Cryptococcal IRIS in Africa: clinical manifestations and pathogenesis

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Cryptococcal IRIS in Africa clinical
manifestations and pathogenesis

• Paul R. Bohjanen, M.D., Ph.D.
• Associate Professor of Microbiology and Medicine
• University of Minnesota
• Minneapolis, MN, USA
• Professor in Residence
• Infectious Diseases Institute
• Makerere University
• Kampala, Uganda

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• Outline
• Role of immune activation in HIV pathogenesis.
• Use of microarrays to assess immune activation in
  HIV-infected Ugandan patients before and after
  initiation of antiretroviral therapy.
• Outcomes of cryptococcal meningitis in Uganda in
  the era of antiretroviral therapy (ART).
• Clinical features of HIV Immune Reconstitution
  Inflammatory Syndrome (IRIS) in patients with
  recent cryptococcal meningitis after initiation
  of ART.
• Use of microarrays to assess biomarkers of IRIS
  after initiation of ART in patients with or
  without recent cryptococcal meningitis.

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Primary HIV Infection
Viral Dissemination
Partial Immune Containment
Chronic Immune Activation
Destruction of Lymphoid Tissue
Decreased Circulating CD4 T Cells
AIDS
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Immune Reconstitution

• Potent ARV therapy blocks viral replication and
  prevents the destruction of CD4 T cells.
• This shifts the balance toward CD4 T cell
  regeneration and improvement in immune function.
• CD4 T cell counts increase.
• Antigen-specific immune responses are restored.
  

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Immune Reconstitution

• The bottom line is that patients who respond to
  ART have improved immune function and are at
  lower risk for the development of opportunistic
  infections.

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Is immune reconstitution always beneficial?
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Immune Reconstitution Inflammatory Syndromes
(IRIS)

• Immune Reconstitution Paradox Recovery in the
  function of the immune system with ART can
  promote an inflammatory reaction to antigens that
  were previously not recognized by the immune
  system.
• This inflammatory reaction can sometimes lead to
  worsening of a current or latent opportunistic
  infection.
• The onset of IRIS often occurs 2-8 weeks after
  initiation of ARV therapy but can occur earlier
  or later.

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IRIS Triggering Antigens

• In IRIS, the flaring of specific immune responses
  to microbial antigens occurs in the setting of
  improving immunity after the initiation of
  effective ART.
• IRIS may represent either an appropriate
  inflammatory response that was previously masked
  by severe immune deficiency or a pathological
  exaggerated inflammatory reaction.
• Inciting antigens may be from an active infection
  (replicating microorganisms) or from the remnants
  of a treated infection (microbial debris) or
  latent infection.
• IRIS is also associated with autoimmune disorders
  or malignancies such as Kaposis sarcoma and
  lymphoma.

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Pathogens associated with IRIS
Mycobacterium avium Mycobacterium
tuberculosis Mycobacterium leprae Cryptococcus
neoformans Pneumocystis jiroveci Histoplasma
capsulatum
Hepatitis B virus Hepatitis C virus Varicella-zos
ter virus Cytomegalovirus BK Virus Parvovirus
B19 JC virus Papilloma virus HHV-8 (KS)
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Clinical Presentation

• IRIS can occur as early as a few days after
  starting ARV therapy. In patients with baseline
  CD4 T-cell counts below 50 cells/mm3, most
  events will happen within the first 8 weeks of
  therapy. Late IRIS with symptom onset after more
  than 1 year of ARVs have been described.
• Patients typically become ill in the setting of
  improving virologic and immunological measures.
• IRIS may be mistaken for a new opportunistic
  infection, but it can sometimes be distinguished
  by an atypical manifestation, such as localized
  inflammation where one would expect disseminated
  disease.
• IRIS may also present as paradoxical worsening of
  a known opportunistic infection.
• Depending on the site and activity of the
  immunologic response, the severity of clinical
  symptoms can vary widely from mild to
  life-threatening events.

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IRIS Case Definition

• Evidence of clinical response to ART with
• On ART
• gt1 log10 copies/mL decrease in HIV RNA (if
  available)
• Infectious or Inflammatory condition within 6
  months of ART initiation
• Symptoms can not be explained by either
• Newly acquired infection
• Expected clinical course of a previously
  recognized and successfully treated infectious
  agent
• Treatment failure
• Side effects of ART.
• Complete ART non-compliance

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IRIS Associated with Crytococcal Meningitis

• IRIS may be associated with cryptococcal
  meningitis following initiation of ART.
• Upon initiation of ART, 25 of CM patients
  experience IRIS with increases in headache,
  intracranial pressure, signs of inflammation, and
  in 25, serious complications include loss of
  vision, cranial nerve palsies, reduced cognition
  and death.

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IRIS Management

• Evidence-based treatment recommendations are
  lacking.
• Identify the inciting pathogen and treat it.
• Most cases of IRIS are managed without stopping
  ARVs.
• In severe cases, treatment options include
  stopping ARVs, steroids, NSAIDS, and surgical
  treatment (for example drainage of abscesses).

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Why is so much IRIS seen in Africa?

• IRIS occurs most often in patients with advanced
  HIV disease and severe immunosuppression.
  Because of limited availability of ART in Africa,
  treatment is often reserved only for patients
  with advanced disease.
• Opportunistic infections associated with IRIS,
  such as tuberculosis and cryptococcal meningitis,
  occur frequently in Africa.
• Limited diagnostic capabilities in resource poor
  regions may impair the diagnosis of alternative
  etiologies, such as a second opportunistic
  infection. The diagnosis of IRIS is often
  invoked when no other definitive diagnosis is
  found.

