Comparative Study of Tacrolimus and Short-Term Methotrexate: 2-Day versus 3-Day Methotrexate as Graft-versus-Host-Disease Prophylaxis after Umbilical Cord Blood Transplantation in Adults.

Methotrexate (MTX) in combination with a calcineurin inhibitor has been commonly used for prophylaxis of graft-versus-host disease (GVHD) following umbilical cord blood transplantation (UCBT) in Japan. However, the appropriate prophylactic MTX dosage in UCBT has not been established to date. To determine the preferential GVHD prophylaxis in UCBT, this study retrospectively investigated the administration of short-term MTX for 2 days versus 3 days. Of 103 adult patients submitted to UCBT enrolled in the study, 73 received tacrolimus (TAC) with 2 days of MTX given at 10 mg/m2 on day 1 and 7 mg/m2 on day 3 (very short-term [vs] MTX), whereas 30 patients received TAC with 3 days of MTX given at 10 mg/m2 on day 1, 7 mg/m2 on day 3, and 7 mg/m2 on day 6 (short-term [s] MTX). In univariate analysis, neutrophil engraftment was shown to be significantly better (P = .039) in the vsMTX/TAC group. Among high-risk patients, the vsMTX/TAC group also exhibited earlier neutrophil engraftment (P = .042); however, the incidence of acute GVHD was higher in the vsMTX/TAC group (P = .035) on univariate analysis. In multivariate analysis, compared with sMTX/TAC, vsMTX/TAC was associated with lower risk of relapse (hazard ratio, .27; 95% confidence interval, .11 to .64; P = .003) . These results suggest that vsMTX/TAC can be appropriate GVHD prophylaxis after UCBT, especially in higher-risk patients.

Monitoring TIGIT/DNAM-1 and PVR/PVRL2 Immune Checkpoint Expression Levels in Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia.

After allogeneic stem cell transplantation (alloSCT), several immune checkpoints play an important role in the antileukemic immune response in the bone marrow (BM) microenvironment. However, immune checkpoint expression levels in the BM have not been reported after alloSCT in patients with acute myeloid leukemia (AML). We investigated the clinical impact of immune checkpoint expression in BM samples after alloSCT for AML. Higher expression of T cell immunoreceptor with Ig and ITIM domains (TIGIT) was associated with a decreased incidence of acute graft-versus-host disease (P = .048) and poor overall (P = .046) and progression-free survival (P = 0.024). In addition, higher expression of TIGIT at engraftment after alloSCT was correlated with a decreased number of natural killer cells in BM (P = .019). Monitoring TIGIT expression in the BM could be useful for predicting outcome after alloSCT for AML. Our findings raise the possibility that blockade of TIGIT would improve survival.

Improved prognosis of extranodal NK/T cell lymphoma, nasal type of nasal origin but not extranasal origin.

Extranodal NK/T cell lymphoma (NKTCL), nasal type (ENKL) that shows no apparent nasal involvement, is termed extranasal NKTCL or non-nasal NKTCL. In this study, we aimed to explore therapeutic approaches and outcomes in patients with extranasal NKTCL in current clinical practice. A data set of patients with newly diagnosed NKTCL who were diagnosed at 31 institutes in Japan between 2000 and 2013 was used for analysis. The patients' fitness for steroid, methotrexate, ifosfamide, L-asparaginase, and etoposide (SMILE) chemotherapy was assessed using the major inclusion criteria of the SMILE phase 2 study. Of 358 patients, 47 (13%) had extranasal NKTCL. The most frequent extranodal sites of involvement in extranasal NKTCL were skin/subcutaneous tissue (n = 18). Six (13%) of the patients with extranasal NKTCL had localized disease and were diagnosed before 2010. With a median follow-up of 5.8 years, the 2-year overall survival (OS) in patients with nasal and extranasal NKTCL was 70% (95% confidence interval [CI], 65-75%) and 34% (95% CI, 21-47%), respectively. OS in patients with nasal NKTCL had a trend toward better according to treatment era (P = 0.063). In contrast, no obvious improvement of OS was observed in extranasal NKTCL (P = 0.43). The major inclusion criteria of the SMILE-P2 were met in 21% (10/47) of patients with extranasal NKTCL and 60% (188/311) of those with nasal NKTCL (P < 0.001). Despite the advent of new treatments for ENKL, OS remains unfavorable in extranasal NKTCL. A more effective therapy is needed for extranasal NKTCL.

