Primary immunodeficiency Flashcards
- What is DiGeorge syndrome (HY)?
Failure to develop 3rd and 4th pharyngeal pouch due to 22q11 mutation
What are presentation of DiGeorge syndrome?
• T cell deficiency- problems fighting viral and fungal infection (due to lack of thymus as thymus develops from 3rd and
4th pouch)
• Hypocalcemia (due to lack of parathyroid)
• Abnormalities of heart, great vessels, and face
What is SCID (severe combined immune deficiency)?
Pt have defective cell-mediated and humoral immunity (both T and B).
Etiology of SCID?
• Cytokine receptor defects (main cause) • Adenosine deaminase deficiency (second main cause)(HY) - enzyme necessary for deamination of adenosine and deoxyadenosine. In lack of enzyme, adenosine and deoxyadenosine accumulates in immune cells causing toxicity. • MHC class II deficiency - CD4 won't be able to be activated. It leads to defective function of CD8 and B cells.
Presentations of SCID?
- Lack of T cells result in fungal and viral infections
- Lack of B cells result in bacterial and protozoal infections
- Increased opportunistic infection and be wary to give live vaccines.
Treatment of SCID?
- Sterile isolation (bubble babies)
* Stem cell transplant
What is X-linked agammaglobulinemia? What is the mutation?
- Name suggests pt lacks gammaglobulin (antibodies) in blood. There’s a complete lack.
- Occurs because naïve B cells can’t mature to plasma cells.
- Mutation is Bruton tyrosine kinase. It’s a signaling receptor that helps maturation of B cells.
What is presentation of X-linked agammaglobulinemia?
- Recurrent bacterial, enterovirus, and Giardia infection (HY).
- Enterovirus affects mucosa of GI tract. IgA protects mucosal surface, and lack of IgA results in enterovirus infection.
- Bacterial infection occurs because lack of antibodies affect opsonization.
- Giardia occurs for same reasoning as enterovirus.
- Presents after 6 month of life – because mom’s antibodies last for about 6 months
- Don’t give them live polio vaccines
What is common variable immunodeficiency disease?
Pt has low antibodies due to defective B or T cell
Presentation of x linked agammaglobulinemia
- Pt has increased risk of bacterial, enterovirus, giardia infection, often in late childhood.
- They have increased risk of autoimmune disease and lymphoma. (HY)
What is IgA deficiency?
This is most common Ig deficiency. Pt have low serum and mucosal IgA which increases risk of mucosal infections especially viral
Note – pt with celiac disease usually have IgA deficiency.
. What is pathophysiology of Hyper-IgM syndrome? What is presentation?
• Patient has mutation in CD40 or CD40 receptor. Due to this, B cells can’t activate CD4. In lack of good CD4, cytokines
necessary for Ig class switching is not produced. Pt will have low IgA, IgG, and IgE.
• Presentation is recurrent pyogenic infections, especially at mucosal sites. IgG is a opsonin, low amount results in more
formation of pus.
What is Wiskott-Aldrich syndrome (WAS)? What causes it? (just memorize)
- Pt have thrombocytopenia, eczema, and recurrent infections. Pt have defective humoral and cellular immunity.
- Happens due to mutation in WASP (Wiskott-Aldrich syndrome protein) gene and is x-linked.
What are the consequence of the following complement deficiencies? (just memorize)
- Deficiency from C5-C9 - increased risk of Neisseria infection (HY)
- C1 inhibitor deficiency - hereditary angioedema characterized by edema of skin (especially periorbital) and mucosal