5.8 immuno deficiencies Flashcards
What are some immunodeficiencies
X-lined aggamalobinemia of Bruton, Common variable immunodeficiency, IgA deficiency, Hyper-IgM Syndrome, DiGeorge Syndrome, Severe combined immunodeficiency diseases (SCIDs)
X-linked agammablobinemia of Bruton
failure of b-cell precursors to mature. No b-cells and no antiboides. Defect after rearrangement of heavy chaings. Mutations in a tyrosine kinase (Btk), seen in males, apparent at 6 months after exhaustion of maternal antibodies
Effects of x-linked agammablobinemeia
increased suceptibility to common pathogenic bacteria and enteroviruses, H flu, Strep Pneum, Saph, echovirus, increases frequency of autoimmune diseases
Why can’t you immunize with live polio virus in x-linked agammaglobinemia
bc you don’t have the ability to make your own ab
in X-linked agammabloginemia what parasite are you succeptible to
lack of IgA so succeptible to giardia lamblia
how is X-lined agammaglobinemia treated
in the past all died young ut no there is replacement Ig that is given to expand life to adulthood. BUT you still don’t have the capacity to respond so if you see new things you’re in trouble.
Common variable immunodeficiency
low levels of all classes of ab, defect not known but associated with IgA deficiency. Incrased incidence of autoimmune disease. Increased incidence of lymphoid malignancies especially in females. 50% increase in gastric cancer;.
how does common variable ID compare to Bruton’s
Symptoms similar to Bruton’s but both genders affected and later onset. Different than bruton’s in that there are plenty of B-cells but they cannot differentiate into plasma cells.
IgA deficiency
very common 1:600 Western Europeans, most asymptomatic, familial and sporadic, familial associated with CVID, Normal numbers of IgA B-cells but most cannot go on to become plasma cells, Symptomatic pts have respiratory, GI and urogenital infections, high incidence of AI such as SLE, Can’t make plasma cells for IgA
Hyper IgM syndrome
defect in isotype switching, can mediate primary response but no IgG, A, or E, No isolated B-cell defect but failure of CD40 (B cells) and CD40L (T-cells) to interact. Most cases (70%) its CD40L deficiency on T cells. CD40L on X chromosome. Others not X-linked so thought to be in CD40. Pyogenic infections like other ab def. But also high incidence of pneumocystis strongly suggesting further T-cell problems.
DiGeorge Syndrome
T-cell deficiency bc of developmental failure of the 3rd and 4th pharyngeal pouches. Thus no thymus or thymic hypoplasia. Also no parathyroids, congenital heart defects and FLK, cytogenic dletion of genes at 22q11, variable amounts of T-cell deficiencies dependent on amount of thymus, Partial DiGeorge, deficiency goes away in 5 years
SCIDs
collection of defects with simialr outcomes, defects in both humoral and cellular immunity, rapid onset after birth with wide range of types of infections, most common form X-linked, thus males predominate, X-linked defect in common chain in cytokine receptors, remaining are autosomal recessives, adenosine deaminase deficiency most common, bone marrow transplantation is the only therapy
Wiskott-Aldrich Syndrome
X-linked disorder, Thrombocytopenia, eczema, recurrent infections and early death, defect in protein that maintains cytoskeletal integrity, marked loss of peripheral T-cells with normal thymine development
Genetic Deficiencies in complement
deficiencies in all components known with variable effects, C2 most common, Some increased susceptibility to infections but low. Increased incidence of SLE. C3 in both pathways and deficiency devastating, Deficiencies in late components MAC increased bacterial infections
