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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.

Hemotropic mycoplasmas are common pathogens in animals, but it remains unclear what role these pathogens play in human infections. We report clinical and biologic characterization of Candidatus Mycoplasma haemohominis infection in a 42-year-old man in Japan. The patient had severe hemophagocytic syndrome 1 month after an accidental needlestick injury. Metagenomic deep sequencing identified Candidatus M. haemohominis and determined its draft genome for an isolate from serum of the patient. A high copy number of the Candidatus M. haemohominis genome was detected in serum and bone marrow samples. Electron microscopy examination showed morphologic characteristics of Candidatus M. haemohominis. Levofloxacin monotherapy induced resistance caused by a gyrase A gene mutation in the quinolone resistance–determining region, but a combination treatment with moxifloxacin and minocycline was effective. We identified Candidatus M. haemohominis in a patient who had life-threatening symptoms related to multiple organ infection. Human infection with this mycoplasma might occur more frequently than has been generally recognized.

The refined disease risk index (R-DRI) is a well-designed prognostic parameter that is based on only the disease type and status and is used for stratifying patients undergoing allogeneic hematopoietic stem cell transplantation (allo HSCT) into 4 risk groups. However, the application of the R-DRI for rare diseases has remained unclear.We evaluated 135 patients who underwent allo HSCT for hematological malignancies including rare diseases, such as acute leukemia of ambiguous lineage, acute T-cell leukemia/lymphoma, extranodal natural killer T-cell lymphoma, and lymphoblastic lymphoma, at our institute.According to the R-DRI, overall survival (OS) and progression-free survival at 2 years for patients with the low, intermediate, high, and very high groups were 66.7% and 66.7%, 60.8% and 56.0%, 27.1% and 23.7%, and 5.9% and 5.1%, respectively (P .0001 and P .0001, respectively). OS showed no significant difference between B-cell non-Hodgkin lymphoma (B-NHL) and T-cell non-Hodgkin lymphoma (T-NHL) (P = .71). Moreover, OS at 1 year was 80%, 14.3%, 60%, and 0% for the intermediate risk group, the very high-risk group of B-NHL, the intermediate risk group, and the high-risk group of T-NHL, respectively (P = .035).We showed the applicability of the R-DRI for hematological malignancies, including rare disorders. However, we suggest that T-NHL patients may be better to be assigned between the nodal group and the extranodal group in the R-DRI.

Post-transplant lymphoproliferative disorder (PTLD) and other iatrogenic immunodeficiency-associated lymphoproliferative disorders (OIIA-LPD) are iatrogenic lymphoproliferative disorders (LPD) that develop in association with immunosuppressive treatment in the setting of organ transplantation and autoimmune disease, respectively. Each has a spectrum of pathologies ranging from lymphoid hyperplasia to lymphoma. To clarify the characteristics of the diffuse large B-cell lymphoma (DLBCL) subtype in a cohort of 25 patients with PTLD or OIIA-LPD from our institute, we selected 13 with a histological subtype of DLBCL, including 2 cases of PTLD and 11 of OIIA-LPD. The median patient age at diagnosis was 70 years, with a female predominance. Both PTLD cases developed after kidney transplant. Of the patients with OIIA-LPD, 10 had rheumatoid arthritis, 1 had mixed connective tissue disease, and 8 were treated using methotrexate. Both of the PTLD patients and 6 of the OIIA-LPD patients had extranodal manifestations. All patients except for one were classified as having the non-germinal center B-cell (non-GCB) subtype according to the Hans algorithm. Tissue samples from 8 patients were positive for CD30 and 8 were positive for Epstein-Barr virus (EBV)-encoded small RNA. Seven patients had MYC-positive tissue samples, but none had MYC translocation. Our study suggests that extranodal manifestations and the non-GCB subtype are common, that EBV is associated with the DLBCL subtype of PTLD and OIIA-LPD, and that anti-CD30 therapy is applicable. In addition, our patients with the DLBCL subtype of PTLD and OIIA-LPD exhibited MYC overexpression without MYC translocation, suggesting an alternative mechanism of MYC upregulation.

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

The availability of alternative donor sources could allow elderly patients to receive allogeneic hematopoietic cell transplantation (HCT). We retrospectively evaluated the outcomes of single-unit cord blood transplantation (CBT) in 1577 patients aged ≥60 years with acute myeloid leukemia (AML) in Japan between 2002 and 2017. In total, 990 (63%) patients were not in complete remission (CR) at the time of CBT. A myeloablative conditioning regimen (52%) and calcineurin inhibitor (CI) + mycophenolate mofetil (MMF)-based graft-versus-host disease (GVHD) prophylaxis (45%) were more commonly used. With a median follow-up for survivors of 31 months, the probability of overall survival and the cumulative incidence of leukemia-related mortality at 3 years was 31% and 29%, respectively. The cumulative incidence of non-relapse mortality (NRM) at 100 days and 3 years were 24% and 41%, respectively. The cumulative incidences of grade II-IV and grade III-IV acute GVHD at 100 days and extensive chronic GVHD at 2 years were 44%, 16%, and 14%, respectively. The cumulative incidence of neutrophil engraftment was 80% at 42 days. Results of multivariate analysis indicated that the following factors were significantly associated with higher overall mortality: performance status ≥1, hematopoietic cell transplantation-specific comorbidity index ≥3, adverse cytogenetics, extramedullary disease at diagnosis, and non-CR status at CBT. By contrast, female sex, HLA disparities ≥2, mycophenolate mofetil-based GVHD prophylaxis, and recent CBT were significantly associated with lower overall mortality. In conclusion, single CBT offers a curative option for AML patients aged ≥60 years with careful patient selection.

