Immunology Flashcards
What is thymic hyperplasia?
1) The presence of B cell germinal centers within the thymus (not normal)
2) Commonly observed in Myasthenia gravis
Absence of thymus due to a deletion in chromsome 22q11
DiGeorge syndrome- results in defective cell mediated immunity
What is a thymoma?
1) Tumor of thymic epithelial cells
2) Occurs in adults over 40
3) Three types
What are the three types of thymomas?
1) Noninvasive (consists of medullary type epithelial cells)
2) Invasive (consists of cortical type epithelial cells)
3) Thymic carcinoma (squamous cell carcinomas)
Name the antibodies found in the body.
1) IgM (pentamer, activates complement)
2) IgG (most abundant, crosses placenta)
3) IgA (dimers, found on mucosa)
4) IgE (involved with allergic reactions)
5) IgD
What is the antibody that presents naturally against ABO antigens? What antibody is involved with an immune response?
1) IgM
2) IgG
How do you know when there is an immune response to exposure of allogenic blood antigens?
1) When there is IgG present
2) Can occur during pregnancy or transfusion
What do you give to a pregnant mother who is Rh negative?
1) RhoGam
What chromosome are the ABO genes located on?
1) Chromosome 9
2) A= N acetyl galactosamine
3) B = D galactose
4) O= nothing added
What antibody recognizes Rh antigen? Do antibodies for Rh antigen naturally occur?
1) IgG
2) No
What blood group antigen is associated with intravascular hemolysis when an incorrect transfusion is given?
ABO
What blood group antigens are associated with extravascular hemolysis when an incorrect transfusion is given?
All others
What commonly occurs in IgA deficient pt. who receive a blood transfusion?
1) Allergic reaction to transfused blood
2) Due to the presence of IgA in the transfused blood which are recognized by anti-IgA antibodies
What is the separation of whole blood into components known as?
Apheresis
How does hemolytic disease of the newborn occur?
1) It is an immunological reaction that occurs when maternal IgG antibodies cross over the placenta and target antigens of the baby
2) Common in Rh negative moms
Intravascular hemolysis due to blood transfusion.
ABO mismatch
Describe the steps of inflammation to acquire leukocytes
1) Marginization
2) Rolling
3) Activation
4) Crawling
4) Migration
Describe the function of each:
1) IL-3
2) IL-10
3) IL-8
1) stimulates growth of stem cells in bone marrow; produced by activated T cells
2) anti-inflammatory cytokine; produced by macrophages
3) Trigger neutrophils to enter site of infection; produced by macrophages
Recurrent sinopulmonary and GI tract infections due to an immune defect; Increased amounts of IgG selective for IgA
Selective IgA deficiency
What is the result when a pt. with IgA deficiency is given blood with IgA
Fatal anaphylactic reaction
Combined defect of both humoral and cell mediated immunity
Severe combined immune deficiency
Immunodeficiency due to a deletion in chromosome 22 leading to the maldevelopment of the 3rd and 4th pouch. What other findings will occur?
1) DiGeorge syndrome
2) Hypoparathyroidism
Defect in the formation of CD18 or integrin; delayed separation of the umbilical cord, recurrent cutaneous infections without pus and poor wound healing
Leukocyte adhesion deficiency
7 month old boy with oral candidasis, loose stools, broncholitis, low serum gamma-globulin level, and absent thymic shadow
Severe combined immunodeficiency
Immunodeficiency caused by insufficient production of mature B cells
X-linked (Bruton’s) agammaglobulinemia
Deficiency of immunoglobuins secondary to failed B cell differentiation
Common variable immunodeficiency
Impaired B and T cell functioning that presents as SCID but also has thrombocytopenic purpura and eczema; low IgM levels
Wiskott-Aldrich syndrome
What MHC molecule is found on all nucleated cells?
MHC class I
What is the structure of an MHC class I receptor?
1) Heavy chain
2) B2 microglboulin
What MHC molecule is found on antigen presenting cells?
MHC class II
What is the structure of an MHC class II receptor?
Consists of alpha and beta polypeptide chains
What is the function of MHC class I receptors
Present antigens to CD8 T cells
What is the function of MHC class II receptors?
Present antigen to CD4 T helper cells
What antigens does MHC class I present? Class II?
1) Virus and tumor protein; antigens processed in the cytoplasm
2) Bacterial, antigens digested by lysosomes
What opportunistic infx. in HIV may occur if CD4 count <200
Pneumocystitis jirovecii
What opportunistic infx. in HIV may occur if CD4 count <100
Toxoplasma gondii and Histoplasmosis
What opportunistic infx. in HIV may occur if CD4 count <50
Myobacterium avium and CMV
What cytokine is produced exclusively by lymphocytes?
