Crisis management in the treatment of childhood acute lymphoblastic leukemia: putting right what can go wrong (emergency complications of disease and treatment).

The improvement in overall survival in children with acute lymphoblastic leukemia (ALL) over the last 5 decades has been considerable, with around 90% now surviving long term. The risk of relapse has been reduced to such an extent that the risk of treatment-related mortality is now approaching that of mortality caused by relapse. Toxicities may also lead to the suboptimal delivery of chemotherapy (treatment delays, dose reductions, dose omissions), potentially increasing relapse risk, and short- and long-term morbidity, adding to the "burden of therapy" in an increasing number of survivors. Thus, the need to reduce toxicity in pediatric ALL is becoming increasingly important. This work focuses on the risk factors, pathogenesis, clinical features, and emergency management of the life-threatening complications of ALL at presentation and during subsequent chemotherapy, including leucostasis, tumor lysis syndrome, infection, methotrexate encephalopathy, thrombosis, and pancreatitis. Potential strategies to abrogate these toxicities in the future are also discussed.

NFAT isoforms play distinct roles in TNFα-induced retinal leukostasis.

The objective of this study was to determine the role of individual NFAT isoforms in TNFα-induced retinal leukostasis. To this end, human retinal microvascular endothelial cells (HRMEC) transfected with siRNA targeting individual NFAT isoforms were treated with TNFα, and qRT-PCR was used to examine the contribution of each isoform to the TNFα-induced upregulation of leukocyte adhesion proteins. This showed that NFATc1 siRNA increased ICAM1 expression, NFATc2 siRNA reduced CX3CL1, VCAM1, SELE, and ICAM1 expression, NFATc3 siRNA increased CX3CL1 and SELE expression, and NFATc4 siRNA reduced SELE expression. Transfected HRMEC monolayers were also treated with TNFα and assayed using a parallel plate flow chamber, and both NFATc2 and NFATc4 knockdown reduced TNFα-induced cell adhesion. The effect of isoform-specific knockdown on TNFα-induced cytokine production was also measured using protein ELISAs and conditioned cell culture medium, and showed that NFATc4 siRNA reduced CXCL10, CXCL11, and MCP-1 protein levels. Lastly, the CN/NFAT-signaling inhibitor INCA-6 was shown to reduce TNFα-induced retinal leukostasis in vivo. Together, these studies show a clear role for NFAT-signaling in TNFα-induced retinal leukostasis, and identify NFATc2 and NFATc4 as potentially valuable therapeutic targets for treating retinopathies in which TNFα plays a pathogenic role.

Superselective intraophthalmic artery chemotherapy in a nonhuman primate model: histopathologic findings.

IMPORTANCE: We describe the histopathologic findings in a nonhuman primate (NHP) model of superselective intraophthalmic artery chemotherapy (SSIOAC), detailing ocular and orbital vascular adverse effects. OBJECTIVE: To further document, using comprehensive ocular and orbital histopathology, previously reported toxic effects observed with real-time ophthalmoscopy during SSIOAC in a NHP model. DESIGN: Comparative interventional case series. SETTING: Preclinical trial approved under the guidelines of the Institutional Animal Care and Utilization committee. PARTICIPANTS: Six adult male rhesus macaques (Macacca mulatta). INTERVENTIONS: The right eye of each NHP was treated with 3 cycles of SSIOAC using either melphalan (5 mg/30 mL) or carboplatin (30 mg/30 mL). Both eyes in each animal were enucleated 6 hours after the final procedure, before euthanasia and formalin perfusion of the NHP; we then performed orbital dissection of the arterial vasculature and optic nerves. MAIN OUTCOME MEASURES: Histopathologic examination of the eyes, optic nerves, and orbital vessels of the 6 treated NHPs. RESULTS: We found leukostasis with retinal arteriole occlusion in all treated eyes. Retinal endothelial cells stained positive for 2 inflammatory markers, intercellular adhesion molecule 1 and interleukin 8. Transmission electron microscopy revealed occlusion of the retinal vessels with ultrastructural changes in the endothelial cells and surrounding pericytes. Additional findings included nerve fiber layer infarcts, central retinal artery thrombosis, hypertrophy and occlusion of choroidal arteries with disruption of the internal elastic lamina, patchy choroidal inflammation, and birefringent intravascular foreign bodies. Orbital findings included ophthalmic artery and central retinal artery wall dissection, fracturing of the internal elastic lamina, intimal hyperplasia, and eyelid vessel damage. Optic nerves displayed hemorrhage, leukostasis, and foreign body crystallization. Control eyes, optic nerves, and orbital vessels were normal. CONCLUSIONS AND RELEVANCE: Histopathologic examination of our nonhuman primate model for SSIOAC revealed significant toxic effects in the ocular and orbital vasculature. These findings substantiate previous observations with real-time retinal imaging and parallel reported vascular toxic effects in children with retinoblastoma treated with SSIOAC.

