The hypereosinophilic syndrome: fluorescence in situ hybridization detects the del(4)(q12)-FIP1L1/PDGFRA but not genomic rearrangements of other tyrosine kinases

BACKGROUND AND OBJECTIVES

According to WHO criteria, the idiopathic hypereosinophilic syndrome (HES) is defined as persistent eosinophilia (>1.5x10(9)/L) without underlying causes, which is associated with signs or symptoms of organ involvement. Increased bone marrow blasts (>5%) or cytogenetic/genetic markers indicate chronic eosinophilic leukemia (CEL). A cryptic deletion of 4q12, i.e. del(4)(q12), producing the FIP1L1/PDGFRA fusion gene, identifies a distinct CEL subgroup (4q-/CEL). Our aims were: a) to use interphase-fluorescent in situ hybridization (FISH) to detect the cryptic 4q12 deletion; b) to compare the clinico-hematologic features of 4q-/CEL with other HES; c) to investigate whether PDGFRB, FGFR1, ABL1, and ETV6-activated tyrosine kinases are rearranged in CEL/HES.

DESIGN AND METHODS

This multicenter study included 20 patients fulfilling the WHO criteria for HES and 6 patients without signs/symptoms of end-organ involvement. Double-color FISH was applied in all cases to investigate del(4)(q12). Further interphase-FISH assessed whether PDGFRB/5q33, FGFR1/8p11, ABL1/9q34, and ETV6/12p13, undergo rearrangements in HES.

RESULTS

Ten of the 26 patients (9 males and 1 female) had a cryptic del(4)(q12)-FIP1L1/PDGFRA which was confirmed by reverse transcription polymerase chain reaction (RT-PCR) analysis in four. Hepatomegaly and splenomegaly were significantly more frequent in these 10 than in the other 16 patients. Seven of these 10 patients received imatinib mesylate therapy and all achieved hematologic remission. In 3 of the patients interphase-FISH and RT-PCR demonstrated cytogenetic and molecular remission. Improvements were observed in signs and symptoms of cardiac and central nervous system involvement in 2 and 1 patient, respectively. Rearrangements of PDGFRB, FGFR1, ABL1, or ETV6 were not detected in this study.

INTERPRETATION AND CONCLUSIONS

FISH is a reliable diagnostic test for differentiating 4q-/CEL from other forms of HES, allowing an early diagnosis of good responders to imatinib mesylate therapy. For the first time we show that PDGFRB, FGFR1, ABL1 and ETV6 are not rearranged in HES and 4q-/CEL cases we studied.

Involvement of nitric oxide in farnesyltransferase inhibitor-mediated apoptosis in chronic myeloid leukemia cells

The mechanism of action of farnesyltransferase inhibitors (FTIs) has not been fully clarified. We investigated the cytotoxic effects of various FTIs in chronic myeloid leukemia (CML), using LAMA cells and marrow cells from 40 CML patients in chronic phase. FTI-mediated cytotoxic effect was observed in LAMA cells and in 65% of primary CML cells, whereas marrow cells from controls were only weakly affected. Cytotoxic effects were partially related to enhanced apoptosis; however, Fas-receptor (FasR) and Fas-ligand (FasL) expression were not modified by FTIs. Susceptibility to FTI-mediated inhibition did not correlate with FasR/FasL expression in CD34+ CML cells. Moreover, intra-cellular activation of caspase-1 and -8 were not altered by FTIs, and their blockade did not reverse FTI toxicity. However, we observed FTI-induced activation of caspase-3, and its inhibition partially reverted FTI-induced apoptosis. FTIs did not modulate bcl2, bclxL, and bclxS expression, whereas they increased inducible nitric oxide (iNOS) mRNA and protein levels, resulting in higher NO production. Furthermore, C3 exoenzyme, a Rho inhibitor, significantly increased iNOS expression in CML cells, suggesting that FTIs may up-regulate NO formation at least partially through FTI-mediated inhibition of Rho. We conclude that FTIs induce selective apoptosis in CML cells via activation of iNOS and caspase-3.

Effects of cyclosporine on hematopoietic and immune functions in patients with hypoplastic myelodysplasia: in vitro and in vivo studies

BACKGROUND

Immunosuppression may benefit some patients with hypoplastic myelodysplasia (HMDS) and refractory anemia (RA), but its mechanism of action is still obscure.