1) IL-2
2) Produced exclusively by antigen-stimulated T lymphocytes
What is required for a leukocyte to undergo rolling?
1) P and E selectin on endothelial cells
What is required for tight binding of the leukocyte to the vessel wall?
1) ICAM on the vasculature
2) LFA-1 (integrin)
Leukocyte travels inbetween endothelial cells and exits blood vessel
Diapedesis
General Causes of a dry tap bone marrow aspiration
Fibrosis and/or hypercellularity
Common findings associated with a dry tap
ThrombocytopeniaPeripheral bloodNucleated rbcsTear drop rbcs
Variant of multiple myeloma in which the malignant population produces free monoclonal light chains with no associated heavy chains; light chains are small enough to be filtered by the kidneys
Light Chain Disease
What do the light chains in Light Chain disease become once they have been filtered by the kidney?
Bence-Jones proteins (eventually combined with Tamm-Horsfall proteins and cause cast nephropathy)
Most common cause of agranulocytosis
drug toxicity
What are the general causes of leukocytosis (4 total)
- Increased production in bone marrow
- Increased release from marrow and storages
- Decreased marginization
- Decreased extravasation into tissues
Common diagnoses of a dry tap aspiration
Metastatic carcinoma (most common)
Chronic myelogenous leukemia
Primary myelofibrosis
Hairy cell leukemia
Common findings associated with a dry tap
Thrombocytopenia
Peripheral blood
Nucleated rbcsTear drop rbcs
Cytological findings in Neutrophilic leukocytosis
Dohle bodies- blue bodies of dilated endoplasmic reticulumToxic granules (abnormal azurophilic granules)- coarse, darker than normal granules
What is a tingible-body macrophage
It is a macrophage found in chronic nonspecific lymphadenitis that is filled with nuclear debris
Causes of follicular hyperplasia
HIV, Toxoplasmosis, and Rheumatoid arthritis
What are features of a reactive follicular hyperplasia rather than a neoplastic cause?
1) Preservation of lymph node structure
2) Marked variation in the shape and size of follicles
3) Presence of mitotic figures
4) Tingible macrophages in germinal centers
5) Lack of BCL-2 expression6) Poly clonal
What are the different presentations of chronic lymphadenitis
Reticular hyperplasia- increase in the number and size of the lymphatic sinusoidsFolicular hyperplasia- increase in size of the germinal centersParacortical hyperplasia
What are causes of hypersegmented neutrophils (>3-4 lobes) and macro-ovalocytes
Megaloblastic anemia (deficiency in B12 or folate) and myelodysplastic disorder
Cytological findings in Neutrophilic leukocytosis
Dohle bodies- blue bodies of dilated endoplasmic reticulum Toxic granules (abnormal azurophilic granules)- coarse, darker than normal granules
Autosomal dominant anomaly that consists of enlarged pale basophilic inclusions within neutrophils; also associated with giant platelets and thrombocytopenia
May-Hegglin anomaly
Autosomal recessive disorder that has abnormally large leuckocytic granules due to lysozyme fusion
Chediak-Higashi syndrome
What are features of a reactive follicular hyperplasia rather than a neoplastic cause?
1) Preservation of lymph node structure
2) Marked variation in the shape and size of follicles
3) Presence of mitotic figures
4) Tingible macrophages in germinal centers
5) Lack of BCL-2 expression
6) Poly clonal
What are the different presentations of chronic lymphadenitis
Reticular hyperplasia- increase in the number and size of the lymphatic sinusoids
Folicular hyperplasia- increase in size of the germinal centers
Paracortical hyperplasia
Disease associated with genetic mucopolysaccharideoses; leukocytes appear to have azurophilic granules (resembles toxic granulation)
Alder-Reilly anomaly
Disease caused by a lack of lysozomal enzymes to breakdown mucopolysaccharides
Mucopolysaccharideoses
What does a Dohle body consist of?
It consists of remnants of free ribosomes and rough ER
What are the reactive changes in neutrophils?
Toxic granules and dohle bodies
What disease is associated with Auer rods?
Acute myelogenous leukemia - leukocytosis with immature cells that do not mature; assoc. with promyelocytes
At what point is agranulocytosis a serious risk for infection?
<500 cells
What is an Auer rod?
It is a pink/red rod shaped cytoplasmic inclusion consisting of fused lysosomal (peroxidase) granules
How can you differentiate a Dohle body from a May- Hegglin anomaly?
