Issues Regarding QualificationImplementation of an Antibody Test for Trypanosoma cruzi

1
Issues Regarding Qualification/Implementation of
an Antibody Test for Trypanosoma cruzi

• Susan L. Stramer, PhD
• American Red Cross
• Blood Products Advisory Committee Meeting
• April 26, 2007

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Outline

• Clinical study design and results
• 8/28/06 to 1/28/07
• 3 regions (West Division) SoCal, NoCal, AZ
• MMWR 2/23/07 56 (07)141-143
• Implementation AABB Association Bulletin 06-08
• IVD results 1/29/07-4/17/07 approx 65 collected
  blood US
• ARC, UBS, 15 other blood centers and gt50
  hospitals
• Distribution in US and accuracy of predictions
• Test performance
• ELISA, RIPA, T. cruzi IFA, Leishmania IFA,
  Special Protocol
• Lookback results
• Donor demographics
• Risk factors
• Possible autochthonous cases (indigenous, native)

3
Chagas Protocol/Assumptions

• FDA request of Ortho to expand clinical studies
  to include areas where T. cruzi antibody
  prevalence previously documented
• Pivotal clinical trial yield 0 confd pos (of
  40,665 tested) 99.998 specificity (PI)
• 100,000 donations defined the study
• Testing would continue through test licensure and
  implementation
• SoCal, NoCal and AZ (West ARC Division)
• FDA requirements for donor informed consent
• Use of an information sheet with signature on BDR
  acknowledging receipt not allowed
• Specific signature and date required on info
  sheet matched to tubes that were tested
• Due to these requirements, other blood centers
  declined

4
ARC Prevalence Study T. cruzi Results
8/28/06-1/28/07
40,859 refusals/detection rate of 14655 9
undetected donors!
5
The prevalence of infection with T. cruzi in the
US varies by region and might now be higher than
previously thought, especially in geographic
areas such as Los Angeles County, where a
substantial proportion of blood and organ donors
have emigrated from Chagas-endemic
countries.MMWR 55 (29) 2006
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Implementation

• According to AABB Assn Bull 06-08
• Collaboration with the CDC and FDA
• Component mgmt
• Components from RR donors quarantined/withdrawn
  from the market (3 calendar days)
• Index
• Prior in-date donations
• As long as electronic records exist
• Recipient tracing
• Autologous unit release with approval of auto
  donors referring physician
• Inventory testing (in-house or distributed) not
  recommended each facility assess risk

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Implementation

• Donor mgmt
• RRs notified/deferred
• Supplemental testing encouraged, although no FDA
  licensed confirmatory/supplemental test exists
• RIPA most sensitive test, however not 100
• Leishmania testing on supplemental test
  unconfirmed no mention Plasmodium or
  Paracoccidiodes braziliensus
• Donor counseling including donor follow-up
  studies encouraged
• No donor reentry
• Refer supplemental test positive donors to
  knowledgeable physician
• Referrals from personal physician, blood center,
  Am Assoc Tropical Med or CDC
• Recipient tracing from supplemental test positive
  donors
• Licensed test for Ab detection has suitable
  performance characteristics for blood donor
  screening and as such may be useful in testing of
  the above individuals.
• COI and Component Labels
• Component tested by a licensed test and the
  results are negative/nonreactive

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Models for Testing/Implementation

• Universal
• Immunosuppressed patients
• Puts burden on hospitals to identify correct
  units for recipients at highest risk
• Geographic models
• By US census data/WHO seroprevalence by country
• Test one-time-only per donor where only new
  donors are tested repeat donors are questioned
  re risk and only yes responses are tested
• Assumes donor understands the questions,
  questions may be culturally sensitive, assumes no
  autochthonous risk
• Must be validated each positive requires
  knowledge of risk and when it occurred
• Logistically complex relative to sample tracking
  and component management
• Financial benefit has not been validated
• Confusing message to test kit developers

