Abstract

A major cause of morbidity and mortality for patients who undergo hematological stem cell transplantations (HSCT) is acute graft-versus-host disease (GVHD), a mostly T cell mediated disease. The examination of the T cell receptor (TCR) repertoire of HSCT patients and through the use of next generation nucleotide sequencing leads to the question of whether features of TCR repertoire reconstitution might reproducibly associate with GVHD.HYPOTHESIS: We hypothesized that the peripheral blood TCR repertoire of patients with steroid non-responsive, acute GVHD would be less diverse. We also hypothesized that patients with GVHD who shared HLA might also share common clones at the time of GVHD diagnosis, thereby potentially providing potential clinical indicators for treatment stratification. We further hypothesized that HSCT recipients with the same HLA mismatch might share a more similar TCR repertoire based on a potentially shared focus of alloreactive responses.METHOD: We studied two separate patient cohorts and two separate platforms to measure TCR repertoire. The first cohort of patients are from a multicenter, phase III, randomized, double-blinded clinical trial of patients who developed acute GVHD (NCT01002742). The second are samples from biobanks from two centers and the CIBMTR of patients who mismatched HSCT.CONCLUSION: There were no statistically significant differences in the TCR diversity of steroid responders and non-responders among patients with acute GVHD on the day of diagnosis. Most clones in the repertoire were unique to each patient, but a small number of clones were found to be both exclusive to, and shared, amongst GVHD non-responders. We were also able to show a strong correlation between the presence of VSS 20 and VSS29 and steroid responsiveness. Using the Bhattacharya coefficient, those patients who shared the same HLA mismatch were shown to be no more similar to one another than to those who had a completely different mismatch. Using two separate clinical cohorts and two separate platforms for analyzing the TCR repertoire, we have shown that the sampled human TCR repertoire is largely unique to each patient but showed glimmers of common clones of subsets of clones based on responsiveness to steroids in aGVHD on the day of diagnosis. These studies are informative for future strategies to assess for reproducible TCR responses in human alloreactivity and possible markers of GVHD responsiveness to therapy.

View details for DOI 10.1016/j.bbmt.2020.01.020

View details for PubMedID 32081787