Immunpathology Flashcards
1
Q
X-linked agammaglobulinemia
A
Pre-B cells fail to proliferate into B cells, leading to absence of gamma globulin in the blood. B cell maturation stops after heavy chain rearrangement due to mutations in Burton tyrosine kinase, which is needed for pre-B cell signal transduction.
- Germinal centers will appear smaller
- Treat with IVIG
2
Q
Common Variable Immunodeficiency
A
- Characterized by low antibody levels and recurrent infections.
- Patients usually develop autoimmune disorders and lymphoid tumors
3
Q
Isolated IgA deficiency
A
- IgA is found in mucosal secretions, thus the lack of it will cause weakened mucosal defenses in the airways and GI tract. This further leads to increased susceptibility to infections
- Associated with autoimmune diabetes
4
Q
Hyper-IgM syndrome
A
- Normal amounts of IgM, but this cannot be further class-switched to IgG, IgA and IgE
- There’s an underlying defect in T cells to induce B cell isotype switching
- Main symptom: recurrent pyogenic infections
5
Q
DiGeorge syndrome
A
- Congenital defect in development of the thymus, with consequent deficient T cell maturation -> no T cells in lymph nodes, spleen or peripheral blood
- 90% of cases are related to deletion in chromosome 21q11
6
Q
Severe Combined Immunodeficiency (SCID)
A
- Defects in humoral and cell-mediated immunity
- The thymus is hypoplastic
- Lymph nodes and lymphoid tissues are atrophic; no GCs or paracortical T cells
- Treated by a bone marrow transplant
7
Q
Wiskott-Aldrich syndrome
A
- XR inheritance
- Clinical features: thrombocytopenia, eczema, increased infection risk
- Depletion of T cells causes loss of cellular immunity
8
Q
Genetic deficiencies in complement proteins and their consequences
A
- Inherited C3 deficiency -> increased risk for pyogenic bacterial infections
- Inherited C5-C9 deficiencies -> increased risk for Neisseria infections (very susceptible to MAC)
- Inherited C1 inhibitor deficiency: constant C1 activation -> hereditary angioedema
