Microbiome implications in transplantation and oncology

At birth, infants become colonized with trillions of commensal microbes that play important roles in health and disease. The majority of these microbes reside in the gastrointestinal tract. Complex microbial communities are also found on all human surfaces, including the skin, oropharynx, vagina, and lung. These microbiomes are highly abundant-bacteria represent an astounding 50% to 90% of the cells within or on our bodies and are accompanied by less well-defined numbers of viruses, fungi, and archaea. In this chapter, we discuss three emerging themes that relate the microbiome to children undergoing hematopoietic stem cell transplantation, treatment for cancer, or solid organ transplantation. First, the microbiome influences risk for infection. Although many infections in immunocompromised patients originate from endogenous microbes, a healthy microbiome also prevents colonization, overgrowth, and invasion by exogenous pathogens. Second, the microbiome influences immune system function in children at risk for graft-versus-host disease and allograft rejection. Third, the microbiome has the potential to be a powerful tool to predict and prevent infections and other complications in immunocompromised children. Overall, the human microbiome contains thousands of microbial species that have profound and specific impacts on the health of immunocompromised children.

Duke Scholars

Author Matthew Kelly Pediatrics, Infectious Diseases