Laura Villani

Characteristics and clinical correlates of MPL 515W>L/K mutation in essential thrombocythemia.

Among 994 patients with essential thrombocythemia (ET) who were genotyped for the MPLW515L/K mutation, 30 patients carrying the mutation were identified (3.0%), 8 of whom also displayed the JAK2V671F mutation. MPLW515L/K patients presented lower hemoglobin levels and higher platelet counts than did wild type (wt) MPL; these differences were highly significant compared with MPLwt/JAK2V617F-positive patients. Reduced hemoglobin and increased platelet levels were preferentially associated with the W515L and W515K alleles, respectively. MPL mutation was a significant risk factor for microvessel disturbances, suggesting platelet hyperreactivity associated with constitutively active MPL; arterial thromboses were increased only in comparison to MPLwt/JAK2wt patients. MPLW515L/K patients presented reduced total and erythroid bone marrow cellularity, whereas the numbers of megakaryocytes, megakaryocytic clusters, and small-sized megakaryocytes were all significantly increased. These data indicate that MPLW515L/K mutations do not define a distinct phenotype in ET, although some differences depended on the JAK2V617F mutational status of the counterpart.

EZH2 mutational status predicts poor survival in myelofibrosis.

We genotyped 370 subjects with primary myelofibrosis (PMF) and 148 with postpolycythemia vera/postessential thrombocythemia (PPV/PET) MF for mutations of EZH2. Mutational status at diagnosis was correlated with hematologic parameters, clinical manifestations, and outcome. A total of 25 different EZH2 mutations were detected in 5.9% of PMF, 1.2% of PPV-MF, and 9.4% of PET-MF patients; most were exonic heterozygous missense changes. EZH2 mutation coexisted with JAK2V617F or ASXL1 mutation in 12 of 29 (41.4%) and 6 of 27 (22.2%) evaluated patients; TET2 and CBL mutations were found in 2 and 1 patients, respectively. EZH2-mutated PMF patients had significantly higher leukocyte counts, blast-cell counts, and larger spleens at diagnosis, and most of them (52.6%) were in the high-risk International Prognostic Score System (IPSS) category. After a median follow-up of 39 months, 128 patients (25.9%) died, 81 (63.3%) because of leukemia. Leukemia-free survival (LFS) and overall survival (OS) were significantly reduced in EZH2-mutated PMF patients (P = .028 and P < .001, respectively); no such impact was seen for PPV/PET-MF patients, possibly due to the low number of mutated cases. In multivariate analysis, survival of PMF patients was predicted by IPSS high-risk category, a < 25% JAK2V617F allele burden, and EZH2 mutation status. We conclude that EZH2 mutations are independently associated with shorter survival in patients with PMF.

Anaemia characterises patients with myelofibrosis harbouring MplW515L/K mutation

The clinical and haematological phenotype of patients with myelofibrosis harbouring MPLW515L/K mutation has not been thoroughly investigated. Of 217 myelofibrosis subjects, 18 (8·2%) had an MPL mutation, four of which (22%) co‐existed with JAK2V617F mutation. When compared with MPL wild‐type patients, irrespective of JAK2V617F status, those with MPLW515L/K, were more frequently female, were older (61 years vs. 57 years; P = 0·02), presented with more severe anaemia (haemoglobin, 101 g/l vs. 121 g/l; P = 0·002) and were more likely to require regular transfusional support (P = 0·012). These data indicate that MPL mutation in myelofibrosis characterises patients with more severe anaemic phenotype.

Gastric Carcinoids and Related Endocrine Growths

A series of 30 gastric endocrine tumours has been revised in the light of available available cytologic and clinicopathologic information. Among 24 well differentiated endocrine tumours-16 with and 8 without chronic atrophic gastritis (CAG)-3 gastrin cell tumours have been distinguished from 21 argyrophil carcinoids, 15 of which showed light- and/or electronmicroscopy patterns of enterochromaffin-like (ECL) cell tumours, 2 of EC cell tumours and 1 of D1/P cell tumour. One case of mixed carcinoid/adenocarcinoma and 5 cases of endocrine carcinomas, 4 poorly and 1 moderately differentiated, were also identified. Achlorhydria, due to type A CAG or HCl-suppressing drugs, and bombesin hyperstimulation are among possible factors inducing G cell hyperfunction and/or hyperplasia. Hypergastrinaemia is among causative agents of argyrophil ECL cell hyperplasias and, possibly, of tumours of the oxynticopeptic mucosa, while chronic inflammation and gland atrophy with or without concomitant hypergastrinaemia are important factors in inducing both hyperplastic and tumour argyrophil growths in CAG mucosa.