Dexamethasone in patients with acute lung injury from acute monocytic leukaemia.

The use of steroids is not required in myeloid malignancies and remains controversial in patients with acute lung injury (ALI) or acute respiratory distress syndrome (ARDS). We sought to evaluate dexamethasone in patients with ALI/ARDS caused by acute monocytic leukaemia (AML FAB-M5) via either leukostasis or leukaemic infiltration. Dexamethasone (10 mg every 6 h until neutropenia) was added to chemotherapy and intensive care unit (ICU) management in 20 consecutive patients between 2005 and 2008, whose data were compared with those from 20 historical controls (1994-2002). ICU mortality was the primary criterion. We also compared respiratory deterioration rates, need for ventilation and nosocomial infections. 17 (85%) patients had hyperleukocytosis, 19 (95%) had leukaemic masses, and all 20 had severe pancytopenia. All patients presented with respiratory symptoms and pulmonary infiltrates prior to AML FAB-M5 diagnosis. Compared with historical controls, dexamethasone-treated patients had a significantly lower ICU mortality rate (20% versus 50%; p = 0.04) and a trend for less respiratory deterioration (50% versus 80%; p = 0.07). There were no significant increases in the rates of infections with dexamethasone. In conclusion, in patients with ALI/ARDS related to AML FAB-M5, adding dexamethasone to conventional chemotherapy seemed effective and safe. These results warrant a controlled trial of dexamethasone versus placebo in AML FAB-M5 patients with noninfectious pulmonary infiltrates.

Role of IL-6 in angiotensin II-induced retinal vascular inflammation.

PURPOSE: The production of proinflammatory cytokines has been shown to play a critical role in a variety of retinal vascular diseases. Angiotensin II and VEGF have been implicated in the initiation of vascular inflammation and retinal vascular disease. However, detailed mechanisms of this process and interactions between inflammatory agonists and angiotensin II in promoting retinopathy are poorly understood. The present study was an investigation of the role of interleukin (IL)-6 in angiotensin II-induced retinopathy. METHODS: Rats and IL-6-deficient and wild-type mice were treated with angiotensin II or IL-6, and their retinas were analyzed for leukocyte adhesion or for the expression and localization of VEGF or IL-6. Leukocyte adhesion was assayed by concanavalin A labeling. Vascular density was determined by morphometric analysis. NADPH oxidase activity was assayed by dihydroethidium imaging of superoxide. RESULTS: Intravitreal injection of angiotensin II caused increases in IL-6 mRNA and protein and in leukocyte adhesion to the retinal vessels. IL-6 protein was localized to CD11b-positive microglia and macrophage-like cells. Angiotensin II treatment stimulated increases in retinal levels of VEGF expression and NADPH oxidase activity, which were associated with increased surface area and remodeling of the retinal vessels. These effects were blocked by knocking out IL-6. Intravitreal IL-6 directly induced leukocyte adhesion in both wild-type and IL-6-deficient mice. CONCLUSIONS: The results indicate that IL-6 expression is essential for angiotensin II-induced increases in retinal VEGF expression, leukostasis, and vascular remodeling. The data suggest a critical role for IL-6 in mediating angiotensin II-induced retinal vascular inflammation and remodeling.

