7 acute promyelocytic leukemia patients. The patients with CD34+CD38− leukemia cells with high aldehyde dehydrogenase activity manifested a significantly lower complete remission rate, as well as poorer event-free and overall survivals. The leukemic clone’s most immature phenotype was heterogeneous with respect to CD34, CD38, and ALDH expression, but correlated with acute myeloid leukemia risk groups and outcomes. The strong clinical correlations suggest that the most immature phenotype detectable in the leukemia might serve as a biomarker for “clinically-relevant” leukemia stem cells. ClinicalTrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT01349972","term_id":"NCT01349972"}}NCT01349972

Association of acute myeloid leukemias most immature phenotype with risk groups and outcomes

The precise phenotype and biology of acute myeloid leukemia stem cells remain controversial, in part because the “gold standard” immunodeficient mouse engraftment assay fails in a significant fraction of patients and identifies multiple cell-types in others. We sought to analyze the clinical utility of a novel assay for putative leukemia stem cells in a large prospective cohort. The leukemic clone’s most primitive hematopoietic cellular phenotype was prospectively identified in 109 newly-diagnosed acute myeloid leukemia patients, and analyzed against clinical risk groups and outcomes. Most (80/109) patients harbored CD34(+)CD38(−) leukemia cells. The CD34(+)CD38(−) leukemia cells in 47 of the 80 patients displayed intermediate aldehyde dehydrogenase expression, while normal CD34(+)CD38(−) hematopoietic stem cells expressed high levels of aldehyde dehydrogenase. In the other 33/80 patients, the CD34(+)CD38(−) leukemia cells exhibited high aldehyde dehydrogenase activity, and most (28/33, 85%) harbored poor-risk cytogenetics or FMS-like tyrosine kinase 3 internal tandem translocations. No CD34(+) leukemia cells could be detected in 28/109 patients, including 14/21 patients with nucleophosmin-1 mutations and 6/7 acute promyelocytic leukemia patients. The patients with CD34(+)CD38(−) leukemia cells with high aldehyde dehydrogenase activity manifested a significantly lower complete remission rate, as well as poorer event-free and overall survivals. The leukemic clone’s most immature phenotype was heterogeneous with respect to CD34, CD38, and ALDH expression, but correlated with acute myeloid leukemia risk groups and outcomes. The strong clinical correlations suggest that the most immature phenotype detectable in the leukemia might serve as a biomarker for “clinically-relevant” leukemia stem cells. ClinicalTrials.gov: NCT01349972

Tumor-Infiltrating Macrophages in Post-Transplant, Relapsed Classical Hodgkin Lymphoma Are Donor-Derived

<div><p>Tumor-associated inflammatory cells in classical Hodgkin lymphoma (CHL) typically outnumber the neoplastic Hodgkin/Reed-Sternberg (H/RS) cells. The composition of the inflammatory infiltrate, particularly the fraction of macrophages, has been associated with clinical behavior. Emerging work from animal models demonstrates that most tissue macrophages are maintained by a process of self-renewal under physiologic circumstances and certain inflammatory states, but the contribution from circulating monocytes may be increased in some disease states. This raises the question of the source of macrophages involved in human disease, particularly that of CHL. Patients with relapsed CHL following allogeneic bone marrow transplant (BMT) provide a unique opportunity to begin to address this issue. We identified 4 such patients in our archives. Through molecular chimerism and/or XY FISH studies, we demonstrated the DNA content in the post-BMT recurrent CHL was predominantly donor-derived, while the H/RS cells were derived from the patient. Where possible to evaluate, the cellular composition of the inflammatory infiltrate, including the percentage of macrophages, was similar to that of the original tumor. Our findings suggest that the H/RS cells themselves define the inflammatory environment. In addition, our results demonstrate that tumor-associated macrophages in CHL are predominantly derived from circulating monocytes rather than resident tissue macrophages. Given the association between tumor microenvironment and disease progression, a better understanding of macrophage recruitment to CHL may open new strategies for therapeutic intervention.</p></div

H/RS cells are patient-derived while the majority of the inflammatory infiltrate is donor-derived.

<p>Sections of lung from a female patient (Patient D) with recurrent Hodgkin lymphoma following an allogeneic BMT (brother) are shown. An overview of one of the lesional areas is shown (A, DAPI nuclear staining). XY FISH was performed on this section, and a high power view of the boxed area in red is shown in B (X = red, Y = green). An adjacent tissue section was stained for CD30 (C), highlighting numerous H/RS cells (arrow, higher magnification, D). While not possible to align perfectly, the H/RS cells in this patient were positive for EBV (in situ hybridization for EBER, panels E, F). The majority of the smaller nuclei are donor-derived (XY, red and green, 78% including only DAPI-positive nuclei with distinct FISH signals). By comparison with the H&E, these cells predominantly represent an inflammatory infiltrate. A separate area from this specimen demonstrating similar findings is shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163559#pone.0163559.s001" target="_blank">S1 Fig</a>.</p

Tumor-infiltrating macrophages in recurrent Hodgkin lymphoma are predominantly donor- and, therefore, bone marrow-derived.

<p>A portion of the same field highlighted in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163559#pone.0163559.g001" target="_blank">Fig 1A</a> (white box) is shown at higher magnification. Prior to analysis by XY FISH, the same slide was stained for CD68 using standard immunohistochemical techniques in order to identify macrophages (A). The images of the DAPI nuclear stain and the CD68 cytoplasmic stain are overlaid (B) to better identify individual cells in the corresponding FISH images (C). Where possible to discern, the tumor-infiltrating macrophages are all derived from the male donor (arrows, XY, red and green). However, by this method we found that in 21 +/- 4% of DAPI-positive nuclei, it was not possible to score X, Y status due to sectioning and/or other technical limitations. Of note, this patient had 100% donor chimerism in her bone marrow when tested near the time of this biopsy. H/RS cells (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163559#pone.0163559.g001" target="_blank">Fig 1</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163559#pone.0163559.s001" target="_blank">S1 Fig</a>) and areas of residual, uninvolved lung tissue were female (not shown). An overview of the density of macrophage infiltrate is shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0163559#pone.0163559.s002" target="_blank">S2 Fig</a>.</p

Demographic information.

<p>Demographic information.</p

Composition of the Inflammatory Infiltrate.

<p>Composition of the Inflammatory Infiltrate.</p