HIV Diagnosis, Acute Infection and Superinfection

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HIV Diagnosis, Acute Infection and Superinfection

• Don Kurtyka, ARNP, MS, MBA
• University of South Florida College of
  MedicineTampa General HospitalHillsborough
  County Health Department

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Objectives

• Discuss the diagnosis of HIV and available tests
• Describe the approach to the diagnosis of acute
  retroviral syndrome
• Debate the advantages and disadvantages of early
  treatment of acute HIV infection
• Discuss the evidence for the possibility of
  superinfection / reinfection and the
  implications for patient education and management

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Anonymous vs Confidential

• Anonymous
• Identifying information not provided
• Results not linked to identifying information
• Allows reporting of HIV infection without
  breaching confidentiality
• Disadvantage may not be able to locate clients
  for test results
• Confidential
• Clients linked to test result by identifying
  information
• Results remain confidential
• Informed consent

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Pre-Test Counseling

• Goal reduce HIV acquisition and transmission
• Accurate and current information about HIV
• Obtain informed consent
• Transmission and acquisition
• HIV test info risk, benefits, meaning of
  potential test results
• Assessment of individuals risks and appropriate
  risk reduction activities
• Capacity to comprehend HIV testing and consent

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Post-Test Counseling

• Accurate and current information about HIV
• Local resources
• Risk reduction education
• Referrals for ongoing care and support
• Healthy living strategies
• Meaning of test results and state reporting
  guidelines
• Mental health support / counseling

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Diagnosis of HIV Infection

• Viral antibodies
• Viral antigens
• Viral RNA/DNA
• Culture

Lancet, 1996 348 176.
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Enzyme Immunoassay Enzyme-Linked Immunosorbent
Assay(EIA, ELISA)

• Primary HIV antibody screening test
• Serum plasma, dried blood spots, oral fluids,
  urine
• HIV-1/2, HIV-1, HIV-2
• High degree sensitivity and specificity
• Repeatedly reactive confirmatory testing

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Negative Antibody Test Results

• HIV negative
• Recent infection too early for seroconversion
• CDC follow-up testing at 6 weeks, 12 weeks, 6
  months

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Confirmation Process

• Non-negative screenings should be confirmed
• Western Blot (WB)
• Immunofluorescent Antibody Assay (IFA)
• Higher specificity than EIA
• Interpretation can be subjective

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Predictive Value HIV Ab Tests

• Depends on the prevalence of HIV infection in the
  population
• Low HIV prevalence predictive value of a
  positive test is low
• HIV Ab testing of low prevalence populations
  likely to produce more false-positive than
  true-positive results

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Window Period

• Time delay from infection to positive EIA
• Average 10-22 days
• Most seroconvert within six months

Am J Med 2000 109
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HIV-1 vs HIV-2

• HIV-1 Most cases
• Group M predominant strain world-wide
• Subtypes (clades) A to K, N, O
• Clade B
• US and Europe
• 98 of HIV-1 in US
• Most non-B subtypes were acquired outside US
• Clade C Southeast Asia
• N (new) 1998
• Group O West Africa
• Recombination between viruses of different clades
  becoming more common

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Predominant HIV-1 Subtypes

• A West/East/Central Africa, East Europe,
  Mideast
• B North America, Europe, Mideast, East Asia,
  Latin America
• C South Africa, South Asia, Ethiopia
• D East Africa
• E Southeast Asia

JAIDS 2002 29184
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HIV-2

• Primarily found in West Africa
• Causes immune deficiency due to depletion of CD4
  cells
• 5-8 fold less efficient transmission compared to
  HIV-1
• Associated with lower viral load
• Slower rate of CD4 decline and clinical
  progression
• Negative Ab tests in 20-30 depending on EIA
  assay
• WB not well standardized nor FDA approved

Bartlett, JG 2003 Medical Management of HIV
Infection, p5.
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Testing Recommendations HIV-2

• Natives of endemic areas
• Needle-sharing and sex partners of persons from
  endemic areas
• Sex or needle-sharing partners of persons with
  known HIV-2 infection
• Transfusion or non-sterile injection recipients
  in endemic areas
• Children of HIV-2 infected women

