immune deficiency Flashcards
How many URI, otitis media and gastroenteritis do children get per year
First 10 yrs - 6-8 URI / year. First 2-3 yrs - ≤ 6 episodes otitis media, 2 episodes gastroenteritis / year
sources of immunodeficiency
- malnutrition- PEM/ total calorie ( kwashiorkor/ marasmus), Vit A, iron, micronutrients. 2. HIV-1/ AIDS. 3. Age
- Name four components of immune function.
1) Anatomic (skin, mucosal barriers). 2) Phagocytes - neutrophils and macrophages. 3) Cellular immunity - CD4+ T cells, CD8+ T cells (CTL), Natural killer cells (NK). 4) Humoral immunity -Specific antibodies (B cells), Complement
List primary and secondary immunodeficiencies related to Anatomic barriers and the pathogens involved
Primary: eczema, CF. Secondary: Burns, IV lines, post-viral (lungs), chemo (GI/oral)
pathogens involved in Burns/ eczema
Staph aureus, Pseudomonas aeruginosa
pathogens involved in IV lines
staph aureus
Pathogens involved in CF or post viral infection of lungs
Pseudomonas aeruginosa, strep pneumoniae, staph aureus.
Pathogens involved in chemo immunodeficiency
e. coli, candida (both GI/ oral)
List the normal percentages of PMNs and monocytes
PMN: 60%. Monocytes: 10%
List common infections associated with chemo- induced neutropenia- intestine, periodontal and skin
Intestine: GNR (e coli), candida, enterococcus. Transcytosis from epithelium or perirectal abscess. Periodontal: anaerobic abscess, oral streptococci. Skin/ catheters: MRSA, strep, GNR (pseudomonas aeruginosa)
describe chronic granulomatous dz- cause, sx, diagnosis
Primary immunodeficiency. Sufficient phagocyte number but decreased function due to defect in NADPH oxidase. Recurrent skin abscesses, severe prolonged pneumonia, bone. Diagnose by NBT test of PMNs
List bugs involved in chronic granulomatous dz
Risk for catalase positive organisms that destroy oxygen radicals: Staph. aureus, Serratia, Nocardia, Salmonella, Aspergillus*
Causes of decreased cellular immunity
Malnutrition, oral steroids, immunotherapy, chemo, transplantation, HIV/ AIDS. All are secondary
List common causes of pneumonia in elderly, young adult, AIDs, nosocomial, Asia/Africa
elderly: S. pneumoniae, H. influenzae, Influenza (winter). Young adult: M. pneumoniae, C. pneumoniae, S. pneumoniae. AIDS: strep pneumonia, P. jirovecii (PCP). Nosocomial: GNR, Staph aureus. Asia/Africa: TB
List bacterial infections associated with impaired cellular immunity
Listeria* - Mycobacteria - Legionella - Nocardia* - Salmonella*
List fungal infections associated with impaired cellular immunity
Cryptococcus - Aspergillus sp. - Candida (mucosal) - Pneumocystis* - Cocci. immitis -Histoplasma
List viral infections associated with impaired cellular immunity
HSV, CMV, varicella
List protozoan/helminth infections associated with impaired cellular immunity
toxoplasma, cryptosporidium, strongyloides
Antibody structure
F(ab): binds to antibody. Fc: defines isotypes (IgA, IgG, etc) and binds phagocytes via Fc receptors
List the infections associated with antibody deficiencies
Mostly respiratory infections, encapsulated bacteria (S. pneumoniae),some viruses (enteroviruses); Giardia lamblia
IgG1 vs IgG2
IgG1: recognizes proteins. IgG2: recognizes polysaccharides
Which bacteria have polysaccharide capsules
H flu type B, strep pneumoniae, N. meningitidis, Group B strep, Klebsiella, salmonella typhi
IgM vs IgA
IgM is found in blood and mucosal. IgA is mucosal > blood
List primary and secondary causes of humoral immunodeficiency
primary: IgA deficiency, CVID, IgG 2 subclass deficiency, Hyper IgE syndrome (Jobs syndrome). Secondary: CLL ( low Igs), Multiple myeloma (High monoclonal IgG, low IgM and IgA)
selective IgA deficiency
Most common primary “immunodeficiency.” Increased autoimmune dis; + malignancy. Normally we produce more IgA than IgG and IgM.
CVID- what is it, age of onset, Sx, risks
Common Variable Immunodeficiency - Decreased IgG, IgM, IgA, with nl number of B cells and normal T cells. Onset in teens or 20s. Sx: chronic diarrhea ( G. lamblia, C. jejuni) with GI lymphoid hyperplasia, increased risk of bacteremia, increased PCP, fungi, mycobacteria, recurrent HSV. Increased risk of autoimmune dz, gastric cancer and lymphoma
function of complement
Classical pathway (Ig), lectin or alternative pathway activates C3 > activates C5-C9 > membrane attack complex lyses GNR. Also, C3 opsonizes bacteria and facilitates phagocytosis
complement deficiency
C2 is most common. C1-2 (classical) is pyogenic. C5-9 (terminal) - Neisseria
define CD4 T cell count in early, intermediate and advanced HIV/ AIDS
Early: >500cells/ul. Intermediate: 200-500 cells/ul. Advanced/ AIDs: < 200cells/ul
Immunodeficiency in HIV
Low CD4+ T cells number, Decreased CD4+ T cell function, NK cell dysfunction, B cell dysfunction ( hypergammaglobulinemia, decreased memory B cells, decreased response to new antigens, high rates of autoimmunity), PMNs and macrophages are normal
Which bacterial infection is common in HIV
cryptococcus- 30-70% mortality in 3 months. Median T cell cound is 19. cryptococcus has a large polysaccharide capsule (usually responded to by Ig2, complement and phagocytes)
Labs to test for phagocytic immunodeficiency
CBC and diff. PMN <100-500. Decreased function seen with NBT test
labs for cellular immunodeficiency
CBC and diff: lymphs < 500.
Labs for humoral immunity
protein/ albumin: decreased globulin, anti-A/B (RBC) for function tests. SPEP: decreased gamma globulin. Quantitative Igs: decreased IgG, M, A. CH50 decreased
describe NBT test
Nitroblue tetrazolium dye reduction; clear NBT reduced by H2O2->blue (CGD-not blue [chronic granulomatous disease])
