Ove Juul Nielsen

Incidence, clinical features and outcome of essential thrombocythaemia in a well defined geographical area

Abstract: In an attempt to characterise the clinical features, incidence and outcome of essential thrombocythaemia (ET) we report our experience in a large unselected series of patients from a well defined region. All new cases of ET in the County of Copenhagen were registered during the period 1977–98. We identified 96 cases of ET, yielding an age‐ and sex‐adjusted annual incidence rate of 0.59/100.000 and a point‐prevalence at last follow up of 11/100.000. The overall incidence rate was 0.31 and 1.00 per 100.000 population during the consecutive periods 1977–89 and 1990–98, respectively, corresponding to a 3.2‐fold increase. Median age at diagnosis was 67 yr (females 68 yr, males 66 yr, range 18–87 yr), and the female to male (F/M) ratio was 2.6:1. At diagnosis, 52% of the patients displayed no ET‐related symptoms and were discovered fortuitously by a routine platelet count. Forty‐eight percent presented with thrombohaemorrhagic phenomena, of which microvascular disturbances of the central nervous system (CNS), extremities and skin were most frequently observed (23%). Compared to patients diagnosed after 1989, patients diagnosed before 1990 had a significantly higher mean platelet count, white blood cell (WBC) count, lactate dehydrogenase (LDH) value and alkaline phosphatase value. With a median follow up of 70 months, 5‐yr survival was 76%, significantly lower than the expected survival of an age‐ and sex‐matched control group (p=0.0052). Thirty‐seven patients experienced a total of 55 thrombohaemorrhagic events during follow‐up, corresponding to an incidence of thrombosis and microvascular disturbances or haemorrhage of 8.1% per pt‐yr and 2.5% per pt‐yr, respectively. The number of patients experiencing thrombosis or microvascular disturbances was significantly higher among the 29 patients who never received acetylsalicylic acid (ASA) compared to the 67 patients who received ASA during follow up (45% vs. 21%; p=0.017). This study provides population‐based data suggesting the benefit of treatment with low‐dose ASA in a non‐selected population of patients with ET.

Increased circulating platelet–leukocyte aggregates in myeloproliferative disorders is correlated to previous thrombosis, platelet activation and platelet count

Abstract: Platelet–leukocyte adhesion may occur as a consequence of platelet activation and possibly plays a key role in the deposition of activated platelets and fibrin in the thrombotic plug. The aim of the present study was to assess by whole blood flow cytometry the presence of circulating platelet–leukocyte aggregates (PLA) and the platelet–leukocyte response to platelet agonist stimulation (ADP and TRAP) in 50 patients with chronic myeloproliferative disorders (MPD) and 30 controls. PLA were identified as platelet–granulocyte/monocyte aggregates (PGMA), platelet–monocyte aggregates (PMA) and defined as the percentage of leukocytes coexpressing the platelet‐specific marker glycoprotein Ib. Compared to controls the mean percentage of PGMA and PMA was increased in unstimulated whole blood from patients with MPD (7.98 vs. 1.76%; p<0.001 and 12.34 vs. 3.2%; p<0.001, respectively). The percentage of PGMA was correlated to the platelet count (r=0.46; p<0.001), percentage of P‐selectin (r=0.69; p<0.001) and thrombospondin (r=0.58; p<0.001) positive platelets and platelet expression of GPIV (r=0.33; p=0.02). The mean percentage of PGMA and PMA was significantly increased in ADP‐stimulated whole blood of patients (57.14 vs. 47.92%; p=0.009 and 54.91 vs. 45.89%; p<0.001, respectively). Compared to patients without a history of thrombosis, patients having experienced microvascular disturbances or a thrombotic event had a higher mean percentage of PGMA and PMA in non‐stimulated whole blood (10.07 vs. 6.34%; p=0.025 and 14.81 vs. 10.48%; p=0.021, respectively) and a higher percentage of PGMA in ADP stimulated whole blood (64.32 vs. 51.50%; p<0.01). These data document an increased frequency of PLA in non‐stimulated whole blood in MPD associated with a previous history of thrombosis or microvascular disturbances.

Increased platelet activation and abnormal membrane glycoprotein content and redistribution in myeloproliferative disorders

