Objective. Exosomes are membrane vesicles of endosomal origin that are distinct from apoptotic bodies and are thought to represent an acellular mechanism for antigen transfer to classic antigen-presenting cells, as well as for direct antigen presentation with the capacity to induce immune response or tolerance. Nevertheless, it is not known whether exosomes are involved in the induction or regulation of immune responses against intracellular autoantigens that characterize autoimmune diseases. Exosomes have been shown to be secreted by several types of cells, whereas studies of non-neoplastic epithelial cells are lacking. This study was undertaken to investigate the capacity of nonneoplastic salivary gland epithelial cells (SGECs) to release exosomes, and to determine whether epithelial exosomes contain RNPs, which are major autoantigens in systemic rheumatic diseases.Methods. Exosomes were isolated by ultracentrifugation from culture supernatants of 26 non-neoplastic SGEC lines established from patients with various rheumatic disorders. They were analyzed by electron microscopy, immunoblotting, or immunoprecipitation.Results. All SGEC lines were found to release comparable and significant amounts of exosomes. Similar to other cell systems, exosome secretion was constitutive and was unrelated to activation or apoptotic processes. SGEC-derived exosomes were found to contain the autoantigenic Ro/SSA, La/SSB, and Sm RNPs, as well as epithelial-specific cytokeratins.Conclusion. SGECs constitutively secrete exosomes that contain the major autoantigens Ro/SSA, La/SSB, and Sm. This mechanism may represent a pathway whereby intracellular autoantigens are presented to the immune system with an immunogenic or tolerogenic outcome.Autoimmune diseases are characterized by the development of humoral responses against self antigens, most of which are intracellular proteins. Although thought to involve typical antigen-driven responses, the precise mechanism(s) involved in the presentation of such intracellular autoantigens to the immune system is unclear (1). Apoptosis and the resulting release of autoantigen-containing apoptotic vesicles are considered potential pathways for the generation of autoimmune responses (2).During the last decade, a novel cell-free mechanism of antigen presentation has been recognized (3) that involves small (30-100 nm) membrane vesicles, which are termed exosomes and are distinct from apoptotic bodies. These are different from the exosome protein complex, which is implicated in RNA processing and degradation processes. Exosomal vesicles are secreted following the fusion of multivesicular late endosome/lysosomes with the plasma membrane. Exosome production has been observed in a variety of cell types, including reticulocytes, platelets, cytotoxic T lymphocytes and B lymphocytes, dendritic cells, and neoplastic intestinal epithelial cells, whereas studies of non-neoplastic epithelial cells are lacking. Several physiologic roles have been assigned to exosomes, including the expulsion of obsolete membran...

Epithelial cells appear to play an important role in the initiation and maintenance of autoimmune lesions in the salivary glands of patients with Sjogren's syndrome. Therefore, the detailed study of immunological function of salivary gland epithelial cells (SGEC) may provide useful information for the understanding of Sjögren's syndrome pathogenesis. In this report we aimed to formulate a protocol for the establishment of human non-neoplastic SGEC lines as a tool for the study of the physiology and pathophysiology of these cells. Pointing towards a practical approach, we sought to establish SGEC lines from quite a limited amount of biopsy tissue obtained during the diagnostic evaluation of patients. Herein, the favorable conditions for the long-term maintenance of human non-neoplastic SGEC lines are presented and involve the successive application of a serum-containing and a serum-free culture medium, supplemented with essential epithelial growth factors. This protocol has been found reliable and convenient, as attested by the reproducible establishment of non-neoplastic SGEC lines. The analysis of SGEC phenotypic features, as well as a coculture system for the study of interactions between epithelial cells and lymphocytes, are also described. Such techniques may provide valuable means for the functional and molecular investigation of human SGEC and particularly for the study of Sjögren's syndrome and other disorders of glandular epithelia.

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Background Hepatitis A virus (HAV) infection is one of the major causes of acute viral hepatitis. HAV genotypes and its genetic diversity is rarely investigated in our region as well as worldwide. Aims The aims of the present study were to determine the HAV genotypes and its risk factors and to investigate the genetic diversity of the HAV isolates in the West Bank, Palestine. Study design A cohort of 161 clinically and laboratory-confirmed HAV (IgM-positive) cases and 170 apparently healthy controls from all the districts of the West Bank, Palestine during the period of 2014 to 2016 were tested for HAV infection using IgM antibodies, RT-PCR and sequence analysis of the VP3/VP1 junction region of the HAV genome. Phylogenetic analysis, genetic diversity and haplotypes analysis were used to characterize the VP3/VP1 sequences. Results All the 34 sequences of the HAV were found to be of HAV-IB sub-genotype. The phylogenetic analysis showed four main clusters with cluster III exclusively consisting of 18 Palestinian isolates (18/23-78%), but with weak bootstrap values. A high haplotype diversity (Hd) and low nucleotide diversity (π) were observed. Cluster III showed high number of haplotypes (h = 8), but low haplotype (gene) diversity (Hd = 0.69). A total of 28 active haplotypes with some consisting of more than one sequence were observed using haplotype network analysis. The Palestinian haplotypes are characterized by closely related viral haplotypes with one SNV away from each other which ran parallel to cluster III in the phylogenetic tree. A smaller Palestinian haplotype (4 isolates) was three SNVs away from the major haplotype cluster (n = 10) and closer to others haplotypes from Iran, Spain, and South Africa. Young age, low level of parent’s education, infrequent hand washing before meals, and drinking of un-treated water were considered the major HAV risk factors in the present study. Conclusion Haplotype network analysis revealed haplotype variation among the HAV Palestinian sequences despite low genetic variation and nucleotide diversity. In addition, this study reconfirmed that age and parent’s level of education as HAV risk factors, while hand washing and treating drinking water as protective factors.

Objectives To outline and analyse the national organisation, infrastructure and management of transfusion systems in countries sharing common historical, cultural and economic features and to decipher management trends, in order to potentially benchmark. Background Little is known regarding transfusion systems in Eastern/southern Mediterranean at a time international organisations are calling for the establishment of a safe and sustainable blood system. Materials and Methods Data emanating from eight Arabic‐speaking Eastern/Southern Mediterranean countries who responded to five surveys were collected and tabulated. Results While similarities in terms of supervision by national authorities, authorization of blood centres, quality control and management information system are evident, some significant divergence between these countries do exists. Only Lebanon does not possess a national blood establishment or organisation for blood supply. Blood components are fully government‐subsidised in Algeria and Mauritania. Algeria, Morocco and Tunisia have a blood supply that relies mainly on Voluntary non‐remunerated donors. Plateletpheresis is performed in all countries except Mauritania while plasmapheresis exists only in Algeria and Egypt. Morocco is the sole country outsourcing its plasma for Plasma derived products. Conclusion Despite the various challenges facing these countries, lot of progresses have been made so far in the field of transfusion medicine. Yet, nationally coordinated blood programs overviewed by national regulatory authorities and actively supported by local governments are still needed to ensure the optimum level of blood safety.