A Flexible and Responsive Remote Study Design to Assess Gene Expression Changes During Wildfire Smoke Exposure with homeRNA, an At-home Blood Sampling Kit.

Transcriptomic responses to wildfire smoke are difficult to study given the unpredictability of wildfires and the challenges of collecting blood during active disasters. To overcome these challenges, we developed a flexible study design leveraging homeRNA, our at-home blood collection and RNA stabilization kit. Between June 2021 and April 2022, 58 participants across 10 U.S. states collected 635 blood samples before, during, and after wildfire events. This responsive approach captured three exposure groups: high exposure in Okanogan County, Washington, medium exposure from transported smoke, and low exposure. During the 10-month study, 93% of participants (n=54/58) returned at least 6 samples. In a preliminary exploratory analysis, we analyzed 770 genes with a Nanostring panel from nine participants (6 high, 3 low-medium exposure) using the BloodGen3 framework. In the high exposure participants, we observed trends toward overexpression of inflammation (inflammation aggregates A33 and A35, and modules M13.1 and M13.12), with concurrent underexpression of adaptive immune responses (lymphocytic aggregates A1 and A6, B cell module M13.18, T cell modules M16.24 and M15.38). This study establishes that homeRNA enables flexible, responsive sampling during disasters, overcoming traditional logistical barriers to capture time-sensitive biological data across dispersed populations.