Flashcards in Deficiency of Adaptive Immunity Deck (38):
What are the two categories of immunodeficiency?
What is primary immunodeficiency?
An immunodeficiency caused by mutations in genes required for normal development of parts of the immune system.
What is the normal inheritance pattern for primary immunodeficiency?
There is no one normal inheritance pattern. Different diseases can have differing inheritance patterns with different penetrance.
Is a congenital dysfunction of the thymus or bone marrow considered primary or secondary immunodeficiency?
Immunodeficiency following treatment of immunosuppressive drugs will be considered primary or secondary immunodeficiency?
A block in the development of lymphoid stem cells would cause which cell numbers to be low?
T cells AND B cells
What condition results in a block in the development of the lymphoid stem cell?
Severe Combined Immunodeficiency Disease, or SCID
What are some characteristics of SCID?
Lymphopenia- both T and B cells
Absent thymic shadow on X-ray
Tonsils are small
Mitogen responses and serum immunoglobulins are low
What is the inheritance patterns of most SCID cases?
the rest are autosomal recessive
What is the defect in SCID-X1?
Gene for the gamma chain that forms part of the receptors for IL-2 and other cytokines necessary for lymphoid development
What enzyme do most patients with SCID lack?
Adenosine deaminase (ADA).
What happens when a patient has a deficiency in adenosine deaminase?
Adenosine accumulates in all cells but impairs lymphocyte development selectively
What is the most common mutation that causes SCID in Navajo and Apache children?
Defect in V(D)J recombination
What block would result in normal T cells but low to absent B cells?
A boy presents with recurrent bacterial infections manifesting as pneumonia, chronic diarrhea and enterovirus. What should you have on your differential diagnosis?
X-linked (Bruton) Agammaglobulinemia
What patient population is the reason why we can no longer use oral polio vaccine in America?
X-linked (Bruton) Agammaglobulinemia
High IgM with low IgG and IgA is seen in patients with what type of block?
What defect is seen in Block 3?
Either mutation in CD40 ligand on T cells or
CD40 on B cells
What is the name of a block 3 syndrome?
X-linked hyperIgM syndrome
What is the name of the condition that results in a normal number of pre-B and B cells, but the B cells are difficult to trigger to make specific antibody?
Common Variable Immunodeficiency (CVID)
What is the main phenotype of common variable immunodeficiency?
Recurrent bacterial infection
What is the treatment of someone with common variable immunodeficiency?
CVID have an increase risk of what?
What are the two components of the thymus?
Lymphoid part- derived from bone marrow
Stromal part- derived from endoderm and ectoderm of the 3rd and 4th pharyngeal pouch
DiGeorge syndrome is caused by what mutation?
-Large (45 gene) deletion on chromosome 22
What is the phenotypical presentation of DiGeorge syndrome?
-Unexplained convulsions controllable by calcium because parathyroids also derive from the pharyngeal pouches
-Great vessels of the heart develop abnormally
-Cell mediated immunity is depressed, so viral and fungal infections are common
T cell deficiencies are associated with what type of infection?
-yeast and fungi (esp. Candida albicans and Pneumocystis jirovecii)
B cell deficiencies are associated with what type of infections?
"high-grade" (extracellular, pyogenic = pus-producing) bacterial pathogens such as Staphylococcus aureus, Haemophilus influenzae and Streptococcus pneumoniae
Issac is a 9 month old patient brought into the ER by his mother who tells you that her son has been having recurrent and persistent Gram-positive bacterial infections. You check Issac's IgG levels and see that they are low. What should be on you differential diagnosis for a patient of this age?
And, how long would you expect this to last?
Transient hypogammaglobulinemia of infancy
Up to 18 months
15% of all chronic diarrhea in infants is due to this condition
What are the symptoms of someone with selective IgA deficiency?
-Diarrhea and sinopulmonary infections
-Increased frequency and severity of allergies
What is the inheritance pattern of ataxia telangiectasia?
What are the phenotypical characteristics of someone with ataxia telangiectasia?
What cellular deficiency is seen in someone with ataxia telangiectasia?
T and B cell deficiency. IgA is especially depressed
Describe some characteristics of Wiscott-Aldrich syndrome.
-Platelet and B cell deficiency
-Many bacterial infections
Name some immunosuppressive viruses.
What is the treatment for immunodeficient patients?
2. Prophylactic antibiotics
3. Human immunoglobulin (where B cells are deficient)
4. Transplantation of fetal thymus or cultured thymic stromal cells in DiGeorge syndrome
What is the recommended treatment of kids with SCID?
Transplant purified stems cells from sibling