Naomi Rahimi-Levene

Conventional dose fludarabine-based regimens are effective but have excessive toxicity in elderly patients with refractory chronic lymphocytic leukemia.

The best approach to elderly patients with relapsing chronic lymphocytic leukemia (CLL) or disease refractory to conventional therapy with alkylating agents has not yet been established. Fludarabine and its combination with mitoxantrone and/or cyclophosphamide, which is the most effective treatment in younger patients, has not been extensively utilized in the elderly CLL. Here we report our results with fludarabine-based chemotherapy in 32 previously treated patients over the age of 65 years. The overall response rate was 59% with no complete remission, 3 nodular partial remissions and 16 partial remissions. The median time to progression of disease was 7 months. Only 10 patients completed the entire treatment program, because of poor compliance due to toxicity. Eight patients developed neutropenic fever, 14 severe bacterial infections and 2 patients showed progressive encephalopathy. For comparison, in a younger group of patients with refractory CLL (<65 years), 38 of 50 patients completed the treatment plan, and the ORR was 80% (10 CR, 11 PR-nodular, 19 PR) with a median response of 12 months. Neutropenic fever was diagnosed in 10 and severe bacterial infection in 4 patients. In conclusion, fludarabine-based chemotherapy is effective for refractory CLL, however, excessive toxicity such as severe infections and neurological complications, do not allow completion of treatment in the majority of the elderly patients. Because maintenance of a good quality of life should be the main goal in the elderly CLL population, dose reduction of fludarabine and the appropriate use of myeloid growth factors and prophylactic antibiotics appear mandatory in this group of patients.

Enhanced generation of monocyte tissue factor and increased plasma prothrombin fragment1+2 levels in patients with polycythemia vera: Mechanism of activation of blood coagulation

Polycythemia vera (PV) is associated with a high incidence of thrombosis. The association of apparent and secondary polycythemia with thrombosis is not clear. It was suggested that activation of the coagulation system contributes to thrombus formation in PV. However, the mechanism of activation is unknown. Monocytes generate a potent tissue factor (TF) upon stimulation with various substances, which is involved in thrombus formation in various disorders. Therefore, we studied the possibility that the factor is involved in the activation of coagulation and thrombus formation also in PV. Unstimulated peripheral blood mononuclear cells (PBMC) from each of the different types of polycythemia expressed weak TF activity (2 U) and antigen (41.4 to 52.9 pg/ml), which were similar to normal controls. Following stimulation with endotoxin, PBMC from normal controls and from apparent and secondary polycythemia showed a 3.9‐ to 4.5‐fold increase in TF, while cells from PV showed a 21‐fold increase (P < 0.001). Similar levels were generated by PBMC after treatment of PV and at the spent phase. TF was generated by monocytes but not by lymphocytes. Plasma prothrombin fragment1+2 (F1+2) levels, assayed at the same time, were significantly higher in PV (2.46 nm) compared to normals and apparent and secondary polycythemia (0.22 to 0.32 nm), and were in a significant correlation with monocyte TF activity and antigen levels (r = 0.77, 0.87). The high levels of F1+2 confirm that the coagulation system is activated in PV. The increased capacity of monocytes to generate TF may be responsible for the activation of the coagulation system and thrombus formation. The hypercoagulability state that is induced by this mechanism suggests that long‐life oral anticoagulation should be considered once thrombosis has been developed in PV. Am. J. Hematol. 56:5–11, 1997

The onset of p53-dependent apoptosis plays a role in terminal differentiation of human normoblasts

The p53 tumor suppressor gene was found to play a role in the differentiation of several tissue types. We report here that p53-dependent apoptosis plays a role in the final stages of physiological differentiation of normoblasts, resulting in nuclear condensation and expulsion without cell death. Blood samples of healthy newborns, cord blood as well as bone marrow, were analysed for apoptosis by TUNEL and p53 expression by immunostaining. While some samples exhibited simultaneously several distinct patterns of apoptosis, such as perinuclear, diffused nuclear or nuclear apoptotic bodies, others presented a single defined pattern. Overexpression of p53 protein was detected in normoblasts exhibiting either perinuclear or diffused nuclear p53, corresponding to the nuclear apoptotic pattern in the same sample. Similar results were also evident with colonies cultivated for 12–14 days in culture. Differentiated erythroid colonies exhibited overexpression of p53 and positive TUNEL staining only in the normoblasts. We further examined the state of caspase 3/7 and observed a decrease of this activated enzyme during erythroid differentiation in culture. This study suggests a novel role for apoptosis in normoblast differentiation where nuclear degradation occurs with a delay in the actual cell death. A pivotal role for the p53-dependent apoptosis in the erythroid lineage development is implied. However, this apoptotic process is not fully executed because of the exhaustion in caspase 3/7 and thus cells are diverted towards final stages of differentiation.

