Graft-versus-leukemia effect with a WT1-specific T-cell response induced by azacitidine and donor lymphocyte infusions after allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Azacitidine (Aza) and donor lymphocyte infusion (DLI) therapy has recently been reported as an effective salvage therapy for relapsed acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). Despite the high response rate and relatively long period of remission, most patients relapse again. The immunologic mechanism of the response and limited efficacy remain unknown. CASE REPORT: Aza + DLI therapy was performed for a patient with therapy-related MDS (t-MDS), who had relapsed after allogeneic peripheral blood stem cell transplantation. We observed a powerful graft-versus-leukemia (GVL) effect accompanied by an evident Wilms tumor antigen 1 (WT1)-specific CD8 T-cell response. Remission continued for 15 months, but finally the patient relapsed. The kinetics of the WT1-specific CD8 T cells were inversely associated with WT1 messenger RNA (mRNA), suggesting a WT1-driven GVL effect. DISCUSSION: A difference of T-cell phenotype between the whole T cells and the WT1-specific CD8 T cells was observed. It is of note that the memory phenotype of the WT1-specific T cell was limited and decreased early. The immunoescape mechanism was partly supported by loss of the memory phenotype due to failure of expansion and differentiation. CONCLUSION: Our data suggested that a WT1-specific T-cell response at least partly contributes to the GVL effect induced by Aza + DLI. A strategy for maximizing and maintaining the memory phenotype of the CTL may be required for durable remission.

A Long-term Survivor after Congenital Acute Myeloid Leukemia with t(8 ; 16)(p11 ; p13).

The treatment of patients with congenital leukemia is difficult and often results in a poor prognosis. We present here the case of a female child with congenital acute myeloid leukemia (AML) with t(8 ; 16) (p11 ; p13) who received chemotherapy and survived for more than 10 years without relapse. A novel MOZ-CBP chimera was found in her diagnostic sample. Although adult AML patients with MOZ-CBP have mainly been reported as having therapy-related AML and showed poor prognoses, the present case supports the idea that AML with MOZ-CBP in the pediatric population might show better prognoses.

Transient myeloproliferative disorder with partial trisomy 21.

Myeloid malignancy with Down syndrome (ML-DS) is estimated to have a step-wise leukemogenesis including GATA1 mutation. Trisomy 21 is essential for ML-DS; however, we do not know exactly which gene or genes located on chromosome 21 are necessary for the ML-DS. We report a female infant with transient myeloproliferative disorder (TMD) and partial trisomy 21. SNP array analysis showed 10 Mb amplification of 21q22.12-21q22.3, which included DYRK1A, ERG, and ETS but not the RUNX1 gene. With two other reported TMD cases having partial trisomy 21, DYRK1A, ERG, and ETS were the most likely genes involved in collaboration with the GATA1 mutation.

The expression of cell adhesion molecule 1 and its splicing variants in Sézary cells and cell lines from cutaneous T-cell lymphoma.

Cell adhesion molecule 1 (CADM1) is aberrantly expressed by T-cell neoplasms such as adult T-cell leukemia/lymphoma (ATLL) and mycosis fungoides (MF). We studied the expression of CADM1 and its splicing variants in Sézary syndrome (SS), MF, other cutaneous T-cell lymphoma (CTCL), and cell lines derived from T- and B-cell lymphomas. Soluble CADM1 was measured in the patients' sera. CADM1+ cells in the blood and skin lesions were examined by flow cytometry and immunostaining, respectively. Soluble CADM1 was measured by ELISA, and the splicing variants of CADM1 transcripts were determined by reverse transcriptase-polymerase chain reaction, followed by sequencing. As a result, circulating CADM1+ cells were significantly increased in seven out of 10 patients with SS, ranging from 7.9% to 74.5% of the CD3+CD4+ fractions (median 33.7%; cut-off value 6.5%). The percentages of CADM1+ cells were usually less than those of circulating Sézary cells. CADM1 was expressed, to various degrees, in six of nine T-cell lines derived from SS, MF, ATLL, and anaplastic large cell lymphoma (ALCL), but negative in B-cell lymphoma-derived cell lines. CADM1+ cells were present in the skin infiltrates of MF, SS, ATLL and ALCL. Serum levels of soluble CADM1 were not significantly elevated in SS/MF. Three major splicing variants of CADM1 expressed by neoplastic T-cells contained different combinations of the exons 7, 8, 9 and 11, including a putative oncogenic variant composed of exons 7-8-9-11. In conclusion, CADM1 is frequently expressed in Sézary cells and cell lines from CTCL.

ABL kinase mutation and relapse in 4 pediatric Philadelphia chromosome-positive acute lymphoblastic leukemia cases.

The tyrosine kinase inhibitor (TKI) imatinib mesylate (IM) revolutionized the treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-ALL), which had showed poor prognosis before the dawn of IM treatment. However, if Ph-ALL patients showed IM resistance due to ABL kinase mutation, second-generation TKI, dasatinib or nilotinib, was recommended. We treated 4 pediatric Ph-ALL patients with both IM and bone marrow transplantation (BMT); however, 3 relapsed. We retrospectively examined the existence of ABL kinase mutation using PCR and direct sequencing methods, but there was no such mutation in all 4 diagnostic samples. Interestingly, two relapsed samples from patients who were not treated with IM before relapse did not show ABL kinase mutation and IM was still effective even after relapse. On the other hand, one patient who showed resistance to 3 TKI acquired dual ABL kinase mutations, F359C at the IM-resistant phase and F317I at the dasatinib-resistant phase, simultaneously. In summary, Ph-ALL patients relapsed with or without ABL kinase mutation. Furthermore, ABL kinase mutation was only found after IM treatment, so an IM-resistant clone might have been selected during the IM treatment and intensive chemotherapy. The appropriate combination of TKI and BMT must be discussed to cure Ph-ALL patients.