To assess the influences of blood sampling volumes or sites on toxicological and toxicokinetic (TK) evaluations, 4-week duration animal studies and a single-dose TK study of imipramine were conducted. In the toxicological evaluation, six-week-old Sprague-Dawley rats were divided into no blood and blood sampling groups. Fifty microliters (microsampling) or 100 μL (larger sampling) of blood/time point was collected from the jugular vein (50 μL of data was reported previously as Yokoyama et al., 2020) or the tail vein 6 to 7 times on days 1/2 and in week 4. Although no parameters were affected by the 100 μL sample from the tail vein, the 100 μL jugular vein sampling decreased the red blood cell parameters in females, possibly due to hemorrhage at the sampling site. Regarding the TK assessment, 50 μL of blood/site/time point was collected at 6 time points from the tail and jugular vein of the same male rats after single oral administration of 10 or 100 mg/kg imipramine, which was selected as a representative drug with high distribution volume. Although there were no differences in the AUC0-24hr and Cmax values between the sites, the plasma concentrations at the early time points were significantly lower from the tail vein than the jugular vein. From our studies, 50 μL of jugular and tail vein microsampling did not affect the toxicity parameters or AUC/Cmax. However, appropriate toxicity considerations and/or selection of the blood sampling site may be important in the case of larger sampling volumes or blood concentration assessment.

Hemophagocytic lymphohistiocytosis (HLH) is an uncontrolled hyperinflammatory disorder driven by an overactive immune system that results in high mortality. Post-transplant-associated hemophagocytic lymphohistiocytosis (PT-HLH) is a type of secondary HLH that occurs following allogeneic hematopoietic stem cell transplantation (allo-HSCT). The clinical features of PT-HLH remain unclear and diagnostic and prognostic tools have not yet been established. Here, we retrospectively evaluated the clinical manifestations and outcomes of PT-HLH in 94 patients who underwent allo-HSCT. According to our PT-HLH criteria (hyperferritinemia and increased macrophage count in bone marrow), PT-HLH occurred in 12 patients (12.8%). The PT-HLH patients showed splenomegaly (P = .001), a higher risk of engraftment failure (P = .013), and an increased percentage of macrophages and hemophagocytes in bone marrow aspirates (P = .0009 and P = .0006, respectively). Moreover, univariate and multivariate analyses revealed that the survival rate was lower in PT-HLH patients than non-PT-HLH patients (P = .0017 and P = .034, respectively). This study defines the clinical features of PT-HLH and PT-HLH criteria that could be useful tools for diagnosing PT-HLH.

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.

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.

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.

The most common cause of death in patients with acute myeloid leukemia (AML) who receive allogeneic hematopoietic stem cell transplantation (allo-HSCT) is AML relapse. Therefore, additive therapies post allo-HSCT have significant potential to prevent relapse. Natural killer (NK)-cell-based immunotherapies can be incorporated into the therapeutic armamentarium for the eradication of AML cells post allo-HSCT. In recent studies, NK cell-based immunotherapies, the use of adoptive NK cells, NK cells in combination with cytokines, immune checkpoint inhibitors, bispecific and trispecific killer cell engagers, and chimeric antigen receptor-engineered NK cells have all shown antitumor activity in AML patients. In this review, we will discuss the current strategies with these NK cell-based immunotherapies as possible therapies to cure AML patients post allo-HSCT. Additionally, we will discuss various means of immune escape in order to further understand the mechanism of NK cell-based immunotherapies against AML.

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.

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.

Studies showed red cell distribution width (RDW) can improve the detection of morphological changes in red blood cells and the understanding of their contribution to dyserythropoiesis in myelodysplastic syndrome (MDS). The purpose of the study was to evaluate dyserythropoiesis in MDS by RDW analysis and to explore the utility of RDW in clinical practice. We retrospectively analyzed laboratory and clinical data of 101 patients (59 patients was refractory anemia (RA) according to the French-American-British (FAB) classification). In patients with RA, RDW was showed weak inverse correlation with both hemoglobin concentration (Hb) (rs = −0.37, P = 0.0035) and mean corpuscular hemoglobin concentration (MCHC) (rs = −0.36, P = 0.0047). On the other hand, RDW was showed weak correlation with the number of ringed sideroblasts in bone marrow (rs = 0.31, P = 0.023). The increased RDW (≥15.0%) was associated with shorter overall survival (OS) (P = 0.0086). In patients with refractory anemia with excess blasts (RAEB) and RAEB in transformation (RAEB-t), effect of RDW on OS was less evident. These results suggested that increased RDW might reflect dyserythropoiesis, associated with deregulated hemoglobin synthesis and iron metabolism in MDS. Furthermore, increased RDW may have potential to be a prognostic significance in RA.

Cord blood transplantation (CBT) is an alternative approach to allogeneic stem cell transplantation. However, CBT is associated with issues including pre-engraftment immune reaction (PIR), engraftment syndrome (ES), and graft failure (GF). Tacrolimus (TAC) and short-term methotrexate (sMTX: days 1, 3, 6, and/or 11) are used for graft-versus-host disease (GVHD) prophylaxis during CBT; however, sMTX does not accelerate neutrophil engraftment. Therefore, we hypothesized that lower doses of sMTX [very-short-term MTX (vsMTX): 10 and 7mg/m(2) on days 1 and 3, respectively] with TAC reduce the risk of GF without increasing post-transplantation immune reactions during CBT. We retrospectively analyzed 40 patients who received TAC with vsMTX for GVHD prophylaxis. PIR and ES developed in 4 patients. The cumulative incidence of neutrophil engraft at day 60 was 92.5%. No cases of primary graft failure were noted. The cumulative incidence of grades II-III GVHD was 48.1% at day 100, and the cumulative 100-day incidence of nonrelapse mortality was 12.5%. This study suggests that TAC with vsMTX reduces the risk of PIR and ES during CBT and stimulates neutrophil engraftment, but may be associated with slightly higher aGVHD compared with calcineurin inhibitor and sMTX. Therefore, we recommend vsMTX plus TAC as an option for GVHD prophylaxis during CBT.