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T. cruzi Reactive Donors by State of Residence
(01/29/07 04/17/07)
1
4
1
3
2
7
5
3
10
6
3
2
7
3
6
1
12
4
3
6
4
2
4
3
6
2
37
1
1
15
3
1
3
8
1
2
PR
Nos. indicate 265 RR donors by state no RR
donors or testing not occurring in 6 states 48
confirmed pos (2) in 17 states 19 CA, 11 FL, 3
MD, 2 NY, UT, VA 1 AR, CT, GA, MA, MT, NC, NJ,
OR TN, WA, (AZ)
8
4
5
3
2
2
56
10
RR donations reported to the AABB 4/24/07 7
facilities reporting 4 sites with RR donors 272
total RR
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Confirmed pos reported to the AABB website
Of 228 21.5
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Do the states in which confirmed positive donors
agree with models based on immigration?
14
Based on immigration and test positive rates for
endemic countries
N.J. - N.Y. Metro
L.A. County
Washington, D.C.
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Test Performance

• Clinical trial (8/28/06-1/28/07)
• PPV 32 RIPA pos/63 RR51 pos in 2 states
• RR rate 63/148,969 0.042
• Prevalence 32/148,969 14655
• Specificity 148,906 test neg/148,90631 false
  pos 99.979
• 99.997 in PI
• Nationwide screening (1/29/07-4/17/07)
• PPV 50 RIPA pos/224 RR RIPA tested 22 pos
  in 17 states
• 30 of 50 (60) RIPA pos from 2 states (S CA, FL)
• RR rate 265 RRs (213 ARC 52 BSL)/1,757,800
  donations 0.015
• Projected prevalence based on 22 PPV of RIPA
  tested 130,150
• Specificity (ARC) first week 124,934 test
  neg/124,93428 false pos 99.978 (6 pos)
• Overall prevalence 121,100, and 27 rate of
  RIPA positivity

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Variability of ELISA/RIPA

• 3 samples in 10 negative gray zone that were
  RIPA pos
• 2 samples /- RIPA (index serum pos/neg in retd
  plasma)
• Samples ELISA reactive _at_ index, nonrx retd
  plasma, reactive in f/u

94 RIPA pos concordance 30 retd plasma/32
index serum
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Retesting Retrieved Frozen Plasma

• 51 confirmed pos donors by single to multiple
  RIPA gt retested using ELISA or other research
  test 14-31 of low level reactivity is lost
  overall 67-84 reactivity retained
• Retrieved Plasma Results

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Confirmatory RIPA vs IFA

• 54 RR samples (from which plasma units available
  for further testing) from the IND study were sent
  to Focus for IFA and titers if IFA pos
  (encouragement of S. Wendel)
• 24 (44.4) RIPA pos 11 IFA pos (20.4)
• 16 discordant
• 14 IFA-/RIPA
• 2 IFA/RIPA-
• Overall agreement
• 38/5470.4

also Leish IFA reactive
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Leishmania Testing

• All reactive, RIPA unconfirmed (IR in IND RR in
  IVD) sent to Focus for Leishmania IgM/IgG IFA
• 4 species L. donovani, L. braziliensis, L.
  tropica, L. mexicana
• IND 65 IRs gt 36 sent for Leish testing (index,
  retd plasma unit and follow up)
• 31 RIPA neg 5 RIPA pos (due to low level EIA
  S/CO values of 0.93-1.22)
• IVD 104 RRs RIPA neg to date sent for Leish
  testing (retd plasma only)

