HIV & Hepatitis Flashcards
HIV genome
2 copies ssRNA, negative-sense
HIV - 2 important glycoproteins
gp41 & gp120
HIV - 3 important enzymes
Protease, RT, integrase
-all in nucleocapsid
HIV - 3 genes and what each encodes
gag - p24 (capsid), p17, p6
pol - RT (p51), p66
env - gp41, gp120
This HIV appears early in the infection. Why is it not a good confirmatory protein?
p24
p24 disappears because host develops immunity to it
HIV - spread mainly through… Anything covered in ___ is more infectious
Sexual contact
Blood
-HIV in all bodily fluids, but blood is especially infectious
Healthcare workers can be exposed to HIV through
Prick
- 1 in 300 workers
- also splash, exposure, etc
Why does having an preexisting STD increase likelihood for HIV?
Lots of inflammation and CD+ cells in the area
HIV binds to this receptor… Requires these co-receptors
CD4
CXCR4 = T cells
CCR2 & CCR5 = macrophages
HIV - Where does integrase cut the host genome?
Anywhere
Why is it hard to make vaccines for HIV?
Antigenic variation
-HIV is an RNA virus, lacks proofreading mechanism
HIV - clinical manifestations
Hypergammaglobulinemia
Increase p24 (initially)
Decreased CD4 - less lymphocytes
<200 cells / ul
HIV - screening & confirmatory tests
ELISA for gp120
Western blot for at least 2 out of 3 bands
A patient has HIV when their CD4+ cell count drops below… What’s the normal CD4:CD8 ratio? What’s the ratio for an HIV+ person?
<200 cells / ul
2:1
<1:1
What kind of HIV testing should be performed on an infant?
RT-PCR
HIV - What are some downsides of using ELISA testing?
False positive or false negative
-expired kits, handling, pre-analytical, patient in window period
Process for confirmation HIV+ patient
ELISA for gp120
Second ELISA to confirm
Western blot for 2/3 of these proteins - p24, gp41, gp120/gp160
Advanced liver disease results in…
Cirrhosis (scarring)
-cannot be reversed
Liver disease - clinical presentations
Jaundice
Urine/feces color change
Appetite loss
Cold/flu-like symptoms
Liver tenderness
Hepatomegaly
Why does liver damage cause dark urine?
Bilirubin from broken down RBCs
- highly toxic
- brain damage if accumulates
Liver disease - lab findings (3)
Elevated Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST), Bilirubin
Hepatitis - how many types are there? Which ones are DNA and which ones are RNA?
5
A through E
B is DNA, rest are RNA
Antibodies are needed against Hepatitis B to ___ the virus
Neutralize
A recent Hepatitis infection shows elevated levels of ___. After 6 months, elevated levels of ___ are detected
IgM
IgG & IgA
Vaccinating against Hep B also protects you from…
Hep D
Hep B and Hep D infecting at the same time is called… Hep D infecting after Hep B is called
Coinfection
Superinfection - high chance of chronicity
Hep A - acute infection marker is…
anti-HAV - IgM antibody directed against Hepatitis A (HAV)
What are the antibody markers for Hep B?
anti-HBc
anti-HBe
anti-HBs
Hep B - the two core proteins are
Core protein
E protein
Hep B - markers that appear in the blood in order
HBs Ag - surface antigen
HBe Ag - E protein
HBc Antibody
HBe Antibody
HBs Antibody
-mnemonic = “seces” (pronounced sexist)
anti-HBc IgG in the blood indicates what?
Person had a Hep B infection, but not a Hep B vaccination
- vaccination targets HBs
- IgG indicates recovery from disease & an infection that happen awhile ago
HBe and HBs antigens in the blood after 6 months indicates what?
Infected person never recovered from acute infection. Infection becomes chronic
-anti-HBc IgM and total anti-HBc do develop
High HBe antigens with no anti-HBe antibodies in the blood indicates what?
Infected person is not recovering. Very severe
- HBe = indicates high degree of infectivity
- anti-HBe = person is recovering
Vaccinated people only have this antibody in their blood
anti-HBs antibody only
anti-HBs antibody in the blood indicates what?
Person is infected, resolved their infection, or had a vaccination
Chances of developing chronic liver disease when infected with Hep B? Hep C?
The younger you are when you get a Hep B infection, the more likely you will get cirrhosis or chronicity later in life
Hep C = 90% will develop chronic liver disease regardless of age
Hep B monitoring panel consists of 4 things
HBs Ag
anti-HBs antibody
HBe Ag
anti-HBe antibody
-screen, diagnose, monitor
Which two Hep B markers are acute markers?
HBs antigen
HBe antigen
-both appear and decline < 6 months
Once this antibody appears during an acute Hep B infection, the person is considered “protected”
anti-HBs
-anti-HBe will develop around same time to resolve infection in blood
Hep C - acute infection marker is
anti-HCV
Hepatitis transmission routes
Hep A, Hep E = oral-fecal
-mnemonic = “AtE”
Hep B, Hep C, Hep D = parenteral
