Allergy/Immunology Flashcards
Screening tests for B-cells:
- IgG, IgM, IgA levels
- Vaccine Ab titers (tetanus, H.flu, Diptheria, Pneumococcal)
- IgG subclass levels
- B-cell enumeration (CD19 or CD20)
- Antibody response to vaccines
Screening tests for T-cells:
- Lymphocyte count and morphology
- Thymic size by x-ray (newborns)
- Delayed skin tests (over age 2)
- T cell enumeration (CD 3/4/8)
- PHA and/or antigen
- Lymphoproliferation
- HIV testing
Screening tests for Phagocytic cells:
- WBC count, morphology
- IgE level
- Dihydrorhodamine or NBT test for CGD
- Chemotaxis assay
Screening tests for complement:
CH50 level
C3 level, C4 level
- Specific complement component assay
- C1 esterase inhibitor activity and level
Most immunodeficiencies are ___
Secondary
- Lag in Ig synthesis
- Recurrent bacterial infections at 4-24mos, diarrhea, FTT
- Food intolerance, eczema, ex-prematurity
- Igs low but present, Abs variable, B cells present, neutropenia occasional
TRANSIENT HYPOGAMMAGLOBULINEMIA OF INFANCY
Rx: watch and wait, continuous ABX, rarely IVIG
- Complete absence of B-cells
- Onset after age 6mos of pyogenic infections
- Absent tonsils and lymph nodes
- Bronchiectasis, enterovirus encephalitis, vaccine-related polio infection
- Very low Igs (
X-linked Agammaglobulinemia (Bruton’s)
Rx: IVIG, ABX, no vaccines
- Low IgG, IgA
- High IgM
+/- Neutropenia - X-linked
Hyper-IgM Syndromes
Rx: IVIG, GCSF, Transplantation
- Onset after age 10
- URIs, sinusitis, pneumonia, bronchiectasis, diarrhea
- Autoimmunity, blood disorders, malignancy, granulomata
- Igs low (
Common Variable Immunodeficiency
Rx: IVIG, ABX
- IgA B cells deficient
- 25% asymptomatic, 25% respiratory infections, 25% allergies, 25% autoimmunity
Selective IgA Deficiency
Rx: Avoid Ig, ABX, Medic alert badge, vaccines ok
- Recurrent URI, PNA, sinusitis
- IgG subclass deficiency
IgG Subclass Deficiencies
Rx: ABX, IVIG-very rare
- Older than age 2
- Recurrent URI and lung infections, sinusitis, otitis
- Poor antibody responses to serotypes in pneumovax (<70% ages 6-60)
- Sometimes transient, sometimes lifelong
Impaired Polysaccharide Responsiveness
Rx: continuous ABX, prevnar 13 vaccine, IVIG rarely
- Early skin, respiratory, and GI infections
- FTT
- PCP, moniliasis, rashes, malabsorption, chronic cough
- Absent lymph nodes and tonsils
- Very low T cells, B and NK cells variable
- No thymus or TRECs
Severe Combined Immunodeficiency (SCID)
- AR, XL, sporadic, 18 variants
- Rx: Transplant, gene therapy for XL-SCID
- Eczema
- Thrombocytopnia
- Severe infections
- MICROPLATELETS
- IgA and IgE high, IgM low, T cell function decreased
Wiskott-Aldrich Syndrome
- WASP gene defect
Rx: ABX, splenectomy, BMT
- Progressive ataxia, telangiectasia
- Sinopulmonary infections
- Premature aging
- Cancer
- Swallowing problems, Slow cognition
- ELEVATED ALPHA-1-FETOPROTEIN
- IgA deficiency, variable T-cell defects, chromosome instability
Ataxia-telangiectasia
Rx: IVIG, ABX, nothing very effective
- T cell defect with thymic and parathyroid abnormalities
- Hypcalcemia
- Cardiac outflow tract defects
- Variably low T cells and TRECs, occasional SCID phenotype
DiGeorge Syndrome
- Don’t want to give CMV blood
- T cell defect to Candida antigen
Mucocutaneous Candidiasis
- Rx: local and systemic antifungals
- Inability to form reactive O2 with decreased phagocyte killing because of a NADPH oxidase defect
- Bone, lung abscesses with S. aureus, Serratia and Aspergilla
- Large spleen, liver, nodes
- Poor wound healing