Dohle body = toxic granulations and left shiftMay-Hegglen anomaly = thrombocytopenia and giant platelets
Reaction of immature red and white blood cells due to abnormal infiltrates in the bone marrow
Leukoerythroblastic reaction
What is the difference between a leukemoid reaction and a leukoerythroblastic recation?
Leukemoid = major left shift of just WBC; due to infectionLeukoerythroblastic = major left shift and immature rbcs; due to bone marrow infiltrate
Causes of basophilic leukocytosis
myeloproliferative diseases (chronic myeloid leukemia)
Causes of eosinophilic leukocytosis
Allergies, parasitic infection, drug reactions, Hodgkin lymphoma (increased IL-5)
Causes of Monocytosis
Chronic infections, bacterial endocarditis, malaria, rickettsiosis, SLE (positive ANA) and myelodysplastic syndrome
How can you differentiate a Dohle body from a May- Hegglin anomaly?
Dohle body = toxic granulations and left shift
May-Hegglen anomaly = thrombocytopenia and giant platelets
When is pseudo- Pelger Huet anomaly observed
Myelodysplastic disorders and drug therapy
What is the difference between a leukemoid reaction and a leukoerythroblastic recation?
Leukemoid = major left shift of just WBC; due to infection
Leukoerythroblastic = major left shift and immature rbcs; due to bone marrow infiltrate
Lymphocytes with fine, hair-like cytoplasmic projections or irregular pseudopods and a round/folded nucleus
Hairy cells (found only in hairy cell leukemia)
Fragile lymphocytes tat are disrupted in the process of making a smear; NOT DIAGNOSTIC, associated with chronic lymphocytic leukemia
Smudge cells
What is the differential diagnosis for lymphadenopathy?
1) Infection (common, HIV, EBV, Bartonella)
2) Sarcoidosis
3) Cancer
4) Lymphoma
5) Leukemia
When are reactive neutrophils observed
Leukemoid reaction and neutrophilia
What treatment is used for pt. that suffer neutropenia due to a myelosuppressive chemotherapy?
CSF-GM and CSF-G
Causes of lymphopenia?
1) immunodeficiency
2) high cortisol state
3) autoimmune destruction (lupus)
4) whole body radiation (lymphocytes are most sensitive)
What are the pathologic features of infection mononucleosis
1) Lymphocytosis of CD8 T-cells (atypical cells)
2) Splenomegaly (increased in the periarterial lymphatic sheath (PALS)
3) Hyperplasia of the paracortex of lymph nodes
What is T-cell acute lymphoblastic lymphoma associated with?
Teenagers and a thymic mass
Common inherited aplastic anemia that has assoicated findings in the skin, skeleton, CNS, or genituourinary tract; Increased MCV
Fanconi anemia
Disease due to a congenital deletion of chromosome 22 that results in failure to develop 3rd and 4th pharyngeal pouches
DiGeorge syndrome
What are pt. with DiGeorge syndrome at risk for?
1) Viral and fungal infections due to decreased T cells
2) Hypocalcemia leading to seizures
3) Cardiac defects
Disease that has the development of obliterative marrow fibrosis
Primary myelofibrosis
What is the result of C1 esterase inhibitor deficiency?
1) Hereditary angioedema
What is the result of C3 deficiency?
1) Severe recurrent pyogenic sinus and respiratory infections; increased susceptibility to Type III hypersensitivity reactions
What infection is at an increased risk due to C5-C9 (MAC complex) deficiency?
Neisseria bacteremia
Type I hypersensitivity reaction against plasma proteins in transfused blood
Allergic reactions
Blood had a blood transfusion and now has urticaria, pruritus, wheezing, fever. What type of blood transfusion reaction is this?
Allergic reaction
Type II hypersensitivty reaction where host’s antibodies against donor HLA antigens and leukocytes occurs. Pt has fever, headache, chills and flushing
Febrile nonhemolytic transfusion reaction
Type II hypersensitivity reaction with intravascular hemolysis has occurred due to ABO blood group incompatibility
Acute hemolytic transfusion reaction
+ANA, Anti dsDNA, Anti-smith indicates
SLE
+ ANA and Antihistone
Drug induced Lupus
+ anti CCP
Rheumatoid arthritis
+ anticentromere
CREST syndrome
+ Anti-Scl-70
Diffuse scleroderma
+ AMA
Primary biliary cholangitis
+ Anti-Ro and Anti-La
Sjogren’s syndorme
+ Anti-Jo1-1
Polymyositis
What is the result of no Tcells?