METHODS

Using flow cytometry, we studied Fas-receptor (Fas-R), Fas-ligand (Fas-L), and interferon-gamma (IFN-gamma) expression in CD34(+) cells and lymphocytes obtained from 11 HMDS and 20 RA patients. In colony assays and long-term cultures, the effects of Fas triggering, IFN-gamma blockade, or cyclosporine(CsA) on the growth of hematopoietic progenitors (colony-forming cells [CFC]) were determined. The effects of CsA at daily doses of 1-3 mg/kg for at least 3 months in HMDS patients were also studied.

RESULTS

In basal conditions, committed and immature progenitor cells were found decreased in myelodysplastic (MDS) patients. No significant differences between HMDS and RA patients were detected. IFN-gamma-expressing CD4(+) cells were significantly increased in HMDS patients, whereas intracytoplasmic Fas-L expression was only borderline elevated in CD3(+) MDS cells. Increased numbers of CD34(+) cells expressing Fas-R were found in HMDS and RA patients. CFC and secondary CFC showed higher susceptibility to Fas-L-mediated inhibition and the blockade of IFN-gamma improved marrow primary, but not secondary, CFC growth. CsA added in vitro to patient's lymphocytes significantly decreased the number of IFN-gamma-expressing CD4(+) cells, but not Fas-L production. These effects were associated with increased colony formation. Similar to IFN-gammablockade, production of secondary CFC was not enhanced by CsA. Administration of CsA to patients resulted in prolonged partial hematologic improvement in 8 of 11 HMDS patients.

CONCLUSIONS

Increased frequency of IFN-gamma producing CD4(+) cells supports the involvement of lymphocyte-mediated suppression of hematopoiesis in the development of cytopenia in MDS patients. The ability of CsA to decrease in vitro IFN-gamma production may improve hematopoietic function, explaining the beneficial effect of this agent in HMDS patients.

Partial deletions of long arm of chromosome 6: biologic and clinical implications in adult acute lymphoblastic leukemia

Within 285 adult acute lymphoblastic leukemias (ALL) included in the multicenter GIMEMA 0496 trial and prospectively studied by conventional cytogenetics, 18 cases (6%) with long arm deletion of chromosome 6 (6q) were identified. These cases were divided into: (i) del(6q) only (n = 6); (ii) del(6q) plus other numerical and/or structural abnormalities (n = 8); (iii) del(6q) and other 'specific' translocations (n = 4). The biologic and clinical features of the patients carrying this anomaly, as well as their outcome, were compared with those of 267 patients without del(6q). A T cell phenotype was more frequently associated with del(6q) cases in general (P = 0.001) and particularly with cases presenting del(6q) as the isolated abnormality (P = 0.0027). No significant difference with respect to multidrug resistance (MDR)/P glycoprotein expression was observed between the two groups of patients (21% vs 28% of MDR-positive cases, respectively). A BCR-ABL fusion transcript was less frequently detected in cases with del(6q) (11%) compared with those without the anomaly (29%). p15 and p16 deletions were identified by Southern blot analysis in 21% of cases with del(6q) and in 26% of cases without del(6q). In this latter group, a T cell phenotype was less frequently associated with p15 and/or p16 deletion than in the group carrying del(6q) (36% vs 100% of cases, P = 0.011). Overall, patients with ALL and del(6q) had a high complete remission (CR) rate (83%); however, they had a lower 18 month event-free survival (31% vs 41%) and a higher relapse rate (70% vs 37%, P = 0.02) compared with patients without del(6q). To date, this is the largest series of adult ALL cases reported with del(6q) homogeneously treated, which have also been prospectively studied for MDR expression and for the detection of known fusion genes. This anomaly, as an isolated change, identifies a subset of cases with hyperleukocytosis (median WBC count 52 x 10(9)/l) and a strict correlation with a T cell phenotype. Overall, del(6q) seems to be associated with an unfavorable clinical outcome, although this finding will need to be confirmed by extended FISH analysis.

