Improper Restraint Use in Fatal Pediatric Motor Vehicle Collisions.

PURPOSE: Motor vehicle collisions (MVC) are the second leading cause of death in children and adolescents, but appropriate restraint use remains inadequate. Our previous work shows that about half of pediatric MVC victims presenting to our trauma center were unrestrained. This study evaluates restraint use among children and adolescents who did not survive after MVC. We hypothesize that restraint use is even lower in this population than in pediatric MVC patients who reached our trauma center. METHODS: We reviewed the local Medical Examiner's public records for fatal MVCs involving decedents <19 years old from 2010 to 2021. When restraint use was not documented, local Fire Rescue public records were cross-referenced. Patients were excluded if restraint use was still unknown. Age, demographics, and restraint use were compared using standard statistical methods. RESULTS: Of 199 reviewed cases, 92 met selection criteria. Improper restraint use was documented in 72 patients (78%). Most decedents were White (72% versus 28% Black) and male (74%), with a median age of 17 years [15-18]. Improper restraint use was more common among Black (92% vs 73% White, p = 0.040) and male occupants (85% vs 58% female, p = 0.006). Improper restraint use was lower in the Hispanic population (73%) compared to non-Hispanic individuals (89%), but this difference was not statistically significant (p = 0.090). CONCLUSION: Most pediatric patients who die from MVCs in our county are improperly restrained. While male and Black patients are especially high-risk, the overall dismal rates of restraint use in our pediatric population present an opportunity to improve injury prevention measures. TYPE OF STUDY: Retrospective Comparative Study. LEVEL OF EVIDENCE: Level III.

Murine models of Pneumocystis infection recapitulate human primary immune disorders.

Despite the discovery of key pattern recognition receptors and CD4+ T cell subsets in laboratory mice, there is ongoing discussion of the value of murine models to reflect human disease. Pneumocystis is an AIDS-defining illness, in which risk of infection is inversely correlated with peripheral CD4+ T cell counts. Due to medical advances in the control of HIV, the current epidemiology of Pneumocystis infection is predominantly due to primary human immunodeficiencies and immunosuppressive therapies. To this end, we found that every human genetic immunodeficiency associated with Pneumocystis infection that has been tested in mice recapitulated susceptibility. For example, humans with a loss-of-function IL21R mutation are severely immunocompromised. We found that IL-21R, in addition to CD4+ T cell intrinsic STAT3 signaling, were required for generating protective antifungal class-switched antibody responses, as well as effector T cell-mediated protection. Furthermore, CD4+ T cell intrinsic IL-21R/STAT3 signaling was required for CD4+ T cell effector responses, including IL-22 production. Recombinant IL-22 administration to Il21r-/- mice induced the expression of a fungicidal peptide, cathelicidin antimicrobial peptide, which showed in vitro fungicidal activity. In conclusion, SPF laboratory mice faithfully replicate many aspects of human primary immunodeficiency and provide useful tools to understand the generation and nature of effector CD4+ T cell immunity.