Chronic myeloproliferative disorders (MPDs) are characterized by a high incidence of thrombohaemorrhagic complications, possibly caused by platelet dysfunction. In an attempt to define platelet functional abnormalities, we assessed the expression of activation‐dependent membrane proteins in unstimulated and agonist [ADP and thrombin receptor‐activating peptide (TRAP)]‐stimulated platelets using quantitative whole blood flow cytometry in samples from 50 MPD patients and 30 controls. The receptor densities of activation markers and glycoproteins (GPs) were quantified using standardized fluorescent beads. Compared with controls, the mean percentage of P‐selectin‐positive (15·3% vs. 7·2%; P < 0·001) and thrombospondin (TSP)‐positive (6·6% vs. 3·7%; P = 0·003) platelets was increased in unstimulated platelets from patients. Patients having experienced a thrombotic event had a higher mean percentage of TSP‐positive non‐stimulated platelets than patients without a history of thrombosis (9·0% vs. 4·6%; P = 0·02) and a higher GPIV molecules of equivalent fluorochrome (MEF) value (33113 vs. 24471 MEF; P = 0·02). Mean MEF values of monoclonal antibodies (mAbs) against GPIb (34055 vs. 38945 MEF; P < 0·001) and GPIIb/IIIa (1416 vs. 1648 MEF; P < 0·001) were significantly reduced among patients, whereas surface expression of GPIV was increased in patients (28273 vs. 16258 MEF; P < 0·001). In TRAP (10 µmol/l) stimulated whole blood, the MEF of P‐selectin (9611 vs. 13293 MEF; P = 0·004) and CD63 (2385 vs. 5177 MEF; P < 0·001) and the ratio of PAC‐1/GPIIb/IIIa MEF (0·98 vs. 2·00; P < 0·001) was reduced in patients, indicating either a reduced granule GP content or an intrinsic cellular defect in receptor‐mediated granule secretion and activation of the GPIIb/IIIa complex. Expressed as the relative change of MEF compared with unstimulated platelets, TRAP induced decrease of GPIb (7·8% vs. 45%; P < 0·001) and increase of GPIIb/IIIa (49·1% vs. 95·7%; P < 0·001) and GPIV expression (17·8% vs. 55·2%; P < 0·001) was attenuated in patients.

Risk group assignment differs for children and adults 1–45 yr with acute lymphoblastic leukemia treated by the NOPHO ALL‐2008 protocol

The prognosis of acute lymphoblastic leukemia is poorer in adults than in children. Studies have indicated that young adults benefit from pediatric treatment, although no upper age limit has been defined.

Rituximab and dexamethasone vs dexamethasone monotherapy in newly diagnosed patients with primary immune thrombocytopenia

In this study, we report the results from the largest cohort to date of newly diagnosed adult immune thrombocytopenia patients randomized to treatment with dexamethasone alone or in combination with rituximab. Eligible were patients with platelet counts ≤25×10(9)/L or ≤50×10(9)/L with bleeding symptoms. A total of 133 patients were randomly assigned to either dexamethasone 40 mg/day for 4 days (n = 71) or in combination with rituximab 375 mg/m(2) weekly for 4 weeks (n = 62). Patients were allowed supplemental dexamethasone every 1 to 4 weeks for up to 6 cycles. Our primary end point, sustained response (ie, platelets ≥50×10(9)/L) at 6 months follow-up, was reached in 58% of patients in the rituximab + dexamethasone group vs 37% in the dexamethasone group (P = .02). The median follow-up time was 922 days. We found longer time to relapse (P = .03) and longer time to rescue treatment (P = .007) in the rituximab + dexamethasone group. There was an increased incidence of grade 3 to 4 adverse events in the rituximab + dexamethasone group (P = .04). In conclusion, rituximab + dexamethasone induced higher response rates and longer time to relapse than dexamethasone alone. This study is registered at http://clinicaltrials.gov as NCT00909077.

A phase III randomized trial comparing glucocorticoid monotherapy versus glucocorticoid and rituximab in patients with autoimmune haemolytic anaemia

The impact of first‐line treatment with the anti‐CD 20 chimeric monoclonal antibody rituximab in patients with warm‐antibody reactive autoimmune haemolytic anaemia (WAIHA) is unknown. We report the first randomized study of 64 patients with newly diagnosed WAIHA who received prednisolone and rituximab combined (N = 32) or prednisolone monotherapy (N = 32). After 12 months, a satisfactory response was observed in 75% of the patients treated with rituximab and prednisolone but in a significantly smaller proportion (36%) of those given prednisolone alone (P = 0·003). Furthermore, relapse‐free survival was significantly better after the combined therapy than after prednisolone monotherapy (P = 0·02). After 36 months, about 70% of the patients were still in remission in the rituximab‐prednisolone group, whereas only about 45% were still in complete or partial remission in the prednisolone group. There was no significant difference between the two groups regarding adverse reactions to the studied medications. Likewise, serious adverse events were equally distributed, and no allergic reactions to rituximab were recorded. In conclusion, our data show that using rituximab and prednisolone combined rather than prednisolone alone as first‐line treatment in WAIHA increases both the rate and the duration of the response.

Sustained remission of platelet counts following monoclonal anti-CD20 antibody therapy in two cases of idiopathic autoimmune thrombocytopenia and neutropenia.

Abstract: Idiopathic autoimmune thrombocytopenia and neutropenia (ITN) is a primary haemocytopenic disorder clinically characterised by recurrent mucocutaneous bleeding episodes and infections. Unlike in simple idiopathic thrombocytopenic purpura, the platelet deficiency of ITN tends to be chronic and difficult to treat. We describe two patients with ITN who obtained sustained remission of their platelet counts after therapy with the chimeric monoclonal anti‐CD20 antibody Rituximab. In one of two cases, Rituximab also induced prolonged normalisation of the neutrophil count and disappearance of auto‐antibodies.

