pathogenic mechanisms in periodontics part 2 Flashcards
What is the primary function of PMNs?
chemotaxis, phagocytosis, and bacterial killing.
How does a phagosome mature?
fusing with lysosomes, forming a phagolysosome.
How do neutrophils recognize opsonized pathogens?
Fc receptors (FcγRIIa) or complement receptors (Mac-1) on their membrane
What happens after neutrophils recognize a pathogen?
The pathogen is internalized into a nascent phagosome.
What is the lab finding associated with a lack of PMN and monocyte cell-surface Mac-1 & LFA-1?
α-subunit of Mac-1 and LFA-1 (CD11b, CD11c)
What functional defects occur with the absence of Mac-1 and LFA-1?
defective leukocyte adherence and impaired adherence-dependent functions, including:
Spreading
Aggregation
Orientation
Ab-dependent cytotoxicity
Phagocytosis
Why is there bone loss in Leukocyte Adhesion Deficiency (LAD) syndromes?
No PMN’s to protect gingiva from invasion by bacteria
Bacteria get into tissues, LPS activated inflammatory cells (macrophages)
This activates osteoclasts
T or F: There is a correlation between clinical attachment loss and CD18 expression on peripheral neutrophils of LAD-1 patients
True
Why does not scaling, oral hygiene, and antibiotic treatment help with bone loss in LAD syndromes?
issue lies in the absence of PMNs to combat bacterial invasion and the resulting immune response, so mechanical debridement and antibiotics do not resolve the underlying problem of immune dysfunction.
What immunopathology is associated with LAD-1 deficiency in periodontitis?
increased IL-17A cytokine mRNA expression levels in periodontitis lesions, contributing to excessive inflammation and tissue destruction.
What does immunohistochemistry reveal about IL-17A in LAD-1 gingiva?
elevated IL-17A expression in LAD-1 gingiva surrounding extracted teeth, indicating heightened inflammatory activity in these tissues.
What role does Th-cell differentiation play in cell-mediated immunity?
promotes by increasing macrophage function.
How does Th-cell differentiation affect humoral immunity?
enhances by increasing antibody production.
What inflammatory responses are promoted by Th-cell differentiation?
PMN response and autoimmune reactions.
What challenges the concept that LAD periodontitis is mainly due to impaired PMN surveillance of infection?
The ineffectiveness of mechanical and antibiotic treatments in LAD challenges this concept.
How do local microbiota and defective PMN recruitment contribute to LAD periodontitis?
They lead to increased IL-17 production, which drives immunopathology.
What is the primary cause of disease pathology in LAD periodontitis?
Increased IL-17 is the main driver of disease pathology in LAD periodontitis.
What is diminished in Leukocyte Adhesion Deficiency (LAD) type II?
Rolling is diminished due to a lack of receptors for endothelial P-selectin and E-selectin.
What receptors are missing in LAD type II?
gp150-Lewis X and Sialo-Lewis X, which are receptors for P-selectin and E-selectin.
What are the oral manifestations of LAD type II?
severe periodontitis in children, gingivitis, and oral ulceration.
What chemotaxis and microbial activity defects are seen in Chediak-Higashi Syndrome?
Chemotaxis defect and sluggish microbial activity, despite increased oxygen consumption and H2O2 production.
Which enzyme deficiencies are associated with Chediak-Higashi Syndrome?
Cathepsin G and Elastase deficiency.
What are the systemic complications of Chediak-Higashi Syndrome?
Lymphomatous-like illness during adolescence, progressive peripheral neuropathy, severe periodontitis, and oral ulceration.
What is the primary hematological characteristic of neutropenia, agranulocytosis and Myelosuppression?
Diminished phagocyte numbers leading to infections and periodontal disease.