Allergy & Immunology Study Guide: Type 1 Reactions

4 common classifications of immunodeficiencies

- Cellular and humoral immunodeficiency

- Combined immunodeficiencies w/ syndromic features

- Antibody deficiencies

- Complement deficiencies

T cell deficiency and B/T cell defects increases the risk for?

infections

DiGeorge syndrome is a (B/T) cell deficiency

T

CATCH 22 mnemonic for DiGeorge syndrome

Cardiac

Abnormal facies

Thymic hypoplasia

Cleft lip/palate

Hypocalcemia

Chromosome 22

What cardiac abnormality is associated with DiGeorge syndrome?

VSD & Tetralogy of Fallot

Characterized by defects in T and B cells and weak NK cells caused by autosomal recessive or X-linked disorder of both humoral and cellular immunity

SCID

which condition has features:

- recurrent cutaneous, GI or pulm infections

- failure to thrive

- presents in first few months of life

- death between 12-24 months

- thrush

-chronic diarrhea

SCID

treatment for SCID?

bone marrow transplant (aka HCT)

which condition has features:

- caused by mutation of ATM gene resulting in defective DNA repair

- progressive cerebellar ataxia, abnormal eye movements

- oculocutaneous telangiectasia

ataxia-telangiectasia

Major risk factor for Ataxia- Telangiectasia

Lymphomas & Leukemias

Bacterial causes of B cell deficiency

S. pneumo, H. flu, S. aureus

Viral causes of B cell deficiency

Enterovirus

Protozoal causes of B cell deficiency

Giardia

Bruton's agammaglobulinemia

X-linked agammaglobulinemia

Mutation of Bruton Tyrosine Kinase (BTK) gene on X chromosome, leading to arrest of B cells and failure to generate plasma cells

no mature B cells = no antibodies

X-linked agammaglobulinemia

what condition has features:

- recurrent ear infections, sinusitis, PNA

- susceptible to infections

- diagnosed via flow cytometry → no CD19+ B cells, no antibodies

- absent response to vaccines (negative titers)

X-linked agammaglobulinemia → tx is IVIG

Primary immunodeficiency disorder characterized by impaired B cell differentiation into plasma cells and defective Ig production

Common variable immunodeficiency (CVID)

Reduced or absent IgG, IgM, and/or IgA & poor or absent response to immunizations

Common variable immunodeficiency (CVID)

What disease has recurrent sinopulmonary infections (bronchiectasis), recurrent diarrhea, malabsorption, noncaseating granulomas (in spleen, liver, lungs, and skin), splenomegaly and ↑ risk of autoimmune disease and lymphoma?

Common variable immunodeficiency (CVID) → tx with IVIG

how is CVID diagnosed?

low serum IgG

low IgM and/or IgA

poor antibody function = no response to vaccines

X-linked condition characterized by normal/increased levels of serum IgM associated with deficiencies in IgG, IgA, IgE, and poor antibody function

inability of B cells to switch from IgM to IgG and IgA

inability of T cells to interact with macrophages

Hyper-IgM syndrome

What is the cause of Hyper-IgM syndrome?

CD40L defect

which condition has features:

- susceptibility to sinopulmonary bacterial infections

- susceptibility to PJP, cryptosporidium, histoplasma organisms

- chronic diarrhea → failure to thrive

- ↑ risk of malignancies

- absence of CD40L

X-linked Hyper-IgM syndrome

What is the curative tx for Hyper-IgM syndrome?

Bone marrow transplant

What B cell defect has NO mature B cells, antibodies, or antibody response present?

X-linked agammaglobulinemia

What B cell defect DOES have mature B cells, low Abs, and antibody response present?

Transient hypogammaglobulinemia

which condition has features:

- drop in IgG levels in infants between 5-24 months of age (delay in production)

- good antibody responses

- recurrent resp, GI and urinary infections

- needs ABX prophylaxis

transient hypogammaglobulinemia of infancy

Tx for IgG deficiency

IVIG/SQIG

Tx for Specific antibody deficiency

IVIG/SQIG

AKA Hyper IgE syndrome

Job syndrome

autosomal recessive mutation in HAX1 gene

Kostmanns syndrome (AD)

leukocytes cannot leave the vasculature to migrate normally into tissues when there is inflammation or infection

leukocytic adhesion deficiency (LAD)

which type of LAD:

- beta-2 integrin family is deficient or defective

- recurrent bacterial infections & persistent neutrophilia

- absent pus formation (hallmark)

- impaired wound healing

LAD1

which type of LAD:

- fucosylated carbohydrate ligands for selections are absent

- severe intellectual disabilities

- short stature

- depressed nasal bridge

LAD2

which type of LAD:

- activation of all beta integrins is defective

- leukocytes and platelets are affects → bleeding

LAD3

which condition has features:

