Daigo Akahane

The JAK2 V617F tyrosine kinase mutation in myelodysplastic syndromes (MDS) developing myelofibrosis indicates the myeloproliferative nature in a subset of MDS patients

The JAK2 V617F tyrosine kinase mutation in myelodysplastic syndromes (MDS) developing myelofibrosis indicates the myeloproliferative nature in a subset of MDS patients

Speciation of arsenic trioxide penetrates into cerebrospinal fluid in patients with acute promyelocytic leukemia

We assessed concentrations of arsenic trioxide (As(2)O(3)) and its metabolites in the plasma and cerebrospinal fluid in acute promyelocytic leukemia patients who achieved complete remission with intravenous As(2)O(3). Arsenic trioxide exists as high molecular mass proteins and low molecular mass proteins in the plasma, and metabolites seem to be able to penetrate blood-brain barrier. Methylarsonic acid (MA) in the cerebrospinal fluid is stably detected and its level was higher than that in plasma after As(2)O(3) treatment. Trivalent arsenic (AS(III)) and dimethylarsinic acid (DMA) became detectable after As(2)O(3) infusion, though the levels of arsenic metabolites in the cerebrospinal fluid was lower than plasma levels. Results suggest that a combinatory treatment of As(2)O(3) with other chemotherapeutics could be effective for APL patients with CNS involvement.

JAK2(V617F) mutational status as determined by semiquantitative sequence-specific primer-single molecule fluorescence detection assay is linked to clinical features in chronic myeloproliferative disorders.

JAK2 V617F mutational status as determined by semiquantitative sequence-specific primer-single molecule fluorescence detection assay is linked to clinical features in chronic myeloproliferative disorders

Human herpesvirus 6 reactivation on the 30th day after allogeneic hematopoietic stem cell transplantation can predict grade 2–4 acute graft‐versus‐host disease

Viral infections and their occult reactivation occasionally cause not only organ damage, but also exacerbation of acute graft‐versus‐host disease (aGVHD), which may increase transplantation‐related mortality synergistically. To determine correlations between viral reactivation and transplantation‐related complications, we performed various viral screening tests on the 30th day after allogeneic hematopoietic stem cell transplantation (HSCT), and assessed the clinical implications.

Lymphadenopathy of IgG4-related sclerosing disease: three case reports and review of literature

Immunoglobulin (Ig) G4-related sclerosing disease is a recently described syndrome characterized by lymphoplasmacytic infiltration of exocrine glands or extranodal tissues and elevated serum IgG4. We report three cases of lymphadenopathy secondary to IgG4-related sclerosing disease. Histologic features of involved lymph nodes included interfollicular immunoblasts and plasma cells, similar to Castleman’s disease. The percentage of IgG4-/IgG-positive plasma cells in the three patients was markedly elevated (30, 50, and 60%). Administration of prednisolone led to remission in every case. One of three cases was consulted to our hospital due to suspected diagnosis of angioimmunoblastic T cell lymphoma (AITL). The case demonstrates many clinical and pathologic similarities between IgG4-related sclerosing disease and AITL. Pathological similarities between AITL and the lymphoplasmacytic subtype of IgG4-sclerosing disease have recently been reported. It is important to accurately diagnose IgG4-related lymphadenopathy given its ready response to steroid therapy and the potential for misdiagnosing lymphoma on clinical grounds.

Activity of a novel Aurora kinase inhibitor against the T315I mutant form of BCR-ABL: In vitro and in vivo studies

