Immunodeficiency Cases Flashcards
What are TRECs?
Pieces of DNA cut out during intrathymic T-cell receptor gene rearrangement
TRECs indicate that T cells are being made.
What lab technique is used to count T cells?
Flow cytometry with fluorescent antibodies to CD3
Naïve T cells will have __________.
CD4-RA (nAïve)
To have SCID, you need to have defective ______________.
T cells (B cells may or may not be defective)
Note: this is why TRECs are used to screen for SCID, as opposed to KRECs.
What protein is defective in X-linked SCID?
The common gamma chain
This is found in the IL-2 receptor, as well as in the receptors for interleukins 4, 7, and 9.
What infections is a SCID baby likely to present with?
Opportunistic infections: PJP, Candida, Aspergillus, CMV, Enterovirus, and Mycobacteria
What protein is responsible for cutting DNA in VDJ recombination?
RAG2
Other than CD16, what surface receptor do NK cells have?
CD56
True or false: NK cells are derived from myeloid precursors.
False. They are derived from lymphoid cells.
Why was SCID added to the newborn screen?
Early diagnosis has been shown to save lives and money.
What is required for a diagnosis of CVID?
1) At least one of the following: • Immune deficiency •Autoimmune manifestation •Granulomatous disease • Polyclonal proliferation
2) Normal B and T cell count with low Ig.
3) Secondary causes – such as malignancy, drug toxicity, and protein loss –need to be excluded.
4) Diagnosis must occur after the fourth year of life.
5) Poor response to vaccines
6) No evidence of T cell dysfunction
Memory B cells express which surface receptor?
CD27
memory T cells will have____
CD45 RO
O for memOry
3 types of SCID
1) defective rearrangement of antigen specific T and B cell receptors (T-, B-, NK+)
2) defective signaling of cytokines or their receptors (T-, B+, NK-)
3) defective purine metabolism (T-, B-, NK-)
In what immunodeficiency will vaccine titers be low?
CVID, they dont make Igs