It is difcult to predict the clinical outcome of gemtuzumab ozo- gamicin (GO) therapy based solely on the previously identified predictive factors. We retrospectively analyzed the relationship between clinical factors and outcomes in 12 patients with relapsed or refractory acute leukemia who received GO monotherapy. The median patient age at initial GO infusion was 56 years, and the average initial dosage was 8.1 mg/m 2 . Four patients (33%) achieved an overall remission (OR) . The time from diagnosis to GO infusion was signicantly longer in patients with OR than in patients with no remission (NR)(1747 vs. 501 days, respectively ; P < 0.01) . The number of karyotype abnormalities before GO infusion was signicantly greater in NR patients (9.5) than in OR patients (0.5 ; P = 0.03) . Monocyte counts in the bone marrow before GO therapy were signicantly lower in OR than in NR patients (100/ µL vs. 1080/μL, respectively ; P = 0.048) . In a multivariate analysis, monocyte count was signicantly associated with overall survival (P = 0.005) . CD14 expression in OR patients was lower than in NR patients, with the exception of 4 patients whose French-American-British subtypes were M4 or M5 (OR, 0.3% ; NR, 2.5% ; P = 0.04) . NR was noted in all 6 patients who underwent allogeneic stem cell transplantation before and/or after GO infusion. Patients showing good sensitivity to conventional chemotherapy with good survival after diagnosis tend to be sensitive to GO as well. A low monocyte count in the bone marrow at infusion of GO might indicate improved efcacy of GO therapy. Further investigation is warranted for establishing appropriate patient selection and for clarifying efcient conditions for GO therapy.

Predictive role of levels of soluble interleukin-2 receptor and C-reactive protein in selecting autologous PBSC transplantation for lymphoma

Both clonal hematopoiesis as defined by genomic alteration and morphological cell dysplasia is a hallmark of pathology of myelodysplastic syndrome (MDS). Studies showed that, red cell distribution width (RDW), a quantitative non-subjective index of red cell anisocytosis, has diagnostic significance in anemia associated with MDS. Our recent study showed that increase of RDW has close association with dyserythropoiesis and also shorter overall survival (OS) in refractory anemia (Leuk Res 2018;67:56-59). To explore the clinical significance of RDW in MDS without increased blasts, we examined the details of correlation between RDW and morphological dysplasia which characterize MDS. We retrospectively analyzed 101 MDS patients, including 66 patients without increased blasts (blasts in the bone marrow of less than 5% and the peripheral blood of 1% or less). RDW was calculated using automated blood cell analyzer. Dysplasia was assessed according to the WHO 2008 classification by different two investigators. 100 cells (at least 25 cells) of myeloid and erythroid series were counted. At least 25 cells of megakaryocyte were also counted. Karyotype of bone marrow cells was analyzed by using routine G-band technique and categorized according to MDS cytogenetic scoring system. Correlations of RDW and clinical variables were analyzed. Based on previous study, MDS patients was divided into two groups, RDW-H (RDW was 15% or more, 48 cases) and RDW-L (RDW was lower than 15%, 18 cases). Comparisons of dysplasia or OS between these two groups were analyzed. In MDS without increase of blasts, weak inverse correlation was found between RDW and hemoglobin (rs = −0.31, P = 0.01). RDW was correlated with the presence of ring sideroblasts (RS) in the bone marrow (rs = 0.40, P = 0.001), and also weakly correlated with budding of nucleus of erythroblasts (rs = 0.33, P = 0.007). Dysgranulopoiesis was less observed than either dyserythropoiesis or dysmegakaryopoiesis (P Table showed the subtype of MDS, details of morphological dysplasia. Between two groups, RDW-H showed significantly higher percentages of dyserythropoiesis, dysgranulopoiesis, and dysmegakaryopoiesis. The increased RDW (≥15.0%) was associated with shorter OS (P = 0.02) (hazard ratio, 1.15e + 9 (95% confidence interval = 2.49-2.49)) (Figure). In contrast, there was no association between RDW and OS in MDS patients with increased blasts. Earlier studies showed increase of RDW was evident in refractory anemia with ring sideroblasts (RARS) which showed erythrocyte anisocytosis called dimorphism. Revised WHO classification (2017) defined MDS-RS with single lineage dysplasia (MDS-RS-SLD) which is characterized with specific mutation of splicing factors, such as SF3B1 and with favorable prognosis. This classification also defined MDS-RS with multi lineage dysplasia (MDS-RS-MLD) which has additional dysplasia in myeloid and/or megakaryocyte lineage in addition to RS. Pathology of MDS-RS-MLD is still to be remained. Our findings partly agree the earlier observations, showing close association between red cell anisocytosis evaluated with increase of RDW and the presence of RS. Furthermore, RDW-H group contained MDS with dysplasia of myeloid and/or megakaryocyte lineage not limited to the erythroid dysplasia(s) with RS. RDW could discriminate MDS-MLD with poor prognosis from MDS-SLD with favorable prognosis. To explore the significance of RDW in MDS, it is necessary to study large number of patient combined with genetic analysis. Nevertheless, RDW is potentially simple and useful laboratory parameters in clinical practice in MDS, representing hematopoietic defect (ineffective hematopoiesis), associated with iron metabolism and hemoglobin synthesis in MDS. Disclosures No relevant conflicts of interest to declare.

