Hyperleukocytosis and leukostasis: management of a medical emergency.

INTRODUCTION: Hyperleukocytosis is defined as a white blood cell count greater than 100,000/mL in patients affected by acute leukemia and often it is associated with increased morbidity and mortality, that can be up to 40% if unrecognized. Areas covered: Risk factors include younger age, myelomonocytic or monocytic/monoblastic morphology, microgranular variant of acute promyelocitic leukemia and T-cell ALL, and some cytogenetic abnormalities. Poor prognosis due to high early death rate secondary to leukostasis. The mechanisms at the origin of leukostasis are still poorly understood. The management of acute hyperleukocytosis and leukostasis involves supportive measures and reducing the number of circulating leukemic blast cells, with careful monitoring of fluid balance, control of uric acid production and control of urine pH to prevent tumour lysis syndrome. Expert commentary: Several studies have been performed to ameliorate the outcome of this setting of patients. The high number of leukocytes may cause 3 main complications: disseminated intravascular coagulation (DIC), tumor lysis syndrome (TLS), and leukostasis. Although hyperleukocytosis and tumour lysis syndrome are still a challenge for clinicians, a better prognosis for these conditions is emerging in the last years.

Leukapheresis treatment in elderly acute leukemia patients with hyperleukocytosis: A single center experience.

AIM: Leukapheresis is an invasive treatment modality used for hyperleukocytosis. Various drugs and fluids are used during the leukapheresis. Aging itself and associated factors such as increased comorbidity, decreased tolerance to drugs, increased drug toxicity give rise to the application of other treatment modalities in elderly patients. Treatment of acute leukemia in the elderly differs from young patients. Consequently, we assumed that outcome, effectiveness, and side effects of leukapheresis treatment used for acute leukemia patients with hyperleukocytosis may be different in elderly compared to younger patients. METHODS: We retrospectively evaluated a total of 39 patients. Eighteen patients were 65 years and older. Indications for leukapheresis were determined as symptoms of leukostasis and prophylaxis. Acid citrate dextrose-A, calcium gluconate, and plasma were used during the leukapheresis. Age, sex, diagnosis, count, and indications of leukapheresis procedures, leukocyte count, and lactate dehydrogenase level were analyzed at the onset of and after leukapheresis; side effects, causes of death, early and total mortality rates were also analyzed. We compared the two groups with regard to effectiveness, clinical outcomes, and side effects. RESULTS: There were no statistically significant differences between the two groups with respect to sex, diagnosis, initial leukocyte count, lactate dehydrogenase level, number of leukapheresis procedures, rates of side effects, or early and total mortality (P > 0.05). Leukapheresis treatment was effective in both groups (P < 0.05) and no significant difference was found in its effectiveness between two groups (P > 0.05). CONCLUSION: Leukapheresis is an effective and safe treatment modality in elderly acute leukemia patients with hyperleukocytosis.

How we approach a patient with symptoms of leukostasis requiring emergent leukocytapheresis.

Hyperleukocytosis can induce leukostasis, which can lead to vascular obstructions (usually in the lungs and central nervous system), tumor lysis syndrome, and disseminated intravascular coagulation. Although it has not been conclusively shown to improve long-term outcome, leukocytapheresis may be used as part of the management of hyperleukocytosis with or without leukostasis to rapidly reduce the white blood cell (WBC) burden. Since leukocytapheresis only temporarily decreases the WBC count, early initiation of more definite therapy, such as hydroxyurea and/or chemotherapy, is essential. In this article, clinical assessment of the patient's clinical status to determine the need for leukocytapheresis as well as a general guideline for management of the technical aspects and complications of the procedure are discussed.

Leucodepletion for hyperleucocytosis--first report on a novel technology featuring electronic interphase management.

