Vaccine and Infectious Disease Division

A look at respiratory infections in transplant patients with Sachiko Seo

Sachiko Seo

VIDD visiting investigator Dr. Sachiko Seo joined the division in 2011 to work with VIDD member Dr. Michael Boeckh on infectious diseases in transplant recipients. She comes to VIDD from a background in hematology and transplant medicine, having practiced as a hematologist in Tokyo for several years.

Rachel Tompa

The Hutchinson Center’s strong commitment to infectious disease research is spurred in part by the fact that transplant patients are vulnerable to so many different infectious agents. Understanding how to prevent and control post-transplant infections is essential to improving the health and survival of this immunocompromised population. Many VIDD scientists study viruses, bacteria and fungi that might have no effect in the healthy but can devastate transplant recipients.

Dr. Sachiko Seo, VIDD visiting investigator working with VIDD member Dr. Michael Boeckh, studies respiratory viruses in transplant patients. In many transplant types, the patients undergo a toxic regimen before the transplant to eradicate many of their own blood cells, both to kill the diseased cells (in the case of patients with blood cancers) and to prevent an immune reaction against the foreign donor cells. This eradication leaves the transplant recipient powerless to fight off infections, so extreme care must be taken to try to prevent infections in the first place and to treat them as soon as possible if they occur.

“Many transplant patients do have problems with infectious diseases after their transplant,” Seo said.

Along with Boeckh and other VIDD colleagues, Seo has conducted two studies on respiratory viruses in transplant patients at the Center. In the first, she studied the use of the antiviral drug palivizumab to treat transplant patients with severe respiratory syncytial virus (RSV) infections. This drug is commonly used against RSV, but no studies have shown its effectiveness in treating RSV pneumonia in transplant recipients. Seo looked at 82 transplant recipients at the Center from 1990 to 2011 who had had RSV-related pneumonia, and found that those who received palivizumab did no better in terms of outcome or survival. As a result, the guidelines at the Center have already changed to not routinely prescribe palivizumab, which is also very expensive, for RSV infections.

Seo and colleagues are also currently conducting a study on parainfluenza virus (hPIV) in transplant patients. This virus is somewhat rare, so large studies of transplant patients with hPIV infection are lacking. Seo’s retrospective study includes 400 patients from the Center with hPIV infection, the largest study of this type to date. She is looking at the patients’ clinical outcome and asking whether steroid use to improve pulmonary function is worthwhile.

Seo is visiting Seattle on a scholarship from the University of Tokyo and will most likely remain with VIDD for at least another year before returning to her native Japan. Before coming to the Hutchinson Center, she trained and practiced at the University of Tokyo as a hematologist with a specialty in transplant medicine.

Seo came to VIDD to learn more about infectious diseases, a complication she had seen in many of her transplant patients in Japan. Additionally, she said, it can be difficult to distinguish between post-transplant infections and graft-versus-host disease (GVHD), another dangerous side effect of transplants where the recipient’s body rejects the donated cells. Infections can also trigger or worsen GVHD. She hopes a deeper understanding of infectious diseases in the transplant population will enable her to better help patients with infections or with GVHD, and to perform transplants more safely.

Additionally, Seo is “very happy to have time to concentrate on research for a while. So many of the investigators here have great ideas, it really helps facilitate my work.”