Polymorphisms in genes encoding nonsarcomeric proteins and their role in the pathogenesis of dilated cardiomyopathy.

Dilated cardiomyopathy (DCM), clinically characterized by contractile dysfunction and ventricular chamber enlargement, is a heterogeneous heart disease leading to progressive systolic heart failure and sudden cardiac death. The etiology of the disease is multifactorial and involves genetic factors, viral infections, autoimmune phenomena, and toxic agents. Within the last two decades, a growing body of evidence has suggested that single-gene mutations play a pivotal role in the development of familial forms of dilated cardiomyopathies. Numerous genes encoding cytoskeletal, sarcomeric, and nuclear proteins have been linked to the pathogenesis of DCM, and most of the respective mutants disrupt the structural integrity of sarcomeres in cardiac myocytes. Frequently, point mutations in cytoskeletal proteins critically diminish force generation and interfere with mechanical transduction within the contractile apparatus of the myocardium, thereby ultimately leading to impaired systolic function. However, hitherto reported sarcomeric gene defects explain the etiology of the disease only in some families, leaving other forms of DCM subentities unresolved. Since one of the major factors in DCM pathogenesis involves autoimmune-mediated damage to cardiac tissue, candidate genes that are involved in controlling immune reactions have currently come into focus in genetic research. We and others have shown that a single-nucleotide polymorphism (SNP) in the gene encoding cytotoxic T-lymphocyte antigen 4 (CTLA4) is associated with the diagnosis of DCM. Cytotoxic T-lymphocyte antigen 4 is an inhibitory receptor molecule expressed on activated T lymphocytes, where it functions as an important negative regulator of T-cell activation by competing with the costimulatory CD28 receptor to bind to B7 receptors localized on the surface of antigen-presenting cells. The observed association between CTLA4 genotypes and DCM suggests that genetic factors contribute to both unbalanced immune responses in the myocardium and the development of left ventricular dysfunction. In this review, we will briefly discuss how these findings may stimulate the search for novel DCM-associated SNPs in human genes expressed in noncardiomyocytes.

Molecular signatures and the study of gene expression profiles in inflammatory heart diseases.

Myocarditis, a common heart disease pathologically defined as an inflammatory reaction of the myocardium, is most frequently caused by infectious agents, including viruses and bacteria, and may develop in later stages into dilated cardiomyopathy (DCM). Several studies have identified inflammatory components engaged in the transition from acute myocarditis to chronic DCM, and there is growing evidence that myocarditis and DCM are closely related. Novel technological advances in genomic screening have gained insight into molecular and cellular mechanisms involved the pathogenesis of inflammatory heart disease and, in particular, in the development of systolic dysfunction resulting from DCM. Detection of differential gene expression profiles have become valid tools in the study of inflammatory heart disease. Molecular signatures are defined as individual sets of genes, mRNA transcripts, proteins, genetic variations or other variables, which can be used as markers for a particular phenotype. These signatures may be useful for clinical diagnosis or risk assessment and, in addition, may help to identify molecules not previously known to be involved in the pathogenesis of these disease conditions. Microarray analyses have dramatically refined our knowledge about tissue-specific gene expression patterns, simply by being able to study thousands of genes simultaneously in a single experiment. In the field of cardiovascular research, microarrays are increasingly used in the study of end-stage cardiomyopathies, such as DCM, that ultimately lead to symptoms of heart failure. By means of microarray analysis, a set of differentially expressed genes can be detected, among them are transcripts coding for sarcomeric and extracellular matrix proteins, stress response and inflammatory proteins as well as transcription factors and translational regulators. Expression profiling may be particularly helpful to improve the differential diagnosis of heart failure and enable novel insight into selected molecular pathways.

[Treatment guidelines for aneurisms of the aorta]. / Behandlungsrichtlinien bei Aortenaneurysmen.