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.

Rituximab with chemotherapy improves survival of non-germinal center type untreated diffuse large B-cell lymphoma

Allogeneic stem cell transplantation (allo-SCT) is used as curative therapy for malignant lymphoma, and reduced-intensity hematopoietic stem cell transplantation (RIST) is sometimes performed to avoid the toxicity and mortality associated with myeloablative allo-SCT. RIST is generally preferred for elderly patients with malignant lymphoma. A 62-year-old woman with follicular lymphoma (FL) involving bone marrow (BM) suffered relapse after autologous SCT. RIST was performed; cells were from an unrelated, fully human leukocyte antigen-matched donor. To study the hematopoietic reconstitution, BM biopsy specimens that were obtained at different times after RIST, were evaluated. Engraftment of donor cells was observed on days 19 and 48 after RIST, and residual FL in BM had completely disappeared by day 73 after RIST. This is the first report to document histological BM regeneration after RIST and disappearance of FL involving the BM.

Background: The aberrant expression of the interleukin-3 receptor (IL3RA or CD123) alpha chain is frequently observed in a subset of leukemic disorders, including acute myeloid leukemia (AML), particularly in leukemia stem cells. Using flow cytometric (FCM) analysis, studies have shown that increased CD123 expression is associated with a poor prognosis of AML. Although FCM is a sensitive technique, the analysis may be limited in a clinical setting because live leukemia cells are required. Immunohistochemistry (IHC) is a more useful alternative compared with FCM because it can be tested long after specimens are collected; however, it is less sensitive. Here we evaluated the impact of blast CD123 expression via IHC analysis for the prognosis of AML. Patients and methods: This study was performed as a retrospective analysis of 70 patients who were diagnosed with de novo AML (M0-M5, n = 48) and AML with myelodysplasia-related changes (MRC) (n = 22) at our hospital from February 2008 to September 2015. The median age at diagnosis was 64.5 years (range: 21-93 years). The median follow-up period was 498 days (range: 2-3052 days). Morphological findings were obtained using HE stains of 3-µm sections. Formalin-fixed, paraffin-embedded specimens were used for immunohistochemical analysis. We analyzed the relationships between the patients' clinical outcome and CD123, p53, CD34, CD71, CD56, and c-kit expressions. [(CD123, CD34, CD71, CD56, and c-kit immunostained slides were defined as positive if >10% of the blast cells had a moderate to strong membranous staining. p53 was evaluated as positive when more than 5% of the cells were positively stained. For each case, the following data were obtained: patient age (>60 years or Results: Of the 70 cases, percentages of the positive immunohistochemical study dates were as follows: CD123: 25.7%; p53: 30%; CD34: 52.8%; CD71: 46.3%; CD56: 25.7%; and c-kit: 77.1%. There were 48 cases with de novo AML: CD123: 29.1%; p53: 75%; CD34: 52%; CD71: 37.5%; CD56: 27%; and c-kit: 79.1%. Moreover, there were 22 cases with MRC: CD123: 18.1%; p53: 31.8%; CD34: 54.5%; CD71: 66.6%; CD56: 22.7%; and c-kit: 72.7%. CD71 is highly expressed in MRC than de novo AML (P = 0.036). Among all patients, the CR rate following first induction therapy was 62.3%. Age (≥60 years), high p53 expression, disease (MRC), and poor karyotype were associated with induction failure (P = 0.011, P = 0.002, P Conclusion: This is the first study to demonstrate that CD123 expression using IHC is associated with poor a CR rate and OS in de novo AML patients; however, this association was not observed in MRC patients. Our results suggest that CD123 expression may predict the refractory to induction therapy and poor OS in de novo AML. Moreover, these results support previous reports using FCM. Therefore, CD123 expression may become one of the important factors used to characterize leukemia blasts and predict the prognosis of AML. In addition, novel therapy with antibodies targeting CD123 is currently under development. Therefore, we suggest that an analysis of CD123 expression using IHC is a clinically important assessment for de novo AML patients at the time of diagnosis. Disclosures No relevant conflicts of interest to declare.