[Development of cardiac tamponade and emergence of arrhythmia during chemotherapy for diffuse large B-cell lymphoma].

Cardiac involvement during lymphoma often causes complications, including arrhythmia. A 68-year-old male with cardiac tamponade was diagnosed with diffuse large B-cell lymphoma with cardiac involvement based on the presence of the tumor mass in the myocardium and lymphoma cells in the pericardial effusion. He developed atrial fibrillation, ventricular tachycardia, and atrial flutter after initiating chemotherapy. Following chemotherapy, sinus rhythm was restored without invasive treatment for arrhythmia, while the cardiac mass disappeared. No recurrent arrhythmias were observed. In lymphoma with cardiac involvement, unexpected arrhythmias can emerge after initiation of chemotherapy, which could potentially be related to accelerated cardiac remodeling owing to the rapid relief of cardiac damage. Follow-up using electrocardiogram is thus necessary during chemotherapy for cardiac lymphoma, despite the absence of arrhythmia at the time of diagnosis.

Early disease progression in patients with localized natural killer/T-cell lymphoma treated with concurrent chemoradiotherapy.

Prognosis of patients with localized nasal extranodal natural killer/T-cell lymphoma, nasal type (ENKL) has been improved by non-anthracycline-containing treatments such as concurrent chemoradiotherapy (CCRT). However, some patients experience early disease progression. To clarify the clinical features and outcomes of these patients, data from 165 patients with localized nasal ENKL who were diagnosed between 2000 and 2013 at 31 institutes in Japan and who received radiotherapy with dexamethasone, etoposide, ifosfamide, and carboplatin (RT-DeVIC) were retrospectively analyzed. Progression of disease within 2 years after diagnosis (POD24) was used as the definition of early progression. An independent dataset of 60 patients with localized nasal ENKL who received CCRT at Samsung Medical Center was used in the validation analysis. POD24 was documented in 23% of patients who received RT-DeVIC and in 25% of patients in the validation cohort. Overall survival (OS) from risk-defining events of the POD24 group was inferior to that of the reference group in both cohorts (P < .00001). In the RT-DeVIC cohort, pretreatment elevated levels of serum soluble interleukin-2 receptor (sIL-2R), lactate dehydrogenase, C-reactive protein, and detectable Epstein-Barr virus DNA in peripheral blood were associated with POD24. In the validation cohort, no pretreatment clinical factor associated with POD24 was identified. Our study indicates that POD24 is a strong indicator of survival in localized ENKL, despite the different CCRT regimens adopted. In the treatment of localized nasal ENKL, POD24 is useful for identifying patients who have unmet medical needs.

Status of Natural Killer Cell Recovery in Day 21 Bone Marrow after Allogeneic Hematopoietic Stem Cell Transplantation Predicts Clinical Outcome.

Rapid immune recovery following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is important for clinical outcome prediction. In most studies, immune recovery after allo-HSCT is monitored via peripheral blood. However, few reports regarding the status of absolute lymphocyte subsets in the bone marrow (BM) microenvironment have been undertaken. Therefore, we evaluated the clinical impact of immune recovery in the early period following allo-HSCT using BM samples. We showed that delayed natural killer cell recovery was independently associated with a poor prognosis for overall survival (hazard ratio [HR], 3.07; 95% confidence interval [CI], 1.37- 6.89; P = .007), progression-free survival (HR, 3.42; 95% CI, 1.47-7.94; P = .004), and nonrelapse mortality (HR, 6.68; 95% CI, 1.82-25.0; P = .004) by multivariate analysis. In addition, low NK cell counts were associated with the presence of 1 or more bacterial, viral, or fungal infections. Our results indicate that investigating absolute lymphocyte subsets in BM in the early phase following allo-HSCT can be useful for predicting and improving survival outcomes.

