452 The Expansion of Gastrointestinal-Associated αβ T Cell Clones in Peripheral Blood Associates with Severe Steroid Refractory Gvhd

Track: Contributed Abstracts
Saturday, February 16, 2013, 6:45 PM-7:45 PM
Hall 1 (Salt Palace Convention Center)
Everett H Meyer, MD PhD , Department of Medicine, Division of Blood and Marrow Transplantation, Stanford University School of Medicine, Stanford, CA
Joanna A Liliental, PhD , Department of Medicine, Translational Research and Applied Medicine Program, Stanford University School of Medicine, Stanford, CA
Mareike Florek, MD , Department of Medicine, Division of Blood and Marrow Transplantation, Stanford University School of Medicine, Stanford, CA
Andrea Lohr, PhD , GigaGen, Inc, San Francisco, CA
Ando Hsu, PhD , GigaGen, Inc, San Francisco, CA
David Johnson, PhD , GigaGen, Inc, San Francisco, CA
Philip Lavori, PhD , Health Research and Policy, Biostatistics, Stanford University School of Medicine, Stanford, CA
James L. Zehnder, MD , Dept. of Pathology, Stanford University School of Medicine, Stanford, CA
David B. Miklos, MD, PhD , Department of Medicine, Division of Blood and Marrow Transplantation, Stanford University School of Medicine, Stanford, CA
Dr. Samuel Strober, MD , Department of Medicine, Rheumatology Division, Stanford University School of Medicine, Stanford, CA
Robert Negrin, MD , Department of Medicine, Division of Blood and Marrow Transplantation, Stanford University School of Medicine, Stanford, CA

Donor T cell alloreactivity in hematopoietic stem cell transplantation (HCT) can result in acute graft-versus-host disease (GVHD) which is a major cause of morbidity and mortality in HCT. We hypothesized that using T cell receptor repertoire sequencing, we could identify the most frequent T cell clones in the gastrointestinal (GI) tract of human patients with GVHD and subsequent tracking of these disease-associated clones in peripheral blood could provide a way to risk stratify patients.

We collected endoscopic GI tract biopsy samples and matched blood for fourteen patients undergoing myeloblative HCT with suspected GI GVHD within one day of corticosteroid therapy. We also collected peripheral blood approximately thirty days after biopsy. Seven of these patients were negative for GVHD or had mild steroid responsive GI GVHD and seven had severe steroid refractory GI GVHD. We extracted genomic DNA and performed TCR beta CDR3 repertoire sequencing at Stanford and with Gigagen GigaMune Rep-Seq, using the Illumina next generation sequencing MiSeq and HiSeq platforms.

For each patient, between 1,000-5,000 unique T cell sequences were identified in the endoscopic tissue. We bracketed the most frequent clones in the GI tissue samples by rank order cut-offs and a floating measure of skewness and followed these clones in the blood. Both methods showed that, on average, the GI identified clones increased in frequency more in severe patients (51.2 +/- 39.2) when compared to mild or negative patients (3.08 +/- 2.8; see Figure 1). Additionally, patients in both groups who received more steroids (mg/kg/day) showed a correlated reduction in GI identified T cell expansion in the blood over time.

These results support the use of T cell repertoire sequencing and associated approaches in human patients to both clarify the pathophysiology of GVHD and may provide an independent immune biomarker that could guide GVHD therapy.

See more of: Poster Session 2: GVH/GVL
See more of: Contributed Abstracts
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