Cell 174, 1277–1292.e14 (2018).

Despite early differences in composition, the immune system of preterm and term children converges to a similar structure in early life.

Previous epidemiology data suggest that early-life environmental exposure shapes an individual’s susceptibility to immune-mediated diseases. Furthermore, a greater understanding of the composition of the neonatal immune system would help prevention and treatment of infection.

Scientists in Sweden were able to sample the cord blood and take four samples of neonatal blood from 100 children in the first 3 months of life. At birth, the immune cell and protein composition was unique to each child, but these converged onto a shared trajectory that seemed to be driven by microbial interactions.