Apoptosis induction in vivo and fate of apoptotic material in the colon of the guinea pig

Short-chain fatty acids (SCFA) in particular butyrate are regarded as an energy source acting in beneficial, protective manner on the colonic mucosa. Previous investigations showed that the colonic mucosa bathed in Ussing chamber with a solution lacking butyrate induced massive apoptosis of epithelial cells. The apoptotic material (bodies and cells) was shed at the mucosa surface. In the present study we aimed to investigate the effects caused in vivo on the colonic mucosa by the absence of butyrate. For this purpose the colon of guinea pigs was perfused in situ with solutions either containing or lacking butyrate. The results show that within 2h of perfusion without butyrate a large amount of epithelial cells underwent apoptosis as in the in vitro experiments. However, apoptotic material instead to be extruded at the epithelial surface accumulates into the intercellular spaces from which it becomes removed by an unusual high number of macrophages. These, engorged with phagocytozed material, lie assembled in a layer below the epithelium. Similar alterations have not been observed after perfusion in the presence of butyrate. The results suggest that this SCFA may protect the colonic mucosa in that it prevents apoptosis. The alterations occurring during 2h of its absence allow to assume that a protracted butyrate deprivation may lead to a breakdown of the integrity of the mucosa thus influencing differently the activity of the macrophages.

Epithelial cell turnover--extracellular matrix relationship in the small intestine of human adults

In the human small intestine, proliferation, migration, differentiation and death of epithelial cells take place in separated compartments along the crypt-villus axis. It has been shown in different cell systems that these basic biological activities are influenced by extracellular matrix proteins. To investigate possible relationships in the epithelium of the human adult small intestine we examined immunohistochemically the distribution of type IV collagen, laminin, fibronectin and tenascin, and compared the sites of their expression with the various cell activities. Epithelial cell proliferation and cell death have been detected by an antibody against Ki-67 and the TUNEL-assay, respectively. The results show that Ki-67 staining is restricted to the crypts and TUNEL-positive cells are only present in the upper villus region. Type IV collagen is uniformly present in the epithelial basement membrane along the crypt-villus axis providing a scaffold for other components of the extracellular matrix. Laminin appears to be associated with epithelial cell differentiation, since it is strongly expressed in the villus basement membrane but only weakly underneath the crypt epithelium. Although fibronectin displays a staining pattern similar to that of laminin, it might rather be responsible for cell adhesion. Strong indications have been found that tenascin could be related to epithelial cell death since it was particularly expressed at the villus tip, where the cells undergo apoptosis.

Characterization of two novel cell lines, DERL-2 (CD56+/CD3+/Tcry5+) and DERL-7 (CD56+/CD3-/TCRgammadelta-), derived from a single patient with CD56+ non-Hodgkin's lymphoma

Two novel IL2-dependent cell lines, DERL-2 and DERL-7, were established from a patient with hepatosplenic gammadelta T cell lymphoma. This patient presented, at diagnosis, two discrete populations of CD56+ cells, one TCRgammadelta+, the second lacking T cell-restricted antigens. The cell lines derived displayed features corresponding to the two cellular components of the disease: DERL-2 was CD56+/CD3+/TcRgammadelta+ while DERL-7 was CD56+/CD3-/TcRgammadelta-. Along with CD56, the two cell lines shared the expression of CD7, CD2, CD158b and CD117. Karyotype analysis showed that both cell lines were near-diploid, with iso-7q and loss of one chromosome 10. In addition, DERL-2 showed 5q+ in all metaphases analyzed, while DERL-7 revealed loss of one chromosome 4. Genotypically, both cell lines shared the same STR pattern at nine loci and demonstrated an identical rearranged pattern of the T cell receptor genes beta, gamma and delta, with respect to the original tumor cells. These data indicated that both cell lines and the original neoplastic populations were T cell-derived and arose from a common ancestor. Among a large panel of cytokines tested, only SCF was able to substitute IL2 in supporting cell proliferation. Moreover, SCF and IL2 acted synergistically, dramatically enhancing cell growth. These cell lines may represent a model to further analyze the overlap area between T and NK cell malignancies, and may provide new information about the synergistic action of IL2 and SCF on normal and neoplastic T/NK cells.

Where's the leadership for quality measurement?

With performance measurement in gridlock, purchasers look to disease intervention to improve medical care. Consumers, meanwhile, are left with member surveys and sketchy info on providers.