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Research Questions

• What is the incidence of IRIS?
• How often is IRIS associated with significant
  morbidity and mortality?
• Who is at greatest risk?
• How should IRIS be treated?
• Can the immune system be modulated to prevent
  IRIS?
• In patients with IRIS-associated infections, such
  as TB or CM, is it better to treat the OI first
  and then start ART?

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IRIS Study Design
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Development of two pilot cohorts 24 patients
in each
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Incidence Rate 35
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Response to ART in Cohort 1 (24 patients)
Baseline CD4 58 60 cells/uL viral load
5.5 5.4 log At 3 months CD4 192 133
cells (P lt .001) with 23 of 24 individuals having
a gt50 CD4 cell/uL increase. viral load
undetectable among 19 of 24 patients (Range of
five detectable subjects 431-1,657 HIV RNA
copies/mL). 20 of 24 patients have been
followed for gt 6 months with 8 study visits, and
100 follow up has occurred.
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IRIS Events (Cohort 1)
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• A patient without prior cryptococcal disease
  and negative serum CRAG at enrollment, developed
  progressive tongue swelling. Biopsy revealed
  encapsulated yeast consistent with a
  cryptococcoma which regressed with two weeks of
  fluconazole therapy.

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Cryptococcal Meningitis Outcomes
Suspected Meningitis N71
Non-CM meningitis N22
Cryptococcal Meningitis N49
On ART, IRIS Event N5
Survived Hospitalization N36
Died during hospitalization N8
Died prior to ART N7
Started ART N24
Lost prior to ART N5
Alive at 6 months N18
Died after ART start N6
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Response to ART in Cohort 2 (24 patients)
Baseline CD4 29 27 cells/uL viral load
350,000 258,000 copies/mL At 3 months CD4
80 63 cells viral load 846 1340 copies/mL
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IRIS Events in Cohort 2
Six patients have died since enrollment.
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• Immune activation in peripheral blood of
  HIV-infected patients in Uganda before and after
  initiation of ART

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Most of the transcripts that were down-regulated
after ART are T cell activation genes.
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Multiple components of TNF and Interferon
response pathways were down-regulated following
initiation of ART
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• Immune activation in peripheral blood of
  HIV-infected patients in Uganda who do or do not
  develop IRIS after initiation of ART

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Expression patterns of hundreds of genes are
altered in patients with CM
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Baseline Gene Expression that Predicts IRIS
P0.005
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Gene Expression Predictors of IRIS (Aim 1)

• Cell Signaling Pathways
• Chemokine Signaling
• PI3Kinase/AKT Signaling
• Cell Death Pathways
• Glycolysis/Gluconeogenesis Pathways
• Drug Metabolism Pathways
• PGK1 metabolism of lamivudine

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Gene Expression Predictors of CM IRIS (Aim 2)

• Cell Signaling Pathways
• NF-?B Signaling
• Toll-like Receptor Signaling
• Death Receptor Signaling
• Cell Death Pathways
• Cell Cycle Pathways
• Transcription Factors

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Biomarkers (signatures) of IRIS and CM IRIS
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Biomarkers (signatures) of IRIS
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Biomarkers (signatures) of CM and CM IRIS
IRIS, non-CM events TB at 6½ months



No OI Controls CM IRIS CM
Controls
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Gene Expression Associated with CM IRIS
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Conclusions

• HIV IRIS occurs frequently in sub-Saharan Africa,
  appearing in more than 1/3 of the patients in our
  study.
• IRIS has a diverse spectrum of clinical
  presentations and a wide range of severity.
• Mortality is high among patients with CM both
  prior to initiation of ART and after ART is
  initiated.
• IRIS occurs frequently in patients with CM with
  manifestations related to CM as well as other OIs
  that may be present.
• The normal response to ART is characterized by a
  decrease in immune activation that can be
  measured in peripheral blood using microarrays.
• Immune activation in IRIS can be measured in
  peripheral blood using microarrays and specific
  biomarkers or patterns of biomarkers (signatures)
  may be useful to diagnose IRIS.
• Even prior to initiation of ART, the expression
  of biomarkers in peripheral blood may be useful
  for predicting patients risk for subsequent
  development of IRIS.

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Research Trainees
Fellows David Meya MBChB (ID-IDI) David
Boulware, MD (ID-U of MN) Irina Vlasova MD,PhD
(Postdoc- U of MN) Students Joshua Rhein (4th
year Med) Sam Goblirsch (4th year Med) Jack
Staddon (Combined MD/PhD) Darlisha Williams (MPH
student) Sarah Lee (Combined MD/MPH) Residents B
rett Handel-Paterson, MD (Med-Peds) Erin Huiras,
MD (Dermatology)
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Faculty Collaborators
IDI/Makerere Univ Univ of Manitoba Andrew
Kambugu (co-PI) Allan Ronald Keith
McAdam Harriet Mayanja-Kizza Duke Univ Moses
Kamya John Perfect Univ of CO Univ of
WA Edward Janoff (co-PI) Merle Sande Univ of
MN Institute of Tropical Paul Bohjanen
(co-PI) Medicine, Antwerp Tim Behrens
Bob Colebunders Phil Peterson Luc
Kestens James Neaton Tracy Bergemann
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