Background: Bendamustine has demonstrated a favorable efficacy and toxicity profile in relapsed or refractory indolent lymphoma. Limited information is available regarding the prognostic factors (particularly laboratory parameters) of bendamustine treatment, although studies have shown a relationship between the hampered effect of bendamustine and an increase in lactate dehydrogenase (LDH) levels. Therefore, we retrospectively evaluated clinical and laboratory factors immediately prior to initiating bendamustine treatment and analyzed its correlation with the clinical outcome among patients with relapsed or refractory indolent lymphoma. Patients and methods: We analyzed 55 relapsed or refractory indolent lymphoma patients who had been treated with bendamustine alone (n = 19) or rituximab plus bendamustine (n = 36) at our hospital from 2000 to 2015. The median age at diagnosis was 65 years and the median follow-up period was 552.5 days. Histological analysis revealed follicular lymphoma (n = 21), mantle cell lymphoma (n = 10), MALT lymphoma (n = 7), lymphoplasmacytoid lymphoma (n = 5), and other low-grade B cell lymphomas (n = 4). We further analyzed the relationships between the clinical outcome [overall response rate (ORR), complete response (CR), progression-free survival (PFS), and overall survival (OS)] and clinical data, including sex, patient age (≥65 years), performance status (≥2), IPI (≥HI), FLIPI (≥HI), no. of previous therapies (≥2), prior purine analogue treatment, response to last treatment, and laboratory parameters [white blood cell count (≥5000/µl), lymphocyte count (≥1000/µl), platelet count (≥10000/µl), LDH (elevated or normal), sIL-2R (elevated or normal), and CRP (elevated or normal)], before starting bendamustine treatment. Results: The median number of cycles of bendamustine was 4 (range: 1-8). The ORR was 80.3% with a CR of 39.2%. Moreover, the CR rate was significantly worse in patients who had elevated sIL-2R and CRP, high or high-intermediate IPI scores, and a high WBC count (P = 0.002, P < 0.001, P = 0.072, and P < 0.046, respectively). Among follicular lymphoma patients, elevated CRP was only associated with a low CR rate (P = 0.028). In multivariate analysis, sIL-2R, CRP, and a high WBC count were all significantly associated with a worse CR rate (P = 0.044, P = 0.002, and P = 0.032, respectively). The 1- and 2- year OS rates were 80.3% and 76.1%, respectively. The OS was significantly higher in a group of the patients who obtained CR after bendamustine, were treated with rituximab plus bendamustine, and did not receive prior purine analogue treatment (P = 0.007, P = 0.008, and P < 0.001, respectively). An elevated CRP was associated with worse OS (P = 0.055). In multivariate analysis, only CR after bendamustine was significantly associated with improved OS (P = 0.023). The 1- and 2-year PFS rates were 69.2% and 60.5%, respectively. PFS was significantly better in patients who obtained CR after bendamustine treatment, had a normal CRP, had not received more than 2 previous therapies, and had a good performance status (P < 0.001, P = 0.007, P = 0.031, and P = 0.033, respectively). In multivariate analysis, any prognosis factors were significantly associated with PFS. Conclusion: This is the first study to demonstrate a correlation between laboratory parameters (i.e., CRP and sIL-2R) and the clinical outcome in patients with relapsed or refractory indolent lymphoma who were treated with bendamustine. In this study, CRP and sIL-2R levels as well as the WBC count were associated with the CR rate. In addition, the CRP levels were associated with OS and PFS, but LDH levels were not associated with any clinical outcomes. Previous studies have reported that the elevation of serum CRP and sIL-2R levels were associated with poor OS or PFS in patients who were treated with rituximab combined with CHOP in diffuse large B-cell lymphoma or follicular lymphoma. Our study indicates that serum CRP and sIL-2R levels are also important laboratory parameters for patients with indolent lymphoma who underwent bendamustine treatment. Disclosures No relevant conflicts of interest to declare.

Acute promyelocytic leukemia (APL) is a subtype of myeloid leukemia characterized by differentiation block at the promyelocyte stage. Besides the presence of chromosomal rearrangement t(15;17), leading to the formation of PML-RARA (promyelocytic leukemia-retinoic acid receptor alpha) fusion, other genetic alterations have also been implicated in APL. Here, we performed comprehensive mutational analysis of primary and relapse APL to identify somatic alterations, which cooperate with PML-RARA in the pathogenesis of APL. We explored the mutational landscape using whole-exome (n=12) and subsequent targeted sequencing of 398 genes in 153 primary and 69 relapse APL. Both primary and relapse APL harbored an average of eight non-silent somatic mutations per exome. We observed recurrent alterations of FLT3, WT1, NRAS and KRAS in the newly diagnosed APL, whereas mutations in other genes commonly mutated in myeloid leukemia were rarely detected. The molecular signature of APL relapse was characterized by emergence of frequent mutations in PML and RARA genes. Our sequencing data also demonstrates incidence of loss-of-function mutations in previously unidentified genes, ARID1B and ARID1A, both of which encode for key components of the SWI/SNF complex. We show that knockdown of ARID1B in APL cell line, NB4, results in large-scale activation of gene expression and reduced in vitro differentiation potential.

Paclitaxel, an antineoplastic agent, was administered intravenously to pregnant Crj: CD (SD) rats daily at dose levels of 0 (saline and vehicle), 0.15, 0.3 and 0.6 mg/kg from day 7 to day 17 of gestation. Results were as follows: 1. The ossification of hyoid bodies was retarded in F1 fetuses by the vehicle. However, the vehicle-treated group had no effect in the other parameters that were measured in this study when compared to the saline-treated group. 2. Body weight gains and food consumption in F0 dams were not affected by paclitaxel during the gestation and lactation periods. 3. Paclitaxel failed to affect the organ weights in F0 dams. 4. Paclitaxel did not alter the prenatal development in F1 fetuses. 5. External, internal and skeletal malformations were not induced by paclitaxel. Further, paclitaxel did not affect the skeletal variations and ossification processes. 6. Paclitaxel did not alter the delivery status of F0 dams or viability and weaning indices in F1 pups. 7. The day required for presence of hair was significantly delayed in 0.6 mg/kg F1 pups at paclitaxel. However, the days required for pinnae detachment, incisor eruption, eye opening, testicular descent and vaginal opening were not affected by paclitaxel. 8. No effects on body weight gains or food consumption were observed in both male and female F1 rats. 9. Paclitaxel did not alter the developmental behavior, learning ability and memory, spontaneous motor activity or emotionality in F1 rats. 10. The reproductive performance in both male and female F1 rats were not affected by paclitaxel. 11. Paclitaxel did not alter the organ weights in both male and female F1 rats. 12. No influence on prenatal development was observed for F2 fetuses even at the highest dose level of paclitaxel. Based on the reproductive and developmental indices, the no toxic-effect dose level of paclitaxel is 0.6 mg/kg/day and 0.3 mg/kg/day for dams (F0) and their offspring (F1), respectively.