Association of Soluble Interleukin-2 Receptor and C-Reactive Protein with the Efficacy of Bendamustine Salvage Treatment for Indolent Lymphomas and Mantle Cell Lymphoma.

Bendamustine has demonstrated favourable efficacy in relapsed or refractory indolent lymphoma and mantle cell lymphoma. We retrospectively evaluated the pre-treatment clinical and laboratory factors and their correlation with the clinical outcome of these lymphomas. We analysed 53 patients who had been treated with bendamustine alone (n = 6) or rituximab plus bendamustine (n = 47). The overall response rate was 81.1%, with a complete response (CR) rate of 39.6%. The CR rate was significantly low in patients who had elevated levels of soluble interleukin-2 receptor (p = 0.024) and C-reactive protein (CRP; p = 0.004). The 1-year overall survival (OS) rate was 79.3%. An elevated CRP was associated with a short OS (p = 0.056). The present findings suggest that the lymphoma microenvironment and immune response were involved in the effects of bendamustine. These findings are also important in order to understand the pathophysiology of refractory lymphoma and to find effective strategies using bendamustine.

Efficacy of palonosetron to prevent delayed nausea and vomiting in non-Hodgkin's lymphoma patients undergoing repeated cycles of the CHOP regimen.

PURPOSE: Few studies have investigated the effect of palonosetron on delayed chemotherapy-induced nausea and vomiting in lymphoma patients receiving the CHOP regimen. We conducted a prospective clinical trial to assess the efficacy of palonosetron in patients receiving the CHOP regimen. METHODS: Complete control (CC: emesis-free and mild nausea) during delayed phase (24-120 h) was the primary endpoint. The secondary endpoint was complete response (CR: emesis-free) during acute (0-24 h), delayed, and overall phases (0-120 h), and CC during acute and overall phases. Palonosetron (0.75 mg) was administered before chemotherapy on day 1 of both the first and second CHOP cycles. RESULTS: The efficacy of palonosetron in preventing emesis was evaluated in 40 patients. Across two cycles, over 85% of patients achieved CR. As the primary endpoint, the proportion of patients achieving CC in the delayed phase increased from 70% (cycle 1) to 85% (cycle 2). CR rate in the delayed phase increased from 85% (cycle 1) to 95% (cycle 2). CONCLUSION: These results suggest that the antiemetic effects during the delayed phase were inferior to those in the acute phase during the first cycle. However, even at the same dose of palonosetron, CR and CC rates increased in the second cycle.

[Syndrome of inappropriate secretion of antidiuretic hormone in multiple myeloma patients treated with bortezomib, lenalidomide, and dexamethasone combination therapy].

Hyponatremia occurs while receiving bortezomib-containing combination therapy in multiple myeloma (MM) ; however, the mechanism of hyponatremia remains unclear. A 65-year-old female with MM was treated with bortezomib, lenalidomide, and dexamethasone. Fourteen days after chemotherapy initiation, she developed hyponatremia (serum sodium, 127 mEq/l, compared with 136 mEq/l before chemotherapy) with plasma hypo-osmolality and urine hyper-osmolality. She exhibited neither dehydration nor adrenal insufficiency. Her serum arginine vasopressin peptide (AVP) level was 1.5 pg/ml. She was diagnosed with syndrome of inappropriate secretion of antidiuretic hormone (SIADH), wherein causative roles of inflammatory cytokines were strongly suggested in the development because (1) SIADH was triggered by the cessation of the dexamethasone treatment and (2) hyponatremia was successfully treated with prednisolone, which was administered for the complication of drug eruption. Perhaps, bortezomib-induced immune reactions could be involved in a subset of hyponatremia during bortezomib-containing antimyeloma chemotherapy.

