HIV Basics

Question 1

Genome and Transcription

Answer 1

Diploid RNA (2 single stranded molecules of RNA)

Rev transcriptase –> dsDNA –> integrates into host genome

Question 2

3 Structural Genes + What Ea Codes

Answer 2

1- env - gp120 (attach to CD4+ cell) and gp41 (fusion and entry)

2 - gag - p24 (capsid protein) and p17 (matrix protein)

3- pol - reverse transcriptase, aspartate protease and integrase

Question 3

HIV and AIDS Dx

Answer 3

Screen - ELISA (antibody to viral proteins)

Confirm - W blot (antibody to viral proteins)

Often false neg in first 2 mo; often false pos in infants to infected moms b/c anti-gp120 crosses placenta so use PCR in these babies

PCR - to tell viral load / prognosis

AIDS = CD4+ count < 200 or AIDS-defining illness or CD4+ < 14%

Question 4

Risks of Infection at CD4 + < 500

Answer 4

Oral thrush

EBV - hairy leuk

Bartonella henslae - bacillary amgiomatosis (neutrophils on biopsy)

HHV-8 Kaposi (lymphocytes on biopsy)

HPV

Question 5

Risks of Infection at CD4+ < 200

Answer 5

Histoplasma capsulatum (oval yeast cells in macrophages)

Dementia from HIV

JC virus reactivation - PML

PJP - score 20 to 0 (ground glass)

Question 6

Risks of Infection at CD4+ < 100

Answer 6

Aspergillus fumigatus

Candida esophagitis

CMV (cotton wool spots)

Cryptococus neoformans - meningitis w/ India Ink

Cryptosporidium - watery diarrhea

EBV - ring-enhancing, solid CNS lymphoma

M avium - non specific

Toxo - ring enhancing bu not solitary on MRI