BACKGROUND AND OBJECTIVES: Therapeutic leucodepletion plays an established role in the initial treatment of patients with acute myeloid leukaemia (AML) and possibly other leukaemias presenting with leucostasis. Recently, a new leucodepletion technology, Spectra Optia IDL, has become available that differs from its predecessor, COBE Spectra MNC, by a variety of electronic supports, including by electronic adjustment of buffy coat positioning at the collection port. Given the paucity of patients in need of leucodepletions and marked differences in clinical presentation as well as blast properties (e.g. size, density), formal clinical trials comparing leucodepletion technologies have never been executed. MATERIALS AND METHODS: Here, we present aggregate data from eight leucodepletions performed in AML patients with clinical signs of leucostasis between 11/2011 and 07/2012 with the new device and compare the apheresis outcomes with those from fifteen leucodepletions performed with the old technology between 06/2010 and 10/2011. RESULTS: Patients did not differ with respect to epidemiological data. Pre-apheresis leucocyte count (WBC) was significantly higher in Spectra Optia IDL patients. Tolerability was excellent with both devices. Basic apheresis denominators such as duration, processed volume, inlet pump rate, ACD-A consumption and product volume were very similar. A negative correlation between pre-apheresis WBC and collection efficiency was noted. Mean collection efficiency for leucocytes with Spectra Optia IDL (47·3%) was similar to that with COBE Spectra MNC (50·5%). Platelet attrition was similar with both devices, approximately 30%. CONCLUSION: The novel, electronically guided leukapheresis system is suitable for leucodepletion.

CD11b+ bone marrow-derived monocytes are the major leukocyte subset responsible for retinal capillary leukostasis in experimental diabetes in mouse and express high levels of CCR5 in the circulation.

We investigated the phenotype of cells involved in leukostasis in the early stages of streptozotocin-induced diabetes in mice by direct observation and by adoptive transfer of calcein-AM-labeled bone marrow-derived leukocytes from syngeneic mice. Retinal whole mounts, confocal microscopy, and flow cytometry ex vivo and scanning laser ophthalmoscopy in vivo were used. Leukostasis in vivo and ex vivo in retinal capillaries was increased after 2 weeks of diabetes (Hb A(1c), 14.2 ± 1.2) when either donor or recipient mice were diabetic. Maximum leukostasis occurred when both donor and recipient were diabetic. CD11b(+), but not Gr1(+), cells were preferentially entrapped in retinal vessels (fivefold increase compared with nondiabetic mice). In diabetic mice, circulating CD11b(+) cells expressed high levels of CCR5 (P = 0.04), whereas spleen (P = 0.0001) and retinal (P = 0.05) cells expressed increased levels of the fractalkine chemokine receptor. Rosuvastatin treatment prevented leukostasis when both recipient and donor were treated but not when donor mice only were treated. This effect was blocked by treatment with mevalonate. We conclude that leukostasis in early diabetic retinopathy involves activated CCR5(+)CD11b(+) myeloid cells (presumed monocytes). However, leukostasis also requires diabetes-induced changes in the endothelium, because statin therapy prevented leukostasis only when recipient mice were treated. The up-regulation of the HMG-CoA reductase pathway in the endothelium is the major metabolic dysregulation promoting leukostasis.

Leukapheresis in management hyperleucocytosis induced complications in two pediatric patients with chronic myelogenous leukemia.

Complications caused by elevated white blood cell count in pediatric patients with CML could be a presenting feature of the disease. Here, we present two adolescents, aged 16 and 17years, who were admitted for investigation of extremely elevated leukocytes and complications of leucostasis. Initial manifestations were priapism and blurred vision, respectively. Diagnosis of chronic phase of chronic myeloid leukemia is established, and conventional measures for leucoreduction began. However, since there were no improvements, a leukapheresis procedure was initiated. After undergoing 3 daily procedures the leukocyte count declined for each patient, with resolution of pripaism and ophtalmological disturbances. Leukapheresis is safe and effective therapeutic option for patients with complications of hyperleucocytosis. If started in a timely manner, permanent organ damage or death could be avoided.

Therapeutic leukapheresis in patients with leukostasis secondary to acute myelogenous leukemia.

