1. Department of Obstetrics & Gynecology, University of Washington, Seattle, Washington, DC, USA;
2. Northwest Perinatal Associates, Portland, OR, USA;
3. Fred Hutchinson Cancer Research Center, Seattle, Washington, DC, USA;
4. Department of Pathology, University of Washington, Seattle, Washington, DC, USA;
5. Department of Pathology, Seattle Children’s Hospital, Seattle, Washington, DC, USA;
6. Department of Pediatrics, University of Washington, Seattle, Washington, DC, USA;
7. Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, Washington, DC, USA