Case 31: Monocytic Ehrlichiosis
Laurel J. Gershwin in Case Studies in Veterinary Immunology, 2017
This chapter discusses basic immunological concepts in the context of actual cases seen in clinics. It discusses in the case of monocytic ehrlichiosis. In some of the tick-borne diseases, such as ehrlichiosis, both polyclonal and mixed gammopathy (restricted oligoclonal gammopathy) have been observed in infected dogs. Canine monocytic ehrlichiosis in particular is known to cause both polyclonal and monoclonal gammopathy. The disease is the result of an infection with the obligate intracellular rickettsia Ehrlichia canis , transmitted via the bite of the tick Rhipicephalus sanguineus . Equine granulocytic ehrlichiosis is caused by infection with the rickettsia Ehrlichia equi , which has been renamed Anaplasma phagocytophilum , based on DNA sequencing. Humans can also develop granulocytic ehrlichiosis. However, neither this nor the equine form of the infection are very similar immunologically to canine and human monocytic ehrlichiosis. The symptoms of acute infection in humans include a moderate to high fever, lower back pain, gastrointestinal discomfort with or without vomiting, and diarrhea.
Chapter 9: Microspheres and Phagocytosis
Zoltán A. Tökés in Micro spheres: Medical and Biological Applications, 2017
This chapter reviews the phagocytic process and discusses the advantages, applications, and limitations of the utilization of microspheres in the study of phagocytosis. The most active mononuclear phagocytes are the promocytes in the bone marrow which enter the blood as monocytes. Light and transmission electron microscopy, utilization of large microspheres, and treatment of fixed phagocyte cells with xylene, chloroform, or dioxane to dissolve extracellular polystyrene particles are among the techniques that have been utilized for this purpose. The phagocytic process can be divided into three general phases: the attachment of foreign particles to the surface of the phagocytic cell, the ingestion of such particles by the phagocytes, and the digestion of the ingested material within the cell. One of the major energetic factors to consider about phagocytosis with respect to small particles is their translational kinetic energy. Electronic analysis and recording of measurements may be performed with or without cell sorting.
Source of Prostaglandins and their Influence on Bone Resorption and Formation
Wilson Harvey, Alan Bennett in Prostaglandins in Bone Resorption, 2020
In situations of pathological localized bone destruction, from which a great deal of our knowledge on the subject has come, there is often fairly clear evidence of the cellular source of the prostaglandins (PGs) implicated in the resorption. Starting with a relatively simple concept, the cells which produce the PGs can be classified as “resident” to bone and surrounding connective tissues, or as “nonresident”. During the 1970s the involvement of PGs with several aspects of inflammation (notably vasodilation, edema, and pain) led to much interest in their production by inflammatory cells. The monocyte-macrophage as a source for bone-resorbing PGs was a popular concept. It fit several pertinent observations, such as the presence of mononuclear phagocytes in healthy bone induced to resorb in tissue cultures, the characteristic infiltration by macrophages of chronically inflamed tissues associated with bone resorption, and the presence in inflamed tissues of many agents which are capable of stimulating PG synthesis in macrophages.
Transcriptomic Network Support Distinct Roles of Classical and Non-Classical Monocytes in Human
Published in International Reviews of Immunology, 2014
Kolandaswamy Anbazhagan, Isabelle Duroux-Richard, Christian Jorgensen, Florence Apparailly
Classical and non-classical monocytes are two well-defined subsets of monocytes displaying distinct roles. They differentially express numerous genes relevant to their primary role. Using five independent transcriptomic microarray datasets, we ruled out several inconsistent genes and identified common genes consistently overexpressed either in classical or non-classical monocytes. One hundred and eight genes were significantly increased in classical monocytes and are involved in bacterial defense, inflammation and atherosclerosis. Whereas the 74 genes overexpressed in non-classical monocytes are involved in cytoskeletal dynamics and invasive properties for enhanced motility and infiltration. These signatures unravel the biological functions of monocyte subsets. HIGHLIGHTS We compared five transcriptomic GEO datasets of human monocyte subsets. 108 genes in classical and 74 genes in non-classical monocytes are upregulated. Upregulated genes in classical monocytes support anti-bacterial and inflammatory responses. Upregulated genes in non-classical monocytes support patrolling and infiltration functions.
A new approach for diagnosing chronic myelomonocytic leukemia using structural parameters of Sysmex XN
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2018
Françoise Schillinger, Elise Sourdeau, Marouane Boubaya, Lucile Baseggio, Sylvain Clauser, Edouard Cornet, Camille Debord, Jean-Pierre Defour, Frédérique Dubois, Marion Eveillard, Anne-Cécile Galoisy, Marie-Odile Geay, François Mullier, Vanessa Nivaggioni, Valérie Soenen, Pascal Morel, Francine Garnache-Ottou, Emily Ronez, Valérie Bardet, Eric Deconinck
According to WHO recommendations, diagnosis of chronic myelomonocytic leukemia (CMML) beforehand requires microscopic examination of peripheral blood to identify dysplasia and/or blasts when monocytes are greater or equal to 1.0 × 109/L and 10% of leucocytes. We analyzed parameters derived from SysmexTM XN analyzers to improve the management of microscopic examination for monocytosis. We analyzed results of the complete blood count and the positioning and dispersion parameters of polymorphonuclear neutrophils and monocytes in 61 patients presenting with CMML and 635 control patients presenting with a reactive monocytosis. We used logistic regression and multivariate analysis to define a score for smear review. Three parameters were selected: neutrophil/monocyte ratio, structural neutrophil dispersion (Ne-WX) and monocyte absolute value. We established an equation in which the threshold of 0.160 guided microscopic examination in the search for CMML abnormalities with a sensitivity of 0.967 and a specificity of 0.978 in the learning cohort (696 samples) and 0.923 and 0.936 in the validation cohort (1809 samples) respectively. We created a score for microscopic smear examination of patients presenting with a monocytosis greater or equal to 1.0 × 109/L and 10% of leucocytes, improving efficiency in laboratory routine practice.
The role of monocytes in atherosclerotic coronary artery disease
Published in Annals of Medicine, 2010
Burak Pamukcu, Gregory Y. H. Lip, Andrew Devitt, Helen Griffiths, Eduard Shantsila
Inflammation plays a key role in the pathogenesis of atherosclerosis. The more we discover about the molecular pathways involved in atherosclerosis, the more we perceive the importance of monocytes in this process. Circulating monocytes are components of innate immunity, and many pro-inflammatory cytokines and adhesion molecules facilitate their adhesion and migration to the vascular endothelial wall. In addition to the accumulation of lipids and formation of atherogenic ‘foam’ cells, monocytes may promote atherosclerotic plaque growth by production of inflammatory cytokines, matrix metalloproteinases, and reactive oxidative species. However, the contribution of monocytes to atherogenesis is not only limited to tissue destruction. Monocyte subsets are also involved in intraplaque angiogenesis and tissue reparative processes. The aim of this overview is to discuss the mechanisms of monocyte activation, the pivotal role and importance of activated monocytes in atherosclerotic coronary artery disease, their implication in the development of acute coronary events, and their potential in cardiovascular reparative processes such angiogenesis.