Aneurysmatic diseases of the aorta usually have a bad prognosis in the case of acute rupture. Guidelines exist for surgical treatment but are relatively old and have not yet been brought up to date. By introducing new techniques, thoracic aneurysms are predominantly treated by endoluminal means, for asymptomatic type B dissections, however, a stent graft insertion cannot be principally recommended. For thoracoabdominal aneurysms, a combined endoluminal and open surgical approach is still under evaluation. For the relatively frequent problem of infrarenal abdominal aortic aneurysms, an endoluminal approach is more and more taken although randomized trials have not yet shown an improvement concerning long-term mortality in favor of endografts. Interdisciplinary guidelines do not yet exist.

[Classification, genetic predisposition and risk factors for the development of cardiomyopathies]. / Klassifikation, genetische Prädisposition und Risikofaktoren für die Entwicklung einer Kardiomyopathie.

Cardiomyopathies are an important and diverse group of heart muscle diseases in which the heart muscle itself is structural or functional abnormal. This often results in severe heart failure accompanied by arrhythmias and/or sudden death. Clinical and morphological diversity of cardiomyopathies can reflect the broad spectrum of distinct underlying molecular causes or genetic heterogeneity. In addition, modifying genes, life style and additional factors were reported to influence onset of disease, disease progression and prognosis. The individual patient's phenotype may reflect a summation and/or interaction of the underlying mutation with other genetic or environmental factors. During the last years major advances have been made in the understanding of the molecular and genetic basis of this type of disease. Nevertheless, much more progress in the identification of underlying mutations, susceptibility genes and modifier genes is important and indispensable for the development of new etiology orientated forms of therapy.

[The heart in cases of viral, bacterial and parasitic infections]. / Das Herz bei viralen, bakteriellen und parasitären Infektionen.

The heart can be the primary target for a viral, bacterial or parasitic infection (primary myocarditis/inflammatory cardiomyopathy). It can also participate in the "collateral damage" due to toxins, chemo- and cytokines, autoreactive antibodies or the native and acquired immune response through T- and B-cells, monocytes and macrophages (secondary myocarditis/inflammatory cardiomyopathy), when it is not the dominant organ of the disease. Infective agents show remarkable organ specificity: viral infections, toxic and autoreactive processes affect primarily the myocardium and the pericardium, whereas bacterial infections prefer endothelial surfaces and cause endocarditis and, less frequently, pericarditis. They are even discussed as part of the inflammatory process involved in coronary artery disease. Infective agents and their adequate diagnosis and treatment are discussed for these clinical entities according to current guidelines and clinical pathways.

[Chronic critical ischemia of the lower leg: pretherapeutic imaging and methods for revascularization]. / Die chronische kritische Unterschenkelischämie: prätherapeutische Diagnostik, Methoden der Revaskularisation.

Each year 1-2% of patients with peripheral arterial occlusive disease (pAOD) develop critical limb ischemia (CLI), characterized by rest pain and peripheral ulcer or gangrene. This aggravation of the disease is accompanied by an increase of the 1-year mortality rate up to 25% and a similarly increased frequency of major amputation. We can choose between conservative, endovascular, and surgical procedures for an adequate therapy of the underlying vascular stenoses or occlusions. Yet, clear therapeutic recommendations only exist for suprapopliteal lesions. However, in a number of cases, especially in diabetics, target lesions have an infrapopliteal location. Since endovascular procedures have undergone significant improvement in the last few years, the following review discusses methods for infrapopliteal revascularization taking into consideration the newest publications on this topic.

[Stenting of the SFA--indications, techniques, results]. / Stents in der A. femoralis superficialis--Indikationen, Technik, Ergebnisse.

Aggressive risk factor modification, change of eating habits, exercise programs, and forceful antiplatelet therapy are the most important tools for the treatment of PAOD in symptomatic patients suffering from intermittent claudication. There are however no guidelines for revascularization at this stage. Endovascular treatment has been increasingly utilized over the last decade and increasingly displaced vascular surgery. Amongst numerous endovascular techniques beside PTA, stents meanwhile play the most important role due to constant technical progress. Results regarding the rate of restenosis or patency rates still remain worse compared to other vascular beds. This paper gives a review over recent results, currently available stent techniques, and possible indications for the endovascular therapy of an artery, which has turned out to be the biggest ordeal for material and construction of stents.