- Abnormal NBT or Dihydrorhodamine reduction
Chronic Granulomatous Disease
XL 67%, AR 33%
Rx: ABX, antifungals, BMT
- Soft tissue infections
- Dermatitis, Peridontitis
- Delayed detachment of umbilical cord (>20days)
- Decreased expression of CD11b on granulocytes
Leukocyte Adhesion Defect-type 1
Rx: ABX, local GM-CSF, BMT
- Coarse features
- Staph infections of skin, lungs, bones, cold abscesses, fractures, scoliosis, dental abnormalities
- STAT-3 defect of TH17 (pro-inflammatory cytokine)
- IgE levels >2000
Hyper-IgE Syndrome (Job/Buckley Syndrome)
Rx: Bactrim, continuous anti-Staph drugs
- Neisserial infections, autoimmunity, and angioneurotic edema
- Abnormal CH50
Complement Defects
What is the approximate half life of IgG in the circulation
20-30days
What is the best test for T cell deficiency
CD4 level
What test best distinguishes male infants with X-linked agammaglobulinemia from transient hypogammaglobulinemia
B cell count
What other immunodeficiency must be excluded in selective IgA deficiency?
IgG2 deficiency
What immunodeficiency has an elevated alpha-1-fetoprotein level?
Ataxia telangiectasia
What is the most common cause of persistent vomiting in a child with CGD
Granuloma
What test is used to screen newborns for SCID?
TREC
What new drugs are available for hereditary angioedema
C1 inhibitor, Kallekrein inhibitor
What IgG subclass contains most of the polysaccharide antibodies?
IgG2
What therapeutic monoclonal antibody is used most often by pediatricians?
Palivuzumab (Synagis)
Two most common viral triggers for asthma
RSV and rhinovirus
- Exp wheezing
- Can speak in sentences
- > = 70% PEF
- SpO2 >=95%
- Pulsus paradoxus <10mm
Mild Asthma
- Exp/Insp wheezing
- Can speak phrases
- PEF 40-69%
- SpO2 90-94%
- Pulsus paradoxus 10-25mm
Moderate Asthma
- Insp/Exp wheezing or quiet
- Can speak only words
- PEF < 90%
- Pulsus paradoxus >25mm
Severe Asthma
Asthma Predictive Index
1 Major Criteria: Atopic Dermatitis, Parental Asthma, Sensitization to aeroallergens
2 Minor Criteria: Allergic Rhinitis, Eosinophilia >4%, Wheezing without URI
Positive if 1 major or 2 minor criteria are met
Immunotherapy has/has not been shown to be effective in the treatment of asthma and food allergy
HAS NOT
Early Spring Allergens
Trees
Late Spring, Early Summer Allergens
Grasses
Late Summer, Fall Allergens
Ragweed
Fall, Damp weather Allergens
Mold
Immunotherapy for Allergic Rhinitis does not work well against these allergens
Molds and dog allergens
Very effective against grass, tree, ragweed pollens, dust mites and cat allergens
Non-IgE mediated food allergy usually only involves the ______ system
GI
- Recurrent otitis media, bronchitis, pneumonia, meningitis, dermatitis, commonly due to S.PNEUMO and H.FLU
- Most viral infections handled fine except for ENTEROVIRUSES
- Normal growth and development
- B cells absent on flow cytometry
- Marked decrease in all Ig levels
X-linked Agammaglobulinemia (Bruton’s)
Rx: monthly IVIG, prophylactic ABX
- Sinopulmonary and GI infections
- Many asymptomatic
Selective IgA deficiency
- Very common
- IgA s
Rx: treat infections
- Abnormal delay in Ab synthesis
- Recurrent URIs
- Self-limited, recover by 18-36mos
- Decreased quantitative IgG and IgA levels
- QUALITATIVE IG LEVELS NORMAL
Transient hypogammaglobulinemia of infancy
Rx: treat infections +/- prophylactic ABX
- Sinopulmonary infections
- Variable age of presentation
- Decreased quantitative Ig’s
- QUALITATIVE IG’s ABNORMAL
Common Variable Immunodeficiency (CVID)
- do not respond to polysaccharides