Safe and feasible outpatient treatment following induction and consolidation chemotherapy for patients with acute leukaemia

Traditionally, patients with acute leukaemia are admitted to hospital during chemotherapy‐induced pancytopenia, although a few recent reports have reported the feasibility and safety of outpatient treatment. We have developed an outpatient treatment programme for patients with acute leukaemia incorporating comprehensive patient education for self‐care management at home during pancytopenia and involvement of patients in care of their tunnelled central venous catheter (CVC). During neutropenia, patients are treated with prophylactic ciprofloxacine, amoxicillin/clavulanic acid and fluconazole. Herein, we report the results of outpatient treatment of 60 patients with acute leukaemia (54 with acute myeloid leukaemia) followed prospectively in the period from March 2004 to 2007. After induction chemotherapy, outpatient treatment was possible after 48 of 73 induction courses, with no readmission in 19 of these (40%). A total of 129 consolidation courses were administered with outpatient treatment following 116 of these, with no readmission in 69 (59%). The median number of days spent at home with neutrophils below 0.5 × 109/L was 8 d per course following induction and 12 d following consolidation chemotherapy. The predominant cause of readmission was neutropenic fever, in most instances of unknown origin. Coagulase‐negative staphylococci and Enterococcus faecium were the most frequently identified bacteria in blood cultures, whereas only four positive blood cultures with multiresistant Escherichia coli were identified in the entire patient cohort, the latter exclusively observed in patients receiving antibiotic prophylaxis. The majority of the patients were able to take care of their CVC including change in dressing and heparin flushing. There were 12 CVC‐related infections. There were no treatment‐related deaths. We conclude that outpatient treatment of patients with acute leukaemia is feasible and safe.

High prevalence of hyperhomocysteinemia due to marginal deficiency of cobalamin or folate in chronic myeloproliferative disorders

Hyperhomocysteinemia is an established risk factor for thrombosis. In patients with myeloproliferative disorders, thrombotic events are common. Our aim was to investigate whether the increased burden of proliferating cells present in these patients implies a risk of homocysteine (HCY) accumulation secondary to depletion of folate and/or cobalamin. Fifty patients (PV, 25; ET, 10; IMF, 15) and 163 healthy volunteers (HV) participated in the study. The prevalence of hyperhomocysteinemia was 56.0% in PV, 70.0% in ET, 60.0% in IMF, and 34.9% in HV. The mean P‐homocysteine (P‐HCY) was 13.88 ± 4.24 μmol/L in PV, 12.78 ± 3.70 in ET, 11.34 ± 4.22 in IMF, and 9.71 ± 2.76 in HV. In PV and ET, but not in IMF, the mean P‐HCY was significantly higher than in the HV group (P < 0.001, P = 0.028, and P = 0.163, respectively). Thirty‐three percent of the patients with hyperhomocysteinemia displayed metabolic changes compatible with cobalamin deficiency (P‐HCY and P‐methylmalonic acid both elevated), while 67% were folate deficient (P‐HCY elevated, P‐methylmalonic acid normal). Supplementation therapy with the relevant vitamin was implemented in 11 vitamin‐deficient patients and led to normalization of metabolite levels in all cases. No correlation between hyperhomocysteinemia and thrombosis was found. Our data indicate that patients with PV, ET, and IMF frequently develop hyperhomocysteinemia due to discrete depletion of cobalamin or folate. Vitamin therapy leads to normalization of P‐HCY and should be considered, even though hyperhomocysteinemia does not seem to be of crucial importance for the thrombotic tendency in the myeloproliferative disorders. Am. J. Hematol. 65:136–140, 2000.

Impaired CD163-mediated hemoglobin-scavenging and severe toxic symptoms in patients treated with gemtuzumab ozogamicin

We describe a novel syndrome of severe toxic symptoms during intravascular hemolysis due to impaired hemoglobin scavenging in 2 children with acute myeloid leukemia undergoing CD33-directed therapy with the immunotoxin gemtuzumab ozogamicin (GO). A simultaneous high plasma hemoglobin, haptoglobin, and low bilirubin after septicemia-induced intravascular hemolysis indicated abrogated clearance of haptoglobin-hemoglobin complexes. This was further supported by low levels of plasma soluble CD163 and a concordant low number of CD163-expressing monocytes. We show that CD163 positive monocytes and macrophages from liver, spleen, and bone marrow coexpress CD33, thus suggesting that the GO-induced cellular cytotoxicity of CD33 positive cells eradicates a significant part of the CD163 positive monocytes and macrophages. The risk of severe toxic symptoms from plasma hemoglobin should be considered after CD33-targeted chemotherapy when the disease is complicated by a pathologic intravascular hemolysis. Furthermore, the cases provide further circumstantial evidence of a key role of (CD163-expressing) monocytes/macrophages in plasma hemoglobin clearance in vivo.