HTLV1,HIV Flashcards
HTLV1 is in what virus family?
Retroviridae
-HIV1/2 in same family
How is HTLV1 transmitted?
Parenterally -IVDU -Transfusion -Sex Transplacental
HTLV1 infects what?
CD4+ T-lymphocytes
HTLV1 Diagnosis (methods).
Screening
-ELISA
Confirmatory
- Western Blot or
- PCR
*Same as HIV
Acute HTLV1 infection is typically asymptomatic, however prolonged incubation period may lead to what sequelae? (2)
- Tropical Spastic Paraparesis (HTLV1 ass/ myelopathy)*
- Adult T-cell Leukemia/Lymphoma (ATLL)
*Shorter incubation/may coincide w/ acute infection
Tropical Spastic Paraparesis (HTLV1 ass/ myelopathy):
- M vs. F
- Demyelinating lesions (locations)
- F>M (3:1)
- Upper Thoracic
- Lower Cervical
What is the lifetime risk of developing Adult T-cell Leukemia/Lymphoma (ATLL) if infected by HTLV1 by age 20.
-Incubation period
5%
-20-30 years
Adult T-cell Leukemia/Lymphoma (ATLL) S/S:
- Physical (5)
- Serum
- Hepatosplenomegaly
- Jaundice
- Weight loss
- Skin rash
- Thirsty
- Hypercalcemia
- IL-2 receptor (free) HIGH
HIV Laboratory tests - ELISA:
- Tests for what?
- Sensitivity
HIV1/2 antibodies to recombinant antigens/peptides
-Sensitivity >99%
*Principle method for HIV screening
When are Anti-HIV antibodies detectable?
*p24 protein
within 6-8 weeks of infection (window period)
*p24 - 2-3 weeks
What is the confirmatory test for HIV?
Western Blot
The CDC has defined a positive HIV1 Western blot as what?
Presence of any 2 bands:
- p24
- gp41
- gp120/160
If one or more bands are present on HIV1 Western Blot but not in combination that meets criteria for positivity, then the test is considered “indeterminate”. What is the next steps?
-Repeat within 6 months
- If repeatedly “indeterminate”:
- No risk factors - Negative
- Risk factors - Nucleic Acid based test is advised
HIV Laboratory tests - CD4 count (Flow Cytometry):
- Considerations (2)
- Frequency of monitoring
- Diurnal variation - test at same time
- Age appropriate ref. ranges
- 6 months while disease is stable
What is the preferred method of assessing response to antiretroviral therapy?
HIV RNA (viral load)
HIV Laboratory tests - HIV Proviral DNA:
- Use/Detection
- Sensitivity/Speficity
Can be used to confirm diagnosis
-Result of HIV RNA reverse transcrition in to cDNA, which then integrates into host genome
Sensitivity - 95%
Specificity - 98%
*Both are low by HIV diagnosing standards
HIV RNA vs. CD4 count:
-Correlation with long term (10 year) outcome
HIV RNA superior
HIV RNA vs. CD4 count:
-Correlation with short term (6 month) outcome
CD4 count superior
HIV Laboratory tests - HIV RNA (viral load, quantification)
-A change in what is considered singificant?
> 0.5 log
*Example: Viral load of 1,000 would be 3 log units, and a change in viral load from 1,000 to 10,000 would be expressed as a 1 log change
Viral load (HIV RNA) is the primary variable used to determine what?
When to initiate Highly Active Antiretroviral Therapy (HAART)
*Viral load also determines the efficacy of the treatment
What is the recommended test in the diagnosis of neonatal HIV infection?
HIV Proviral DNA (PCR testing)
-HIV RNA may be equally good
*Do NOT test umbilical cord blood
