IMMUNODEFICIENCY 1.0 Flashcards
INTRO-INDICATIONS OF IMMUNODEFICIENCY DISORDERS
Classification of Immunodeficiency
a. Primary
b. Secondary
Types of immunodeficiency
a. Humoral (B-cell) Immunodeficiency
b. Cellular (T-cell) Immunodeficiency
c. Combined B-cell and T-Cell Deficiency
d. Other Types
* Iatrogenic Deficiency
* Nutritional Deficiency
Refers to a state in which the immune system’s ability to fight infections and diseases is compromised or entirely absent.
IMMUNODEFICIENCY
This condition can lead to increased susceptibility to infections, more severe illnesses, and a higher risk of developing certain cancers.
IMMUNODEFICIENCY
Refers to a condition characterized by an innate, acquired, or induced inability to develop a normal immune response.
IMMUNODEFICIENCY
TYPES OF IMMUNODEFICIENCY:
- Usually present at birth and are genetic disorders that are usually hereditary.
- Typically become evident during infancy or childhood.
- All are relatively rare!
PRIMARY IMMUNODEFICINECY
There are more than 100 primary immunodeficiency disorders.
TYPES OF IMMUNODEFICIENCY:
- Generally develop later in life.
- Result from use of certain drugs or from another disorder.
SECONDARY IMMUNODEFICIENCY
They are more common than primary immunodeficiency disorders.
TYPES OF IMMUNODEFICIENCY:
These are immunodeficiency disorders that a person is born with, usually due to genetic defects that affect the development or function of the immune system.
PRIMARY IMMUNODEFICIENCY
PRIMARY IMMUNODEFICIENCY, classified based on which part of the immune system is affected.
- Humoral (B-cell) Immunodeficiencies
- Cellular (T-cell) Immunodeficiencies
- Combined T-cell and B-cell Immunodeficiencies
PRIMARY IMMUNODEFICIENCY:
- Group of disorders where there is a deficiency or dysfunction in B cells, the immune cells responsible for producing antibodies (immunoglobulins).
- These antibodies are crucial for identifying and neutralizing pathogens like bacteria and viruses.
Humoral (B-cell) Immunodeficiencies
PRIMARY IMMUNODEFICIENCY:
Genetic Defects under Humoral (B-cell) Immunodeficiencies
- X - linked Agammaglobulinemia
- Selective IgA Deficiency
PRIMARY IMMUNODEFICIENCY:
- A genetic defect in the BTK gene (encodes Bruton’s tyrosine kinase that is essential for B cell development).
- Patients have very few or no B cells, leading to almost no antibody production.
- Recurrent bacterial infections, especially of the respiratory and gastrointestinal tracts, beginning in infancy.
Genetic Defects under Humoral (B-cell) Immunodeficiencies
X - linked Agammaglobulinemia
BTK gene is located on the X chromosome, XLA follows an X-linked recessive inheritance pattern.
* Males do not have a second X chromosome to compensate for the defective gene.
* Females are usually carriers because they have one normal BTK gene on their other X chromosome, which compensates for the defective gene. However, carriers rarely show symptoms.
PRIMARY IMMUNODEFICIENCY:
- The mutation in the BTK gene leads to a failure in the development of B cells, the cells responsible for producing antibodies.
- Without functional B cells, the body cannot produce immunoglobulins.
Genetic Defects under Humoral (B-cell) Immunodeficiencies
X - linked Agammaglobulinemia
The term “agammaglobulinemia” refers to the absence or severe deficiency of immunoglobulins (antibodies) in the blood.
It is a crucial antibody found in mucous membranes lining the respiratory and gastrointestinal tracts, as well as in saliva, tears, and breast milk. It plays a key role in the first line of defense against pathogens entering the body through these routes
IgA
Individuals with selective IgA deficiency have low or undetectable levels of IgA, which impairs their mucosal immunity.
PRIMARY IMMUNODEFICIENCY:
▪ Commonly associated with:
* normal B lymphocytes in peripheral blood
* normal CD4+ and CD8+ T cells
* usually, normal neutrophil and lymphocyte counts
▪ Many are asymptomatic.
▪ Some people may have recurrent respiratory infections (e.g., sinusitis, bronchitis) or gastrointestinal infections due to the lack of IgA.
Genetic Defects under Humoral (B-cell) Immunodeficiencies
IgA Deficiency
PRIMARY IMMUNODEFICIENCY:
- Group of disorders where the body has an inadequate or dysfunctional T-cellmediated immune response.
- T cells are a type of lymphocyte (white blood cell) essential for coordinating the immune system’s response to infections, especially those caused by viruses, fungi, and certain bacteria.
Cellular (T-cell) Immunodeficiencies
DiGeorge Syndrome
When T-cell function is impaired, the body’s ability to fight infections and regulate immune responses is significantly compromised.
PRIMARY IMMUNODEFICIENCY:
- Caused by a deletion in the 22q11.2 region of chromosome 22. This region contains several genes crucial for normal development, and the loss of these genes leads to the various manifestations of the syndrome.
- Leads to thymic hypoplasia or aplasia (underdevelopment or absence of the thymus gland).
- The thymus is where T cells mature, so its underdevelopment leads to T-cell deficiency
Cellular (T-cell) Immunodeficiencies
DiGeorge Syndrome
- Cardiac Abnormalities: TOF, VSD
- Cleft Palate
- Facial Features: Long face, almond-shaped eyes, a broad nasal bridge, small mouth, and a small chin.
- Thymic Hypoplasia or Aplasia:.
- Hypocalcemia: Due to underdeveloped parathyroid glands
- Developmental Delays: Delays in speech, motor skills, and learning.
- Behavioral and Psychiatric Disorders: ADHD