- Vittorio Necchi1,
- Antonella Minelli1,
- Patrizia Sommi1,
- Agostina Vitali2,
- Roberta Caruso3,
- Daniela Longoni4,
- Maria R. Frau5,
- Cristina Nasi6,
- Fabiola De Gregorio7,
- Marco Zecca8,
- Vittorio Ricci2,
- Cesare Danesino1 and
- Enrico Solcia1,*
- 1 Department of Human Pathology and Genetics, Policlinico S. Matteo, Pavia;
- 2 Department of Physiology, University of Pavia, Pavia, Italy;
- 3 Dept. of Pediatric Hematology/Oncology, Transfusion Medicine, IRCCS Pediatric Hospital, Rome, Italy;
- 4 Department of Pediatrics, University of Milano Bicocca, Monza, Italy;
- 5 Azienda Sanitaria ASL Nuoro, Division of Pediatrics, Nuoro, Italy;
- 6 Azienda Sanitaria ASL 17, Division of Pediatrics, Savigliano, Italy;
- 7 Federico II University, Napoli, Italy;
- 8 Pediatric Hematology/Oncology, Fondazione IRCCS Policlinico San Matteo, Pavia, Italy
- ↵* Corresponding author; email:
Background. Shwachman-Diamond syndrome is an autosomal recessive disorder with severe bone marrow dysfunction causing neutropenia and increased leukemia risk. Recently, novel particulate cytoplasmic structures, named PaCSs, rich in ubiquitinated and proteasomal proteins, have been detected in epithelial cells and neutrophils from Helicobacter pylori gastritis and several epithelial neoplasms.
Design and Methods Blood neutrophils from 13 Shwachman-Diamond syndrome cases, 10 with and three without SBDS gene mutation, and 10 controls were investigated by confocal microscopy and ultrastructural immunocytochemistry using antibodies against ubiquitinated proteins, proteasomes, p62 protein, and Helicobacter pylori VacA, urease and outer membrane proteins.
Results. Many extensively disseminated PaCSs, accounting for 22.78+/-5.57% (mean+/-SD) of the total cytoplasm, were found in blood neutrophils from mutated Shwachman-Diamond syndrome patients. PaCSs showed immunoreactivity for polyubiquitinated proteins and proteasomes, but no reactivity for Helicobacter pylori products, which are present in PaCSs of Helicobacter pylori-positive gastritis. Neutrophils from Shwachman-Diamond syndrome patients frequently showed p62-positive autophagic vacuoles and apoptotic changes in 5% of cells. No PaCSs were observed in most control neutrophils; however, in a few cells from two cases, we noted focal development of minute PaCSs, accounting for 0.74+/-0.56% of total cytoplasm (P<0.001 vs PaCSs from mutated Shwachman-Diamond syndrome patients). Neutrophils from non-mutated Shwachman-Diamond-syndrome-like patients resembled controls in two cases, and a third case showed PaCS patterns intermediate between those in control and mutated Shwachman–Diamond syndrome patients.
Conclusions. PaCSs are a prominent feature of neutrophils from Shwachman–Diamond syndrome patients. They may help us to understand the mechanism of granulocyte dysfunction and the neoplastic risk of the disease.
- Received May 25, 2011.
- Accepted January 16, 2012.
- Copyright © 2012, Ferrata Storti Foundation