Investigation on radiofrequency and laser (980 nm) effects after endoluminal treatment of saphenous vein insufficiency in an ex-vivo model.

OBJECTIVES: An ex-vivo model for the experimental evaluation of endoluminal thermal procedures for occlusion of saphenous veins was developed. Radiofrequency obliteration (RFO) and endovenous laser therapy (ELT) were compared using this model. DESIGN: Experimental ex-vivo treatment study. MATERIALS AND METHODS: The model consists of the subcutaneous foot veins from freshly slaughtered cows which were reperfused in situ with heparinised bovine blood. The veins were treated with either radiofrequency (RFO n=5) or with endoluminal 980 nm laser light (ELT n=5) using a continuous pull-back for RFO and a stepwise illumination and pull-back protocol for ELT. Immediately after treatment perivenous tissue and veins were examined macroscopically. In a second study the same treatment parameters were used in four further vein segments with RFO (n=2) and ELT (n=2). These vein segments were examined microscopically in HE-stained histological sections. RESULTS: Induration of the vessel wall and contraction of the vessel lumen were observed after RFO. Laser treatment produced carbonised lesions of the vein wall. After 12-24 laser exposures these lesions often became transmural, causing complete perforation of the vessel wall. Histological evaluation after radiofrequency treatment demonstrated homogenous circular thermal tissue alteration with disintegration of intima and media structures. Histological evaluation after endovenous laser treatment showed large variations of thermal tissue effects. Tissue effects ranged from major tissue ablation and vessel wall disruption to minor effects located between laser exposures and on the opposite vessel wall. CONCLUSIONS: Our model is suitable for systematic scientific evaluation of endovenous thermal occlusion procedures. Our first results and theoretical considerations indicate that endovenous laser treatment should be modified in order to ensure controlled homogenous circular thermal damage, avoiding vessel wall perforation and damage to perivascular structures.

Pathophysiology and aetiological diagnosis of inflammatory myocardial diseases with a special focus on parvovirus B19.

Inflammatory processes induced by viral or bacterial infections are believed to be one of the major pathogenetic mechanisms in myocardial diseases. Although the reason for progression to myocardial failure is not fully understood, postulated mechanisms include persistent viral infection alone or in combination with autoimmune processes. A variety of cardiotropic viruses have been identified to elicit myocarditis, with enteroviruses and adenoviruses as the most frequent causative agents in children and adolescents. However, parvovirus B19 (PVB19) has recently emerged as another potential pathogen in adult patients associated with inflammatory heart disease. Many dimensions of inflammatory heart disease coexist while different phases of the disease progress simultaneously: phase 1 is dominated by viral infection, phase 2 by the onset of (probably) multiple autoimmune reactions, and phase 3 by the progression to cardiac dilatation without the role of an infectious agent and cardiac inflammation. Taking these mechanisms into account, screening for viral and bacterial genome by polymerase chain reaction (PCR) and detection of inflammatory infiltrates by immunohistochemistry are considered crucial for establishing an aetiological diagnosis, thereby allowing initiation of specific therapeutic strategies. In a large cohort of 3345 consecutive patients with left ventricular dysfunction evaluated over a period of 10 years, prevalence of PVB19, coxsackievirus (CVB), human cytomegalovirus (HCMV), influenza A virus and adenovirus (ADV) genome was assessed by PCR. Inflammatory infiltrates within the myocardium were detected by immunohistochemistry according to the WHF criteria and by histopathology according to the Dallas criteria of myocarditis. For control, endomyocardial samples of patients with arterial hypertension were studied. Parvovirus B19 was the most often detected virus in all patient subgroups, with positivity ranging from 17% to 33%. Except for PVB19, CVB RNA (3%), ADV (2%) and CMV (3.9%) were the most frequently detected viral genomes. Interestingly, detection of PVB19 genome was significantly correlated with inflammatory heart disease and reduced ejection fraction. Importantly, an aetiological diagnosis requires the immunohistochemical and molecular biological investigation of endomyocardial biopsies. Such an approach may change the management of these diseases in the future. One of the aims of the study was to reveal the underlying dominant pathophysiological mechanisms in a for deciding on the most approriate therapy.