1) Sepsis
2) Increased viral infection
3) Candida and PCP
More fungal and viral
What is the result of no Bcells?
1) Infection with encapsulated organisms
2) Increased risk of Giardia
What is the results of no complement system?
Increased risk for Neisseria
X linked disease of the BTK gene; no B cell maturation
Bruton’s Agammaglobulinemia
Most common pirmary immunodefieicny
Selective IgA deficiency
Pt presents with recurrent bacterial infections after 6 months from birth; decreased number of B cells and antiboides of all classes
Bruton’s Agammaglobulinemia (x-linked)
What type of infections are more common in Bruton’s Agammaglobulinemia?
1) Infections by capsular organisms (Strep. pneumo, H. influenzae, Neisseria, E. coli, Salmonella, Klebsiela, S. agalactae)
What are common finidngs of a pt. with selective IgA deficiency?
1) Majority asymptomatic
2) Sinopulmonary infections
3) GI infections
4) Anaphylaxis to IgA containg blood products
What disease is associated with an anaphylactic response normal blood transfusion
IgA deficiency
Disease caused by a defect in B cell maturation; normal B cells, decreased plasma cells
Common variable immunodeficiency (CVID)
What is the result of a IL-12 receptor deficiency
Decreased TH1 response; disseminated myobacterial infection
Pt. presents with coarse facies, cold staphylococcal abscesses, retained primary teeth, Increased IgE, and dermatologic problems
Job’s syndrome (Hyper IgE syndrome)
What is the presentation of Hyper IgE syndrome
think: FATED
1) Facies are coarse
2) Abscessess on skin
3) Teeth from childhood retained
4) increased IgE
5) Dermatologic findings
What is the result of an adenosine deaminase deficiency
SCID
What is the results of a defective IL-2 receptor?
SCID
Pt. presents with failure to thrive, chronic diarrhea, thrush, recurrent viral, fungal and protozoal infections; absence of thymic shadow, germinal centers, and B cells
Severe combined immunodeficiency
Defect in ATM
Ataxia-telangiectasia
Pt. presents with cerebellar defects, spider angiomas, and IgA deficiency
Ataxia-telangiectasia
Defective CD40L on helper T cells
Hyper IgM syndrome
remember: CD40L on T cell is important in the process of isotype switching
What are complications of a pt. with Hyper IgM syndrome
Severe pyogenic infections early in life
Pt. presents with Thrombocytipenic purpura, Infections, and eczema
Wiskott-Aldrich syndrome (x-linked)
What are immunoglobulin levels in Wiskott-Aldrich syndrome
Increased IgE and IgA, Decreased IgM
Giant granules in neutrophils
Chediak-Higashi syndrome
What are the findings of a hyperacute transplant rejection?
1) Occlusion of graft vessicles, causing ischemia and necrosis
What type of hypersensitivity is hyper acute transplant rejection?
1) Type II
What are the findings of an acute transplant rejection?
1) Vasculitis of graft vessels with dense intersitital lymphocytic infiltrate
What are the findings of a chronic transplant rejection?
1) Obliterative vascular fibrosis
2) Fibrosis of the graft tissue and blood vessels
What are the findings of a graft versus host transplant rejection?
1) Maculopapular rash
2) Jaundice
3) Hepatosplenomegally
4) Diarrhea
What do you have to be aware of when a pt. is given several transfusions of blood?
1) hypocalcemia
2) Caused by citrate in blood that chelates with calcium and magnesium
What cytokine is a major factor in the manifestation of the paraneoplastic disorder of cachexia
TNF-alpha
Immune complex disease in which antibodies to the foreign proteins are produced. Immune complexes form and are deposited in membranes, where they fix complement.
Serum Sickness
How long does it take to get serum sickness
5-10 days after antigen exposure
Local subacute reaction that occurs with intradermal injection of antigen; characterized by edema necrosis, and activation of complement
Arthus reaction
How does a pt. who has serum sickness present?
Fever, urticaria, arthalgias, proteinuria, and lypmphadenopathy 5-10 days after antigen exposure
What causes serum sickness?
Drugs
What is the results of serum sickness and arthus reaction?
Decreased complement (serum C3 level)
What type of hypersensitivity reaction is serum sickness?
Type III
Treatment for Hairy cell leukemia?
Cladribine (adenosine analog resistant to adensoine deaminase)
What is a marker used to determine anaphylaxis?
Tryptase (released from degranulated mast cells)
How does degranulation of mast cells occur?
Results from IgE bound to its antigen that forms an aggregation; mast cells bind to the Fc portion on the mast cell surface which produces granulation
