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Adaptive immune system in patients with primary immunodeficiencies
Klocperk, Adam ; Šedivá, Anna (advisor) ; Filipp, Dominik (referee) ; Litzman, Jiří (referee)
(ENG) This thesis summarizes the results of a project dedicated to adaptive immune system of patients with partial DiGeorge syndrome caused by deletion of 22q11.2. The introduction sets the DiGeorge syndrome into a broader context of international pathophysio- clinical classification of primary immunodeficiencies and goes into detail describing its history, causes, clinical phenotype, therapeutic options and changes of the immune system. The attached manuscripts illustrate the premature aging of the T cell population, but also impaired development of B cells with low class-switched memory and high naïve subpopulations, along with high serum levels of BAFF, a B cell survival factor. The surprising lack of T independent marginal zone- like (MZ-like) B cells is reflected in decreased natural anti-α-Gal antibodies. The faulty B cell maturation and imperfect germinal center response is not caused by a deficit of follicular helper T cells, which are in fact increased in DiGeorge syndrome patients, and in most cases doesn't lead to hypogammaglobulinaemia. Despite the high incidence of autoimmune disease, in particular thyroiditis and thrombocytopenia, and a trend towards hypergammaglobulinaemia in adolescence and adulthood, we saw normal proportion of regulatory T cells (Tregs) and normal expression of...
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Adaptive immune system in patients with primary immunodeficiencies
Klocperk, Adam ; Šedivá, Anna (advisor) ; Filipp, Dominik (referee) ; Litzman, Jiří (referee)
(ENG) This thesis summarizes the results of a project dedicated to adaptive immune system of patients with partial DiGeorge syndrome caused by deletion of 22q11.2. The introduction sets the DiGeorge syndrome into a broader context of international pathophysio- clinical classification of primary immunodeficiencies and goes into detail describing its history, causes, clinical phenotype, therapeutic options and changes of the immune system. The attached manuscripts illustrate the premature aging of the T cell population, but also impaired development of B cells with low class-switched memory and high naïve subpopulations, along with high serum levels of BAFF, a B cell survival factor. The surprising lack of T independent marginal zone- like (MZ-like) B cells is reflected in decreased natural anti-α-Gal antibodies. The faulty B cell maturation and imperfect germinal center response is not caused by a deficit of follicular helper T cells, which are in fact increased in DiGeorge syndrome patients, and in most cases doesn't lead to hypogammaglobulinaemia. Despite the high incidence of autoimmune disease, in particular thyroiditis and thrombocytopenia, and a trend towards hypergammaglobulinaemia in adolescence and adulthood, we saw normal proportion of regulatory T cells (Tregs) and normal expression of...
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Laboratory diagnosis of disorders of phagocytosis
POLÍVKOVÁ, Ivona
Phagocytosis is one of the oldest processes of absorbing particles like amoeba, which is one of the basic mechanisms of the immune system to defend the body against infections. Failure of these processes is clinically manifested like immune deficiency and it can cause a very serious complication which could leads to the death of the patient. Phagocytosis is performed by specialized cells (macrophages, dendritic cells, neutrophils and other phagocytic myeloid cells) which are able to absorb the target particles, especially microorganisms, dead cells and foreign objects. These processes are essential for stability of homeostasis. Absorption of micro-organisms leads to activation of adaptive immunity response, elimination of apoptotic and destroyed cells and starts the reparation processes of damaged tissue. Phagocytosis as a complex process can be divided into several phases: active movement of phagocytes to the inflammation zone, adherence, ingestion and intracellular degradation which leads to the killing of pathogens. There are two mechanisms of killing pathogens. First is independent on oxygen where antimicrobial substances are stored in azurophilic granules which could be released into phagolysosom. Second mechanism is oxygen-dependent called oxidation (respiratory) flare which leads to the formation of biologically active mediators where oxygen molecules have considerable oxidation potential. Defects in phagocytic system are mainly caused by low number or malfunction of neutrophils which leads to severe infections mainly caused by staphylococci, Enterobacteriaceae or fungi. Among malfunctioning of phagocytosis processes belongs LAD I and LAD II syndrome. The other possible disorder of phagocytic malfunction is defect in enzymes. The NADPH oxidase is necessary for bacterial lyses mechanism of phagocytes and lack of these enzyme caused serious inherit disorder called chronic granulomatous disease. Lack or completely missing of enzyme myeloperoxidase stored in the azurophilic granules of neutrophils and monocytes is more and more common autosomal recessive disorder of phagocytosis. In this diploma work I focused on detection of these rare and serious disorders defects using flow cytometry to detect respiratory burst activity of neutrophils in blood samples. This laboratory procedure is called a burst test. In this test we quantitatively evaluate the respiratory burst activity of granulocytes in heparinized blood samples using the flow cytometery. Principle of this method is an oxidation-reduction reaction of dihydrorhodamine 123 to green fluorescent rhodamine 123 using peroxide, hydroxyl radicals and superoxide anions which are activated by respiratory burst. This process is one of the significant characteristic of phagocytic cells which are characterized by multi-stage activation of NADPH oxidase. This oxidase catalyzes electron reduction of molecular oxygen to superoxide. This step plays a very important role in our immune system and allows to kill and degrade particles and bacteria in phagocyte cells. Since 2009 - 2012 I analyzed the results of 611 patients who were tested for respiratory burst of neutrophils on a request of their physician. Among all of these results we obtain only two positive results of reduction of stimulation index (SI) and significant decrease percentage of activated granulocytes. Both of these parameters: reduced percentage of (activated granulocytes stimulated by PMA and E. coli) and low stimulation index pointing to a potentially serious disorder of phagocytosis mechanism. In specific tests of these cases proved the enzyme defect in phagocytosis mechanism which is the most common disorder in this type of immunodeficiency. These results indicate that the major primary defects of phagocytosis are very rare and their detection is usually in childhood for suspicion of primary immunodeficiency. This test is very helpful for discovering a prime immunodeficiency.
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