Host-Microbe Interactions Flashcards
What are the main targets for Phagocytes (Neutrophils and Macrophages)?
Bacteria and Fungi
What are the main targets for T Lymphocytes?
Bacteria, Fungi and Protozoa
What are the main targets for Antibodies?
Bacteria
What are the main targets for Eosinophils?
Worms, Protozoa and Fungi
What are the main targets for Mast Cells?
Worms
What are the main targets for the Complement System?
Bacteria
What are causes of Impaired Phagocyte Function?
Cytotoxic Chemotherapy
Acute Leukaemia
Myelodysplasia
Cell count normal but function is decreased
What are causes of Impaired T Lymphocyte Function?
Advanced HIV Infection (CD4+ T Cells)
Lymphoma
SCID
What are causes of Impaired B Lymphocyte Function?
Myeloma
Certain Immunosuppressants e.g. Rituximab
Primary Immunodeficiency Syndromes
What is the main Immunological Cell for destroying Cancer Cells?
CD8+ T Cells
Which antibodies are released in Acute and Chronic Infection?
IgM for Acute Infection due to Weak Affinity to Antigen and so, binds weakly (produced initially)
IgG for Chronic Infection due to Better Affinity to Antigen and so, binds better (produced subsequently)
How can Neurological Disease cause infection?
Neurological Disease can impair Swallowing Ability and so, causes a higher risk of Aspiration and therefore, Infection
What immune cell does HIV infection impact?
CD4+ T Cells, causing progressive decrease in cell count and therefore, increasing susceptibility to infection
What common pathogens does decreasing CD4+ T Cell count cause vulnerability to?
Pneumococcal infection risk for general decreasing CD4+ Cell count.
CD4+ < 350 = TB and Candidiasis
CD4+ < 250 = Toxoplasma Gondii, Jirovecii
CD4+ < 100 = CMV
What is Hyposplenism?
Decreased Splenic Function
When would a Splenectomy for Hyposplenism be indicated?
In Trauma (emergency splenectomy) Lymphoma
What is Functional Hyposplenism?
What is it caused by?
Individual has a Spleen but it does not function as well as it should.
Causes include Sickle Cell Anaemia, Cirrhosis and Coeliac Disease
What Organisms is the Spleen important for in terms of protection?
Capsular Organisms e.g. Meningococcus (Neisseria Meningococcus, Strep. Pneumoniae and H. Influenzae
What is Immunocompromise?
Individuals have a Blunted Immune Response and so, do not exhibit the typical symptoms e.g. No fever, lack of Inflammatory Response (CRP/Neutrophilia) and are Non-Specifically Unwell
What is important to consider when treating immunocompromised patients?
They have a lower threshold for treatment and if they acquire infection, it can progress more rapidly.
What pathogens does Steroid Treatment predispose to?
Candida, Aspergillus, Bacteria
What pathogens does Anti-TNF Alpha predispose to?
TB, Aspergillus
What pathogens do Purine Analogues predispose to?
Herpes Simplex and Herpes Zoster
Jirovecii
What conditions are associated with AIDS?
Oropharyngeal Candidiasis
Salmonella Bacteraemia
Recurrent Pneumonia (Pneumococcal Vaccine given as prophylaxis)
What condition is NOT associated with AIDS?
Recurrent Endocarditis
