Prediction of graft-versus-host disease in humans by donor gene expression profiling

Graft-versus-host disease (GVHD) results from recognition of host antigens by donor T cells following allogeneic hematopoietic cell transplantion (AHCT). Notably, histoincompatibility between donor and recipient is necessary but not sufficient to elicit GVHD. Therefore, we tested the hypothesis that some donors may be “stronger alloresponders” than others, and consequently more likely to elicit GVHD. To this end, we analyzed the gene expression profile of CD4 and CD8 T cells from 50 AHCT donors. We found that pre-AHCT gene expression profiling segregates donors whose recipient suffered from GVHD or not. The “dangerous donor” trait (GVHD+ recipient) is under polygenic control and is shaped by the activity of genes that regulate diverse cell functions including TGF-β signaling and cell proliferation. We also performed gene expression profiling in T cells harvested from 40 AHCT recipients on day 365 post-AHCT. The donor gene profile defined on day 0 showed exceedingly strong correlation with that of recipient CD4 and CD8 T cells harvested one year post-AHCT. These data suggest that donor gene profiles linked with GVHD were largely imprinted at the hematopoietic stem cell level. The ability to discriminate strong and weak alloresponders using gene expression profiling could pave the way to personalized transplantation medicine. Keywords: comparative gene profile, cell type comparaison, GVHD+, GVHD- Peripheral blood was obtained from 50 AHCT donors pre-transplant (referred to as day 0) and from 40 recipients on day 365. Donors and recipients were HLA-identical siblings. Recipients were regarded as negative for acute GVHD (aGVHD) when they lived at least 100 days without presenting GVHD. Recipients were considered negative for chronic GVHD (cGVHD) when they remained cGVHD-free for 365 days post-AHCT. CD4 and CD8 T-cell subsets were purified with microbeads. Total RNA was purified, amplified, reverse transcribed and hybridized on microarrays developed by The Microarray Centre of The Toronto University Health Network (http://www.microarrays.ca/). RNA from donor and recipient T cells was hybridized on the human H19K array (19,008 ESTs), and donor T-cell RNA was also hybridized on the ImmunArray (3,411 ESTs from immune related genes).