[Elective therapy of asymptomatic infrarenal aortic aneurysms. Comparison of mortality and morbidity between endovascular and open repair]. / Elektive Therapie des asymptomatischen infrarenalen Aortenaneurysmas. Vergleich der Letalität und Morbidität zwischen endovaskulärer und offener Operation.

Summary. In recent years, endovascular operations on infrarenal aortic aneurysm (EVAR) have not only been acknowledged as an alternative, but have become an indispensable "tool of the trade" for the vascular surgeon. As documented in many studies, perioperative morbidity is definitely much lower than in open surgery. In the long term, open surgery is also subject to complications such as rupture or aorto-enteral fistulae which necessitate secondary operations with their associated risks. There are some valid studies documenting a significantly lower mortality for EVAR than for open surgery. These datas were recently confirmed with high evidence level by the published results of UK-EVAR trial 1. The other randomized trials are currently ongoing. If the lower morbidity and lethality rate for EVAR is confirmed in these studies, the establishment of the indication for aortic aneurysm must be reconsidered with regard to the risk profile and the maximum diameter. The fact that long-term results are not yet available for the endovascular operation introduces a factor of uncertainty. Intensive follow-up observation is therefore an absolute prerequisite in patients who have undergone endovascular treatment. If the establishment of the indication is appropriate, with the new vascular prosthesis endoleaks are no longer an insoluble problem. The two methods should not be regarded as mutually competitive, but as complementary components of the treatment spectrum at every vascular center.

[Vascular injuries in extremities]. / Gefässverletzungen an den Extremitäten.

Vascular injuries of the extremities account for most instances of vascular trauma (ca. 70%), and they entail a risk of amputation about 10-20%. According to the kind of force that has acted, arterial trauma is classified as direct or indirect. The scale of hemorrhage and peripheral ischemia depend on the nature and severity of the arterial lesion. In patients with multiple injuries, routine use of Doppler sonography and duplex sonography can facilitate early diagnosis and treatment of vascular injuries. With great certainty, clinical examination and an AB or WB index of >1.0 can rule out the presence of vascular injury that requires treatment. After excluding further life-threatening injuries, surgery should be performed immediately when there is critical ischemia, squirting hemorrhage, or a rapidly expanding hematoma. Angiography or duplex sonography findings determine the further procedure in vascular injuries that do not require immediate treatment. Occlusion of a reconstructed artery, manifestation of a compartment syndrome, and insufficient anticoagulation are the main factors affecting the risk of amputation.

Coexpression of p21(WAF1/CIP1) in adenovirus vector transfected human primary hepatocytes prevents apoptosis resulting in improved transgene expression.

Replication-deficient adenovirus (Ad vector) is one of the most effective gene transfer systems. However, its employment in human gene therapy trials is hampered by Ad vector associated cytotoxicity and induction of apoptosis of the infected cells. Here, we identify one underlying mechanism as uncoupling of S phase and mitosis of the cell cycle leading to apoptosis and decline of transgene expression. Moreover, we demonstrate a strategy to avoid Ad vector associated cytotoxicity and induction of apoptosis in human primary hepatocytes by coinfection of Ad vector carrying the cDNA of choice and the cell cycle regulator p21(WAF1/CIP1) (p21). In addition, animal experiments were performed using Ad vector directed coexpression of p21 and human alpha 1-antitrypsin. As serum analysis of alpha 1-antitrypsin after Ad vector mediated gene transfer to the liver of mice revealed, this strategy resulted also in the improvement of transgene expression by two orders of magnitude. These data suggest that coexpression of p21 and Ad vector carrying a therapeutic gene may be a promising strategy to avoid cytotoxicity and induction of apoptosis leading to improved safety in human gene therapy.

[Value of MR angiography in follow-up after cruro-pedal bypass surgery]. / Wertigkeit der MR-Angiographie im follow-up nach cruro-pedalen Bypassanlagen.