Rx: monthly IVIG
- Recurrent, severe pyogenic infections
- Opportunistic infections, esp P.carinii
- Decreased IgG and IgA
- ELEVATED/NL IgM LEVELS
- Qualitative Ig levels abnormal
X-linked Hyper-IgM Syndrome
- T cell abnormality - prevents Ab switching from IgM to other Ig classes
Rx: monthly IVIG
- Recurrent bacterial and respiratory infections
- Normal total IgG levels
- IgG subclass decreased (IgG1, IgG2, IgG3, IgG4)
IgG Subclass Deficiency
- THYMIC HYPOPLASIA
- DYSMORPHIC FACIES
- Tetany 2/2 hypocalcemia (parathyroid hypoplasia)
- R-sided aortic arch, conotruncal abnormalities, ASD, VSD
- Usually mildly decreased T cells
- Normal Ig levels
Digeorge Syndrome
- FISH for microdeletion on Chr 22
- T cell function tends to improve with age
- Recurrent CANDIDAL infections of the nails, skin and mucous membranes
- 1st year of life
- Impaired Candida specific T cell responses
Chronic Mucocutaneous Candidiasis
Rx: antifungals
- Very sick in first few months of life
- FTT
- Chronic diarrhea
- Frequent viral, bacterial, fungal and protozoal infections
- Opportunistic infections with Candida, P.carinii
- Fatal if not treated
- B AND T CELL DYSFUNCTION
- SEVERELY LYMPHOPENIC (newborn ALC
Severe Combined Immunodeficiency (SCID)
Rx: stem cell transplant
- ECZEMA
- THROMBOCYTOPENIA
- SMALL, DEFECTIVE PLATELETS
- Recurrent bacterial and viral infections
- Normal IgG levels, decreased IgM levels, increased IgA and IgE levels
- Decreased qualitative antibody responses to polysaccharide antigens
Wiskott-Aldrich Syndrome
- X-linked recessive
- Increased incidence of malignancy and autoimmune disorders
Rx: BM transplant, splenectomy if excessive bleeding
- Onset by 2yrs of age
- PROGRESSIVE CEREBELLAR ATAXIA
- OCULOCUTANEOUS TELANGIECTASIA develop between 3-6 years of age
- Recurrent bacterial, sinopulmonary infections
- Variable antibody and cell-mediated immunodeficiency
Ataxia Telangiectasia
- AR d/o
- High incidence of malignancy
- Recurrent intracellular bacterial and fungal infections with catalase-positive organisms (S.aureus, Aspergillus, S.marcescens, Nocardia sp, and Burkholderia)
- GRANULOMA and ABSCESS formation
- Normal T and B cell function
Chronic Granulomatous Disease (CGD)
- X-linked or autosomal recessive disorder
- Defective production of reactive oxygen intermediates to kill microorganisms by phagocytes
- NBT positive
- NO ABN IN NEUTROPHIL COUNT OR CHEMOTAXIS
Rx: treat infections early and aggressively, prophylaxis with TMP/SMX and Antifungals
- Recurrent bacterial and fungal infections
- Delayed separation of umbilical cord
- Impaired wound healing
- Severe PERIDONTAL disease
- Leukocytosis
Leukocyte adhesion deficiency (LAD)
- AR
- Impaired WBC chemotaxis
Rx: treat infections agressively and early
- Recurrent infections with pyogenic bacteria
- HSM
- Partial occulocutaneous albinism
- CNS abnormaliteis
- GIANT CYTOPLASMIC GRANULAR INCLUSIONS in WBC and plts
- Abnormal neutrophil chemotaxis AND intracellular killing of organisms
Chediak-Higashi Syndrome
- AR
- High incidence of malignancies
Rx: BM transplant
- EOSINOPHILIA
- ECZEMA
- ELEVATED IGE
- Recurrent staph infections of skin, subcutaneous tissues, lungs, upper airways and bones
- Coarse facial features
Job’s Syndrome (Hyper IgE Syndrome)
Rx: IV antistaphylococal ABX
- Looks like antibody deficiencies
- Recurrent bacterial infections
- Check C3, C4, CH50 levels = entire pathway
- Disseminated Neisseria infections (GC and meningococcus)
Late Complement Component Deficiency