Protein Z levels and central retinal vein or artery occlusion

Abstract:  Objectives: Central retinal vein occlusion (CRVO) and central retinal artery occlusion (CRAO) are common disorders associated with risk factors for atherosclerosis. Protein Z is a cofactor for the inactivation of activated factor X (Xa) by the protein Z dependent protease inhibitor. Protein Z deficiency was recently linked to increased risk of arterial thrombosis. We investigated whether CRVO and CRAO are associated with low protein Z levels. Patients and methods: Patients with CRVO, CRAO or recurrent branch retinal vein occlusion were recruited to the study. Protein Z level, lupus anticoagulant (LAC), anticardiolipin antibodies (ACA) and activated protein C resistance (APCR) were determined in plasma from patients (n = 36) and healthy controls (n = 42). Results: Thirty patients in the study group had traditional risk factors for retinal vessel occlusion and six patients had none. There was no significant difference in protein Z levels between the whole study group patients and controls (1995 ± 810 vs. 2010 ± 603 ng/mL, P = 0.922). However, patients with no risk factors for retinal vessel occlusion had significantly lower protein Z levels than controls (1379 ± 682 vs. 2010 ± 603 ng/mL, P = 0.022). Positive LAC was found in six patients and one control subject (P = 0.04). There were three patients and one control subject with abnormal APCR (P = 0.3) and none with positive ACA. Low protein Z level (lower than fifth percentile of control) was not associated with the presence of LAC or APCR. Conclusion: Low protein Z level may be another risk factor for retinal vessel occlusion in patients without traditional risk factors for these disorders.

Richter's transformation to diffuse large B-cell lymphoma: A retrospective study reporting clinical data, outcome, and the benefit of adding rituximab to chemotherapy, from the Israeli CLL Study Group

Richters syndrome (RS) is the rare development of an aggressive lymphoid malignancy in a patient with pre‐existing chronic lymphocytic leukemia (CLL). Data on RS is sparse and mostly derived from case reports or small series of patients and only a few larger cohorts have been published. The purpose of this large retrospective study was to summarize our national experience with RS in CLL, examine possible risk factors, and analyze relevant demographic, laboratory and clinical parameters, including results of therapy and outcome. We first evaluated data obtained from 119 patients with RS diagnosed during 1971–2010 from 12 medical centers in Israel. The final cohort summarized consisted of 81 patients with RS who developed only diffuse large B‐cell lymphoma (DLBCL) after exclusion all cases with insufficient data and those who were not DLBCL. Median overall survival from time of diagnosis of RS was 8 months; after applying the Richter score, patients could be stratified into three prognostic groups, while all other clinical and laboratory parameters evaluated had no prognostic significance. Prior therapy for CLL had no impact on RS survival (P = 0.8) and patients with therapy “naïve” RS and those who had already received chemotherapy prior to developing RS, had the same survival. The addition of rituximab to chemotherapy for RS improved 2 years overall survival from 19% in the chemotherapy alone arm to 42% (P value of 0.001). Although prognosis of patients with RS remains dismal, this retrospective observation provides support for the use of chemo‐immunotherapy in DLBCL‐RS. Am. J. Hematol. 89:E218–E222, 2014.

JAK2V617F allele burden is associated with transformation to myelofibrosis

Abstract The JAK2V617F mutation has emerged in recent years as a diagnostic as well as treatment target in patients with polycythemia vera (PV). We analyzed JAK2V617F allele burden (JAK2V617F) in a Jewish population with PV. Results were correlated with disease symptoms and complications. Median JAK2V617F was 48% and 54% in patients of Ashkenazi and non-Ashkenazi origin, respectively (p =0.75). Higher JAK2V617F was seen in patients with imaging-proven splenomegaly (p =0.01). A correlation between JAK2V617F and the weekly hydoxyurea dose needed for disease control was found (p =0.043). In addition, a trend for higher allele burden in patients with longer disease duration (p =0.064) and those treated with cytoreductive drugs other than hydroxyurea (p =0.056) was noted. Higher JAK2V617F was seen in patients with transformation to myelofibosis (p =0.0001), but not in patients with vascular complications. JAK2V617F may assist in prognostic stratification of patients with PV.

