Immunodeficiencies Flashcards
(43 cards)
define immunodeficiency
The decreased ability of the body to fight infections and other diseases
when part of the immune system is absent
define autoimmunity
When the cause of this deficiency is the system of immune responses of an organism against its own healthy cells, tissues and other normal body constituents
Define primary immunodeficiency disease (PIDD)
when the deficiency is hereditary/genetic
primary immunodeficiencies
In the most common primary immunodeficiency diseases, different forms of these cells or proteins are missing or do not function
This creates a pattern of repeated infections, severe infections and/or infections that are unusually hard to cure
These infections may attack the skin, respiratory system, the ears, the brain or spinal cord, or in the urinary or gastrointestinal tracts
examples of PIDD in specific organs,glands,cells,tissues
heart defects are present in some PIDDs
Other PIDDs alter facial features, some stunt normal growth and still others are connected to autoimmune disorders such as rheumatoid arthritis
T or F: Serious PIDDs typically become apparent in infancy
T
For example, severe T-cell or combined immune deficiencies typically present in infancy
Some may present in older children or adults
in milder forms, it often takes a pattern of recurrent infections before PIDD is suspected
important signs that may indicate PIDD:
-Recurrent, unusual or difficult to treat infections
-Poor growth or loss of weight
-Recurrent pneumonia, ear infections or sinusitis
-Multiple courses of antibiotics or IV antibiotics necessary to clear infections (can lead to resistance)
-Recurrent deep abscesses of the organs or skin
-A family history of PIDD
-Swollen lymph glands or an enlarged spleen
-Autoimmune disease
Secondary immune deficiency
occurs when the immune system is compromised due to an environmental factor
ex: infection (HIV), medications (chemotherapy or systemic steroids), severe burns or malnutrition
examples of treatments for primary immune deficiency
transplantation (bone marrow, stem cell, thymus), immunoglobulin replacement (antibodies to reinforce protection), preventative antibiotics and strategies to manage autoimmune disease
Gene therapy has been successful in specific types of PIDD
quality of life has improved drastically in these diseases
What are characteristics of PIDDs?
susceptibility to infections, autoimmunity and inflammation
increased risk of malignancies due to impaired immune homeostasis + surveillance
Depending on the nature of the immune defect, the clinical presentation may vary and may include…
recurrence of upper and lower respiratory tract infections, invasive bacterial and/or fungal infections, infections sustained by poorly virulent or opportunistic pathogens (“weak” pathogens)
diagnostic approach to PIDD
-a detailed family hx
-clinical history
-physical examination
-appropriate laboratory tests
steps 1-5
1: too many infections
2: rule out common causes of infection and secondary immune deficiency
3: consider PIDD
4: categorize patient and order appropriate screening
5: consider referral to immunology specialist and secondary testing
Selective IgA deficiency
most common primary immunodeficiency disorder
estimated 1 in 500, many asymptomatic(!!)
(side note: IgA has potent antiviral activity)
if symptomatic:
Patients are most susceptible to infections with encapsulated (extra protection) bacteria
-ex. Haemophilus influenzae, Streptococcus pneumoniae, Neisseria meningitides
Frequent and recurrent sinusitis, otitis (ears), and bronchitis (IgA is found in secretions)
diagnosis
Undetectable serum IgA levels (< 7 mg/dL) with normal levels of IgG and IgM
Some patients may have antibodies against IgA
Plasma and blood transfusions can contain IgA and cause anaphylaxis (shock)
treatment
Antibiotics as needed for infections
Some cases of IgA deficiency may spontaneously remit
Common Variable Immunodeficiency (CVID)
Most common symptomatic PID
Onset is generally in early adulthood
1 in 25,000 in the United States, most cases are sporadic; about 10–20% are familial
CVID
-Frequent sinopulmonary infections (affecting the paranasal sinuses and the airway of the lungs)
-Low serum immunoglobulin levels
-Deficient functional antibody responses (vaccines don’t work. V for vaccines and Variable)
-Primary defect may be with B cells or T cells (cannot produce antibodies for a vaccine)
-Heterogeneous immunodeficiency disorder clinically characterized by an increased incidence of recurrent infections, autoimmune phenomena, and neoplastic diseases (lump)
How to diagnose CVID
Diagnosis is made in patients who have reduced serum immunoglobulins (IgG, IgM, or IgA) and poor antibody response to vaccines, after exclusion of secondary causes, such as:
-Proteinuria
-Protein-losing enteropathy
-Drug effects (eg, rituximab, antiepileptics)
-Chronic lymphocytic leukemia, lymphoma, and plasma cell myeloma
Treatment
Should be treated aggressively (because symptomatic) with antibiotics at the first sign of infection; antibiotic therapy should cover encapsulated bacteria
-As infections may be prolonged or associated with unusual complications such as meningitis or sepsis
Subcutaneous or intravenous immunoglobulin replacement therapy, typically provided every 1–4 weeks, with a typical monthly dose of 300–600 mg/kg
-Adjust dosage or infusion interval on the basis of clinical response and serum IgG levels
which drugs are the choice to attack cell walls/encapsulated bacteria
penicillin and amoxicillin “all day”
Specific (functional) Antibody Deficiency
Characterized by decreased or absent IgG(!) antibody response to vaccines
-In the setting of normal or mildly decreased serum immunoglobulin levels
Can range from mild symptoms managed with antibiotics and vaccination to more rarely to recurrent infections with features very similar to CVID
side note:
small nuggets of difference between many of these
