Presented at:
American Transplant Congress, Boston, MA,
May 16, 2004
Mechanisms of donor-specific unresponsiveness in tolerant recipient of combined non-myeloablative HLA-mismatched bone marrow and kidney transplantation
Juanita M. Shaffer, Tatsuo Kawai, Yasuhiro Fudaba, A. B. Cosimi, Susan Saidman, Frederic Preffer, David Dombkowski, Francis Delmonico, Steven McAfee, Nina Rubin-Tolkoff, Bimalangshu Dey, Thomas R. Spitzer, David H. Sachs, Megan Sykes.
Massachusetts General Hospital/Harvard Medical School, Boston, MA
Purpose: To evaluate T cell recovery and tolerance in vitro following combined non-myeloablative bone marrow and renal transplantation from a related haploidentical mismatched donor.
Methods : Under an ITN protocol, patients with ESRD received combined non-myeloablative bone marrow and renal transplantation with perioperative cyclosporine (CYA). Donor chimerism was measured by peripheral blood microsatellite markers or by flow cytometry using HLA allele-specific mAbs. T cell recovery was followed by flow cytometry. In vitro assays were performed to evaluate tolerance.
Results : The first patient is currently >420 days post-transplant with normal renal function and no rejection episodes, despite being off all immunosuppression since Day 240. Lymphoid and myeloid chimerism was detectable on Day 7, but undetectable by Day 14. By Day 115, with 110 CD3+ T cells/ul blood, a robust anti-3 rd party MLR response (stimulation index [SI] 106) was seen, with unresponsiveness to donor (SI 1.7). Day 187 (434 T cells/ul) MLR assays were globally hyporesponsive, but a 3 rd party CML response (percent specific lysis [PSL] 56%) and a weak anti-donor CML response (PSL 17%) were detected. Cultures of Day 187 enriched T cells primed against donor completely suppressed PreTx CTL responses against the donor, but not against 3 rd party. Cultures of Day 187 T cells primed against 3 rd party also completely suppressed PreTx CTL responses against donor, but not against 3 rd party. In contrast, cultures of PreTx cells primed against donor only partially suppressed (by 50%) PreTx CTL responses against donor or 3 rd party. On Days 271 and 367 (T cells >665 cells/ ul), a 3 rd party CML response (PSL 47.5% and 58.2%), but no anti-donor CML response, was detected. Specific hyporesponsiveness to donor persisted in MLR (SI 2 and 50 to donor and 3 rd party, respectively). Removal of Day 367 CD25+ cells revealed an anti-donor MLR response among CD3+CD25- cells (SI 27). Removal of non-T cells revealed a weaker anti-donor MLR (SI 14). An anti-donor CML response (PSL 11%) was revealed only by the removal of CD25+ T cells.
Conclusion: Despite loss of chimerism, a patient with tolerance to a donor kidney developed systemic donor-specific unresponsiveness, which may reflect both non-T and T cell-mediated suppressive activity.