Long-Term Results of Prophylactic Donor Lymphocyte Infusions for Patients with Multiple Myeloma after Allogeneic Stem Cell Transplantation.

The major reason for treatment failure after allografting in multiple myeloma (MM) is relapse. Donor lymphocyte infusions (DLIs) are considered a valuable post-transplant strategy mainly for relapsed patients but using them to prevent relapse in MM has been reported rarely. In the present study, we examined the efficacy of prophylactic DLIs after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in myeloma patients with a long-term follow-up of more than 5 years. A total of 61 patients with MM who did not relapse or develop disease progression after allo-HSCT were treated with prophylactic DLI in an escalating fashion (overall 132 DLI procedures) to deepen remission status and prevent relapse. Overall response rate to DLI was 77%. Thirty-three patients (54%) upgraded their remission status, 41 patients (67%) achieved or maintained complete remission, and 26% achieved a molecular remission. Incidence of acute graft-versus-host disease (GVHD) grade II to IV was 33% and no DLI-related mortality was noted. After a median follow-up of 68.7 months from first DLI the estimated 8-year progression-free survival (PFS), and overall survival (OS) in a landmark analysis was 43% (95% confidence interval [CI], 28% to 57%) and 67% (95% CI, 53% to 82%), respectively, with best outcome for patients who acquired molecular remission (8-year PFS was 62% and 8-year OS was 83%). Prophylactic escalating DLI in a selected cohort of MM patients to prevent relapse after allograft resulted in a low incidence of severe GVHD and encouraging long-term results, especially if molecular remission is achieved.

Impact of Molecular Genetics on Outcome in Myelofibrosis Patients after Allogeneic Stem Cell Transplantation.

Molecular genetics may influence outcome for patients with myelofibrosis. To determine the impact of molecular genetics on outcome after allogeneic stem cell transplantation, we screened 169 patients with primary myelofibrosis (n = 110), post-essential thrombocythemia/polycythemia vera myelofibrosis (n = 46), and myelofibrosis in transformation (n = 13) for mutations in 16 frequently mutated genes. The most frequent mutation was JAK2V617F (n = 101), followed by ASXL1 (n = 49), calreticulin (n = 34), SRSF2 (n = 16), TET2 (n = 10), U2AF1 (n = 11), EZH2 (n = 7), MPL (n = 6), IDH2 (n = 5), IDH1 (n = 4), and CBL (n = 1). The cumulative incidence of nonrelapse mortality (NRM) at 1 year was 21% and of relapse at 5 years 25%. The 5-year rates progression-free (PFS) and overall survival (OS) were and 56%, respectively. In a multivariate analysis CALR mutation was an independent factor for lower NRM (HR, .415; P = .05), improved PFS (HR, .393; P = .01), and OS (HR, .448; P = .03). ASXL1 and IDH2 mutations were independent risk factors for lower PFS (HR, 1.53 [P = .008], and HR, 5.451 [P = .002], respectively), whereas no impact was observed for "triple negative" patients. Molecular genetics, especially CALR, IDH2, and ASXL1 mutations, may thus be useful to predict outcome independently from known clinical risk factors after allogeneic stem cell transplantation for myelofibrosis.

Ras signaling enhances the activity of C/EBP alpha to induce granulocytic differentiation by phosphorylation of serine 248.

The transcription factor C/EBP alpha regulates early steps of normal granulocyte differentiation since mice with a disruption of the C/EBP alpha gene do not express detectable levels of the granulocyte colony-stimulating factor receptor and produce no neutrophils. We have recently shown that C/EBP alpha function is also impaired in acute myeloid leukemias. However, how the transcriptional activity of C/EBP alpha is regulated both in myelopoiesis and leukemogenesis is not fully understood. The current study demonstrates that activated Ras enhances the ability of C/EBP alpha to transactivate the granulocyte colony-stimulating factor receptor promoter and a minimal promoter containing only C/EBP DNA binding sites. Ras signaling activates C/EBP alpha via the transactivation domain because it enhances the transactivation function of a fusion protein containing a Gal4 DNA binding domain and the C/EBP alpha transactivation domain and does not change C/EBP alpha DNA binding. Ras acts on serine 248 of the C/EBP alpha transactivation domain, because it does not enhance the transactivation function of a C/EBP alpha serine 248 to alanine point mutant. Interestingly, serine 248 of C/EBP alpha is a protein kinase C (PKC) consensus site, and a PKC inhibitor blocks the activation of C/EB alpha by Ras. Ras signaling leads to phosphorylation of C/EBP alpha in vivo. Finally, mutation of serine 248 to alanine obviates the ability of C/EBP alpha to induce granulocytic differentiation. These data suggest a model where Ras signaling enhances the activity of C/EBP alpha to induce granulocytic differentiation by phosphorylation of serine 248.