Diseases Flashcards
Chronic Granulomatous Disease (CGD)
Cause: defect in NADPH oxidase causes NO production of superoxide radicals and other antibacteriocidal compounds
Cytochorme B (subunit of NADPH) is mutated in X-linked recessive inheritance or Autosomal recessive
Bacteriocidal activity = impaired; chronic bacterial and opportunistic infections
Formation of granulomas
Patients present with high rate of infection of Catalase (+) Bacteria (see notes for why)
Treatment with prophyloactic antibiotics and Y-interferons (goal is to boost ability of macrophages and neutrophils to utilize O2 independent pathway
Leukocytes adhesion deficiency
-Autosomal recessive
Cause: absence of CD18 (required for phagocytic adhesion and migration across vessel walls–>phagocytes cannot get to infection site leading to impaired B and T-cell functions
-Symptoms: chronic infection with encapsulated bacteria
-Integrin can’t bind selectin and get into endothelial cells
Chediak Higashi syndrome
- Defect in vesicle fusion within macrophages
- LYST: lysosomal transport gene (without fusion of lysosome/phagosome, you cannot degrade microbial agents)
- Patients have increased infections; albinism is correlated
DiGeorge Syndrome aka Thymic aplasia
- No functional thymus
- Absence of parathyroid gland/ congenital heart defects
- No T-cell mediated immunity; greatly reduced serum lg
- Low calcium due to absence of parathyroid; hypocalcimia)
- Don’t present immunodef until around 6 months b/c of mo)
- Phenotype: low set ears, wide set eyes (hypertelorism), and fish-shaped mouth
Severe combined immunodeficiency (SCID)
- X-linked mutation in gamma chain of IL2 receptor
- Autosomal recessive: mutations in ADA–adenosine deaminase and PNP–purine nucleotide phosphorylase
- Lack of cell-mediated and humoral immunity
- Opportunistic infections
- Children kept in isolation: antigen free environments
Wiscott Aldrich Syndrome
- Rare, x-liniked disorder (loss of CD43)
- Severely impaired cell mediated and humoral immunity
- Loss of protein WASP (Wiscott Aldrich Syndrome Protein) whose fxn is unknown except that it is involved in cytoskeletal movement (Tcells are there but they cannot receive proper signals)
- Rhobocytopenia (decreased platelets)
- No actin polymmerization, impaired vascular transport and cell signalling
Mucocutaneous Candidiasis
- Autosomal dom or rec
- Selective defect in T-cell immunity (candida antigens)
- Chronic candida infections of skin, nails, mucous membranes
- Tcell immunity to most antigens is in tact
- Endocrine dysfxn
- Oral candidiasis: THRUSH (Tcells/Bcells fxn normally, w/ exception of being able ot respond to Candida: repeated infections)
HIV
-retrovirus
-Infects CD4+ cells
-Gradual decrease in CD4+ cells –> breaks down immune response
AIDS: CD4+ < 200 mm^3
-Infection w/ opportunistic organism (Pneumocystis jiroveci, CMV, Kaposi’s sarcoma)
X-linked Agammaglobulinemia–Bruton’s
- No circulating B cells
- Diagnosis: deficiency/absence of all Ab classes
- Btk defect: B cells halted at pre-B cell stage (no Tyrosine kinase)
- Increased susceptibility to extracellular bacteria; especially encapsulated organisms
- Chronic upper respiratory problems
- No tonsils!
- Absence of antibodies in blood
- Should not be given live viral vaccines
Transient Hypogammaglobulinemia of infancy
- LOW IgG
- recurrent respiratory tract infections
- Usually normal IgM and IgA
- More pronounced in infants born prematurely
- IgG transferred during fetal development from mom
- When born, fairly high level of IgG present w/ limited lifespan
- After a few months, the IgG levels plummet and the child’s immune system has not developed the ability to make IgA and IgG (susceptible to microbial infections)
Selective IgA Deficiency
- Very low/absent IgA; other classes are normal (or elevated)
- Increased association w/ allergies and autoimmunity
- Susceptibility to respiratory infections caused by encapsulated organisms
- No replacement therapy
X-Linked Hyper-IgM
- Elevated IgM; only trace levels of all other isotypes
- T-cell defect; no CD40L expression
- No class switching
- Limited response to T-independent antigen
- Infections with extracellular bacteria; opportunistic organisms