Identification of a retinal aldosterone system and the protective effects of mineralocorticoid receptor antagonism on retinal vascular pathology.

Blockade of the renin-angiotensin-aldosterone system (RAAS) is being evaluated as a treatment for diabetic retinopathy; however, whether the mineralocorticoid receptor (MR) and aldosterone influence retinal vascular pathology is unknown. We examined the effect of MR antagonism on pathological angiogenesis in rats with oxygen-induced retinopathy (OIR). To determine the mechanisms by which the MR and aldosterone may influence retinal angiogenesis; inflammation and glucose-6-phosphate dehydrogenase (G6PD) were evaluated in OIR and cultured bovine retinal endothelial cells (BRECs) and bovine retinal pericytes (BRPs). In OIR, MR antagonism (spironolactone) was antiangiogenic. Aldosterone may mediate the pathogenic actions of MR in the retina, with 11beta-hydroxysteroid dehydrogenase type 2 mRNA being detected and with aldosterone stimulating proliferation and tubulogenesis in BRECs and exacerbating angiogenesis in OIR, which was attenuated with spironolactone. The MR and aldosterone modulated retinal inflammation, with leukostasis and monocyte chemoattractant protein-1 mRNA and protein in OIR being reduced by spironolactone and increased by aldosterone. A reduction in G6PD may be an early response to aldosterone. In BRECs, BRPs, and early OIR, aldosterone reduced G6PD mRNA, and in late OIR, aldosterone increased mRNA for the NAD(P)H oxidase subunit Nox4. A functional retinal MR-aldosterone system was evident with MR expression, translocation of nuclear MR, and aldosterone synthase expression, which was modulated by RAAS blockade. We make the first report that MR and aldosterone influence retinal vasculopathy, which may involve inflammatory and G6PD mechanisms. MR antagonism may be relevant when developing treatments for retinopathies that target the RAAS.

Leukostasis and pigment epithelium-derived factor in rat models of diabetic retinopathy.

PURPOSE: Spontaneously diabetic Torii (SDT) rats, an animal model of type 2 diabetes, have a low incidence of neovascular formation and an absence of non-perfused areas in their retinas at the proliferative stage that presents tractional retinal detachment with fibrous proliferation. The aim of this study was to determine whether leukostasis is present in the retina, to evaluate the levels of pigment epithelium-derived factor (PEDF) and intracellular adhesion molecule-1 (ICAM-1) levels in the blood of SDT rats, and to examine the effects of PEDF on leukostasis. METHODS: SDT rats, streptozotocin-induced diabetic (STZ) rats, and control Sprague-Dawley (SD) rats were studied. The index of leukostasis in the retina was determined immunohistochemically by counting the number of labeled adherent leukocytes. The levels of PEDF and the soluble intracellular adhesion molecule (sICAM)-1 in the plasma were measured. To investigate the effect of PEDF and vascular endothelial growth factor (VEGF) on leukostasis, the adhesion of monocytes to human umbilical vein endothelial cells (HUVECs) was assayed in vitro. RESULTS: SDT and STZ diabetic rats showed a significant increase of retinal leukostasis compared to that of control SD rats, but SDT rats had noteworthy lower levels of leukostasis than STZ rats in long term experiments. The sICAM-1 levels and PEDF expression were up-regulated in both STZ and SDT rats, but the SDT rats showed significantly higher levels of PEDF than STZ rats. In vitro studies showed that exposure of HUVECs to VEGF increased the number of adhering monocytes, and PEDF inhibited the VEGF-induced leukostasis in a dose-dependent manner. CONCLUSIONS: The inhibition of the VEGF-induced leukostasis by PEDF is most likely responsible for the low incidence of capillary occlusion and retinal neovascularization in SDT rats.

TNF-alpha is critical for ischemia-induced leukostasis, but not retinal neovascularization nor VEGF-induced leakage.

Vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-alpha) show significant overlap with regard to their effects in the eye. It has been postulated that VEGF-induced leukostasis, breakdown of the blood-retinal barrier, and ischemia-induced retinal neovascularization may be mediated, at least in part, through TNF-alpha. In this study, we used mice deficient in TNF-alpha to test our hypothesis. Compared to wild type mice, TNF-alpha-deficient mice showed an 80% reduction in leukocyte accumulation in retinal vessels after intravitreous injection of VEGF, and 100% reductions after intravitreous injections of interleukin-1beta (IL-1beta) or platelet-activating factor (PAF). The increase in retinal vascular permeability induced by injection of PAF was significantly reduced in mice lacking TNF-alpha, but VEGF- and IL-1beta-induced leakage was unaffected. Compared to wild type mice with oxygen-induced ischemic retinopathy, TNF-alpha-deficient mice with ischemic retinopathy showed significantly reduced leukostasis and mild reduction in vascular leakage, but no significant difference in retinal neovascularization. These data suggest that TNF-alpha mediates VEGF-, IL-1beta-, and PAF-induced leukostasis and vascular leakage mediated by PAF, but not leakage caused by VEGF or IL-1beta. Ischemia-induced retinal neovascularization, which has previously been shown to require VEGF, does not require TNF-alpha and is unaffected by attenuation of leukostasis.

Vascular endothelial growth factor (VEGF)-induced retinal vascular permeability is mediated by intercellular adhesion molecule-1 (ICAM-1).

Two prominent vascular endothelial growth factor (VEGF)-induced retinal effects are vascular permeability and capillary nonperfusion. The mechanisms by which these effects occur are not completely known. Using a rat model, we show that intravitreous injections of VEGF precipitate an extensive retinal leukocyte stasis (leukostasis) that coincides with enhanced vascular permeability and capillary nonperfusion. The leukostasis is accompanied by the up-regulation of intercellular adhesion molecule-1 expression in the retina. The inhibition of intercellular adhesion molecule-1 bioactivity with a neutralizing antibody prevents the permeability and leukostasis increases by 79% and 54%, respectively. These data are the first to demonstrate that a nonendothelial cell type contributes to VEGF-induced vascular permeability. Additionally, they identify a potential mechanism for VEGF-induced retinal capillary nonperfusion.

Tumor necrosis factor induces tumor necrosis via tumor necrosis factor receptor type 1-expressing endothelial cells of the tumor vasculature.

Activation of endothelial cells, fibrin deposition, and coagulation within the tumor vasculature has been shown in vivo to correlate with the occurrence of tumor necrosis factor (TNF)-induced tumor necrosis in mice. In the present study we investigated which target cells mediate the TNF-induced necrosis in fibrosarcomas grown in wild type (wt), TNF receptor type 1-deficient (TNFRp55-/-), and TNF receptor type 2-deficient (TNFRp75-/-) mice. TNF administration resulted in tumor necrosis exclusively in wt and TNFRp75-/-, but not in TNFRp55-/- mice, indicating a dependence of TNF-mediated tumor necrosis on the expression of TNF receptor type 1. However, using wt and TNFRp55-/- fibrosarcomas in wt mice, we found that TNF-mediated tumor necrosis was completely independent of TNF receptor type 1 expression in tumor cells. Thus we could exclude any direct tumoricidal effect of TNF in this model. Soluble TNF induced leukostasis in wt and TNFRp75-/- mice but not in TNFRp55-/- mice. TNF-induced leukostasis in TNFRp55-/- mice was restored by adoptive bone marrow transplantation of wt hematopoietic cells, but TNF failed to induce tumor necrosis in these chimeric mice. Because TNF administration resulted in both activation and focal damage of tumor endothelium, TNF receptor type 1-expressing cells of the tumor vasculature, likely to be endothelial cells, appear to be target cells for mediating TNF-induced tumor necrosis.

Leukostasis followed by hemorrhage complicating the initiation of chemotherapy in patients with acute myeloid leukemia and hyperleukocytosis: a clinicopathologic report of four cases.

