Immune Deficiencies (compare and Contrast) Flashcards
What immune Deficiencies result in a complete lack of CD4+ and CD8+ cells?
- Common Features?
- How do these diseases Differ, where does the problem arise?
Common Feature:
- No CTLs or Helper T cells would result in no B cell activation and no killing of Virally/intracellularly infected cells.
Diseases:
- ADA / PNP defect - toxic nucleotides build up killing all T cells and B cells
- CD3 deficiency - without CD3 no positive selection can take place for CD8 or CD4 cells
- DiGeorge Syndrome - No Thymus = No T cells
What immune deficiencies lead to differential numbers of CD8 and CD4 T cells?
- How do these diseases differ?
- Which cell type is depressed?
- Is the remaining Cell type still effective?
Diseases:
- ZAP-70 - this is needed for ITAM signaling => CD8 cells DIE, CD4 cells survive but are INeffective
- MHC II Bald Lymph. Syndrome - CD4 cells DIE b/c they cannot be Positively selected; CD8 cells are ALIVE and EFFECTIVE
- MHC I Bald Lymph. Syndrome - CD8 cells DIE b/c they cannot be Positively Selected; CD4 cells are ALIVE and EFFECTIVE
- CD8 protein mutation - see MHC-I BLS ^
What are they only SCID disease in which CD4 and CD8 cells are present in normal numbers?
- What renders these cells ineffectual?
- Distinguishing Clinical Features?
- Distinguishing immunological Features?
Wiskott-Aldrich
- Cytoskeletal Issues Prevent Cross-Talk
- THROMBOCYTOPENIA
- B cells = normal STRUCTURE and Numbers
Common Gamma Chain Defects:
- No Interleukin Signaling (from: IL-2, IL-4, IL-7, IL-9, or IL-15)
- B cells = BALD B CELLS, normal B cell numbers
JAK-3 deficiency:
- Same effect as common gamma chain defect
What patients with SCID could also mount a T-INdependent response to an encapsulated bacteria?
*In order to generate T-independent response, B cells should be present in normal Numbers and have a normal Structure
- MHC II Bald Lymphocyte Syndrome
- CD3 Defects
- DiGeorge Syndrome
Why does Omenn Sydrome suck so bad?
- A few Oligoclonal T-cells are left in the repertoire and these are self reactive so you end up with an Autoimmune Defect in addition to SCID
In which SCID diseases would you expect Development Defects independent of the immune deficiency?
- ADA and PNP deficiency
- DiGeorge Syndrome
What Immune Deficiencies are specific to CD8 T cells?
- Do these cause SCID?
- Explalin.
CD8 specific Diseases:
- CD8 protein Defects - Prevents Positive Selection
- TAP transporter Defects - No TAP = Degraded MHC-I => Prevents Positive Selection
- Perforin Deficiency- No Killing Function of CD8 cells OR of NK cells
SCID?:
- These diseases do NOT cause SCID because both CD4 T cells and B cells are still functional
*Perforin Defect would be the most devastating
Of the CD8 T cell specific Diseases, which will result in Reduced CD8 cell count?
Both CD8 mutations and TAP transporter mutations would result in Low CD8 cell count
- Perforin Deficiency would NOT change the number of CD8 T cells
What Immune Deficiencies Result in complete lack of CD4 T-cells?
- what is the result of no CD4 T-cells?
- How do these diseases differ, where does the problem arise?
Overall Result:
- NO CD4 -> NO B CELLS produces SCID because there is no APC or B cell activation
Diseases:
- Bare Lymphocyte Syndrome - no MHC II will be on APCs - Problem arises in Positive Selection
- ADA / PNP deficiency - Toxic Nucleotide Catabolites Kills almost all Lymphocytes (T and B cells) in development
- COMPLETE DiGeorge Syndrome - Individuals are Athymic (No CD8 or CD4)
- CD3 Deficiency - No CD4 or CD8 cells b/c of Absence of Thymic Selection
What deficiency should be suspected of a patient who suffers from disseminated Listeria or Mycobacterium Avium infections but appears to respond adequately to most other types of infection?
- is this an issue with the Cell mediated or Humoral Response?
IL-12 or IL-12 Receptor Deficiency should be suspected
- with intracellular bacteria being the only susceptibility you can assume this is an issue of TH1 macrophage activation via IFN-gamma
1
**No other Deficiency would target just these cells (besides IFN-gamma)
Besides IL-12/IL-12 receptor Deficiency, what other disease polarizes patients away from TH1 cell activation?
- Why does this polarization happen?
- how is this different from IL-12 deficiencies?
Hyper IgE syndrome / Job Syndrome:
- Results from Ineffective STAT3 receptors that are needed for signal transduction in NEUTROPHILS and in IFN-gamma signal transduction
- Without IFN-gamma stimulation TH0 cells are much more likely to take on the TH2 phenotype - IL-4 production by TH2 promotes IgE production
- STAT3 deficiencies differ in that Neutrophils cannot respond to signals (was not mentioned by Dr. M, but it seems like disseminated intracellular bacterial infections would be an issue for these people too)
What immunodeficiency results in low B and T cell numbers in addition to elevate Alpha Fetal Protein (AFP)?
- what causes this disorder?
- other clinical features?
- Is this an acquired or Innate Immune Disorder
Ataxia Telangiectasia
- lack of ATM (a DNA repair enzyme) results in this phenotype
Other Clinical Features:
- Ataxia
- Spider Angiomas
- IgA or IgE deficiency
*Acquire Immunodeficiency
What two diseases resemble mutliple myeloma?
- what are some defining characteristics of these diseases?
*Both usually occur in people 50 and up
Waldenstrom Macroglobulinemia
- Abnormal B cell proliferation (Cancer) causing too much IgM to form
- More common in men
- NO BONE LESIONS like their are in Multiple Myeloma
- CAUSES ANEMIA
Benign Monoclonal Hypergamma (Monoclonal gammapathy)
- Asymptomatic
- NO BENCE JONES PROTEINURIA
What non-SCID diseases result in lowered or absent numbers of B cells?
- Common Features of these diseases?
- How does the pathogenesis of these diseases differ?
CVID
- Not typically diagnosed until 20 or 30 y/o
- Patients will have Hypogammaglobulinemia but NOT Agammaglobulinemia
XLA (X-linked Agammaglobulinemia)
- Bruton Tyrosine Kinase Issue = NO B CELLS
- UNDERDEVELOPED TONSILS
Ataxia Telangiectasia
- ATM defect (ATM needed for DNA repair)
- ELEVATED ALPHA FETAL PROTEIN
Pre-B cell Receptor (lambda 5)
- Mutation of Lamba 5 Surrogate Light Chain
- B cells undergo APOPTOTIC death
A white female with a known acquired immunodeficiency is given a blood transfusion after a car accident. She immediately becomes hypovolemic and experiences tachycardia.
- What immune deficiency did she likely have?
- What diseases is she predisposed to?
IgA deficiency
- Patients with IgA suffer from Anaphylactic Shock if they are given a blood transfusion with IgA in the transfused blood
Other Disease:
- Autoimmune Diseases such as SLE, Rheumatoid Arthritis, and Immediate type Hypersensitivities are more common in these patients