Serum immunoglobulin levels at diagnosis have no prognostic significance in stage A chronic lymphocytic leukemia: a study of 1113 cases from the Israeli CLL Study Group

Hypogammaglobulinemia, commonly encountered in chronic lymphocytic leukemia (CLL), is one of the main causes of morbidity and mortality; however, its prognostic significance in patients diagnosed in early stages of disease remains uncertain. The aim of this study was to evaluate the predictive power of hypogammaglobulinemia at Bonet stage A.

Efficacy and safety of front-line therapy with fludarabine-cyclophosphamide-rituximab regimen for chronic lymphocytic leukemia outside clinical trials: the Israeli CLL Study Group experience

This study aimed to evaluate the efficacy and safety of the fludarabine-cyclophosphamide-rituximab regimen for young physically fit patients with chronic lymphocytic leukemia in the “real-life” setting. We specifically focused on the impact of dose reduction on patient outcomes. The patient cohort consisted of 128 patients with chronic lymphocytic leukemia (≤70 years) treated at 10 Israeli centers with front-line fludarabine-cyclophosphamide-rituximab. We defined reduced chemotherapy as two-thirds or less of the total indicated dose. Patients treated with rituximab were divided into two groups and compared: those who received full dosages of 375 mg/m2 or 500 mg/m2, and patients given less than six cycles with either dose. Overall and clinical complete response rates (92.8% and 70.4%), as well as toxicities and overall survival (median not reached at 6 years), were similar to other reported clinical trials, but progression-free survival was shorter (42.5 months). Almost 50% of patients had some dose reduction of chemotherapy, 21% receiving less than two-thirds of the indicated dose, while close to 30% did not complete six cycles of rituximab. Reduced doses of chemotherapy and rituximab were independently associated with shorter progression-free survival (hazard ratio 3.6, P<0.0001 for reduced chemotherapy; hazard ratio 2.5, P=0.003 for incomplete-treatment with rituximab). Achieving a complete response was associated with longer overall survival but was not linked to the given dose of chemoimmunotherapy. In younger physically fit patients, front-line fludarabine-cyclophosphamide-rituximab therapy in the “real-life” setting achieves long remissions (albeit shorter than in clinical trials) and prolonged overall survival. However, dose reductions are commonly administered and may impact outcome.

Benign familial microcytic thrombocytosis with autosomal dominant transmission

Familial thrombocytosis is an extremely rare disorder, so far reported in only a handful of families. In the majority of cases the characteristics were of essential thrombocythemia. Most patients presented with a platelet count above 800000/mm3, were diagnosed as having a myeloproliferative disease, and some required chemotherapy. We describe a benign form of familial thrombocytosis with autosomal dominant inheritance in five healthy members of three generations of a family, all of whom had moderate thrombocytosis within the range 422 000–662 000/mm3, characterized by low mean platelet volume. A careful medical history and a 5‐year follow up of the subjects did not reveal any untoward clinical development. This variant of familial thrombocytosis is therefore of a benign nature. Possible mechanisms linking thrombocytosis with platelet microcytosis in this family are discussed.

Survival trends among 1,325 patients with chronic lymphocytic leukemia seen over the past 40 years in Israel

In the light of recent data showing survival improvement of patients with chronic lymphocytic leukemia (CLL), we investigated clinical characteristics and survival patterns of patients with CLL over the last 40 years in Israel. Demographic and clinical data collected in the database of the Israeli CLL Study Group were analyzed. Of the 1,325 patients, 221 were diagnosed during the time period 1968–1989, 456 during 1990–1999, and 639 during 2000–2010. There was shift toward older age (median, 71 vs. 68 vs. 66 years) and a higher proportion of patients at Binet stage A at diagnosis (77.6% vs. 66.7% vs. 60.3%) in the more recent time periods. Median survival for the entire cohort was 10.9 years; 12.2 years for patients diagnosed at Binet stage A, 8.5 years for stage B, and 6.4 years for stage C patients. Older age, high‐beta 2‐microglobulin level, and expression of ZAP‐70 predicted shorter survival. There were no apparent changes over time regarding gender, age or different clinical stages. Young patients with Binet stage A had lower life expectancy than the general population; but, in older ages, the survival rates were comparable. There were increased proportions of CLL patients diagnosed in early stages, and, at older age, during the last decades, however, survival rates according to sex, age, or stage remained stable. CLL continues to be an incurable disease affecting survival even in patients diagnosed at early stages. Survival benefit shown in recent trials using chemoimmunotherapy has still to be proven in wider general practice. Am. J. Hematol. 86:985–992, 2011.