Despite promising results from clinical studies of ABL kinase inhibitors, a challenging problem that remains is the T315I mutation against which neither nilotinib nor dasatinib show significant activity. In the present study, we investigated the activity of a novel Aurora kinase inhibitor, VE‐465, against leukemia cells expressing wild‐type BCR‐ABL or the T315I mutant form of BCR‐ABL. We observed a dose‐dependent reduction in the level of BCR‐ABL autophosphorylation in VE‐465‐treated cells. Exposure to the combination of VE‐465 and imatinib exerted an enhanced apoptotic effect in K562 cells. Combined treatment with VE‐465 and imatinib caused more attenuation of the levels of phospho‐AKT and c‐Myc in K562 cells. Further, the isobologram indicated the synergistic effect of simultaneous exposure to VE‐465 and imatinib in K562 cells. To assess the in vivo efficacy of VE‐465, athymic nude mice were injected intravenously with BaF3 cells expressing wild‐type BCR‐ABL or the T315I mutant form. The vehicle‐treated mice died of a condition resembling acute leukemia by 28 days; however, nearly all mice treated with VE‐465 (75 mg/kg, twice daily; intraperitoneally for 14 days) survived for more than 56 days. Histopathological analysis of vehicle‐treated mice revealed infiltration of the spleen. In contrast, histopathological analysis of organs from VE‐465‐treated mice demonstrated normal tissue architecture. Taken together, the present study shows that VE‐465 exhibits a desirable therapeutic index that can reduce the in vivo growth of T315I mutant form and wild‐type BCR‐ABL‐expressing cells in an efficacious manner. (Cancer Sci 2008; 99: 1251–1257)

Identification and functional signature of genes regulated by structurally different ABL kinase inhibitors.

Dasatinib is an ATP-competitive, multi-targeted SRC and ABL kinase inhibitor that can bind BCR-ABL in both the active and inactive conformations. From a clinical standpoint, dasatinib is particularly attractive because it has been shown to induce hematologic and cytogenetic responses in imatinib-resistant chronic myeloid leukemia patients. The fact because the combination of imatinib and dasatinib shows the additive/synergistic growth inhibition on wild-type p210 BCR-ABL-expressing cells, we reasoned that these ABL kinase inhibitors might induce the different molecular pathways. To address this question, we used DNA microarrays to identify genes whose transcription was altered by imatinib and dasatinib. K562 cells were cultured with imatinib or dasatinib for 16 h, and gene expression data were obtained from three independent microarray hybridizations. Almost all of the imatinib- and dasatinib-responsive genes appeared to be similarly increased or decreased in K562 cells; however, small subsets of genes were identified as selectively altered expression by either imatinib or dasatinib. The distinct genes that are selectively modulated by dasatinib are cyclin-dependent kinase 2 (CDK2) and CDK8, which had a maximal reduction of <5-fold in microarray screen. To assess the functional importance of dasatinib regulated genes, we used RNA interference to determine whether reduction of CDK2 and CDK8 affected the growth inhibition. K562 and TF-1BCR-ABL cells, pretreated with CDK2 or CDK8 small interfering RNA, showed additive growth inhibition with imatinib, but not with dasatinib. These findings demonstrate that the additive/synergistic growth inhibition by imatinib and dasatinib may be mediated in part by CDK2 and CDK8.

Unrelated-Donor Bone Marrow Transplantation with a Conditioning Regimen Including Fludarabine, Busulfan, and 4 Gy Total Body Irradiation

We investigated the feasibility of reduced-intensity conditioning with 4 Gy total body irradiation, fludarabine (30 mg/m2 for 6 days), and busulfan (4 mg/kg for 2 days) for bone marrow transplantation from a serologically HLA-matched unrelated donor. Seventeen adult patients (median age, 55 years; range, 27-67 years) with various hematologic malignancies (6 in remission, 11 not in remission) were treated. Successful engraftment was achieved in all patients at a median of day 18 (range, day 14-35) after transplantation, although subsequent secondary graft failure was observed in 2 patients. The cumulative incidence of acute graft-versus-host disease (GVHD) of grades II to IV at day 100 was 48%. With a median follow-up of 286 days (range, 56-687 days), the rates of 1-year overall survival, 100-day nonrelapse mortality, and 1-year nonrelapse mortality were 41%, 14%, and 46%, respectively. Eleven patients died, and the causes of death were relapse (n = 4), pulmonary complications (n = 4), acute GVHD (n = 2), and sepsis (n = 1). The remaining 6 patients (at transplantation, 2 were in remission, and 4 were not in remission) are currently still in remission. These results suggest that this regimen reduces the risk of graft failure, but further studies are needed to ameliorate transplantation-related toxicities, primarily GVHD and/or pulmonary complications. cr 2007 The Japanese Society of Hematology

Reduced-intensity cord blood transplantation without prior remission induction therapy induces durable remission in adult patients with relapsed acute leukemia after the first allogeneic transplantation

