A new study led by Vanderbilt University Medical Center researchers has identified key immune cell populations that predict how well pediatric hematopoietic stem cell transplant (HCT) recipients will respond to the influenza vaccine.
The findings, reported in Blood Advances, suggest that the timing of flu vaccination could be tailored to an individual child’s immune profile to optimize protection against the potentially life-threatening virus.
“Pediatric and adult stem cell transplant patients are highly vulnerable to influenza infections, but they often have a suboptimal response to the flu vaccine, especially early after transplant,” said Justin Amarin, MD, a PhD student in Epidemiology and lead author of the study. “Our goal was to determine if specific immune cell populations could predict vaccine response and potentially guide the optimal timing of vaccination.”
The researchers used mass cytometry to identify 33 immune cell subpopulations in blood samples from 156 pediatric HCT recipients enrolled in a multicenter influenza vaccine study. Statistical analyses revealed that the pre-vaccination numbers of seven B cell, CD4+ T cell, and CD8+ T cell subpopulations significantly predicted antibody responses to all three circulating flu strains 28-42 days after a two-dose vaccine series.
“We found that the numbers of naive B cells, memory B cells, naive CD4+ T cells, and circulating T follicular helper cells were strongly associated with flu vaccine responses, irrespective of the dose and the post-transplant timing of vaccination,” said Spyros Kalams, MD, professor of Medicine and corresponding author. “This suggests we could potentially use immune cell profiles to identify which patients are likely to respond well and which may need alternative vaccination strategies.”
While time post-transplant is known to influence vaccine response, the study demonstrated that certain cell populations were predictive even after accounting for this factor. The identified cell subsets also correlated with sustained vaccine-induced antibody levels up to six months post-vaccination.
“Rather than a one-size-fits-all approach, our data indicates we could use a patient’s immune reconstitution profile to personalize when and how we administer the flu vaccine and perhaps additional precautions to achieve optimal protection,” Amarin said. “With further validation, this could ultimately help us reduce influenza-related morbidity in this high-risk population.”
The researchers note that future studies in larger cohorts are needed to confirm the findings and evaluate the predictive value of the identified cell populations for other vaccines. However, the results highlight the potential of high-dimensional immune profiling to guide precision vaccination approaches for vulnerable immunocompromised patients.
Others from VUMC on the study include Daniel Dulek, MD, Joshua Simmons, Haya Hayek, MD, James Chappell, MD, PhD, Cindy Nochowicz, Carrie Kitko, MD, and Kalams’ co-senior authors, Natasha Halasa, MD, MPH, and Andrew Spieker, PhD.
The study was supported by the National Institutes of Health (U01AI125135, UL1TR002243, P30AI110527).