Patients after crural or pedal revascularization need a consequent surveillance to prevent graft failure. We compared the results of the clinical examination including duplexscanning with contrast-enhanced magnetic resonance angiography (MRA). 26 bypass grafts were evaluated for potential stenosis in five locations. Using both techniques, 93 of 109 locations were classified identically. 10 of 16 locations which were categorized differently were reviewed angiographically (DSA). In contrast to duplexscanning, MRA detected 3 high grade stenosis, which had to be dilatated percutaneously. MRA should be used regularly in surveillance programs of distal bypass grafting.

[Stage-adapted therapy concept in ascending thrombophlebitis]. / Stadiengerechtes Therapiekonzept bei aszendierender Varikophlebitis.

Varicophlebitis is the most frequent and important acute complication of a varicosed long and/or short saphenous vein. In view of the controversial discussion about the either conservative or surgical treatment, a clinically relevant classification of this syndrome appears useful: Stage I includes varicophlebitis without involvement of the respective junctional valve--in the groin or at the knee--and deep veins. While in Stage II the proximal part of the thrombus has reached the respective junctional valves of the long or short sapheneous vein, in Stage III it has entered the deep veins by means of these valves. In Stage IV the thrombus migrates via insufficient perforating veins into the deep system. Stages I and IV should be treated conservatively first, removal of the varicous veins should be performed after regression of the acute symptoms. Stages II and III should be considered an indication for urgent surgery. The surgical strategy consists of crossectomy, resection of the saphenous vein without stripping, radical excision of all varicous veins and ligature of insufficient perforating veins. In stage III the thrombectomy of the deep veins using the Fogarty-procedure must be carried out before any other measures are taken. In 1996 a total number of 40 limbs with ascending varicophlebitis (stage I = 16, stage II = 19, stage III = 5) was observed. 10 extremities (stage I = 2, stage II = 5, stage III = 3) underwent surgical treatment. 1 patient developed a deep infection of the groin, the average stay in hospital was 9 days.

In vitro susceptibility to TRAIL-induced apoptosis of acute leukemia cells in the context of TRAIL receptor gene expression and constitutive NF-kappa B activity.

The TNF-related apoptosis-inducing ligand (TRAIL) is currently under evaluation as a possible (co-)therapeutic in cancer treatment. We therefore examined 129 cell samples from patients with de novo acute leukemia as to their constitutive susceptibility to TRAIL-induced apoptosis In vitro. Only 21 (16%) cell samples revealed at least 10% TRAIL-susceptible cells/sample as detected by flow cytometric annexinV staining after 24 h culture compared with medium control. Precursor B cell ALL samples (11 (27%) of 41) were more TRAIL-susceptible compared with AML (5 (9%) of 54; P < 0.05) but not compared with precursor T cell ALL (5 (15%) of 34; P = 0.20). Furthermore, we examined constitutive mRNA expression levels of TRAIL receptors R1-R4 by semi-quantitative RT-PCR (n = 58). Expression levels were heterogeneous, however, there was no significant correlation between the expression of the signal-transducing receptors (R1, R2) as well as of the decoy receptors (R3, R4) and TRAIL sensitivity in this series. Constitutive NF-kappa B activity has been shown to influence TRAIL susceptibility of leukemic cells. In 39 leukemic cell samples examined, we found a generally high NF-kappa B activity as detected by electrophoretic mobility shift assay which did not differ between TRAIL-susceptible and TRAIL-resistant cases. Finally, 49 acute leukemic cell samples were coincubated with doxorubicin in vitro. Doxorubicin sensitized four of 35 initially TRAIL-resistant samples and augmented TRAIL-induced apoptosis in two of 14 TRAIL-susceptible samples. In summary, constitutive TRAIL susceptibility differs between leukemia subtypes and does not correlate with mRNA expression levels of the TRAIL receptors R1-R4 as well as constitutive NF-kappa B activation status. The observed sensitization of leukemic cells to TRAIL by doxorubicin in vitro indicates that TRAIL should be further evaluated as to its possible role as an in vivo cotherapeutic in acute leukemia.

