Quantitative Data Tutorial Notes

‭Quantitative data‬ ‭ ‬ ➔ ‭Monocytes have a marginal hen and a hen circulating in the ¾ ratio for marginated cells‬ ‭(attached to endothelial cells), ¼ elements circulating. The half-life in the blood is 8 hours and the‬ ‭total number of circulating monocytes is 0.2 to 1 giga/L. The monocyte remains in the blood for 8‬ ‭hours, leaves it to go to different tissues where they will become macrophages and we can have‬ ‭several types of macrophages: non-specialized or specialized which have a particular morphology‬ ‭compared to the tissue that they have colonized.‬ I‭ n MO:‬‭Macrophages are large elements: 20 to 80 micrometers‬‭in diameter. They can have one or‬ ‭more nuclei with fine chromatin, we can see a nucleolus because they are active elements and‬ ‭therefore have the morphology of activated cells. The cytoplasm has an irregular outline, numerous‬ ‭signs of phagocytosis are highlighted: intracytoplasmic vacuoles of different sizes, intracytoplasmic‬ ‭inclusions, pigmented deposits.‬ ‭ For example, a patient in whom we look for subarachnoid hemorrhage, therefore the presence of‬ ✪ ‭blood in the cerebrospinal fluid, the patient did not present immediately to the emergency room and‬ ‭we want to know if there was a hemorrhage meningea and we ask for the search for siderophages‬ ‭which are macrophages which have phagocytosed iron from red blood cells and to highlight this‬ ‭siderophage we use the Perns stain which highlights iron in macrophages. So that there is‬ ‭phagocytosis of red blood cells it is necessary that there has been degradation of the red blood cells‬ ‭inside the macrophage.‬ ‭ Certain macrophage bears the name of histiocyte, these are the macrophages which are not‬ ✪ ‭specialized, we find them in the connective tissue (supporting the mucous membranes for example)‬ ‭on the other hand at the hepatic level the macrophages are called Kupfer cells, they are‬ ‭macrophages which will store iron among other things. In the lung we highlight alveolar‬ ‭macrophages which have numerous cytoplasmic vacuoles, significant cytoplasmic expansions while‬ ‭in the serosa (pleura, peritoneum), the macrophages have more of an ovoid appearance, the‬ ‭cytoplasmic expansions are few in number and the vacuoles little present.‬ ‭ Please note: A macrophage is described as having a dendritic “appearance”, these are not not‬ ✪ ‭dendritic cells but the appearance is dendritic due to the expansion cytoplasm.‬ I‭ n ME:‬‭the numerous expansions, the very developed‬‭vacuolar apparatus. From a cytochemical‬ ‭point of view we find myeloperoxidase and esterases. From an immunological point of view‬ ‭cytochemical which is common to the monocyte and macrophage, we can highlight synthetic‬ ‭products such as lysozyme which is an enzyme which is capable of lysing the bacterial walls, this is‬ ‭also an important element if a patient has acute leukemia, we want to know if it is rather an attack‬ ‭of the myeloid lineage or monocytic we will seek to do a dosage of this lysozyme. On the other‬ ‭hand in monocytes/macrophages we can highlight alpha 1 antitrypsin, alpha 1 antichymotrypsin‬ ‭which are protease inhibitor proteins.‬ ‭ onocytes/macrophages have differentiation antigens at the membrane surface: They have‬ M ‭receptors for FC fragments of Ig, receptors for fragments of the complement, this intervenes in the‬ ‭phenomenon of opsonization. On the surface of these cells we highlight the class II molecules of‬ ‭the major complex histocompatibility (MHC). These class II molecules are essential for the‬ ‭presentation of antigens to T lymphocytes.‬ ‭➔‬ ‭Role of the monocyte/macrophage in immunity:‬ ‭It's an effector cell immunity. It can destroy tumor cells by the secretion of oxygenated derivatives.‬ s‭ ecretion of TNF alpha. These macrophages can destroy infectious agents: there can be intracellular‬ ‭destruction after phagocytosis or extracellular destruction if phagocytosis does not occur. possible‬ ‭because the agent is too large. If there is phagocytosis, whether there is activation of lysozymes or‬ ‭peroxidases, there must be a lowering of PH inside the phagosome which will become a‬ ‭phagolysosome after phagosome and lysosome fusion.‬ ‭ THE Macrophages are very sensitive to interferon gamma which triggers oxidative metabolism,‬ ✪ ‭interferon which can be secreted by connective tissue fibroblasts and by T lymphocytes. For‬ ‭example on diagram: A macrophage will present an antigen to a T lymphocyte that he will have‬ ‭shaped, that he expressed in association with the class II molecules of the MHC, then there will be‬ ‭stimulation of the T lymphocyte with TNF alpha for example.‬ ‭ The T lymphocyte will reactr, will self-stimulate by secreting interleukin 2 and at the same time it‬ ✪ ‭secretes the receptor for interleukin 2 so it is an autocrine regulatory loop. The T lymphocyte will‬ ‭secrete interferon gamma which will stimulate the macrophage and on the two types cells, if‬ ‭initially there was simply presentation of the antigen in association with the class II molecule, we‬ ‭will have expression of so-called co- stimulation molecules which reinforces the contact between‬ ‭the two cell types and therefore the immune reaction.‬