INFECTIOUS MONONUCLEOSIS Flashcards
Also known as:
• “Mono”
• Kissing disease
• Glandular fever
Most common
causative agent:
Epstein-Barr Virus (EBV)
• Can also cause:
• Burkitt’s lymphoma
• Nasopharyngeal carcinoma
An acute, benign, and self-limiting lymphoproliferative condition
Infectious mononucleosis
EBV is most commonly spread through saliva by:
• Kissing
• Sharing drinks and food
• Sharing drinking cups, eating utensils, or toothbrushes
• Having contact with toys that children have drooled on
EBV can also spread through
blood and semen during
sexual contact
blood transfusions
organ transplantations
Signs and symptoms
INFECTIOUS MONONUCLEOSIS
• Extreme fatigue
• Fever
• Sore throat
• Headaches and body aches
• Swollen lymph modes in the neck and armpits
• Swollen liver or spleen or both
Rash
• Lymphocytosis with prominent atypical lymphocytes
Hematological
• (+) Heterophile and EBV antibodies
• Heterophile antibodies (non- specific)
• EBV antibodies (specific)
Serological
• Increased lymphocyte count in the blood (more than 50% of total white blood cells).
Lymphocytosis
Atypical lymphocytes:
• Also known as______, these are large, irregularly shaped lymphocytes seen under the microscope.
Downey cells
• These are non-specific antibodies that react with antigens from different species (e.g., sheep or horse red blood cells).
Heterophile Antibodies (Non-Specific)
are often a strong indicator of infectious mononucleosis, but they are non-specific (meaning they don’t target EBV directly).
Positive heterophile antibodies
they are stimulated by one antigen (like a virus or bacteria) but can react with unrelated antigens found on cells from other species (e.g., sheep, horse, or cow).
This means they can bind to substances from different mammals, even though they were triggered by a different organism.
Heterophile antibodies
Reacts with (3)erythrocytes:
• IgM heterophile antibodies can cross-react with red blood cells (erythrocytes) from these animals, which is the basis for tests like the Monospot or Paul-Bunnell test.
horse, ox, and sheep
When mixed with____ red blood cells, the heterophile antibodies get absorbed, meaning they bind to and “disappear” from the serum.
beef
Heterophile antibodies do not bind to_______, which helps differentiate heterophile antibodies from other types of antibodies.
guinea pig kidney cells
Does not react with ________antigens:
• Although heterophile antibodies are associated with infections like infectious mononucleosis, they do not target EBV-specific antigens. They are nonspecific antibodies produced during the infection.
Epstein-Barr virus (EBV)-specific
A______ refers to the concentration of antibodies in the blood.
A titer of _____or higher is considered significant, meaning that the level of heterophile antibodies is high enough to support a diagnosis of infectious mononucleosis.
titer
1:56
The________ test is a hemagglutination test used to detect heterophile antibodies in the serum of patients, particularly those suspected of having infectious mononucleosis.
Paul-Bunnell
Paul Bunnell test
Test Procedure:
1. Patient Serum: A sample of the patient’s blood is collected, and the serum (the liquid part of blood) is inactivated by heating to remove any natural antibodies. 2. Mixing with\_\_\_\_\_: The inactivated serum is then diluted and mixed with sheep red blood cells (erythrocytes), which carry antigens that can react with heterophile antibodies. 3. Incubation and Centrifugation: The mixture is incubated for a specific time, then centrifuged to allow any agglutination (clumping of red blood cells) to become visible. 4. Examination for Agglutination: After centrifugation, the sample is examined macroscopically (with the naked eye) for any signs of agglutination. If the red blood cells clump together, it indicates a positive reaction, meaning\_\_\_\_\_\_
Sheep Erythrocytes
heterophile antibodies are present.
Forssman antigen is a glycolipid protein found on the surface of red blood cells (RBCs) in a wide range of species, including:
• Guinea pig
• Dog
• Cat
• Mouse
• Fowl
• Horse
Forssman antigen is a glycolipid protein found on the surface of red blood cells (RBCs) in a wide range of species, including:
• Guinea pig
• Dog
• Cat
• Mouse
• Fowl
• Horse
Forssman antibodies that are formed against Forssman antigens have the ability to agglutinate_______
_________ are found in normal serum and in serum sickness
sheep RBCs
Forssman antibodies
•Forssman antibodies are found in(2)
normal serum and in serum sickness
The ______________is a more detailed version of the Paul-Bunnell test and is designed to differentiate the type of heterophile antibodies present in the serum.
This test is especially useful for identifying heterophile antibodies linked to infectious mononucleosis and serum sickness.
Paul-Bunnell-Davidsohn test
Davidsohn Differential
• Principle:
ABSORPTION and AGGLUTINATION
• Identify what type of heterophile antibody is present in serum
• Specific absorption by antigens and subsequent testing with SHEEP
RBC
Davidsohn Differential
Guinea Pig Kidney Cells (GPKC)
• Serum sickness, Forssman
Beef/Ox Erythrocyte Ag (BEA)
Serum sickness
Infectious Mononucleosis
MONOSPOT TEST
Basis:
Latex Agglutination Test
MONOSPOT TEST
• Uses: ________as the primary substrate
• Detects:____________
equine erythrocytes
specific heterophile antibodies against EBV infection
MONOSPOT TEST
- Mechanism of the test:
• Suspension of________ coated with highly purified _______from bovine red cell membranes.