Age and Bone Marrow Cellularity are Associated with Response to Eltrombopag in Japanese Adult Immune Thrombocytopenia Patients: A Retrospective Single-Center Study.

In the present retrospective single-center study, we examined the efficacy and safety of eltrombopag, a thrombopoietin (TPO) -receptor agonist (TPO-RA), and found clinical factors associated with its efficacy in Japanese patients with chronic immune thrombocytopenia (ITP). According to the definition of a response, which is to attain a platelet count of more than 50,000/µL at least once during eltrombopag treatment, 42 enrolled patients were divided into two groups: responders (29 patients, 69%) and non-responders (13 patients, 31%). In analyses of the clinical and laboratory data of these two groups, we extracted two factors that are significantly associated with a better response to eltrombopag, which have not been recognized previously, namely, (1) an older age of patients at eltrombopag initiation (≥ 70 years old) and (2) normal or decreased cellularity of iliac bone marrow (BM) biopsy at diagnosis. The significance of patient age contradicts previous findings from studies in which the Caucasian population was the major focus. However, factors such as changes of pharmacokinetics might modulate the effects of eltrombopag in older patients in Japan because East Asians show higher bioavailability of eltrombopag by as-yet-unknown mechanisms. BM cellularity in ITP may represent an impairment and/or lower responsiveness of pluripotent hematopoietic stem cells, not limited to the megakaryocyte (MgK) -platelet axis, to endogenous TPO, because recent evidence shows that TPO-RA can successfully restore hematopoiesis in aplastic anemia. These results should be useful for the therapeutic use of TPO-RA for ITP and also related thrombocytopenia in Japan.

CD20 gene deletion causes a CD20-negative relapse in diffuse large B-cell lymphoma.

In diffuse large B-cell lymphoma (DLBCL), a CD20-negative relapse is clinically significant because it is associated with chemo-refractory phenotypes and loss of a therapeutic target. The alteration of the CD20 gene is reported as infrequent in CD20-negative relapse in B-cell lymphoma. We established a DLBCL cell line with loss of CD20 expression (SD07) from a patient at CD20-negative relapse. She was initially diagnosed with CD20-positive DLBCL and received repeated immuno-chemotherapy that included rituximab. SD07, which has an immunoglobulin κ rearrangement identical to that of lymphoma cells at CD20-negative relapse, showed homozygous deletion of the CD20 gene with loss of the copy number of 11q12. SD07 is the first case in which it is proven that the loss of CD20 expression in relapsed DLBCL is the result of deletion of the CD20 gene. Deletion of the CD20 gene is a molecular mechanism of CD20-negative relapse in a subset of DLBCL.

[Bilateral renal infiltration of acute lymphoblastic leukemia cells at relapse after allogeneic stem cell transplantation].

A 44-year-old male patient was diagnosed with acute lymphoblastic leukemia (CD10+, CD19+, CD20 weak) and underwent unrelated bone marrow transplantation (uBMT) with a conditioning regimen of cyclophosphamide plus total body irradiation during first complete remission (CR). Twenty months post-uBMT, the serum creatinine level (Cre) increased gradually, up to ≥ 1.5 mg/dl at 23 months. Since the increase in Cre was observed continuously, imaging examinations were performed and showed significant bilateral enlargement of the kidneys. Renal biopsy showed diffuse invasion of TdT, CD10 and CD19 positive lymphoid cells in the tubulo-interstitial region. Since leukemia cells were observed in the bone marrow, it was diagnosed as relapse in the bone marrow and kidney. Following reinduction chemotherapy, both kidneys returned to normal size. The patient entered into a second CR, but relapse occurred 6 months thereafter. The patient underwent uBMT again with a reduced-intensity conditioning regimen and CR has been maintained up to 5 months post-second uBMT. Although it is considered rare for relapse to occur with diffuse enlargement of both kidneys, as shown in this case, it is important to confirm the state of the kidney by performing blood tests and image diagnosis during the early phase, when renal dysfunction of an uncertain cause occurs after transplantation.

