VI - Immunodeficiency Disorders Flashcards
State in which the immune system’s ability to fight infectious disease is compromised, can occur if any of the four major components of the immune system are compromised
Immunodeficiency
Major Components of the Immune System
B-cells (antibodies), T-cells, phagocytes, complement
Recurrent infections with pyogenic bacteria indicate
B-cell Deficiency
Recurrent infections with fungi, viruses or protozoa indicate
T-cell Deficiency
Immunodeficiency: Genetic susceptibility to infections since childhood
Primary
Immunodeficiency: Acquired susceptibility to infection as a result of external processes or disease
Secondary
Very low levels of all immunoglobulins, virtual abscence of B-cells due to tyrosine kinase mutation, cell-mediated inmmunity is normal
X-Linked/Bruton’s Agammaglobulinemia
B-Cell Disorders: Male infants, 6 mos. old, recurrent pyogenic bacterial, enteroviral infections and giardiasis
X-Linked/Bruton’s Agammaglobulinemia
X-Linked/Bruton’s Agammaglobulinemia: Treatment
pooled gamma globulin
Failure of isotype switching, recurrent bacterial sinus and lung infections
Selective IgA Deficiency
Why shouldn’t you treat Selective IgA Deficiency with gamma globulin preparations?
formation of antibodies against foreign IgA → cross-reaction depletes their already low IgA or may cause anaphylaxis
Defect in B-cell maturation to plasma cells, diagnosis of exclusion, recurrent pyogenic bacterial infections, most common form of severe antibody deficiency affecting both children and adults
Common Variable Immunodeficiency
Common Variable Immunodeficiency: Treatment
pooled gamma globulin
Profound deficit of T-cells from failure of development of thymus and parathyroids due to a defect in the 3rd and 4th pharyngeal pouches, humoral immunity is normal
Di George Syndrome
T-Cell Disorders: Tetany due to hypocalcemia, severe viral, fungal or protozoal infections during childhood
Di George Syndrome
Di George Syndrome: Treatment
transplant of fetal thymus (< 14 wks old)
Specific T-cell deficiency for Candida albicans, other T-cell and B-cell functions are normal, recurrent candidiasis (skin, mucous membranes), in children
Chronic Mucocutaneous Candidiasis
Chronic Mucocutaneous Candidiasis: Treatment
azole antifungal drugs
X-Linked Severe Combined Immunodeficiency (SCID)
defect in IL-2 receptors in T-cells
Autosomal Severe Combined Immunodeficiency (SCID)
ADA deficiency
Recurrent bacterial, viral, fungal and protozoal infections at 3 mos., enclosure in plastic bubble, bone marrow transplant
Severe Combined Immunodeficiency (SCID)
X-linked, male infants, inability to mount IgM response, mutation in WASP gene for actin filament assembly recurrent pyogenic infections, eczema and bleeding due to thrombocytopenia, bone marrow transplant
Wiskott-Aldrich Syndrome
Autosomal recessive, mutations in DNA repair enzymes, IgA deficiency, ataxia, telangiectasia, recurrent infections by 2 years of age, supportive management
Ataxia-Telangiectasia
Lack of NADPH oxidase activity, failure of oxidative burst, normal B- and T-cell activity, recurrent infections with catalase (+) bacteria and fungi (A. fumigatus), widespread granulomas of unknown etiology, antibiotic chemoprophylaxis
Chronic Granuloma Disease
Chronic Granuloma Disease: Diagnosis
Nitroblue Tetrazolium Test (NBT)
Autosomal recessive, failure of phagolysosomal fusion, faulty microtubules impair neutrophil chemotaxis, recurrent pyogenic infections caused by staphylococci, antibiotics
Chediak-Higashi Syndrome
Autosomal recessive, mutation in integrins, defective adhesion (LFA-1) proteins on the surface of phagocytes, severe pyogenic infections in infancy, delayed separation of umbilical cord, antibiotics, bone marrow transplant
Leukocyte Adhesion Deficiency (LAD)
Early Complement Deficiency
C2 & C3 Deficiency
Terminal Complement Deficiency
C5b-C9 Deficiency
Most common complement defect, usually asymptomatic but may develop septicemia of SLE
C2 Deficiency
Complement deficiency with recurrent pyogenic infections due to Staphylococcus aureus
C3 Deficiency
Inability to form membrane attack complexes, bacteremia with Neisseria meningitidis and gonorrhoeae, vaccination
C5b-C9 Deficiency
Secondary Immunodeficiency: Decreased supply of AA and synthesis of IgG and complement, malnourished child with recurrent pyogenic infections, antibiotics, nutritional support
Malnutrition
HIV infects and kills
CD4+ helper T-cells
Secondary Immunodeficiency: Loss of cell-mediated immunity, opportunistic infections caused by bacteria, viruses, fungi and protozoa
AIDS
AIDS: Treatment
Highly-Active Antiretroviral Therapy (HAART)