Leukostasis is a relatively uncommon but potentially catastrophic complication of acute myelogenous leukemia (AML). Prompt leukoreduction is considered imperative to reduce the high mortality rate in this condition. Leukapheresis, usually associated with chemotherapy, is an established approach to diminish blast cell counts. We report a single center experience in managing leukostasis with leukapheresis. Fifteen patients with leukostasis of 187 patients with AML (8.02%) followed at our institution were treated with leukapheresis associated with chemotherapy. The procedures were scheduled to be performed on a daily basis until clinical improvement was achieved and WBC counts were significantly reduced. Overall and early mortalities, defined as that occurred in the first 7 days from diagnosis, were reported. A high proportion of our patients with leukostasis (46.66%) had a monocytic subtype AML (M4/M5, according to French-American-British classification). The median overall survival was 10 days, despite a significant WBC reduction after the first apheresis procedure (from 200.7 × 109/L to 150.3 × 109/L). Almost half of patients (7/15) had an early death. Therapeutic leukapheresis, associated or not to chemotherapy, is an effective approach to reduce WBC counts in patients with AML and leukostasis; however, this therapeutic procedure does not appear to change significantly the sombre prognosis observed in the majority of patients with this complication. Other forms of treatment must be found to reduce the high mortality rate related to leukostasis.

Correlation between expression of CD56/NCAM and severe leukostasis in hyperleukocytic acute myelomonocytic leukaemia.

OBJECTIVE: The possible contribution of surface molecules to the development of leukostasis syndrome in hyperleukocytic acute myeloid leukaemia (AML) was assessed by routine immunophenotyping and grading of the probability of clinical leukostasis. METHODS: Fifty-three patients (23 women, 30 men, median age 59 yr) with hyperleukocytic AML [white blood count (WBC) above 50 x 10(9)/L] were graded for the probability of clinical leukostasis according to the severity of neurologic, pulmonary and other symptoms possibly caused by leukostasis using a recently published scoring system. Age, WBC, absolute blast count, haemoglobin, cytogenetic risk group, infection, relative CD56 expression and absolute count of CD56 positive blasts were analyzed in multivariate stepwise backward logistic regression analysis. RESULTS: In patients with acute monocytic leukaemia (AML M4/M5) the absolute count of leukaemic blasts expressing CD56/NCAM was highly associated with the development of symptoms graded as highly probable leukostasis and all three patients succumbing to early death were CD56 positive. Only the absolute count of CD56 positive blasts was a significant predictor of risk of severe leukostasis (P = 0.020). This was not found in AML without monocytic involvement (AML M1, M2, M3v). CONCLUSIONS: The expression of CD56/NCAM, a surface marker used in routine immunophenotyping of AML, may help to predict severe and potentially fatal leukostasis in hyperleukocytic acute myelomonocytic leukaemia. These results emphasize the usefulness of this four-stage clinical grading scale for analysing the factors, which lead to severe leukostasis in hyperleukocytic patients. We extend previous findings that the mechanisms of leukostasis are different depending on the involvement of the monocytic lineage.

Case report: mantle cell lymphoma, prolymphocytoid variant, with leukostasis syndrome.

A 76-year-old man presented with leukostasis syndrome, including oculodynia, blurred vision, and visual field defects, due to mantle cell lymphoma, prolymphocytoid variant, with marked leukocytosis, 1227 x 10(9)/l. He had splenomegaly but no lymphadenopathy or hepatomegaly. The tumor cells were CD5+, CD19+, CD20+, FMC-7+, and kappa light chain restricted. Immunohistochemistry showed expression of p53 and of cyclin D1. Fluorescent in situ hybridization demonstrated t(11;14) with translocation between CYCLIN D1 and the immunoglobulin heavy-chain genes. The patient received leukapheresis and aggressive chemotherapy, but the leukocyte count remained above 100 x 10(9)/l. The patient's condition rapidly deteriorated with lymphomatous infiltration of his lungs and soft tissues, and he expired 6 months after diagnosis. While it is known that mantle cell lymphoma may have a leukemic phase, the degree of leukocytosis in this case exceeds that previously reported in the literature and resulted in a clinical syndrome of leukostasis.