Increased serum C-reactive protein is an adverse prognostic factor in low-risk myelodysplastic syndromes.

Inflammatory cytokines play a role in hematopoiesis and development of myelodysplastic syndromes (MDS). Although increased serum levels of inflammatory cytokines are associated with poor survival in MDS patients, clinical management does not include assessment of inflammation. We investigated the significance of inflammation in MDS using serum C-reactive protein (CRP) levels, an indicator of the degree of systemic inflammation that can be used in routine practice. We hypothesized that serum CRP levels can be used to further classify low-risk MDS. We conducted a retrospective analysis of 90 patients with low-risk MDS, defined by the international prognostic scoring system (IPSS). We examined the prognostic relevance of CRP and known prognostic factors at diagnosis. Increased serum CRP (≥ 0.58 mg/dL) was associated with poor survival (hazard ratio [HR]: 17.63, 95% confidence interval [CI] 5.83-53.28, P < 0.001) both overall and among the 73 patients with low-risk MDS as defined by the revised IPSS (HR: 28.05, 95% CI 6.15-128.04, P < 0.001). Increased CRP might predict poor prognosis and serum CRP levels can indicate clonal hematopoiesis and non-hematological comorbidity in patients with low-risk MDS.

Elevated C-reactive protein level is associated with poor prognosis in follicular lymphoma patients undergoing rituximab-containing chemotherapy.

Although follicular lymphoma (FL) is a pathological entity characterized by relatively uniform histological and molecular findings, its clinical course is highly variable. Establishment of therapeutic strategies based on a simple and practical prognostic model is important. C-reactive protein (CRP) is an adverse prognostic marker for various tumors and aggressive lymphomas. However, the significance of serum CRP levels as a prognostic index in low-grade lymphomas, such as FL, has not been thoroughly investigated. We retrospectively analyzed the relationship between serum CRP levels at diagnosis and the prognosis in patients with FL (n = 61) undergoing rituximab-containing chemotherapy. Elevated CRP levels showed a significant association with elevated fibrinogen (P = 0.002) in univariate analysis. Patients with higher CRP levels (> 5 mg/L) had a significantly shorter progression-free survival in multivariate analysis (P = 0.044). We concluded that serum CRP levels are important in prognostic stratification of patients with FL.

Outcome of 93 patients with relapse or progression following allogeneic hematopoietic cell transplantation.

Relapse/progression after allogeneic hematopoietic cell transplantation (allo-HCT) remains the major cause of treatment failure. In this study, the subsequent clinical outcome was overviewed in 292 patients with leukemia/myelodysplastic syndrome who received allo-HCT. Among them, 93 (32%) showed relapse/progression. Cohort 1 was chosen to receive no interventions with curative intent (n = 25). Cohort 2 received reinduction chemotherapy and/or donor lymphocyte infusion (n = 48), and Cohort 3 underwent a second allo-HCT (n = 20). Sixty-three patients received reinduction chemotherapy, and 27 (43%) achieved subsequent complete remission (CR). The incidence of nonrelapse mortality (NRM) was similar among the three cohorts (4, 15, and 5%). The 1-year overall survival (OS) after relapse was significantly better in patients with a second HCT (58%) than in others (14%, Cohorts 1 and 2; P <.001). However, the 2-year OS did not differ between the two groups, which suggests that it is difficult to maintain CR after the second HCT. Multivariate analysis showed that reinduction chemotherapy, CR after intervention, second HCT, and longer time to post-transplant relapse were associated with improved survival. In conclusion, for patients with relapse after allo-HCT, successful reinduction chemotherapy and a second HCT may be effective for prolonging survival without excessive NRM. However, effective measures to prevent disease progression after a second HCT clearly need to be developed.

Risk factors and timing of autologous stem cell transplantation for patients with peripheral T-cell lymphoma.

