serology exam 3

Know the interpretation of lab results with previous algorithm (ELISA + Western Blot)

slide 41 ch 24

Why is there no vaccine for HIV

because the virus mutates rapidly, and it integrates itself into hosts DNA

Normal CD4:CD8 ratio, what ratio is most likely seen in AIDS

normal = 2:1

untreated = less than 1:1

What is the advantage of 4th generation HIV tests?

• it can diagnose 2-3 weeks after exposure and they test for both p24 antigen and HIV antibodies

What test is best test to monitor the effectiveness of antiretroviral therapy?

HIV viral load test

List some opportunistic infections associated with AIDS:

Kaposi sarcoma (HSV8), Histoplasma, Pneumocystis jirovecci, Cryptococcus neoformans, esophageal thrush, coccidiomycosis, toxoplasmosis

What cells does HIV preferably infect?

CD4 - T helper cells

Fact: One of the screening tests available for HIV is an ELISA method, we did it in lab

true

In terms of HIV what is a provirus

the form HIV takes after its DNA is integrated into host genome

Which method can detect infection with HIV sooner: antibody test or molecular?

molecular testing (nucleic acid test)

What do the reverse transcriptase, protease, and integrase enzymes do

• reverse transcriptase = converts RNA to DNA

• protease = cleaves viral proteins

• integrase = aids in incorporation of viral DNA into genome of the infected cell

Know the current HIV testing algorithm

slide 42 ch 24

What are nucleic acid tests for HIV infection used for?

can detect HIV sooner, used when serological tests are inconclusive or to be used in infants

• also for a recent HIGH RISK exposure, possible exposure, and have early symptoms of HIV infection, or to resolve discrpancies

Patients in the AIDS (3rd stage) of infection will most likely have __(increased/decreased) CD4 cells, about how many??

decreased

• CD4 count of less than 200/uL 

What does hepatitis mean?

inflammation of the liver

For which of the Hep viruses we have a high infection rate from mother to baby

HBV

hep A

• fecal oral route, close person to person

• risk = people who use drugs, homeless, and men who have sex with men

• RNA virus

• VACCINE

• acute infection = + IgM anti-HAV

• immunity = + total anti-HAV along with -IgM anti-HAV

hep B

• DNA virus

• sexual contact, IV drug use, needlestick injury, DURING BIRTH PROCESS

• risk = infants born to infected mothers, infected sex partners, drug users, health care workers, hemodialysis patients

• no treatment for acute

• interferon a, inhibitor of polymerase, antiviral drugs, liver transplant = chronic

• HAS VACCINE

hep C

• RNA virus

• most common bloodborne infection

• chronic liver infection, infections not seem due to universal blood product testing

• new cases are related to injection drug use

hep D

• RNA but REQUIRES CO-INFECTION with HEP B = satellite virus

• parenteral or perinatal

• no vaccine for D but can vaccinate for B

hep E

• RNA virus

• HEV 1,2 fecal oral route, 3,4 by consumption of infected pork

• acute infection = IgM anti-HEV

• past exposure = IgG anti-HEV 

• NO VACCINE

Which are transmitted through fecal oral route? (hepatitis)

Hep A, Hep E

What is the mode of transmission for B, C, D hepatitis

contacted with infected blood and body fluids

For which Hep viruses is there a vaccine

Hep A, Hep B

Do all patients with Hep B and C have observable symptoms

no, in acute infections and chronic they can be asymptomatic 

The majority of patient with antibodies to Hep_____will develop chronic infection and active liver disease

C

What is the “core window” in terms of hepatitis refer to?. What markers are available during this time?

core window- HBsAg is not detectable and just before other antibodies appear

• total anti-HBc, HBc IgM, HBsAg, anti-HBs 

What does it mean to be a chronic carrier of HBV

virus remain in the persons body after the acute infection has ended

• persists for 6 or more months

• typically remain asymptomatic

• increased risk for chronic liver cirrhosis and hepatocelullar carcinoma

Know everything about appearance, disappearance of HBV antigens and antibodies in acute and chronic phase (a lot of questions here)

insert pics here

What is the expected serological response in an immunocompetent patient who has been vaccinated for Hepatitis B?

What Hep B markers are performed on blood products?

IgM anti-HBc and HBsAg

What are some of the clinical signs and symptoms seen in viral hepatitis (enzymes, jaundice….) basic info

What disease conditions are associated with EBV?

infectious mono, nasopharyngeal carcinoma, burkitt lymphoma

Presence of _____lymphs seen in patients with EBV

atypical (20% or more)

There is 1 question about the heterophile antibody testing with guinea pig kidney/beef bovine RBCs

What other infections may cause mononucleosis like syndrome

CMV, toxoplasmosis, HIV, rubella, Hep A/B/C, adenovirus

What is an heterophile antigen

antibodies (usually IgM) that are capable of reacting with similar antigens from 2 or more unrelated species

Diagnostic test most specific for EBV

How is EBV transmitted

intimate contact with salivary secretions (kissing disease)

Know the sequence of antibodies for infectious mono, which are present in current vs past infection (VCA,EA,EBNA)

EA- early acute

VCA - late phase

EBNA - latent phase

• recent - IgM anti-VCA, anti-EA, IgG anti-VCA without anti-EBNA

• past. - anti-EBNA, IgG anti-VCA without IgM anti-VCA

What antibodies caused a positive heterophile antibody test for infectious mono?

