Immunology1 Flashcards
Locations of abnormalities of development in: SCID
block in development of lymphoid stem cell -> results in lymphopenia of both T and B cells.
Locations of abnormalities of development in: X-linked (Bruton) Agammaglobinemia
block is between pre-B and B cells, and results in low numbers of B cells (normal T cells).- block is a defective bruton tyrosine kinase
Locations of abnormalities of development in: X-Linked HyperIgM Syndrome
Defect in Tfh’s CD40 or in B cell CD40 →defect in IgM switching to IgGCD40: surface marker that induces the switch
Locations of abnormalities of development in: Common Variable Immunodeficiency (CVID)
normal #s of pre-B and B cells but:B cells cannot become plasma cells → cannot make specific antibody
Locations of abnormalities of development in: DiGeorge syndrome
large (45 gene) deletion on chromosome 22→ Abnormal development of 3rd and 4th pharyngeal pouches → abnormal stroma → cannot support thymic lymphoid development → pt will have absent T cells.
Which abnormal lymphocyte development is related to tetralogy of fallot?
DiGeorge
infections you would expect in a pure B cell deficiency
“high grade” (extracellular, and pyogenic) infections from bacterial pathogens such as S. aureus, H. influenzae, and S. pneumoniae.
infections you would expect in a pure T cell deficiency
severe infections from intracellular pathogens such as viruses, certain bacteria, yeasts and fungi (esp. Candida albicans & Pneumocystis jirovecii).
clinical features of DiGeorge syndrome
○ Hypertelorism (eyes are far apart; wide-space) ○ Down-slanting eyes ○ Fish mouth deformity ○ Micrognathia (undersized jaw) ○ Low set ears ○ Can be born with Tetralogy of Fallot, hypocalcemia, and absent T cells.
incidence of selective IgA deficiency - associated syndrome?
• Most common immunodeficiency disease with frequency of about 1 in 500. ○ 10-15x more frequent in those with celiac disease
immunological problem of the Nude mouse - name the human immunodeficiency condition it resembles.
results in absence of thymic stroma (and hair) → no T cells. Immunologically similar to DiGeorge.
enzyme which is absent in some cases of SCID.
adenosine deaminase is absent → accumulation of adenosine in cells severely impairing lymphocyte development → lymphopenia of both T and B cells.
Possible approaches to replacing adenosine deaminase in people with SCID
Replace the enzyme: transfusions of irradiated red cells can be helpful(adenosine deaminase is abundant in blood)
Discuss transplantation therapy in DiGeorge. complication?
○ Fetal thymus or cultured thymic stromal cells have been used to try to minimize graph vs host disease; better diagnosis of DiGeorge would aid in the selection of appropriate cases.
Discuss transplantation therapy in SCID complication?
○ BETTER to transplant purified stem cells rather than bone marrow. -Bone marrow transplantation has had about 50% success rate, but graph vs host disease… - Prefer sibling donors with Class II MHC match and at least one Class I MHC match.
