Interpersonal stress during adolescence and young adulthood can threaten healthy developmental trajectories. A "primed" proinflammatory response to acute stress may serve as an underlying process that results in negative outcomes for youth. The present pilot study examined the relation between interpersonal stress and two proinflammatory cytokines in a sample of 42 university-recruited emerging adults with recent suicidal thoughts and behaviors. Participants completed self-report measures of mood, suicidal thoughts and behaviors, recent peer-related stressors, and interpersonal sensitivity. They also participated in an acute laboratory social stress task and provided three saliva samples to measure their proinflammatory responses (IL-6 and TNF-α) to the stressor. Participants reported significant increases in sadness and exclusion, and significant decreases in inclusion, following task participation. Importantly, no participants reported an increase in or onset of suicidal thoughts. No significant associations between interpersonal stress and proinflammatory cytokines were found. Changes in affect during the task coupled with lack of increased suicidal thoughts indicate it is acceptable to use this exclusion and rejection paradigm with this population, with proper debriefing and positive mood induction procedures. Given all other nonsignificant associations, future research considerations are discussed, including impact of COVID-19 on task potency and incorporation of multiple stress response systems.