Fact: EBV likes to attach to the receptor on B lymphocytes

true

What is the seroprevalence (%) in United States in adults in EBV

95% in adults

Fact: It is very important to screen blood products for CMV for
newborn/immunocompromised transfusion

true

Fact: Most common congenital infection in the United States

CMV - true

Fact: CMV appears to suppress cell mediated immunity, and you may see a decrease in both CD4 and CD8 lymphs. I know I did not mentioned this in class but I just notices this is a commonly asked question in review books

true

What is the seroprevalence (%) in United States in adults in CMV

over half of adults have been infected with CMV by age 40

initial disease is chickenpox. _______is the possible reactivation of virus

shingles

You see inflammation of ____glands (mumps)

parotid glands

Primary clinical manifestation (mumps)

parotitis (30-40%) - parotid glands

rubella is also known as

german measles or III day measles

Why are we concerned about transmission primarily in the 1st trimester of pregnancy (rubella)

it can cause congenital abnormalities, miscarriage, and stillbirth infants

• in the 1st trimester is can infect the fetus through the placenta “congenital rubella syndrome”

how is measles transmitted

respiratory droplets

how contagious is measles

very, it can live for up to two hours in an airspace

• 90% of people close to one infected person will get it

• infected people can spread 4 days before/after rash appears

fact: may cause immune amnesia (measles)

true

how do HSV 1 and 2 differ in location of the infection

what is the primary manifestation of HTLV

usually asymptomatic

• very small amount will get adult T cell leukemia/lymphoma (ATL) and HAM/TSP

what cells does HTLV preferably infect

CD4 T helper cells

antigenic shift vs drift

• drift = result of minor changes caused by mutations

• shift = result of reassortment in a doubly infected cell, creating a new virus

what are H and N surface glycoproteins

H (hemagglutinin) = which binds surface sialic acid

N which cleaves sialic acid

Fact: Examples of tests used to diagnose Influenza: Antigen tests, molecular, direct fluorescent tests (like the one we observed in the back microscope for RSV-you can do it for a lot of respiratory pathogens like parainfluenzae, adenovirus…)

true

direct vs indirect immunofluorescence (RSV)

how can we protect ourselves from RSV

When are respiratory viruses more prevalent

Fact: This virus is responsible for respiratory bronchiolitis in infants

RSV

does corona virus cause severe acute respiratory syndrome

yes it is SARS

what is the animal reservoir in west nile virus

birds

what is the most common manifestation in west nile virus

fever, joint pain

• few very get severe encephalitis and meningitis

what is the vector for west nile virus

mosquito

What viruses are in the Herpes Virus family and what do they have in common?

8 Viruses

• HSV 1 and 2, VZV, EBV, CMV, and human herpes viruses (HHV 6 7 8 and kapsoi sarcoma)

most common = latent infection that can be reactivated, and are surrounded by protein capsid and outer envelope

What viruses are associated with the TORCH panel?

T-  toxoplasmosis

O- other

R- rubella

C- CMV

H- herpes

What does it mean to be in the window period

time between exposure to an infectious agent and when a test can accurately detect it 

What are CD8 and CD4 cells?

CD4 - T helper cell, activate other immune cells

CD8 - cytotoxic T cells, directly kill

Cells involved in cell mediated immunity

T cells, CD4 and CD8

Newborns suspected of having a virus should be tested for what antibody type

IgM as it would be their antibody and NOT the mothers

A positive single titer in any healthy individual is mostly likely due to __________

What is latency

the ability of a virus or bacterium to remain dormant in the body without causing active symptoms 

Fact: Mechanisms that viruses use to evade the immune system include downregulation of MHC class I molecules, latency, mutations, suppression of immune system

true

What does a low avidity IgG antibody indicate

recent infection

How do interferons alpha and beta help the host fight off viral infections

Know viruses for which we have a vaccine

• varicella

• flu 

• rubella

• mumps

• hep a and b

What does the presence of an IgM antibody mean? Current or past infection?

current or recent infection - IgM appear first

What does the 4th fold increase in IgG titer mean?

evidence of recent or current infection

What is the classic antibody response in infection?

Know the rise and fall of IgG and IgM antibodies and significance in disease (white paper that you have in your lab desk)

Would a patient that just got exposed to a virus develop antibodies right away?

no there is a lag phase, then IgM would be first after around 1-3 weeks and then IgG after a week-10 days

Would a patient receiving immunosuppressive therapy be able to mount a good antibody immune response?

no as the medications/therapy are suppressing the immune system

Would a patient infected with a genetically rare strain of a virus be able to test positive on a regular serological antigen test?

yes as it would be looking for antibodies produced to a viral infection

Do you think autoantibodies in individuals having an autoimmune disorder would exhibit cross reactivity in certain antibody serological tests?

yes - molecular mimicry, can lead to false positives and incorrect results

Do you think most antibodies present in the cord blood of a newborn baby are of maternal or fetal origin?

maternal origin

What are T lymphocytes and what are their main functions?

cell mediated immunity, directly killing infected or cancerous cells

When should acute and convalescent blood specimens be collected for the detection of antibody concentration (how far apart in days)?

acute = early in illness

convalescent = 2-10 weeks later

What molecule is the most immunogenic, proteins, carbohydrates or lipids?

proteins

What is the most significant class of microbial targets for NK cells

viruses

what is the order of ab/ag order in hepatitis