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HIV-2 Endemic Areas

• Benin
• Burkina Faso
• Cape Verde
• Cote dIvoire
• Gambia
• Ghana
• Guinea Guinea-Bissau
• Liberia

• Mali
• Mauritania
• Niger
• Nigeria
• Sao Tome
• Senegal
• Sierrra Leone
• Togo

West Africa
Other

• Mozambique

• Angola

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Confirmation Process WB

• Detects antibodies to HIV-1 proteins
• Core p17, p24, p55
• Polymerase p31, p51, p66
• Envelope gp41, gp120, gp160
• Negative no bands
• Positive
• Reactivity to gp41 gp120/160 or
• Reactivity to p24gp120/160
• Indeterminate
• EIA repeatedly reactive
• Presence of any band pattern not meeting criteria
  for positive results

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False Negative Results

• High-prevalence population 0.3
• Low-prevalence lt0.001
• Usually due to testing during window period
• Rare patients seroconvert in late-stage disease
• Technical or clerical error
• Type N or O
• HIV-2

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False Positive Test Results

• Much less common than in earlier times
• Frequency 0.0004 to 0.0007
• Causes
• Autoantibodies (single case, Lupus, ESRD)
• HIV vaccines
• EIA 68
• WB 0-44
• Technical / clerical error

NEJM 1988319961
Ann Intern Med 1989110617
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Indeterminate Results

• 4-20 of WB assays with positive bands
• Testing during seroconversion
• p24 usually appears first
• Late stage HIV loss of core antibody
• HIV vaccine recipients
• Technical / clerical error
• Infection with O strain or HIV-2

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Indeterminate Results (continued)

• Cross-reacting nonspecific antibodies
• Collagen-vascular disease
• Autoimmune disease
• Pregnancy
• Organ transplantation
• Lymphoma, other malignancies
• Liver disease
• Multiple sclerosis
• Recent immunization

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Indeterminate Results

• Evaluate HIV risk
• Low risk almost never infected with HIV-1 or
  HIV-2
• Repeat testing often continued indeterminate
• Cause frequently not established
• HIV unlikely
• Follow-up serology in 3 months
• Seroconversion usually WB in 1 month
• Repeat testing at 1, 2, 6 months
• Counseling to reduce potential transmission

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Frequency of HIV Testing

• High risk behavior every 6-12 months
• Annual seroconversion
• General population 0.02
• Military recruits 0.04
• MSM 0.5 - 2
• IDU in high prevalence area 0.7-6

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Alternative Testing

• Home test kits
• Rapid Testing
• Alternative body fluids
• Saliva
• Urine
• Vaginal secretions
• Viral detection

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Home Testing

• Home specimen collection
• Self-dried blood spot obtained with lancet
• Anonymous coding
• Mail/courier to testing facility
• Double EIA and confirmatory IFA/WB
• Sensitivity/Specificity 100
• Results relayed to user by telephone after user
  initiates request
• Negative prerecorded message
• Positive live conversation and counseling

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Rapid HIV Antibody Detection

• Results in 15-20 minutes
• Occupational exposure
• Women in labor with unknown HIV status
• Clients unlikely to return for visits
• Outreach
• ERs

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Rapid HIV Antibody Detection

• OraQuick HIV-1 Antibody Test (OraSure)
• Results read by provider in 20 minutes
• Sensitivity 99.6 / Specificity 100
• 20-30
• Testing initially delayed due to CLIA
  requirements
• Fingerstick sample of blood
• Negative test definitive
• Positive test needs standard serology
  confirmation
• Not recommended for HIV-2 screening

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Rapid HIV Antibody Detection

• Single Use Diagnostic System (SUDS) HIV-1 Test
• Venipuncture
• Results 15-30 minutes
• Confirmatory WB required
• Double Check (Organies)

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Type N, Type O, HIV-2

• EIA may fail to detect O subtype
• N group causes false-negative EIA but may be WB
  positive
• HIV-2 false negative EIA in 20-30
• Consider specific HIV-2 testing

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P24 Antigen

• Part of blood bank algorithms since 1996
• Uncommon in clinical practice
• Detects free, non-complex HIV antigens in
  peripheral blood

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Typical Course of Primary HIV
1 mil
HIV RNA
100,000