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Leishmania Testing

• 4 Leish pos donors (2 IND 2 IVD)
• 17.5 yo female FT donor (CA) who was T. cruzi
  RIPA neg/IFA 116 ()
• index 132 IgG (L. tropica)/plasma (-) plasma
  116 IgG (L. donovani)/index (-)
• Asian American visited maternal relatives for 2
  weeks in 1996 in urban areas of Brazil (mother
  and grandmother lived in Brazil) no travel risk
  for L. tropica follow up testing negative
  mother also tested negative for T. cruzi and
  Leishmania
• 18 yo male RPT donor (CA)
• plasma 116 IgG (L. donovani)/index (-) 3 total
  donations
• No travel risk follow up testing negative
• 71 yo female RPT donor (MA) 2 total donations
  116 L. braziliensis IgG no follow up
• 64 yo female RPT (MI) 19 total donations 120
  L. braziliensis IgM and 140 L. donovoni IgM no
  follow up
• Likely all false pos for both T. cruzi by EIA and
  Leish by IFA
• Recommendation discontinue Leish following BPAC
  discussion

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Other Testing Results/Procedures

• IND study
• Follow up of 36 donors 16 of 32 confirmed pos
• 1/16 PCR positive hemoculture pending/negative
• Sample handling??
• IVD testing pending
• Special Protocol for PCR and hemoculture
• Increase sensitivity by having regions initiate
  processes
• Pooling EDTA whole blood samples in
  guanidine/EDTA solngtPCR (lyses cells and
  stabilizes kinetoplasts containing mutliple
  copies of DNA) store at 2-8C
• Pooling heparinized whole blood samples,
  centrifuge/removal of plasma (Ab) mix buffy coat
  and red cells with LIT media store at 2-8C
• 23 samples submitted 1 PCR pos donor to date (22
  neg)

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IND Lookback Results

• 32 confirmed positive donors during IND
• 17 repeat donors (allogeneic/directed)
• 140 prior donations gt 170 components
• Of 170 components
• 6 whole blood (destroyed)
• 3 platelets (2 destroyed, 1 transfused)
• 80 red cells (7 destroyed, 38 transfused, 35
  pending)
• 81 plasma (11 destroyed, 4 transfused, 65 frac, 1
  pending)
• Of 1, 38 and 4 transfused components
• 1 platelet recipient gt deceased 11 days post
  transfusion
• 38 red cell recipients gt 15 living, 13 deceased,
  10 unknown
• 11 recipients tested from 8 donors (red cells
  transfused 7-36 days) all ELISA/RIPA neg (7 also
  PCR neg)
• 4 plasma recipients gt deceased

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IVD Lookback Results

• 41 confirmed positive donors since licensed test
  implemented
• 21 repeat donors (allogeneic/directed)
• 171 prior donations gt 108 components (reported
  to date)
• Of 108 components
• 17 platelets (6 destroyed, 6 transfused, 5
  unknown)
• 49 red cells (1 destroyed, 9 transfused, 39
  pending)
• 41 plasma (1 destroyed, 2 transfused, 27 frac, 11
  pending)
• 1 cryo (1 pending)
• Of 6, 9 and 2 transfused components
• 6 platelet recipients gt 5 deceased, 1 living gt
  ELISA and PCR neg (RIPA pending)
• 9 red cell recipients gt 6 deceased, 1 unknown 2
  living gt ELISA, RIPA and PCR neg (RIPA pending
  on one)
• 2 plasma recipients gt 2 living gt ELISA neg
  (RIPA and PCR pending)

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Lookback Summary

• Recipients from 10 RIPA pos donors tested
• IND
• 11 red cell recipients tested from 8 donors
• IVD
• 1 platelet recipient tested from 1 donor
• 2 red cell recipients tested from same donor
• 2 plasma recipients tested from 1 donor
• Total 16 recipients test negative to date

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Lookback Significance

• Lookback case summary platelets/whole blood,
  considered to be highest risk
• 1 of 4 Leiby LA and Miami (NEJM 1999)
• 4 of 9 Kirchhoff Mexico (Transfusion 2006)
• 0 of 1 Stramer (IVD, unpub)
• 5 of 14 36
• Why not higher?
• Donor must be parasitemic (intermittent)
• Parasites must remain viable/infectious in
  component during processing/handling
• Acute infections are most frequently recognized
  in immunosuppressed patients