BACKGROUND: Pulmonary and cerebral leukostasis, or parenchymal hemorrhage in these organs, are well-known early complications developing in patients with acute myeloid leukemia (AML), particularly when myelomonocytic features, hyperleukocytosis, and/or a coagulation disorder are initially present. Commonly, these complications arise during increasing leukocyte counts (WBCs). METHODS: The authors describe four patients with AML and hyperleukocytosis who developed leukostasis followed by parenchymal hemorrhage. RESULTS: Bleeding in all patients occurred while their WBCs were decreasing following cytosine-arabinoside chemotherapy, and in the absence of disseminated intravascular coagulation or severe thrombocytopenia. Radiologic and histopathologic findings underscoring possible mechanisms are presented in the article. CONCLUSIONS: Alterations of cell adhesion associated with chemotherapy-induced blast lysis or cellular differentiation are possible factors contributing to this particular sequence (cytosine arabinoside-based chemotherapy, leukostasis, and subsequent hemorrhage). Prophylactic measures for managing this early complication of AML treatment include leukapheresis to reduce the WBC prior to the initiation of chemotherapy.

[Chemically-induced paraneoplastic hyperleukocytic lung]. / Poumon hyperleucocytaire paranéoplasique chimio-induit.

Dyspnea is the principal clinical feature of pulmonary leukostasis, a syndrome called "poumon hyperleucocytaire" in French. It is a common complication of chronic myeloid leukemia. In the course of pulmonary carcinoma, leukocytosis is frequently noted. One of the etiologies is a paraneoplastic syndrome with production of colony stimulating factor. We report a case of pulmonary hyperleukostasis following antineoplastic chemotherapy for pulmonary carcinoma.

[Trypsin-induced leukostasis: granulocyte migration in airspaces]. / Leucostase induite à la trypsine: migration de granulocytes dans les espaces aériens.

Injection of trypsin triggers the delayed appearance of a lung emphysema. Classically, emphysema is attributed to elastase, more particularly to leucocyte elastase. Indeed the acute phase of this experiment is characterized by a granulocyte sequestration within the lung microvessels in diverse species. We also found granulocytes within the terminal airspaces; this fact implies a granulocyte extravasation and directed migration. In order to evaluate this airspace invading by granulocytes during trypsin induced-vascular leucostasis, we washed the lung in cats since this species develop leucocytosis easily. One lobe only was washed for avoiding to harvest the cells present in the trachea and the main bronchi. This study was designed in several parts: (1) the lungs were washed in normal condition and several months later when trypsin was given; (2) in a kinetic experiment, 3 lavages were made consecutively a day either in normal condition or under trypsin treatment; (3) the lung was washed one day after trypsin administration. The granulocytes, and among them the neutrophils particularly, increased in number or in percentage transiently within the terminal airspaces under trypsin treatment; these granulocytes found within the airspaces are about 20% of the lung granulocytes.

The trypsin-induced leucostasis which leads to emphysema in the hamster is not due to contaminating endotoxins.

Intravenous injection of trypsin in the rat induces early lung leucostasis and emphysema of delayed onset. This report confirms that this emphysema is not rat-specific and that the leucostasis is not related to the presence of contaminating endotoxin in the trypsin. In hamsters (n = 37), leucostasis did not occur when they were injected with heat-treated trypsin, but numerous granulocytes were sequestered in the vessels of hamsters receiving a fresh solution of trypsin. In these hamsters, the number of granulocytes harvested by lavage increased significantly (1.87 x 10(6) per ml, P < 0.001) compared with hamsters injected with either heat-denatured trypsin (0.89) or saline (0.86), or compared with controls (0.86). Emphysema was inconstantly observed in hamsters 6 or 12 weeks after injection with trypsin for 1 h. It was frequently (17/20) present and always (20/20) well developed (intercept + 180 per cent) in the 2-h perfused hamsters whose lungs were abnormally heterogeneous (index + 100 per cent) relative to the seven controls and to the nine saline-injected hamsters. The efficiency of trypsin in triggering emphysema (percentage of hamsters having abnormal values of intercept) was dependent on the time of perfusion. This form of experimental emphysema is thus considered to be due to an endotoxin-independent leucostasis.