Donor monocyte–derived macrophages promote human acute graft-versus-host disease
Laura Jardine, … , A.J. Simpson, Matthew Collin
Laura Jardine, … , A.J. Simpson, Matthew Collin
Published May 26, 2020
Citation Information: J Clin Invest. 2020;130(9):4574-4586. https://doi.org/10.1172/JCI133909.
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Research Article Immunology

Donor monocyte–derived macrophages promote human acute graft-versus-host disease

Abstract

Myelopoiesis is invariably present and contributes to pathology in animal models of graft-versus-host disease (GVHD). In humans, a rich inflammatory infiltrate bearing macrophage markers has also been described in histological studies. In order to determine the origin, functional properties, and role in pathogenesis of these cells, we isolated single-cell suspensions from acute cutaneous GVHD and subjected them to genotype, transcriptome, and in vitro functional analysis. A donor-derived population of CD11c+CD14+ cells was the dominant population of all leukocytes in GVHD. Surface phenotype and NanoString gene expression profiling indicated the closest steady-state counterpart of these cells to be monocyte-derived macrophages. In GVHD, however, there was upregulation of monocyte antigens SIRPα and S100A8/9 transcripts associated with leukocyte trafficking, pattern recognition, antigen presentation, and costimulation. Isolated GVHD macrophages stimulated greater proliferation and activation of allogeneic T cells and secreted higher levels of inflammatory cytokines than their steady-state counterparts. In HLA-matched mixed leukocyte reactions, we also observed differentiation of activated macrophages with a similar phenotype. These exhibited cytopathicity to a keratinocyte cell line and mediated pathological damage to skin explants independently of T cells. Together, these results define the origin, functional properties, and potential pathogenic roles of human GVHD macrophages.

Authors

Laura Jardine, Urszula Cytlak, Merry Gunawan, Gary Reynolds, Kile Green, Xiao-Nong Wang, Sarah Pagan, Maharani Paramitha, Christopher A. Lamb, Anna K. Long, Erin Hurst, Smeera Nair, Graham H. Jackson, Amy Publicover, Venetia Bigley, Muzlifah Haniffa, A.J. Simpson, Matthew Collin

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Figure 7

Cytoxicity of alloactivated macrophages in vitro.

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Cytoxicity of alloactivated macrophages in vitro. (A) Direct cytotoxicit...
(A) Direct cytotoxicity of MLR macrophages to the keratinocyte cell line HaCaT was assessed by coculture of HaCaT and MLR macrophages at a range of effector/target ratios for 5 hours. Keratinocytes were identified as CD45– cells by flow cytometry, and the proportion of dead keratinocytes was quantified by annexin V and 7-AAD staining. Representative flow cytometry plots from keratinocytes alone (top row) and keratinocytes cultured with MLR macrophages at a 50:1 ratio (bottom row). (B) Quantitation of keratinocyte apoptosis versus effector/target ratio in 2 independent experiments. (C) Experiments using the skin-explant model of GVHD (see Methods for details). MLR outputs were sorted to yield macrophages and lymphocytes and cocultured with shave biopsies of recipient skin for 3 days. Explants were fixed and stained with H&E. Representative images from explants cultured for 3 days in control medium or medium with MLR macrophages, as indicated. (D) Summary of histological damage to the dermoepidermal junction graded on the Lerner scale from 6 independent experiments. **P < 0.01, Kruskal-Wallis and Dunn’s multiple comparison tests. Mac, macrophages; lymph, lymphocytes.