Paclitaxel, an antineoplastic agent, was given to Crj: CD (SD) rats of both sexes at 38, 50, 65 and 85 mg/kg by single intravenous administration to investigate its acute toxicity. The results obtained are summarized as follows: 1. Tachypnea and decreased activity with prone position were noted for vehicle and all paclitaxel groups, and alopecia for all paclitaxel groups. 2. Deaths occurred for one out of 5 males and 2 out of 5 females at 85 mg/kg. One female died of respiratory insufficiency induced by vehicle on Day 0. One female and one male died of the systemic toxicity of paclitaxel such as hypoplasia of the bone marrow and lymphoid depletion of lymphatic organs on Days 6 and 12, respectively. 3. On Days 4 and 5, all paclitaxel groups showed decreases of reticulocyte and white blood cell counts, as well as decrease of differential count of neutrophils. These changes were generally recovered by a week after dosing. 4. Histopathological examinations revealed atrophy of the thymic medulla, hypoplasia of the bone marrow and lymphoid depletion of the spleen for a few males at 85 mg/kg, and hypospermatogenesis and tubular atrophy of the testes for all paclitaxel groups. Based on these results, 85 mg/kg of paclitaxel was lethal to rats, and hematopoietic, lymphoid and male reproductive systems were primarily affected under this condition.

Background: Rituximab with cyclophosphamide, doxorubicin, vincristine, and prednisolone every 21 days (R-CHOP-21 therapy) has been the standard therapy for diffuse large B-cell lymphoma (DLBCL) over the last decade. However, the optimal number of CHOP cycles has not been confirmed, as there is no evidence regarding the comparison of outcomes according to the number of R-CHOP-21 cycles. Methods: We analyzed patients with de novo DLBCL in clinical stage II or more; they were diagnosed between November 2002 and December 2012 at our institutions and were treated with 6 or 8 R-CHOP or R-CHOP-like cycles as a first-line regimen for a historical cohort study. Progression free survival (PFS) between 6 and 8 R-CHOP cycles was compared. To avoid patients treated with additional cycles of the therapy for treatment failure, those with ≤6-month PFS were excluded. To adjust for selection bias of patient characteristics between the 6 and 8 cycle groups, propensity scores were calculated using variables including IPI risk factors and laboratory data at diagnosis. Results: In total, 233 patients (male 128, female 105) were enrolled. Median age at diagnosis was 68.7 years (22–93 years). Of these, 150 and 83 patients received 6 and 8 cycles, respectively. Clinical stages were II (n = 91), III (n = 58), and IV (n = 84); revised IPI were very good risk (n = 14), good risk (n = 88), and poor risk (n = 131). No significant differences were detected in PFS between patients treated with 6 cycles and those treated with 8 cycles according to Cox regression analysis using inverse-probability-of-treatment weighting method, based on the propensity scores (HR 1.05; 95% CI 0.68–1.64; P = 0.82). Conclusions: Eight R-CHOP or R-CHOP-like cycles were not superior to 6 cycles. Thus, 6 R-CHOP cycles is sufficient for the majority of patients with untreated DLBCL. A criterion for selecting optimal number of R-CHOP cycles is needed for patients belonging to specific risk groups.

Dear Editor, Cold agglutinin disease (CAD) is an uncommon autoimmune hemolytic anemia characterized by the production of cold agglutinins (CA) [1]. CA exhibits the strongest affinity for the antigen at 0–4°C but binding may occur at temperatures approaching the normal body temperature of mammals, depending on the thermal amplitude of the antibody. Rituximab has been demonstrated to be useful in treating CAD that is refractory to conventional therapies [2]. However, CA titers did not concur with the observed clinical and hematologic responses, and it has become apparent that the CA titer is not an important index for the clinical features of CAD. The detailed effect(s) of rituximab on CAD have not been reported. We present a case of a 68-year-old man who was diagnosed with Waldenstrom’s macroglobulinemia with CAD in 1999, in whom the thermal amplitude was improved after rituximab treatment. His Hb level was 4.9 g/dL, and an immunoglobulin M (IgM) kappa monoclonal protein was evident at diagnosis (IgM, 58.2 g/L). His bone marrow was diffusely infiltrated with CD20+ lymphoplasmacytoid lymphocytes. The direct antiglobulin test was positive for complement (C3d). CAwas positive with a titer of 8,192 at 4°C. He underwent six courses of cyclophosphamide, adriamycin, vinctistine, and prednisolone and low-dose prednisolone up to July 2007. Due to worsening anemia with acrocyanosis, he was treated with rituximab alone at 375 mg/m four times every 8 weeks. Although the CAD-related symptoms were improved, the high-CA titers at 4°C remained. He relapsed 42 weeks after the initial treatment, and the duration to response was 10 months. After informed consent was obtained, we determined the agglutination titer and tested the thermal amplitude of the patient’s plasma and serum, as described previously [3]. As shown in Table 1, 4 weeks after the initial injection of rituximab, increases of hemoglobin and improvement of the thermal amplitude of the antibody were observed simultaneously. Up to 24 weeks later, the improvement of the thermal amplitude remained. Hemoglobin increased progressively up to 28 weeks. Based on the changes of the thermal range in reactivity of the antibody, the clinical sign(s), such as acrocyanosis, improved along with amelioration of the symptoms related to anemia. Temperatures of 30°C and lower normally occur in the superficial skin vessels of the parts of the body exposed to cold air or water. The thermal range of the antibody is more important than the agglutination titer for clinical symptoms [4]. The present findings suggested that both elevation of hemoglobin and resolution of clinical sign(s) are closely associated with improvement of thermal amplitude of the CA after rituximab treatment. The present case suggested that hemoglobin was elevated as a consequence of the improvement of thermal amplitude after rituximab treatment. Schoellkopf et al. observed a significant and persistent reduction of serum IgM concentration after rituximab Ann Hematol (2010) 89:103–104 DOI 10.1007/s00277-009-0773-z