The reagent will only react with _________.
Presence of agglutination:_______
polystyrene latex particles
Paul-Bunnell antigen
IM heterophile antibodies
POSITIVE
Monospot Latex Reagent
• Contains _______coated with_______.
• The reagent is suspended in a buffer solution that includes_______ as a preservative.
polystyrene latex particles ; Paul-Bunnell antigen
0.1% sodium azide
Monospot test
• Positive control
•_________________
• Negative control
•_________________
Reactive diluted human serum
Non-reactive diluted human serum
MONOSPOT test
Patient’s Serum Sample
• ________is required for accurate results.
• If there’s a delay in testing:
• Store the serum between ______for up to_____
• For longer storage,________ to prevent deterioration of the sample.
Fresh serum
2-8°C ; 48 hours
freeze it at -20°C or below
This represents the mechanism behind the Monospot test. Here’s a simplified explanation:
1. Patient’s blood contains\_\_\_\_\_\_\_ if they are infected with the Epstein-Barr virus (EBV). These antibodies are produced in response to viral antigens. 2. The test uses sheep or horse red blood cells (RBCs) because these RBCs can react with the patient’s antibodies in a unique way. 3. There is cross-reactivity (X-reactivity) between the IgM antibodies in the patient’s blood and the antigens on the sheep or horse RBCs. 4. This reaction causes\_\_\_\_\_\_, which is a positive result, indicating the presence of EBV-related antibodies.
In short, if the patient’s blood has the specific IgM antibodies produced due to an EBV infection, they will cross-react with the sheep or horse RBCs, causing visible clumping (agglutination).
IgM antibodies
agglutination (clumping of cells)
MONOSPOT test
: Clumping + speckled appearance = presence of heterophile antibodies (indicative of EBV infection).
: No clumping + homogeneous appearance = absence of heterophile antibodies.
Positive Serum
Negative Serum
Immunochromatographic Assay
• This is a\_\_\_\_\_\_ test, meaning it determines whether or not certain antibodies (in this case, IgM antibodies against EBV) are present, rather than measuring their concentration.
qualitative
Immunochromatography
First Reagent (Horizontal Line):
• This reagent is made from latex particles that are coated with antibodies (from …) that specifically bind to human IgM antibodies.
When the patient’s serum containing IgM antibodies is applied to the test, these antibodies will bind to the blue latex, resulting in a visible horizontal line if IgM is present.
Goat Antihuman-IgM Blue Latex Conjugate
IMMUNOCHROMATOGRAPHY
Second Reagent (Vertical Line):
• This extract contains components from …., which are used as a second marker.
If the patient’s serum contains heterophile antibodies, they will react with this extract, creating a visible vertical line on the test cassette.
Bovine Erythrocyte Extract
Semi-Quantitative Slide Test Procedure (Monospot Test)
1. Preparation: • Ensure that both the latex reagent and the controls (positive and negative) reach \_\_\_\_\_\_\_before starting the test. 2. Resuspend Latex Particles: • Gently shake the latex reagent vial to fully disperse and suspend the latex particles in the buffer solution. 3. Sample Placement: • Place\_\_\_\_\_ of the patient’s serum sample onto a specific section of the test slide. 4. Adding Latex Reagent: • Add \_\_\_\_\_\_reagent next to the serum sample on the slide. 5. Mixing: • Using a stirrer, mix both drops (sample and reagent) thoroughly across the entire surface of the slide. 6. Incubation and Rotation: • Place the slide on a rotary shaker and gently rotate for\_\_\_\_\_ at a speed of \_\_\_\_\_to allow proper mixing and reaction. 7. Result Observation: • After 3 minutes, observe the slide for the presence of agglutination (clumping), which indicates a positive result. 8. Serial Dilutions (if positive): • If agglutination occurs, perform serial dilutions of the sample to determine the relative concentration of the heterophile antibodies.
room temperature
50 µL
one drop of the latex
3 minutes; 60-100 rpm
This method helps in detecting heterophile antibodies associated with EBV. If agglutination is observed, it indicates a positive reaction, and further serial dilutions can provide a more detailed estimate of antibody levels.
In_________ technique,
the presence of agglutination indicates clinically significant concentration of infectious mononucleosis antibody in the sample.
qualitative
- Agglutination, uniformly distributed dark clumps throughout the test circle against a blue-green background
• Positive Test
- Slight agglutination seen against a blue-green background.
Weak Positive
- Slight agglutination seen against a blue-green background.
Weak Positive
- No agglutination. Fine granularty
against a brown/tan background may be observed.
Peripheral color should be interpreted as_______, i.e., a faint blue-green color halo on the periphery of the test circle.
: Negatve Test
negative
In_________ technique, the appropriate titer will correspond to the highest dilution that still presents a clearly visible agglutination.
semiquantitative