HIV RNA
HIV-1 Antibodies
_
10,000
Ab
P24
1,000
Exposure
100
Symptoms
10
0
20
30
40
50
Days
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Rapid Test Results

• Reactive (preliminary positive) rapid test
• Screening test is positive
• Preliminary result
• Confirmatory testing required
• Precautions to avoid viral transmission
• Negative rapid test
• No recent exposure definitive negative
• Possible recent exposure
• Recommend re-test
• Counseling to prevent transmission

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OraQuick Florida DOH

• 6 Month Pilot Studies
• Hillsborough CHD
• Duval County Jail
• Orlando CBO for substance abuse
• Miami 2 sites
• Key West only anonymous site

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Saliva Testing OraSure

• EIA and WB to detect IgG
• Specimen collection device, antibody screen, WB
  confirmation
• Cost 25
• Specially treated pad placed between lower cheek
  and gum for 2 minutes
• Vial sent to lab for processing
• Sensitivity and specificity comparable to
  standard serologic testing (99.5)
• Advantages ease of collection low cost
  improved patient acceptance
• Disadvantage client must return for results

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Urine Testing

• Calypte HIV-1 Urine EIA
• Positive results require standard serologic
  confirmation
• Sensitivity 99 Specificity 94
• Cost 4

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Vaginal Secretions

• IgG EIA
• CDC recommended for rape victims
• Semen contains HIV IgG Ab

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Indications for HIV Viral Detection

• Confusing / indeterminate serologic test results
• Acute retroviral infection
• Neonatal infection
• Window period following exposure
• Not FDA approved for diagnosis of HIV
• Expensive

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Viral Detection

• p24 Antigen
• HIV-1 DNA PCR
• Most sensitive able to detect 1-10 copies of
  proviral DNA
• S/S 99 / 98
• HIV-1 RNA (RT-PCR, bDNA)
• S/S 95-98
• Viral culture of PBMC expensive, labor
  intensive, reliability variable

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Viral Detection HIV-2

• bDNA proficient at quantitation of many non-clade
  B viruses
• Amplicor version 1.5 designed to detect other
  clades

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National RecommendationsFor HIV Testing
ofPregnant Women

• USPHS Recommendations for HIV Screening of
  Pregnant Women (4-22-03)
• Universal testing for all pregnant women as a
  routine part of prenatal care using an opt out
  approach
• Labor and Delivery routine rapid testing if HIV
  status unknown
• Postnatal rapid testing for all infants whose
  mothers status is unknown
• Regulations, laws, and policies about HIV
  screening of pregnant women vary from state to
  state

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Acute HIV Infection
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Acute HIV Infection

• Transient symptomatic illness in 40-90
• Usually mild but can be severe
• 2-6 weeks after infection
• Often not recognized by primary care clinicians
• Symptoms non-specific
• Often resembles influenza, mononucleosis
• Cold symptoms absent
• Can be asymptomatic
• Duration 14 days

DHHS Guidelines July 14, 2003
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Acute HIV Infection
Neuro meningoencepalitis or aseptic meningitis
peripheral neuropathy or radiculopathy facial
palsy, Guillain-Barre syndrome brachial
neuritis cognitive impairment or psychosis
CDC 2002
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Rash in Acute HIV Infection

• Trunk, face, extremities
• Palms and soles rarely involved
• 5-10 mm diameter
• Erythematous, nonpruritic, painless

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Laboratory FindingsAcute HIV Infection

• Lymphopenia ? lymphocytosis
• Atypical lymphocytes
• Transient CD4 decline
• VL 100,000 1,000,000

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Diagnosis of Acute HIV Infection

• Recognition of clinical symptoms
• No true constellation of signs/sympoms
• Presence of any symptom(s)
• History of activity associated with HIV risk
• Detectable plasma HIV RNA
• Highly sensitive
• False positive possible
• Detectable p24 Antigen
• Less sensitive
• False positive rare

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Acute HIV Infection

• High virus levels (105-106 copies/mL)
• 2-9 of HIV-negative have false positive results
• Usually associated with low RNA titers lt10,000
• VL in new infections
• Correlates with rate of CD4 decline
• Prognostic indicator in early disease

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Potential Benefits Early Intervention