High-dose chemotherapy with autologous stem cell transplantation (HDC-ASCT) is an option for patients with peripheral T-cell lymphoma (PTCL); however, neither prospective nor retrospective studies support proceeding with ASCT upfront, and the timing of HDC-ASCT remains controversial. We retrospectively analyzed the risk factors for outcomes of 570 patients with PTCL, including PTCL not otherwise specified (PTCL-NOS) and angioimmunoblastic T-cell lymphoma (AITL), who received ASCT for frontline consolidation (n = 98 and 75, respectively) or alternative therapies after either relapse (n = 112 and 75) or primary induction failure (PIF; n = 127 and 83) between 2000 and 2015. Significant risk factors for overall survival (OS) after upfront ASCT were a ≥ 2 prognostic index for T-cell lymphoma (P < 0.001) and partial response (PR) at ASCT (P = 0.041) in PTCL-NOS patients, and > 60 years of age (P = 0.0028) and PR at ASCT (P = 0.0013) in AITL patients. Performance status of ≥ 2 at ASCT (P < 0.001), receiving ≥ 3 regimens before ASCT (P = 0.018), and PR at ASCT (P = 0.018) in PTCL-NOS patients and > 60 years of age at ASCT (P = 0.0077) in AITL patients were risk factors for OS after ASCT with a chemosensitive PIF status. Strategies that carefully select PTCL patients may allow identification of individuals suitable for ASCT.

Impact of CD123 expression, analyzed by immunohistochemistry, on clinical outcomes in patients with acute myeloid leukemia.

Aberrant expression of the interleukin-3 receptor alpha chain (IL3RA or CD123) is frequently observed in patients with a subset of leukemic disorders, including acute myeloid leukemia (AML), particularly in leukemia stem cells. We analyzed the relationships between immunohistochemical (IHC) expression, including that of CD123, and clinical outcomes. This study involved a retrospective analysis of 48 patients diagnosed with de novo AML (M0-M5, n = 48) at our hospital between February 2008 and September 2015. Among patients with de novo AML, CD123 expression was associated with a failure to achieve complete response (CR) to initial induction chemotherapy (P = 0.044) and poor overall survival (OS) (P = 0.036). This is the first study using IHC to demonstrate that CD123 expression is associated with a poor CR rate and poor OS in de novo AML patients. These results support previous reports using flow cytometry (FCM). CD123 expression may thus be useful for assessing AML patients' prognoses. At the time of diagnosis, CD123 expression analysis using IHC may represent a clinically useful assessment for de novo AML patients.

Impact of T cell chimerism on clinical outcome in 117 patients who underwent allogeneic stem cell transplantation with a busulfan-containing reduced-intensity conditioning regimen.