Introduction Overall survival (OS) of B-cell lymphoma patients, including diffuse large B-cell lymphoma (DLBCL), has markedly improved since the development of rituximab. Rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) have been established as the standard initial therapy for DLBCL patients over past 10 years. However, investigation of risk factors for new prediction models for DLBCL patients in the rituximab-era has been limited. Thus, the International Prognostic Index (IPI) has been used over past 20 years for risk stratification of lymphomas, and although it retains some usefulness, the revised IPI model cannot identify the poor prognosis group with 5-year OS of < 40%. This study aimed to verify risk factors for survival and responses to R-CHOP or R-CHOP-like therapy in DLBCL patients, and to construct a new prediction model to supplant the IPI model. Methods A historical cohort study comprised patients with de novoDLBCL who received R-CHOP or R-CHOP-like therapy as initial therapy at our institutions between January 2002 and July 2013. A retrospective analysis was performed to identify the pre-therapy risk factors for survival and lymphoma progression. Transformed DLBCL and intravascular large B-cell lymphoma patients were excluded. Results Study comprised 254 patients (145 males, 109 females). Median age at diagnosis was 70.0 years (range 20–96 years). Response rates in patients to first regimen of therapy were as follows: 80.7%, CR (n = 205); 9.1%, PR (n = 23); 1.2%, SD (n = 3); and 9.1%, PD (n = 23). Ann Arbor clinical stage was as follows: 42 (16%) patients. stage I; 60 (24%), stage II; 47 (18%), stage III; and 105 (41%), stage IV. B symptom was observed in 40 (16%) patients and a bulky mass in 38 (15%). The revised IPI indicated 23 (9%) very good, 88 (35%) good, and 143 (56%) poor risk cases. In 235 patients, we categorized 80 cases as germinal center B-cell-like (GCB) type and 155 cases as non-GCB type using Hans’s algorithm of immunohistochemistry. Autologous peripheral blood stem cell transplantation was performed in 18 patients. Initial therapy that included radiation was performed in 29 patients. 5-year OS was 59.3% and 5-year progression-free survival (PFS) was 48.7%. According to the revised IPI, 5-year OS was stratified as 100%, very good; 69.2%, good; and 46.4%, poor (P< 0.001). Based on univariate analysis using Log-rank tests, significant poor prognostic factors for OS were as follows: B symptom positivity (P = 0.003), hemoglobin< 12.0 g/dL (P< 0.001), albumin < 4.0 g/dL (lower limit of normal; P< 0.001), C-reactive protein (CRP) > 0.6 mg/dL (P< 0.001), soluble IL-2 receptor (sIL-2R) > 2000 U/mL (P< 0.001), and non-GCB type (P = 0.03) along with all IPI factors including age ≥ 61 (P< 0.001), Ann Arbor clinical stage ≥ 3 (P = 0.005), lactate dehydrogenase (LDH) > 220 IU/L (upper limit of normal; P< 0.001), ECOG performance status ≥ 2 (P< 0.001), and number of extranodal disease sites ≥ 2 (P = 0.02). In multivariable analysis for 235 patients using Cox proportional hazards model including 11 previously noted factors, age (P = 0.003), CRP (P = 0.04), hemoglobin (P< 0.001), and albumin (P = 0.02) were significant. Step-down procedure in multivariable analysis also identified these 4 factors, age [hazard ratio (HR) 2.84, P = 0.002], CRP (HR 2.10, P = 0.003), hemoglobin (HR 2.36, P< 0.001), and albumin (HR 2.16, P = 0.008), as significant in 254 patients. These 4 factors were used to define the ACHA (Age-CRP-Hemoglobin-Albumin) score. ACHA scores stratified 5-year OS as 100%, 82.1%, 64.3%, 51.4%, and 22.3%, and 5-year PFS as 93.9%, 71.2%, 51.5%, 37.3%, and 14.6% as 0 (n = 34), 1 (n = 46), 2 (n = 48), 3 (n = 66), and 4 (n = 60) of the ACHA scores, respectively (OS, P< 0.001: PFS, P< 0.001). Conclusions Although predictive power of this scoring system should be validated using another data set, ACHA scoring factors at diagnosis stratified expected survivals. ACHA was constructed without Ann Arbor staging; thus, computed tomography scanning and bone marrow examination were not required for risk stratification. Moreover, this predictive scoring system could extract poor prognosis patients with 5-year OS < 30% and patients highly likely to be resistant to R-CHOP or R-CHOP-like regimen with 5-year PFS < 20%. New therapy regimens that improve OS for such patients with very poor predicted prognosis are required. Disclosures: No relevant conflicts of interest to declare.