Hyperleukocytic leukemias and leukostasis: a review of pathophysiology, clinical presentation and management.

Acute hyperleukocytic leukemias (AHL) are associated with a very high early mortality rate mostly due to respiratory failure or intracranial bleeding. The pathophysiological process leading to these complications is called leukostasis but the biological mechanisms underlying its development and progression remain unclear. Although traditionally related to "over-crowding" of leukemic blasts in the capillaries of the microcirculation, leukostasis is likely to result from direct endothelial cell damage. This damage is probably mediated by soluble cytokines released during the interaction between leukemic cells and vascular endothelium and by the subsequent migration of leukemic blasts in the perivascular space. Leukemic cell's ability to respond to chemotactic cytokines and their expression of specific adhesion molecules are probably more important in determining whether leukostasis will develop than the number of circulating blasts. This could explain why leukostasis does not develop in all patients with AHL. The identification of the adhesion molecules, cytokines and receptors mediating endothelial cell damage in AHL should become a priority if therapeutic improvements are desired. Leukapheresis is widely used but it is unclear whether it provides additional benefit to a simpler and less invasive intervention with allopurinol, hydroxyurea and intravenous fluids. Cranial irradiation is not generally recommended. Induction chemotherapy should be started without delay. It is hoped that specific pharmacological inhibitors of the interaction between leukemic cells and vascular endothelium will result in an improved outcome for this very high-risk population.

[Unexpected death by leukostasis and lung leukostatic tumors in acute myeloid leukemia. Study of four cases]. / Morte inattesa da leucostasi e da tumori leucostatici polmonari nelle leucemie mieloidi acute. Studio su quattro casi.

Four cases of unexpected death due to acute myeloid leukemia have been studied: myeloblastic M1 (case I and II), promyelocytic M3 (case III), myelomonocytic M4 (case IV). Diagnosis was performed before death only in case III. Histological leukostasis was the most evident feature in all cases, particularly at the lung level, where tumor-like aspects were evident and widely diffused in case II. The last three cases were pregnant at the third trimester. Serious hemorrhagic complications were evident in all cases: CID in the former 3 cases and primary hyperfibrinolysis in the 4th, as demonstrated by the absence of intravascular cloths in many organs and especially in lung and kidney; abundant, on the contrary, in the former three cases. Leukostasis was not associated to hyper-leucocytosis in all 4 cases, but associated to normal number of peripheral white cells (below normal level in case III). This phenomenon, that disagrees with literature data on acute or chronic reactivated myeloid leukemia leukostasis, may be due to the primary confination of the immature granuloblasts in the vascular bed, because of the hemoreologic effects connected with their deficient plasticity, that is essential for normal granulocytes to flow easily in the capillary bed. In all cases death was caused by breathing and cardiocirculatory insufficiency with the associated unceasing hemorrhages.

Central nervous system leukostasis in patients with leukemias and lymphomas.

The clinical and neuropathological investigations have been done on 133 autopsied patients died of leukemia or non-Hodgkin's lymphoma of high malignancy. A study was performed to analyse the role of various factors particularly with respect to adhesion and aggregation in the CNS leukostasis development. The findings were also designated to evaluate the distribution of leukostasis in different CNS regions and to recognize its intensity in various CNS vessels. Basing on the studies the authors conclude that the risk of CNS leukostasis increases evidently when the leukocyte counts are elevated above 50 G/l. The adhesion and aggregation of leukemic and lymphomatous cells as well as local anatomical factors in the CNS vessels play and important role in the CNS leukostasis development, which is more intensive in the white matter and leptomeninges. The medium-sized vessels are much involved, whereas cortical capillaries are relatively less affected by leukostasis. The CNS leukostasis appears to be dynamic and reversible phenomenon, which undergoes fluctuations according to the leukocyte counts increase or decrease.