Helicobacter pylori infection and chronic gastritis: clinical, serological, and histologic correlations in children treated with amoxicillin and colloidal bismuth subcitrate.

Twenty-three children with Helicobacter (Campylobacter) pylori-associated chronic gastritis are reported. Family history of peptic disease, previous digestive procedures, and nonspecific epigastric pain were the most frequently encountered clinical features. Antral nodularity at endoscopy and histologic evidence of follicular gastritis were characteristic morphological aspects. Rapid urease tests suggested the diagnosis in 90% of patients. Significant increases of serum IgG and IgA against Helicobacter pylori allowed the identification of infected children with 95% cumulative sensitivity. Treatment with amoxicillin and bismuth subcitrate eradicated the infection and improved gastritis in 13 of 19 children. These findings provide further evidence for the etiologic role of Helicobacter pylori in chronic antral gastritis in children.

Epithelial Cytotoxicity, Immune Responses, and Inflammatory Components of Helicobacter pylori Gastritis

To clarify the mechanisms of the gastric mucosal immune--inflammatory response to Helicobacter pylori infection, surgical and biopsy specimens from asymptomatic uninfected, gastritis-free individuals and from H. pylori-positive ulcer patients with chronic gastritis were investigated using light and electron microscopy. Activation of the antigen-transporting endocytic--endosomal system, enhanced expression of the antigen-processing enzyme cathepsin E and de novo expression of antigen-presenting human leukocyte antigen (HLA)-DR molecules have been detected in H. pylori-colonized gastric epithelium. These findings may be crucial in the production of a mucosal immune-inflammatory response to H. pylori infection. Cytoplasmic swelling and vacuolation, micropapillary change, mucin loss, erosion of the juxtaluminal cytoplasm and cell desquamation were the main effects of bacterial cytotoxicity on gastric surface-foveolar epithelium. Activated macrophages and granulocytes (partly linked to the mucosal IgG immune response) concentrate in the foveolar-neck region of the mucosa, where they may enhance damage and impair regeneration of the epithelium. Both direct bacterial cytotoxicity and inflammatory cell aggression against gastric epithelium may predispose the patient to peptic ulcer disease.

Altered intercellular glycoconjugates and dilated intercellular spaces of esophageal epithelium in reflux disease

Abstract Background and aims: The usefulness of histological diagnosis of gastroesophageal reflux disease (GERD) is limited by poor specificity or sensitivity of available diagnostic tools. Recently, ultrastructural morphometry showed interstitial space dilation (ISD) to be a reliable sign of reflux disease. Aims of this study were to (a) search for a light microscopy equivalent of ISD, (b) test its diagnostic value, and (c) look for a possible role of intercellular glycoconjugates in its genesis. Methods: Esophageal grasp biopsies were taken during endoscopy, 2–3 cm and 6–7 cm above the squamo- columnar junction, from patients under investigation for GERD symptoms. The biopsies were fixed in aldehyde solutions and embedded in resin for electron microscopy or in paraffin for routine histology, and the glycoconjugates underwent immunohistochemistry using 3-fucosyl-N-acetylactosamine antibodies. Results: Irregular intercellular space dilation was detected in the basal and prickle layers using both light and electron microscopy. Hematoxylin–eosin preparations showed ISD in 20 of 22 (90%) erosive esophagitis cases, 30 of 44 (68%) endoscopy negative GERD cases, and 1 of 12 (8%) controls, with good interobserver (K=0.75) and bioptic site reproducibility. ISD correlated with loss or rearrangement of intercellular glycoconjugates of the overlying layers and with granulocyte (eosinophil and/or neutrophil) infiltration. Conclusions: Light microscopy ISD is a suitable index of GERD. Alterations of intercellular glycoconjugates are likely to have a role in the genesis of ISD and GERD.

