Lymph node fibrosis: a structural barrier to unleashing effective vaccine immunity

Abstract

There is marked variability in vaccine efficacy among global populations. In particular, individuals in low- to middle-income countries have been shown to be less responsive to vaccines than those from developed nations. Several factors, including endemic infections, nutrition, genetics, and gut microbiome composition, have been proposed to underlie discrepancies in vaccine response. In this issue of the JCI, Kityo et al. evaluated response to yellow fever virus vaccine, inflammation, and lymphatic tissue architecture and fibrosis in three cohorts: two from the U.S. and one from Uganda. Compared with the U.S. subjects, the Ugandan cohort exhibited enhanced cytokine responses, increased lymph node fibrosis, reduced CD4+ T cell levels, and reduced vaccine response. Together, these results provide a link among chronic inflammation, damaged lymphoid architecture, and poor vaccine outcome, and set the stage for future studies to identify strategies to overcome these barriers.

Figure 1. Factors driving lower vaccine responsiveness around the globe.

The cartoon bar graph depicts the observed differences in vaccine responsiveness around the globe, and highlights factors that have been associated with vaccine immunogenicity. Factors listed in black have been previously published. Factors listed in red represent the findings in the manuscript by Kityo et al., which evaluated differences in vaccine response in subjects from the U.S. (Minnesota and Georgia, blue) and subjects from Uganda (red).