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Donor Demographics

• 61 RR IND ARC donors
• 32 RIPA pos
• 14 FT, 18 RPT
• 19 male, 13 female
• 17-84 yo (mean 47 yo median 50 yo)
• 30 allo, 1 auto, 1 platelet pheresis
• Countries represented (15 donor surveys
  received) 11/15 endemic areas Mexico (5), US
  (4), El Salvador (2), Bolivia (2), Guatemala (1),
  Argentina (1)
• 213 RR IVD ARC donors
• 41 RIPA pos
• 20 FT, 21 RPT
• 26 male, 15 female
• 39 allo, 1 auto, 1 directed (FT male)
• Countries represented (10 donor surveys
  received) 9/10 endemic areas Mexico (4), El
  Salvador (3), Brazil (1), Bolivia (1), US (1)

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Donor Demographics

• 52 RR IVD UBS donors
• 7 (2) RIPA pos
• 6 FT, 3 RPT
• 8 males, 1 female
• 7 allo, 1 platelet pheresis, 1 auto
• Countries represented Mexico (4), El Salvador
  (2), Guatemala (1) Venezuela (1) (1 unknown)
• Total 328 RR donors
• 82 RIPA pos
• 40 FT, 42 RPT
• 53 males, 29 females
• 76 allo, 2 platelet pheresis, 3 auto, 1 directed
• Countries represented (N33) Mexico (13), El
  Salvador (7), US (5), Bolivia (3), Guatemala (2),
  Venezuela (1), Argentina (1) Brazil (1)
• 28/33 (85) endemic areas vs 28/28 controls from
  nonendemic (US 1 China)

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Possible Autochthonous Cases

• 61 yo female (CA) runner in Griffith Park
• Griffith park zoo and other animals demonstrated
  to harbor T. cruzi (6 sp of triatomine bugs in
  CA 18 mammal species are reservoirs)
• Lived in LA entire life, high quality housing
• Travel outside of the US
• Time share in Cancun where she spends a week
  1990-1999 no camping
• 64 yo female (AZ) retired vet
• Lived in rural Mexico where she volunteered as a
  vet/exposure to infectious material
• 57 yo female (CA) lives in rural area
• Rural area recovering from fire damage
• Has many pets and frequently sees raccoons,
  opossums, skunks on her property and adjacent
  property, also gardens on her property
• Lived in LA entire life, high quality housing
• Multiple transfusions in 1971 in CA
• Asymptomatic
• 50 yo male (AR)
• Lived in US entire life one trip to Nassau
• Asymptomatic
• Only possible risk is time spend in Corpus
  Christi, TX where he slept outside for several
  weeks

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Summary and Conclusions

• Prevalence 121,100
• 82 RIPA pos donors from 328 RR donors in 17
  states during IND/IVD testing of gt1.9 million
  donations
• 60 from California and Florida
• Leishmania
• Adds no value only confusion!
• Lookback (to date)
• 60 transfused components from 278 mfgd from 38
  RIPA pos donors
• 16 recipients tested neg from 10 donors only 1
  platelet recipient
• Donor Demographics
• 28/33 (85) endemic areas vs 28/28 controls from
  nonendemic (US 1 China)
• 5 possible autochthonous cases time of infection
  unknown

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Acknowledgements

• American Red Cross
• Greg Foster, SSO
• David Leiby, HL
• Roger Dodd, HL
• Ross Herron, West Div
• Pamela Kahm, West Div
• Norma Espinoza, West Div
• Kay Crull, West Div
• Muriel Nelson, IT
• Mike Savin, IT

• Blood Systems Laboratories
• Sally Caglioti
• Frank Radar
• Larry Morgan
• Ortho Clinical Diagnostics
• Cheryl Vitow
• Cindy Ballas
• Brian McDonough