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Recent Serologic Studies with Potential Impact on WNV Blood Screening

Recent Serologic Studies with Potential Impact on WNV Blood Screening. Wayne Hogrefe, Harry Prince Focus Technologies. Focus WNV IgG and IgM ELISA. Focus-based WNV serology technology currently used in: Reference laboratories Public health laboratories GenProbe IND study

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Recent Serologic Studies with Potential Impact on WNV Blood Screening

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  1. Recent Serologic Studies with Potential Impact on WNV Blood Screening Wayne Hogrefe, Harry Prince Focus Technologies

  2. Focus WNV IgG and IgM ELISA • Focus-based WNV serology technology currently used in: • Reference laboratories • Public health laboratories • GenProbe IND study • Research projects for donor screening

  3. Recent Studies using Focus IgG and IgM ELISA • Utility of the Focus Technologies WNV IgM Capture ELISA Testing CSF; Lape-Nixon, et al., AMLI 2003 • Prince and Hogrefe, CDLI 10:764, 2003 • Prevalence of West Nile Virus Infection in Frozen Donor Plasma Components Recalled from the Peak Epidemic period in 2002; Tobler, LH, et al., ASH 2003

  4. CSF IgM Testing - Key Finding • 1188 Serum/CSF pairs tested in 2002 • Negative/Negative - 1015 (85.4%) • Positive/Negative - 43 (3.6%) • Positive/Positive - 130 (10.9%) • Negative/Positive - 0

  5. IgM Persistence • Roehrig, et al. EID 9:376, 2003 • 7 of 12 (58%) WNV-infected encephalitis patients had detectable IgM at 500 days • Prince and Hogrefe, CDLI 10:764, 2003 • Not clinically defined patients, rather sequentially submitted samples for WNV serology in 2002 • 5/13 (46%) with detectable IgM at 60 - 111 days after first submitted sample

  6. Prevalence of West Nile Virus Infection in Frozen Donor Plasma Components Recalled from the Peak Epidemic Period in 2002 • Collaborative study between ABC centers and the REDS Study, sponsored by NHLBI • December 2002 frozen products collected during the epidemic period from areas of high WNV activity were collected and quarantined • 1468 frozen plasma components collected between June 23, 2002 and September 28, 2002 • Sample source: IL - 53%; LA - 17%; MI - 17%; MS,OH, KY, TX, NE - 13%

  7. WNV Antibody Profile • IgG IgMFocus ELISA # (%) • Nonreactive Nonreactive 1429 (97%) • Reactive Reactive 7 (0.48%) • Nonreactive Reactive 1 (0.07%) • Reactive Nonreactive 23 (1.57%) • Equivocal Nonreactive 8 (0.54%) • Total 1468

  8. IgG Reactive Samples • Twenty-three IgG positive/IgM negative samples • 13 (57%) with Index values of 1.5 - 2.0 • 7 (30%) with Index values of 2.1 - 3.0 • 3 (13%) with Index values of >3.0 • Seven IgG positive/IgM positive samples • 2 (29%) with Index values of 1.5 • 1 (14%) with Index values of 2.1 - 3.0 • 4 (57%) with Index values of >3.0

  9. PRNT and IgM Reactive Samples • IgM ELISA IgG ELISA WNV PRNT SLE PRNT • 1.14 <1.30 <10 <10 • 7.2 1.64 320 20 • 4.77 1.72 160 10 • 5.29 2.59 640 40 • 5.04 3.46 1280 20 • 4.61 3.64 320 20 • 3.83 3.69 160 20 • 4.06 3.9 640 20

  10. GenProbe TMA and Serology • One of 1468 samples - TMA positive • Focus IgM and IgG negative, PRNT negative • The 7 Focus IgM positive samples repeat 10-fold replicate TMA testing • one sample 7/10 replicates reactive • one sample 2/10 replicates reactive

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