Pervious in vitro studies have shown that molecular alterations of BCR-ABL-positive leukemia cells such as amplification of BCR-ABL gene and/or mutation(s) of abl kinase domain cause resistant to imatinib. However recent study showed that alterations of imatinib bioavailability might be a important factor to cause clinical resistant in BCR-ABL-positive leukemia patients, showing a differences between in vivo and in vitro sensitivity to imatinib of BCR-ABL-positive cells. To analyze mechanism(s) of clinical resistance to imatinib and to overcome the resistance, we have sequentially established and characterized two leukemia cell lines from a patient with myeloid blastic crisis of chronic myeloid leukemia (CML) who showed progressively resistant to imatinib. Case report and establishment of cell lines: a 59-years-old women developed blastic crisis preceded by four years of chronic phase of CML. Increased blasts in crisis was positive for CD13, 33 and showed double Ph-chromosome in addition to complexed chromosomal alterations such as, add(3)(p13), add(3)(q11), add(5)(q11), der(19)(3;19) (p21;q13). After repeated courses of combination chemotherapy including, 600mg of imatinib was administered orally in combination with chemotherapeutic drugs. For a brief period Imatinib showed clinical effects and slowed the increase of BCR-ABL-positive cells, however myeloblast progressively increased in peripheral blood in spite of daily administration of imatinib and she died four months treatment with imatinib. Two myeloid leukemia cell lines, NS-1 and NS-2 were established, after obtaining informed consent, from peripheral blood at day 65 and day 95 after initiation of imatinib administration, respectively. Cell surface phenotype and karyotype of these cell lines were identical to original blasts. NS-1 and NS-2 cell lines were characterized compared with BCR/ABL-positive K562 erythroleukemia cell line as a control Quantitative analysis by real-time polymerase chain reaction showed that copy number of BCR-ABL transcript were 2.2 × 105 and 1.6 × 10 5/μg RNA in NS-1 and NS-2 respectively, showing slightly lower than those (5.8 × 105) in K562 cell line. Although nucleotide sequence analysis showed that a point mutation in abl kinase domain resulted in amino acid substitution pro310ser in NS-1 cell line, no additional mutation was found in NS-2 cell line. Western blot analysis showed levels of both 210 KD BCR-ABL protein and BCR-ABL phosphorylation were similar in NS-1, NS-2 and K562 cells. Although two hours incubation with 10 mM imatinibin vitro did not show any detectable difference in levels of phosphorylation of BCR-ABL protein between NS-1 and NS-2 cell lines, sensitivity to imatinib measured by MTT assay showed that IC50 was 0.1 mM, 0.5 mM and 1.0mMin NS-1, NS-2 and K562 cell lines respectively. The measured IC50 of both NH-1 and NH-2 cell lines were much lower than reported plasma concentrations achieved by oral administration of 600 mg of imatinib (above 10 μM). The present results suggest difference between in vivo and in vitro sensitivity to imatinib indicate that alteration of bioavailability of imatinib possibly involved in clinical resistance to this drug, accumulations of BCR-ABL gene amplification and/or mutation are not necessarily a major reason of progressive clinical resistance to imatinib in BCR-ABL positive leukemia.

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disorder that can be classified into at least three subgroups according to DNA microarray-based expression profiles: germinal center B-cell-like (GC) type, activated B-cell-like type, and type 3. Immunohistochemistry used to determine the GC and non-GC subtypes of DLBCL and to predict survival show results similar to those of cDNA microarray analysis. There are a few reviews of the treatment effect of rituximab in relation to immunohistological protein expression, but there are no reports comparing clinical outcomes of GC-type DLBCL with non-GC-type DLBCL for patients treated with rituximab plus chemotherapy. We analyzed relations between the treatment effect of rituximab plus conventional chemotherapy and immunohistochemically determined subtypes in cases of untreated DLBCL. Immunohistochemical stain results for CD10, bcl-6 and MUM1 were used to subclassify the case as same as previous reported studies. Sixty-nine patients were divided into 2 treatment groups, rituximab plus TCOP (cyclophosphamide, therarubicin, vincristine, and prednisolone) (R-TCOP) and TCOP alone. The R-TCOP group included 38 patients (12 women, 26 men; age range, 53–89 years; mean age, 68.1 years); median follow-up of surviving patients was 13 months. The TCOP group included 31 patients (15 women, 16 men; age range, 45–88 years; mean age, 66.4 years); median follow-up of surviving patients was 25 months. Of the 69 DLBCLs, 26 (38%) were considered GC type and 43 (65%) were considered non-GC type by immunohistochemical analysis. In the R-TCOP group, 18 (48%) DLBCLs were classified as GC type and 20 (52%) were classified as non-GC type. In the TCOP group, 8 (26%) DBLCLs were classified as GC type and 23 (74%) cases were classified as non-GC type. Overall survival (OS) was significantly longer for patients treated with R-TCOP than for those treated with TCOP alone (P=0.002). In both the R-TCOP and TCOP groups, no significant difference in OS was observed between GC-type and non-GC-type DLBCLs (P=0.36 and P=0.16, respectively). Among GC-type cases, OS did not differ significantly between the two treatments, but among non-GC DLBCLs, OS was significantly longer for patients treated with R-TCOP than for those treated with TCOP alone (P=0.005). Furthermore, among the low IPI, non-GC-type cases, OS did not differ significantly between the two treatments (P=0.8), but among the high IPI, non-GC-type cases, a significant difference was observed between the two treatments (P=0.008). In prior studies, the addition of rituximab to conventional chemotherapy was shown to improve outcome in patients with DLBCL. Our findings suggest that these improved outcomes may be due primarily to the beneficial effect of rituximab added to chemotherapy on non-GC DLBCLs, especially when the IPI is high. The non-GC type includes activated B-cell-like DLBCL, which is characterized by activation of NF-kappa B target genes. Rituximab inhibits the constitutive nuclear factor-kappa B signaling pathway in non-Hodgkin lymphoma cell lines; therefore, we believe our results point to the clinical importance of NF-kappa B as a therapeutic target for DLBCL.