Apoptotic response to homoharringtonine in human wt p53 leukemic cells is independent of reactive oxygen species generation and implicates Bax translocation, mitochondrial cytochrome c release and caspase activation.

In the present study, we investigated the in vitro apoptotic response of leukemic cells to the cellular stress induced by homoharringtonine (HHT), a plant alkaloid with antileukemic activity which is currently being tested for treatment of acute and chronic leukemias. A comparison of leukemic cell lines with different p53 gene status revealed a considerably higher sensitivity to HHT-induced apoptosis in the cells with a wt p53, and apoptotic events in wt p53 leukemia cells (MOLT-3 cell line) were studied in more detail. To this end, we examined components of apoptotic cascades including Bax expression and its intracellular localization, changes of mitochondrial membrane potential (MMP), reactive oxygen species (ROS) levels, cytochrome c release from mitochondria and activation of caspases. Bax protein levels did not increase despite an up-regulation of bax at mRNA level. However, Bax translocation from cytosol towards mitochondria was observed. In addition, we observed a release of cytochrome c from the mitochondria, and the localization changes of both Bax and cytochrome c were found already at the early, annexin V-negative stage of HHT-induced apoptosis. HHT-treated MOLT-3 cells revealed loss of MMP as well as activation of caspases demonstrated by DEVD-, IETD- and LEHD-tetrapeptide cleavage activity in the cell lysates. ROS levels only slightly increased in HHT-treated cells and antioxidants did not prevent apoptosis and MMP changes. Therefore, wt p53 leukemic cells respond to HHT-specific cellular stress by induction of ROS-independent apoptotic pathway characterized by translocation of Bax, mitochondrial cytochrome c release and activation of caspases.

Constitutive expression levels of CD95 and Bcl-2 as well as CD95 function and spontaneous apoptosis in vitro do not predict the response to induction chemotherapy and relapse rate in childhood acute lymphoblastic leukaemia.

CD95 (Fas/APO-1) expression and function and Bcl-2 expression, as well as spontaneous apoptosis in vitro, have been shown to be predictive markers for the in vivo response to chemotherapy in acute myeloid leukaemia (AML). To determine the clinical significance of apoptosis-regulating factors in acute lymphoblastic leukaemia (ALL), we investigated cell samples of children with ALL who had been included in the German ALL Berlin-Frankfurt-Münster (BFM) study using flow cytometry for constitutive expression levels of CD95 (n = 110) and Bcl-2 (n = 110). Furthermore, we determined the extent of spontaneous apoptosis in vitro (n = 102) and susceptibility to anti-CD95-induced apoptosis (CD95-sensitivity) (n = 97). We correlated these findings with the functional activity of the multidrug resistance (MDR)-associated P-glycoprotein (P-gp), as detected by the rhodamine123 efflux test, immunophenotype, cytogenetics and clinical data of the patients examined. Good responders to initial prednisone therapy ('prednisone response') revealed significantly higher Bcl-2 expression levels [5.4 +/- 3.4 relative fluorescence intensity (RFI), n = 68] than poor responders (3.7 +/- 2.6 RFI, n = 42; P = 0.002). There was no significant correlation between the other investigated parameters and prednisone response. Moreover, neither the CD95 and Bcl-2 expression levels nor the extent of spontaneous apoptosis in vitro, CD95 sensitivity or P-gp function were correlated with the response to induction chemotherapy or relapse rate, either for B-cell precursor ALL or T-cell ALL. No consistent pattern of change in CD95 (n = 10) and Bcl-2 expression (n = 9) was noted in cases studied at both initial diagnosis and relapse. In conclusion, our findings underline the different cell biological features of primary AML and ALL cells.

Inhibition of in vitro spontaneous apoptosis by IL-7 correlates with bcl-2 up-regulation, cortical/mature immunophenotype, and better early cytoreduction of childhood T-cell acute lymphoblastic leukemia.