Session 5: Morphology and Pathogenesis of Endocrine Hyperplasias, Precarcinoid Lesions, and Carcinoids Arising in Chronic Atrophic Gastritis

Solcia E, Fiocca R, Villani L, Gianatti A, Cornaggia M, Chiaravalli A, Curzio M, Capella C. Morphology and pathogenesis of endocrine hyperplasias, precarcinoid lesions, and carcinoids arising in chronic atrophic gastritis. Scand J Gastroenterol 1991, 26(suppl 180), 146–159The spectrum of endocrine cell changes occurring in 80 cases of body-fundus chronic atrophic gastritis (CAG), mostly type A or multifocal, including various types of hyperplasia, precarcinoid lesions (20 cases), and neoplasia (carcinoid, 24 cases) have been analyzed histologically, histochemically, and ultrastructurally. Changes associated with gland atrophy, pyloric- or intestinal-type metaplasia, regenerative hyperplasia, and hypergastrinemia have been identified and their neoplastic potential evaluated in the light of their proliferative capacity (bromodeoxyuridine incorporation) and clinicopathologic behavior. A close link between disseminated precarcinoid lesions of non-tumor mucosa and multiple carcinoids (carcinoidosis) arising in...

Helicobacter colonization and histopathological profile of chronic gastritis in patients with or without dyspepsia, mucosal erosion and peptic ulcer: A morphological approach to the study of ulcerogenesis in man

Helicobacter pylori colonization and the incidence, severity, activity and topography of gastritis were investigated systematically in antrum and corpus mucosal biopsies of 1177 subjects undergoing endoscopy in the absence of gastric complaints (asymptomatic, 49) or for non-ulcer dyspepsia (NUD; 631 patients, 72 of whom had gastric and/or duodenal erosions), active gastric ulcer (GU, 76 patients), active duodenal ulcer (DU, 138 patients), and healed gastric (HGU, 39 cases) or duodenal ulcer (HDU, 230 cases). In the antrum,H. pylori colonization and the incidence, severity and activity of gastritis increased progressively in the sequence asymptomatic, erosion-free NUD, erosive NUD, healed ulcer and active ulcer. The same trend was observed in the corpus as regardsH. pylori and gastritis incidence, whereas the severity and activity of gastritis were lower in active DU and erosive NUD and higher in active, proximal GU than in the remaining patients. Active DU and erosive NUD showed the highest incidence of nonatrophic gastritis and lowest type-A or AB atrophic gastritis, while active GU had lowest normal mucosa or type-A gastritis and highest type-B atrophic gastritis. In conclusion,H. pylori colonization and gastritis incidence, severity and, especially, activity of the antrum might all contribute to mucosal erosion and ulceration, whereas the same factors, at least in part and with the exception of proximal GU, seem to have a preventive role when affecting corpus mucosa.

Characterization of Four Main Cell Types in Gastric Cancer: Foveolar, Mucopeptic, intestinal Columnar And Goblet Cells: An histopathologic, histochemical and ultrastructural study of “early” and “advanced” tumours

Gastrectomy specimens of 148 gastric cancers, 40 of them being intramucosal or microinvasive, 27 penetrating the submucosa and 81 invading the muscularis propria, with or without involvement of the serosa and perigastric tissues, have been investigated with conventional histopathologic techniques, mucin histochemistry and electron microscopy to characterize the various lines of tumour cell differentiation and to correlate these with the histologic patterns of tumour growth. More or less differentiated intestinal columnar, intestinal goblet, gastric foveolar or mucopeptic cells were recognized in most tumours, of glandular, diffuse or mucoid type. Although simultaneous expression of more than one cell type into the same tumour occurred very frequently, intestinal columnar cells were more prominent in tubular adenocarcinomas, goblet cells (especially of colorectal type) in mucoid cancers, mucopeptic cells in diffuse cancers of invasive desmoplastic type and foveolar cells in diffuse cancers of intramucosal signet-ring cell type. In general, an increased tendency to foveolar cell differentiation and a reduced tendency to mucopeptic differentiation has been found in intramucosal cancers as compared to invasive cancers. It is concluded that the type of tumour cell differentiation, which might have some influence on the natural history of gastric cancer, is better related with more defined tumour subtypes than with the usually recognized glandular or diffuse patterns.