Expression of Bcl-x in erythroid precursors from patients with polycythemia vera.

BACKGROUND: Deregulating the expression of Bcl-xL, an inhibitor of apoptosis, in an erythropoietin-dependent erythroblast cell line averts apoptosis induced by the withdrawal of erythropoietin. Since in polycythemia vera an abnormal clone of erythroid progenitors is independent of erythropoietin, we investigated whether the endogenous expression of Bcl-xL was deregulated in these cells. METHODS: Erythroid colonies from patients with polycythemia vera and normal subjects were cultured in the presence and absence of erythropoietin and assessed by immunocytochemical and flow-cytometric analysis with anti-Bcl-x antibodies that recognize the two species of Bcl-x (Bcl-xL and Bcl-xS). Reverse-transcriptase-polymerase-chain-reaction analysis was used to determine which one of the two species was responsible for anti-Bcl-x staining. Bone marrow mononuclear cells from 8 healthy bone marrow donors, 14 patients with polycythemia vera, 19 patients with other myeloproliferative syndromes, and 12 patients with secondary erythrocytosis were analyzed by flow cytometry with antibodies against Bcl-x and glycophorin A, an erythroid marker. RESULTS: Erythroid cells from patients with polycythemia vera survived in vitro without erythropoietin, and this finding correlated with the expression of Bcl-x protein (Bcl-xL messenger RNA was the main species of Bcl-x found), even in mature erythroblasts that normally do not express Bcl-x. The mean (+/-SD) percentage of cells positive for both glycophorin A and Bcl-x in the 14 patients with polycythemia vera (21.8+/-3.6 percent) was significantly higher than that in 8 normal donors (6.62+/-1.58 percent), 12 patients with secondary erythrocytosis (6.87+/-1.95 percent), 9 patients with essential thrombocythemia (3.81+/-0.97 percent), and 10 patients with chronic myeloid leukemia (2.7+/-0.41 percent). CONCLUSIONS: Deregulated expression of Bcl-x may contribute to the erythropoietin-independent survival of erythroid-lineage cells in polycythemia vera and thereby contribute to the pathogenesis of this disease.

Meropenem versus ceftazidime plus amikacin in the treatment of febrile episodes in neutropenic patients: a randomized study.

BACKGROUND AND OBJECTIVE: Meropenem is the first of a new class of carbapenems which may be administered without cilastatin. This study was performed to assess the clinical efficacy and tolerability of meropenem monotherapy (1 g/8 h) compared with the standard combination of ceftazidime (2 g/8 h) plus amikacin (15 mg/kg/day) for the empirical treatment of infective febrile episodes in neutropenic cancer patients. METHODS: This was a three-center, randomized, non-blind parallel group trial. The primary objective was to compare the clinical efficacy of meropenem monotherapy with that of ceftazidime plus amikacin in the empirical treatment of febrile infective episodes in neutropenic patients. This was evaluated by the number of patients surviving on unmodified therapy at 72 h (primary end point) and by the clinical response at the end of therapy (secondary end point). RESULTS: A total of 93 febrile episodes (46 meropenem, 47 ceftazidime/amikacin) were evaluable. Bone marrow transplant patients accounted for 49.5% of all cases. There was a high incidence of Gram-positive infections but no pseudomonal infections. Microbiologically documented infections, clinically documented infections and unexplained fever accounted for 45%, 10% and 45% of episodes, respectively. There was a similar proportion of patients in the meropenem and ceftazidime/amikacin groups on unmodified empiric therapy at 72 h (80.4% vs 76.6%, p = 0.65,) and cured at the end of therapy (37% vs 36.2%, p = 0.9). No significant difference in tolerability was observed between the groups. Meropenem was well tolerated; of note, there were no cases of nausea/vomiting or seizure related to its use. INTERPRETATION AND CONCLUSIONS: Meropenem monotherapy was well tolerated and produced response rates similar to those obtained with ceftazidime/amikacin. The low overall success rates with both treatments concur with those of other recent studies and are probably due to a combination of several factors, including the adoption of strict assessment criteria.

Autologous peripheral blood stem cell transplantation in a patient with previous invasive middle ear mucormycosis.

A 52-year-old male diagnosed with acute myeloid leukemia (AML) developed an invasive middle-ear mucormycosis during the neutropenic period after consolidation chemotherapy which resolved successfully with surgery and antifungal therapy. The patient underwent autologous peripheral blood stem cell transplantation (APBSCT) in first complete remission with antifungal prophylaxis with liposomal amphotericin B (AmB). There was no clinical, radiological or microbiological data of mycotic reactivation. This is the first reported stem cell transplantation (SCT) in a patient with prior invasive mucormycosis.

Recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) administration after autologous bone marrow transplantation for acute myeloblastic leukemia enhances activated killer cell function and may diminish leukemic relapse.

Leukemic relapse is the major complication following autologous bone marrow transplantation (BMT) in acute myeloblastic leukemia (AML). Previously, we have shown that recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) infusion after autologous BMT has the ability to augment endogenous activated killer (AK) cell function which may play a role in the eradication of minimal residual disease. However, the clinical application of rhGM-CSF in patients with AML has been limited by its potential stimulatory effect on the malignant clone. Here we report the effect of rhGM-CSF 5 micrograms/kg/day infusion on AK cell function in 20 patients with AML undergoing autologous BMT. AK cell function was investigated before autologous BMT, during rhGM-CSF therapy and after withdrawal. In addition, its influence on the actuarial risk of relapse is analyzed and compared with a historical control group of 20 patients transplanted immediately before initiation of this study. rhGM-CSF significantly enhanced AK cell function. During rhGM-CSF treatment, median AK cell function rose from 1.8% before autologous BMT (range 0-8%) to 35% (range 3-80%) and remained increased after cessation of rhGM-CSF (median 20%; range 0-36%; P < 0.001). After a median follow-up of 24 months, the actuarial risk of relapse is 37.4% in rhGM-CSF-treated patients compared with 49.5% in controls (P = 0.05). Interestingly, none of the 7 patients with an AK cell activity > or = 20% in the first 2-5 weeks after autologous BMT have relapsed compared with 6 of 9 patients with an AK cell activity < 20% (P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)