Whole blood biophysical immune profiling of newborn infants correlates with immune responses.

Background: There is a current, absence of reliable, blood-sparing, diagnostic tools to measure and trend real-time changes in the levels of inflammation and its effects on the immune cells in the infant.

Methods: We deployed the BiophysicaL Immune Profiling for Infants (BLIPI) system in the neonatal intensive care unit to describe immune cell biophysical profiles using 50 microliters of blood per sample from term and preterm infants.

Results: A total of 19 infants (8 term, 11 preterm) were recruited and 24 blood samples were collected in their first month. Based on the profiles of immune cells' size and deformation, there was a clear distinction between term and preterm infants, with 48/50 markers significantly different. A preterm infant with late-onset bacterial sepsis had notable size and deformability differences compared to the rest of the preterm cohort. There was a significant correlation between immune cell biophysical profiles and clinical markers such as C-reactive protein, white blood cell counts, and immature-to-total neutrophil (I:T) ratios, with Pearson correlation coefficients for linear regression models of 0.98, 0.97 and 0.94 respectively.

Conclusion: This study highlights the potential for the biophysical immune cell profiling system to provide an overview of the infant's current immune activation and response.

Impact: We present a novel, minimally invasive diagnostic system that leverages the physical properties of immune cells to provide a rapid and direct assessment of the immune status, requiring 20 times less blood volume than standard tests. This study demonstrates the potential of a compact, deployable system that is capable of performing biophysical profiling to assess immune cell activation in term and preterm infants, by revealing distinct differences in cell size and deformation between groups. The system's sensitive, quantitative measures were correlated with routine clinical biomarkers, highlighting its ability to provide a rapid, minimally invasive, real-time monitoring of neonatal immune status.