In normal T-cell development, IL-7 plays a nonredundant role as an antiapoptic factor by regulating Bcl-2 expression in pro-T cells. In the current study, we addressed the roles of IL-7 and related cytokines as apoptosis-modulating factors in precursor T-cell acute lymphoblastic leukemia (T-ALL). To this end, leukemic blasts from pediatric patients with T-ALL were prospectively investigated as to their responsiveness to IL-7, IL-4, and IL-2 (in terms of modulation of spontaneous apoptosis, assessed by flow cytometry), cytokine receptor expression profiles, and expression levels of Bcl-2 and Bax proteins. IL-7, in contrast to IL-4 and IL-2, was highly efficient in apoptosis inhibition, and this effect correlated with the expression levels of IL-7Ralpha chain and with the up-regulation of Bcl-2 protein expression (P <.0001). Subclassification of T-ALL samples (n = 130) according to their in vitro IL-7 responses revealed that IL-7 refractory samples were more frequently positive for CD34 (P <.0001) and the myeloid-associated antigen CD33 (P =.01), whereas IL-7 responsiveness was associated with an expression of more mature differentiation-associated T-cell antigens (CD1a, surface CD3, CD4/8; P <.05). Furthermore, the extent of apoptosis inhibition by IL-7 in vitro quantitatively correlated with early cytoreduction as determined by the prednisone peripheral blood response on day 8 and cytoreduction in the marrow on day 15 (n = 87; P <.05). Multivariate analysis of the apoptosis-related parameters investigated, including spontaneous apoptosis, its inhibition by IL-7, and expression levels of Bcl-2 and Bax, showed that only IL-7 responsiveness has an independent impact on early cytoreduction (P <. 05), thus indicating a potential prognostic relevance of IL-7 sensitivity in T-ALL.

Detection of acute leukemia cells with mixed lineage leukemia (MLL) gene rearrangements by flow cytometry using monoclonal antibody 7.1.

Translocations involving 11q23 are among the most common genetic abnormalities in hematologic malignancies, occurring in approximately 5-10% of acute lymphoblastic leukemia (ALL) and 5% of acute myeloblastic leukemia (AML). In 11q23 translocations, the mixed lineage leukemia (MLL) gene on chromosome 11, band q23, is usually disrupted. The human homologue of the rat NG2 chondroitin sulfate proteoglycan molecule, as detected by the monoclonal antibody (moab) 7.1, was shown to be expressed on leukemic cells with MLL rearrangements of children with acute leukemia. We further investigated the reactivity of the moab 7.1 on 533 cell samples of adults (n = 215) and children (n = 318) with acute leukemias (271 AML, 217 B-lineage ALL, 37 T-lineage ALL, eight CD7+ CD56+ myeloid/natural killer cell precursor acute leukemias) by flow cytometry. In AML, 38 samples were positive for moab 7.1 ('20%-cut-off-level'). These moab 7.1-positive AML cases revealed a myelomonocytic-differentiated immunophenotype with coexpression of the NK cell marker CD56 in 33 of 38 cases. Two of eight cell samples of the recently described CD7+ CD56+ myeloid/natural killer cell precursor acute leukemia entity reacted with moab 7.1. In ALL, 35 samples mostly of the pro-B-ALL subtype (33 pro-B-ALL, one common-ALL, one pre-B-ALL) were positive for moab 7.1. 58 (81%) of 72 samples with MLL rearrangements were positive for moab 7.1 including 28/31 with a t(4;11), 16/17 with a t(9;11), 3/5 with a t(11;19), and 2/6 with a del(11)(q23). All moab 7.1-positive ALL (n = 34) and childhood AML (n = 17) cases revealed MLL rearrangements as detected by Southern blot analysis and RT-PCR. However, 11 adults with AML, and one adult with moab 7.1-positive CD7+ CD56+ myeloid/natural killer cell precursor acute leukemia were negative for MLL rearrangements as proved by Southern blot analysis. We conclude that moab 7.1 is a sensitive but not entirely specific marker for the identification of 11q23-associated AML and ALL by flow cytometry in children and adults.