Within the concept of reduced-intensity stem cell transplantation (RIST) there is a wide range of different regimens used, and little information is available on the clinical impact of chimerism status in patients conditioned with a busulfan-containing regimen. Therefore, we retrospectively reviewed lineage-specific chimerism and the subsequent clinical outcome in 117 patients (median age, 55 years; range: 29-68) who underwent busulfan-containing RIST. The conditioning regimen consisted of busulfan (oral 8 mg/kg or i.v. 6.4 mg/kg) and fludarabine (180 mg/m(2), n = 64) or cladribine (0.66 mg/kg, n = 53), with or without 2-4 Gy total-body irridiation (TBI) (n = 26) or antihuman T-lymphocyte immunoglobulin (ATG; 5-10 mg/kg; n = 31). Chimerism was evaluated with peripheral blood samples taken on days 30, 60, and 90 after transplantation by polymerase chain reaction (PCR)-based amplification of polymorphic short tandem repeat regions. The median follow-up of surviving patients was 1039 days (153-2535). The percent donor-chimerism was significantly higher in granulocyte than T cell fraction throughout the entire course, and the median (mean) values were, respectively, 100% (96%) versus 95% (83%), 100% (98%) versus 100% (89%), and 100% (98%) versus 100% (91%) at days 30, 60, and 90 after RIST. In a multivariate analysis, having received <2 types of chemotherapy regimens before RIST was the only factor that was significantly associated with low donor T cell chimerism (<60%) at day 30 (hazard ratio [HR]: 6.1; 95% confidence interval [CI], 2.1-18.4; P < .01). The median percentage of donor T cell chimerism at day 30 was 9% (0%-63%) in 5 patients who experienced graft failure, which was significantly lower than that (97%; 15%-100%) in the rest of the patients (P < .01). No correlation was found between the kinetics of T cell chimerism and the occurrence of acute or chronic GVHD (aGVHD, cGVHD). The stem cell source and the addition of TBI or ATG were not associated with the degree of T cell chimerism, overall survival (OS) or event-free survival (EFS). In a Cox proportional hazard model, low donor T cell chimerism of <60% at day 30 was associated with both poor OS (HR: 2.2; 95% CI, 1.1-4.5; P = .02) and EFS (HR: 2.0; 95% CI, 1.1-3.8; P = .02). In conclusion, we found that 43% of the patients retained mixed donor T cell chimerism (<90% donor) at day 30, whereas 92% achieved complete chimerism in granulocyte fraction. Low donor T cell chimerism of <60% at day 30 may predict a poor outcome, and a prospective study to examine the value of early intervention based on chimerism data is warranted.

Megakaryopoiesis and platelet function in polycythemia vera and essential thrombocythemia patients with JAK2 V617F mutation.

Patients with Ph chromosome negative myeloproliferative disease (Ph-MPD) have an increased risk of vascular complications. It remains controversial whether patients with the JAK2 V617F mutation (V617F) exhibit increased risk, while recent growing evidence has shown a critical role for V617F in clonal erythropoiesis in Ph-MPD. We studied 53 patients with Ph-MPD especially in relation to megakaryopoiesis, the thrombotic complications and the presence of V617F. Using novel mutation-specific PCR which is a highly sensitive PCR-based assay for detection of JAK2 mutated allele(s), we identified V617F in 38 Ph-MPD, which include 13 polycythemia vera (PV), 23 essential thrombocythemia (ET) and 2 chronic idiopatic myelofibrosis. The numbers of megakaryocytes were significantly increased in PV and ET patients with V617F, but the platelet counts were slightly lower. Although statistically not significant, the incidence of thrombotic events was higher in the group with V617F compared to in those without the mutation. Agonist-induced in vitro platelet aggregation and platelet adhesion were not affected by the presence of this mutation. Nonetheless, we found a hypercoagulable state in Ph-CMPD with V617F by employing whole blood thromboelastography. It suggests pre-thrombotic tendencies in CMPD are complex and JAK2 V617F mutation might have a role in vivo blood coagulation by altering not only the number, but function(s) of all three myeloid cells, including red blood cells, white blood cells and platelets in Ph-CMPD.

Histopathology of bone marrow reconstitution after umbilical cord blood transplantation for hematological diseases.

To study hematopoietic reconstitution in umbilical cord blood transplantation (CBT), bone marrow (BM) histology was investigated in 35 biopsies after bone marrow transplantation (BMT) and in 40 biopsies after CBT. BM biopsies were obtained at different times after transplantation and were evaluated for cellularity, number of megakaryocytes and CD34-positive cells, and fibrosis. In biopsies up to 29 days after BMT, cellularity was increased and megakaryocytes were observed, but at 29 days after CBT, biopsies showed severe cellular depletion and almost no megakaryocytes. In addition, fewer CD34-positive cells were observed after CBT compared to after BMT. After day 30 after CBT, hematopoietic recovery of the BM was gradually observed and after day 100 after transplantation, no essential differences were observed between BMT and CBT. Hematopoietic recovery of the BM after CBT was delayed compared to that after BMT, but engraftment of donor cells after CBT was also observed in histopathologically. To the best of the authors' knowledge this is the first histopathological description of BM reconstitution after CBT.