Prostaglandin E2 promotes survival of naive UCB T cells via the Wnt/β-catenin pathway and alters immune reconstitution after UCBT

The outcome of umbilical cord blood transplantation (UCBT) is compromised by low hematopoietic stem cell (HSC) doses leading to prolonged time to engraftment, delayed immunological reconstitution and late memory T-cell skewing. Exposure of UCB to dimethyl-prostaglandin E2 (dmPGE2) increases HSC in vivo. We determined that exposure of UCB T lymphocytes to dmPGE2 modified Wnt signaling resulting in T cell factor (TCF)-mediated transcription. Wnt signaling upregulated interleukin (IL)-7R and IL-2Rβ, resulting in enhanced survival mediated by the homeostatic cytokines IL-7 and IL-15. dmPGE2 also induced components of the Wnt pathway and Wnt receptors, thereby priming UCB T cells to receive signals via Wnt ligands in vivo. We observed that the Wnt transcription factor TCF7 and its target EOMES were elevated in the T cells of patients who received PGE2-treated UCBs. Consistent with the role of Wnt/β-catenin signaling to induce and maintain naive, memory precursors and long-lived central memory CD8(+) cells, these patients also had increased fractions of CD8(+)CD45RO(-)CD62L(+) plus CD8(+)CD45RO(+)CD62L(+) subsets encompassing these T-cell populations. These effects of the PGE2/Wnt/β-catenin axis may have significant implications for harnessing immunity in the context of UCBT, where impaired immune reconstitution is associated with late memory T-cell skewing.

Autologous bone marrow transplantation therapy for multiple myeloma

We have begun an autologous bone marrow transplantation (ABMT) treatment protocol for patients with myeloma who achieve a minimal disease (less than 10% marrow plasma cells) status. Sites of bony disease are irradiated before BMT. Melphalan 70 mg/m2 on days 1 and 2 is followed by 1200 rads total-body irradiation administered in fractionated doses over 3 d. Autologous marrow which has been previously treated with anti-CALLA, B1, and PCA-1 monoclonal antibodies is then thawed and reinfused. 4 males and 2 females with median age of 46 yr (41-56) have been treated. Granulocytes greater than 500/mm3 and platelets greater than 20,000/mm3 were noted at 21 (12-46) and 23 (12-53) d post-transplant (PT), respectively. Acute mucositis and dermatomal Herpes zoster developed in 3 patients each; all patients are clinically well at 233 (30-807) d PT. All patients achieved pathologically normal marrows, but monoclonal plasma cells and marrow myelofibrosis were each noted in a single patient at 486 and 272 d PT, respectively. A single patient has responded to alpha 2 interferon therapy PT; all others have received no therapy. AMBT offers an exciting new treatment for myeloma; however, relapses post-ABMT suggest that improved ablative regimens and/or marrow purging methods may be required.