- recurrent skin and pulmonary infections + eczema

- scoliosis

- hyperextensibility

- retained primary teeth

- asymmetric jaw, broad nose, prominent forehead, triangular jaw

Job syndrome

which condition has features:

- impaired lysosome degranulation

- recurrent cutaneous and sinopulm infections

- partial oculocutaneous albinism

- peripheral neuropathy

- peripheral smear shows giant granules

Chediak-Higashi → tx is bone marrow transplant

Defects in the enzyme NADPH oxidase, leading to inability to generate microbicidal "respiratory burst" and recurrent, life-threatening bacterial and fungal infections (abscesses) and walled off granuloma formation

Chronic granulomatous disease

Diagnostic testing for chronic granulomatous disease

Dihydrohodamine oxidation test with flow cytometry (DHR)

treatment for chronic granulomatous disease?

interferon-gamma

lifelong prophylactic ABXs

HIV is acquired through ______ transmission

Vertical

what is the treatment for HIV+ neonates?

antiretroviral therapy (zidovudine + nevirapine) right after birth

bactrim at 6 weeks for PJP prophylaxis

CD4 levels every 4 months

Children born with HIV can receive ALL vaccines except _______

Live virus vaccines (MMR, Varicella)

What type of hypersensitivity rxn:

Anaphylactic

Type 1

What type of hypersensitivity rxn:

Mediated by specific IgE antibody

Type 1

What type of hypersensitivity rxn:

Allergic rhinitis, urticaria, food allergies

Type 1

type 1 acute vs late phase hypersensitivity response

acute = w/in 1 hr; H1 induces wheals & pruritus; H2 ↑ gastric acid secretion

late = 3-12 hrs after, lasts for hrs-days

What type of hypersensitivity rxn:

Antibody-mediated cell destruction

Type 2

What type of hypersensitivity rxn:

Antigen-antibody complexes form and are deposited in the lining of blood vessels, stimulating tissue inflammation mediated by compliment system

Type 3

What type of hypersensitivity rxn:

Arthus reaction, serum sickness, vasculitis

Type 3

What type of hypersensitivity rxn:

Previously sensitized T cells interact with antigen, leading to tissue inflammation; reaction occurs 24-72 hrs after exposure

Type 4

What type of hypersensitivity rxn:

Tuberculin (PPD) reaction or contact dermatitis (poison ivy)

Type 4

What is the most common type of anaphylaxis/anaphylactoid reaction?

Cutaneous

Tx for anaphylaxis/anaphylactoid reactions

Epinepherine

Common causes of anaphylaxis reactions

Antibiotics → PCN

Foods → peanuts, shellfish, eggs

Anesthetic agents

Insect stings → bees

common causes of anaphylactoid reactions

ASA

NSAIDs

radiocontrast

sulfites

IgE mediated:

Anaphylactoid reaction or anaphylaxis

Anaphylaxis

NOT IgE mediated, results from mast cell degeneration:

Anaphylactoid reaction or anaphylaxis

A) Anaphylactoid reaction

inflammation of conjunctiva via IgE mediated response and mast cell degranulation and ↑ vascular permeability

allergic conjunctivitis

common allergens for allergic conjunctivitis

cats, smoke, pollen

which condition has features:

- bilateral pruritus

- watery mucoid discharge

- diffuse conjunctival erythema

- papillary edema of palpebral conjunctiva

allergic conjunctivitis → Cromolyn sodium drops

IgE mediated hypersensitivity response to inhalant allergens and degranulation of mast cells causing nasal itching, nasal salute, mouth breathing, infraorbital congestions, watery/mucoid rhinorrhea, cobblestoning of posterior pharyngeal wall, pale/violaceous nasal mucosa and swollen nasal turbinates

allergic rhinitis

Food intolerance or allergy:

Abnormal physiologic response to ingested food, NOT immunologic

Food intolerance

Food intolerance or allergy:

Immunologic reaction that occurs with ingesting food

Food allergy

examples of food intolerance?

lactase deficiency

caffeine

tyramine in aged cheese/MSG

which type of food allergy:

oral allergy syndrome, anaphylaxis, urticaria, angiodema

IgE mediated food allergy

which type of food allergy:

atopic dermatitis & Eosinophilic esophagitis/gastroenteritis

Mixed IgE mediated food allergy

which type of food allergy:

Food protein induced proctocolitis/enterocolitis

Non-IgE mediated food allergy

pruritic/edema of the lips, tongue, palate and throat after eating raw food

oral allergy syndrome

Oral allergy syndrome does NOT occur with _______

Cooked food

postprandial N/V/D, abd pain, and failure to thrive

allergic eosinophilic gastroenteritis

Common food allergens in children

Peanuts, milk, egg, soy, wheat, fish

High allergy foods may be introduced between ages _______ regardless of risk of allergies

4-11 months

management of food allergies?

allergen avoidance

antihistamines

PO steroids

epi-pen