Re-evaluation of epoxy resin sections for light and electron microscopic immunostaining

Epoxy resins provide optimal tissue morphology at both the light and the electron microscopic level and therefore enable correlative studies on semithin and thin sections from the same tissue block. Here we report on an approach to retain these advantages for immunolabeling studies by adapting and combining well-known techniques, i.e., surface etching with sodium ethoxide and heat-mediated antigen retrieval. We propose a simple procedure for immunostaining semithin and thin epoxy resin sections. To check its applicability, well characterized, commercially available antibodies (against E-cadherin, alpha-catenin, and beta-catenin) were used on sections of human small intestine. By light microscopy, the immunostaining efficiency was compared on cryo-, paraffin, and epoxy semithin sections processed in parallel. The most detailed results were obtained on semithin sections, where the labeling precisely delineated the lateral plasma membrane of the enterocytes. At the electron microscopic level the procedure did not damage the structures and allowed an efficient, reproducible immunogold labeling extending homogeneously over exceptionally wide tissue areas. The three antibodies specifically labeled the zonula adherens of the junctional complex between epithelial cells and, in agreement with light microscopic observations, the lateral plasma membrane.

In the mammalian eye type VI collagen tetramers form three morphologically different aggregates

The organization of the aggregates occurring in the stroma: (1) of the murine and human cornea after incubation in an ATP acidic solution; (2) of surgically excised epiretinal membranes (ERM); and (3) of the trabecular meshwork of monkey eyes was investigated morphologically and immunocytochemically on thin section electron microscopy. Morphology. The aggregates in the cornea appeared as cross-banded fibrils. The bands were uniformly electron dense (single banded form); they were separated from each other by interbands consisting of a bundle of filaments emerging in cross section as small areas of randomly assembled dot-like structures. In the ERM, most of the aggregates stood out as heteromorphic cross-banded bodies showing dense bands with electron denser borders (double banded form) and interbands composed of longitudinally oriented, parallel sheets or laminae of amorphous material enclosing thin, similarly oriented filaments. These extended, thinner and double in number (since interlacing with similar components of the opposite sheet), into the pale central zone of the dense band. The aggregates of the trabecular meshwork were heteromorphic, had uniformly dense bands (single banded form as in the cornea), but their interbands displayed longitudinal sheets (as the ERM aggregates). Immunocytochemistry revealed type VI collagen in the three eye aggregates with gold particles preferentially localized at the interbands. The specificity of the antibodies used was tested by Western blot analysis of type VI collagen samples extracted from human placenta and on homogenates of human cornea. In conclusion, the results indicate that the tetramers of type VI collagen may aggregate differently into structures with distinct supramolecular arrangements. These are illustrated in schematic drawings.

Membrana limitans interna and epiretinal membrane lying on macular holes. Some morphological observations

The structure of the membrana limitans interna (MLI) in the region of the macula has been investigated by electron microscopy in (a) 2 enucleated human adult eyes and (b) 38 surgically removed samples associated with an epiretinal membrane (ERM). In the enucleated eye, the glia cells were vitrad bordered either by the lamina rara or, directly, by the lamina densa. Both extended into a coarse network whereby the lamina densa, through repeated branches and anastomoses, delimited large meshes, the lamina rara formed their contents. High magnification revealed that both meshes and contents of this network were composed by a further, finer network. It is suggested that strips and small openings of the finer network are homologous to the cords and intercordal spaces, respectively, which have been indicated as the common, basic structures of most of the basement membranes. The MLI excised with an ERM had the same structure. In some of the ERM associated with a macular hole, myofibroblasts prevailed among the cells. They showed indented nucleus, stress fibers abuting on the plasma membrane or in apparent continuity with bundles of extracellular filaments (microtendons), gap junctions. The cells lay on or were surrounded by a discontinuous basement membrane.

Rheological properties of mixtures of kappa-carrageenan from Hypnea musciformis and galactomannan from Cassia javanica

Mixed gels of kappa-carrageenan (kappa-car) from Hypnea musciformis and galactomannans (Gal) from Cassia javanica (CJ) and locust bean gum (LBG) were compared using dynamic viscoelastic measurements and compression tests. Mixed gels at 5 g/l of total polymer concentration in 0.1 M KCl showed a synergistic maximum in viscoelastic measurements for kappa-car/CJ and kappa-car/LBG at 2:1 and 4:1 ratios, respectively. The synergistic maximum obtained from compression tests carried out for mixed gels at 10 g/l of total polymer concentration in 0.25 M KCl was the same for both kappa-car/CJ and kappa-car/LBG gels. An enhancement in the storage modulus (G') and the loss modulus (G") was observed in the mechanical spectra for the mixtures in relation to kappa-car. The proportionally higher increase in G" compared with G', as indicated by the values of the loss tangent (tandelta), suggests that the Gal adhere non-specifically to the kappa-car network.