• Decrease the severity of acute disease
• Alter initial viral set point ? alter disease
  progression rate
• Suppress viral replication ? reduce rate of viral
  mutation
• Preserve HIV-specific immune responses
• May permit future discontinuation of therapy with
  sustained viral control
• Reduce risk for viral transmission
• May minimize viral evolution and development of
  viral diversity

DHHS Guidelines July 14, 2003
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Potential Risks Early Intervention

• Decreased QOL
• Medication side effects
• Drug toxicities
• Dosing constraints
• Drug resistance if viral suppression inadequate
• Need for indefinite continuing therapy
• Expensive
• Potential for transmission of resistant virus

DHHS Guidelines July 14, 2003
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Potential Risks Early Intervention

• Long term clinical outcome benefit has not been
  documented
• Additional studies are needed to delineate the
  role of ARV therapy during the primary infection
  period

DHHS Guidelines July 14, 2003
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Treatment Acute HIV Infection

• Weigh potential benefits against potential risks
• Certain authorities endorse treatment of acute
  HIV infection on the basis of the theoretical
  rationale and limited but supportive clinical
  trial data

DHHS Guidelines July 14, 2003
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Treatment Acute HIV Infection

• Experienced clinicians recommend consideration of
  therapy for patients among whom seroconversion
  has occurred within the previous 6 months
• Although the initial burst of viremia among
  infected adults usually resolves in 2 months,
  treatment during the 2 to 6-month period after
  infection is based on the probability that virus
  replication in lymphoid tissue is still not
  maximally contained by the immune system during
  this time

DHHS Guidelines July 14, 2003
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Detuned Antibody Testing

• Less sensitive ELISA test
• May help distinguish between recent
  seroconverters and those with long-standing HIV
  infection
• Current ELISAs can detect relatively low levels
  of Ab
• HIV Ab levels increase over first few months
• Recent infection standard ELISA positive
• Detuned assay negative
• Able to diagnose individuals who have already
  seroconverted on a standard ELISA but are still
  early in infection

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HIV Superinfection
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HIV Super-Infection

• Coinfection with a second strain of HIV during
  the course of established HIV-1 infection (Jost,
  NEJM 34710, 2002)
• Known to be theoretically possible
• Little direct evidence to support concept

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HIV Superinfection

• 2000 LTNP (patient A) unprotected intercourse
  with ARV-experienced male with progressive HIV
  disease (patient B)
• Patient A experienced rapid disease progression
• Virus harbored original strain and drug-resistant
  strain from patient B

Angel, J. CROI 2000, Abs LB2
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HIV Superinfection

• Established infection with HIV-1, subtype AE
• Well-controlled viremia on HAART unable to
  remain on ART due to liver toxicity
• Sexual exposure to type B in Brazil
• Unprecedented rise in viral load and rapid CD4
  depletion
• Mixture of B and AE identified
• Rapid emergence of type AE

Jost, S. NEJM 34710, 2002
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HIV Superinfection

• Evidence supports clades from different
  geographic areas have combined
• Likely due to superinfection of an individual
  harboring a virus of one clade with a second
  virus of another clade

McCutchan et al, 1996N AIDS 10 supp Robertson
et al, 1995 J Mol Evol 40
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SIV Superinfection

• SIV superinfection in monkeys may occur, probably
  rare
• Difficult to superinfect a monkey with
  established SIV even with
• High infectious dose
• IV administration
• Possible when challenged with second SIV strain
  during or soon after initial infection with first
  strain
• Possible window of opportunity for
  superinfection

Sharpe et al, 1997 J Gen Virol 78
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SIV Superinfection

• Development of virus-specific immunity over time
• Primary infection immunity absent or too
  immature to effectively prevent infection
• Strengthening of virus-specific immune responses
  ? superinfection less likely

Sharpe et al, 1997 J Gen Virol 78
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SuperinfectionImplications for HC Providers

• Consider the possibility of superinfection
• Counsel patients regarding sexual practices and
  safer sex

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Summary

• Significant advances in assays to detect HIV
  infection
• Alternatives to standard EIA/WB testing may
  facilitate improved, ongoing HIV screening
• Detection of acute HIV infection needs to
  enhanced
• Early intervention in acute HIV infection may
  have clinical benefits
• Superinfection needs to be considered
• Risk reduction counseling must be ongoing

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