To the Editor: Leukemia relapse following allogeneic stem cell transplantation (allo-SCT) remains a major cause of treatment failure (1, 2). Among treatment options, second allo-SCT appears to increase disease-free survival compared with other interventions (3). The most important factors influencing outcomes of second allo-SCT may be the length of remission after the first transplantation and age (2). While disease status may also be an important factor, the probability of remission by re-induction therapy is generally low for relapsed acute leukemia after allo-SCT (4, 5). Limited data exist on other factors, such as conditioning regimens or use of different donors (2). Reducedintensity conditioning (RIC) regimens are now widely used in umbilical cord blood transplantation (CBT) (6). However, few reports exist on the use of RIC regimens in second allo-SCT with CB to treat relapsed patients after first allo-SCT (7). We report the outcomes of RIC CBT without prior reinduction chemotherapy for 11 consecutive adult patients from 2007 to 2009 at our institution (Table 1). Seven had acute myeloid leukemia (AML) and four had acute lymphoblastic leukemia (ALL). Median duration between first SCT and relapse was 6 months (3–24). All but one underwent conditioning with fludarabine (125 mg ⁄m), L-PAM (80 mg ⁄m), and total-body irradiation (TBI; 4 Gy). To achieve the maximum graft-versus-leukemia effect, a relatively low concentration of continuous tacrolimus was used as graft-versus-host disease (GVHD) prophylaxis (mean concentrations for each 10-d period spanning days 1 to 40 were 8.9, 8.9, 10.2, and 9.8 ng ⁄mL, respectively). Six patients received minimal cytoreductive chemotherapy prior to or during conditioning to control the rapid increase in leukemic cells in peripheral blood. Median duration between relapse to second SCT was 37 d (22–60). Four were in complete remission (CR) at the last follow-up (15–37 months). Except for three patients who died early after the second SCT, eight achieved longer CR after the second SCT than after the first. According to the definitions for pre-engraftment immune reaction (PIR) (8) and hemophagocytic syndrome (HPS) following SCT (9), PIR was observed in all cases and HPS in seven. In 10 cases, prednisolone (median dose, 1 mg ⁄kg, ranging 0.2–6.9) was introduced for a short period immediately following the diagnosis of PIR to avoid HPS, which may correlate with graft failure of CB. Graft failure was observed in three patients, two of whom underwent further CBTs as salvage treatment. Complications included severe infections (bacterial, n = 4; viral, n = 5). Other toxicities greater than grade 2 included mucositis (n = 3), sinusoidal obstruction syndrome (n = 2), and generalized skin pain (n = 2). While high grade acute GVHD (III or IV) was not observed in the four patients maintaining CR, all had chronic GVHD. To the best of our knowledge, the largest studies of second allo-SCTs using CB included seven relapsed adult leukemia patients (10) and 22 pediatric (11) leukemia patients; none of the adults and 10 of the pediatric patients received RIC regimens. Compared with these two studies, the interval from first SCT to relapse in the surviving four patients maintaining CR was extremely short in our cohort; in three of four patients, it was 5 months. Compared with the first SCT, an extremely high incidence of PIR was observed with the second SCT (one case vs. all cases), whereas no difference was seen in the incidence of acute GVHD (grade II–IV) and chronic GVHD. Although the biological mechanisms are unclear, PIR is assumed to reflect alloimmune reaction and is observed frequently in CBTs. (8). While the use of CB and a relatively low tacrolimus concentration may have caused the high incidence of PIR and HPS, PIR may have contributed to the suppression of leukemic cells that remained in the early phase after the RIC regimen. Graft failure was a devastating complication that has recently been reported to be closely correlated with HPS following CBT (9). As we previously reported, two of three patients who suffered from graft failure and sepsis underwent successful salvage therapy with a one-day regimen using CB (12). However, further studies are needed to clarify how PIR and HPS should be controlled. LETTER TO THE EDITOR doi:10.1111/j.1600-0609.2010.01555.x European Journal of Haematology 86 (268–271)

Uncontrolled thrombocytosis in polycythemia vera is a risk for thrombosis, regardless of JAK2(V617F) mutational status.

Uncontrolled thrombocytosis in polycythemia vera is a risk for thrombosis, regardless of JAK2 V617F mutational status